The I-Max-2000 antenna exposed on steroids

[@soulwagon1251]

The capacitor in the middle of the antenna is right around 42uf. It's purpose is to couple the signal higher on the antenna. most 5/8ths wave ground plane antennas have their strongest radiation at about 6 feet up from the feed point. by putting that capacitor in the mid section makes the entire antenna radiate to make it perform similar to a dipole antenna. It's one of the reasons the Imax works well without a ground plane.

[@flash001USA]

Thanks for the feedback. I know that Solarcon made different revisions to this antenna so I will point out something about the mid section capacitor. I have measured it on two separate capacitance meters that I trust with one of them being a modern L/C meter with plenty of range and both meters are measuring the mid section capacitor at least on this antenna I have at 10pF. The ECG meter reads 10.0pF and my newer L/C meter reads it at 9.77pF. I've read on other websites that it was 42pF too but the likely that two capacitance meters would be inaccurate is pretty low. I also checked it on a cheap "do it all" volt meter and it too reads in the same ballpark. I think when the HAM radio operators did their measurements it may have been with a different revision of this antenna. I also want to point out that when I made this video I mentioned the IMAX being around 4 feet longer than your average 5/8 wave but in my brain I had a Biden moment when I was making the video and I accidentally made a reference to a half wave antenna and only caught it a couple days later so I just wanted to point that out. I know the MACO 5/8 ground plane antenna is around 20.5 ft in length for the 11 meter band and the IMAX is about 1.7 feet longer in length.

[@SoonDumpingAllGmailAccounts]

*_@ Soulwagon_* I don't understand why you believe the strongest point of radiation is 6 feet up from the bottom feed point. - The current is maximized 1/4 wave down from the tip, where the tip is one of two highest voltage points - the first being 1/2 wave down from the tip @ 180° phase from the tip. I believe this would provide the point of maximum current, and thus *maximum radiation,* to be 1/4 wave down from the tip or _about_ 13.5 feet from the bottom of a bottom-fed full-size 11m 5/8.

[@SoonDumpingAllGmailAccounts]

@@flash001USA It almost appears that the center capacitor is pulled apart a bit - is this just an optical illusion? Would pushing it in all the way provide closer to 42pf?

[@ericdee6802]

@@SoonDumpingAllGmailAccounts You nailed it Santa Cruizer, if that antenna radiated at the 6ft mark from the feed point, the SWR would be around 6,000 to 001 !😏👍

[@SoonDumpingAllGmailAccounts]

@@ericdee6802 The CBer up North, Rosco, says SWR is a good thing, the more the better and says it stands for Strongest Wattage Radiation

[@jikemenkins7098]

I seem to remember reading this antenna was designed as a .64 (wave) length. I'll come back some day and link the article if I ever see it again.

[@flash001USA]

Yes you would be correct about the .64 wave but what people do not realize is that won't be the case over the whole band.The .64 wave will be at it's sweet spot or in a somewhat narrow band of channels.

[@izzzzzz6]

I think the top capacitor separates and delays part of the wave making it act like a stacked co linear array. Probably 1/4 wave over a half wave

[@justme-n-gracie]

it was supposedly a 5/8 for 10M and a 3/4 for 11M.

[@johndyson4109]

I've had my A-99 for over 20 years. It still performs well. I did replace the top element with a 102" steel whip and cut off about 10 inches of it and WALA a perfect match even with running a shoe' almost all through the 11-meter band.. I put the ground plane kit on it and it has a bit better ears'. Other than that I did not see any improvement in TX. At 27.5050 I put just about a thousand watts through the antenna and it remained at a flat match.. I love the antenna I was thinking of getting a MAX 2000..? I run an RCI-2990 today with no shoe'. For the money, the A-99 is a winner-winner chicken dinner!

[@flash001USA]

The Antron 99 was my first fiberglass antenna. It matched great to the radio but it just didn't have the ears in my opinion. Later down the road I tried the IMAX 2000 and that antenna worked very well and it had better receive. A lot of people don't know or aren't aware of this but in reality a 1/2 wave antenna won't perform any better than a 1/4 wave antenna. I have a 1/4 wave star duster on the side of my shop because it's good for testing my radios with plus it works good with listening to shortwave broadcast on and even regular FM radio with. I have compared the 1/4 wave antenna to the 1/2 wave antennas on the same pole at the same height and they're pretty close to performance but when I threw the 5/8 wave antenna into the equation there was no contest in both the TX and the RX.

[@jetcyclezero8907]

6/10 /2022 I just ordered a MAXOPTIMIZER -4 section.I Wonder what inside the 12 inch section and if the middle section still has components inside !!??

[@TheLonesometoad]

You're wrong. 18'+ is a half wave and most 5/8 waves are about 23 feet.

[@samallan6616]

I always did really well with an old standard: The Shakespear Big Stick. A great half-wave antenna because it is fed in the center...actually a vertical sleeve dipole with a 2-watt,10K resistor at the feed point for static bleed. No coils, caps or other lossy stuff. Easy to assemble and the design gave it a flat radiation pattern which made it great for mountain-topping and skip-shooting. The antenna had four problems: First, you could not run more than about 500 watts into it. That was because they used RG-58 to feed the center (they did make a military version of the antenna which could handle much more power). Second, people used to complain the antenna was noisy. I beat that argument by installing a tuned shorted quarter wave stub at the feed-point which acted as a wonderful static bleed...essentially a DC ground. Third, they used a crimped connector in the base. After several years, the connection would become intermittent. I repaired several of these antennas for people by cutting off the bottom 6 inches of the aluminum sleeve which held the connector and removed the connector. Then I would solder a PL259 to the RG-58 cable coming out of the bottom section. A barrel connector made the antenna whole again and they always worked! Fourth, the antenna was not a 'broadband' design. A matcher was needed to 'tweak' the SWR for 'freeband' ops. I cannot find a Big Stick anymore. Someone should make them again for 10-meters as well as a 6-Meter version for ham use (I would buy both). Years ago, I actually contacted the guy who held the original patent on the Big Stick design but he did not want to make them anymore. What a shame! Any entrepreneurs out there want to make antennas from an already proven design?

[@flash001USA]

If I'm not mistaken, I stumbled across a KZbin video where someone showed how to build your own a little over a year ago. Yeah simpler is the way to go. The main reason for my choice of building or decoding the 5/8 wave antenna like this one is from everything I have learned and understand, a 1/2 wave doesn't offer anymore gain than a 1/4 wave antenna or at least if you are building a ground plane antenna. I can tell you hands down that an IMax 2000 antenna totally outperforms a M-400 or what some people call a star duster and I actually tested this myself and was blown away at the TX and RX performance between these antennas. After reading about the gain difference between a 1/4 wave and a 1/2 wave antenna I decided to always stick with a 5/8 wave antenna. It also comes down to what you really need as far as the distance with others that you talk to even on a local level. Right now I am running the Sirio Tornado 27 and it's decent but the IMax 2000 did a bit better and the downfall about the Sirio Tornado 27 is it is not DC grounded by it's design so it can give you static issues. I do have a Sirio 827 that uses a loaded matching coil and that antenna has better specs all the way around. I think I'm going to convert my Tornado 27 over to a 827. I already know what needs to be done and it just comes down to finding the time to pull the antenna down and do the mods. That's another story for another time. Thank you for your reply and info. 73's, Flash.

[@justme-n-gracie]

actually it's a J-Pole....

[@blugrassdave]

You could keep adding capacitors and sections of wire to make it as long as you want

[@flash001USA]

It doesn't quite work that way.

[@CBPunisher1900]

102 in whip as top section will give u a flat swr on cb on the new antenna it adds the extra 6 inches .

[@markcarrington2358]

The Imax 2000 is actually a .64 wave antenna and not a 5/8 wave which is .625 , the centre capacitor is for improving the radiation pattern and not to make it electrically the correct length, a .64 wave is over 22' long

[@flash001USA]

Yeah I'm aware that it's technically a .64 wavelength antenna and that's also depending on the sweet spot frequency and it's not going to stay a true .64 wavelength across the band it's tuned for. I want to point out that when I made this video I mentioned the IMAX being around 4 feet longer than your average 5/8 wave but my brain had a Biden moment when I was making the video and I accidentally made a reference to a half wave antenna and only caught it a couple days later so I just wanted to point that out. I know the MACO 5/8 groundplane antenna is around 20.5 ft in length for the 11 meter band and the IMAX is about 1.7 feet longer in length. The IMAX is a little bit longer then the average 5/8 groundplane antennas on the market. In reality the IMAX antenna is around one or two feet longer than a lot of the aluminum ground plane antennas on the market today. My main reasoning for making this video was to show people the guts of the antenna and how they laid it out for the matching Network. I was surprised when I found the capacitor in the midsection.

[@markcarrington2358]

@@flash001USA Yes i have the Imax which has been up for 10 years now and personally i like it although they benefit from ground planes to help eliminate CMC although a coax wound choke just below the feed point helps. A good upgrade would be to increase the thickness of the radiator and even use silver coated wire. The biggest weakness is the construction as the GRP sections are a bit weak and many are having them snap or splinter in high winds, a copper radiator or even better silver coated is far better than aluminium as it is a much better RF conductor and more efficient , maybe a mix of the Imax and Sirio Gainmaster would be interesting! :) LOL

[@flash001USA]

@@markcarrington2358 There were three reasons why I didn't replace my old IMAX with a newer one. When I purchased my first one it was around $70 including the shipping. The second one was around $109 with shipping and unlike the first one which tuned dead center of the 11 meter band, the second one wanted to tune at 27.600 Mhz then I found out that they actually moved the sweet spot around on it so that it would work in both the 10 and the 11 meter band without any trimming. They should have left it alone but they didn't. They had quite a few unmentioned revisions that you would only figure out if you visited forums on the subject but the tuning thing was a bit annoying. My first antenna was able to hit it's lowest SWR dip at 27.000 Mhz with the rings all the way down and it shipped from the factory tuned almost dead center of the 11 meter band right at 27.185 Mhz right out of the box. I ran mine centered at 27.000 Mhz and it covered all the way from 26.000 all the way up to 28.000 Mhz with a good and acceptable SWR with no tuner. My second antenna went on the same pole in the same spot and with it's rings tuned to the lowest point would reach 27.500 Mhz and at first I thought I was imagining things or I did something wrong but then I found people discussing this online and their point was you couldn't stretch the antenna but you could cut it so why didn't they leave it alone from the original setup? My last reason for not making the purchase was the antenna's price now! It hovers around $190 NOT including shipping. I purchased the Sirio Tornado and it works good but it doesn't have the bandwidth of the IMAX. You are correct about using a current choke especially if you just mount it to the side of a house.

[@markcarrington2358]

@@flash001USA Yes you are right. i have also heard that when Solarcon was taken over the quality went on the slide and some of the newer Max 2000's were only around 22' long and would not SWR on 27 and some suppliers stopped selling them. Mine is a original and like your's i put it up on a 36' mast and i live in a rural location so it's all in free space and the SWR was 1.0 at 27.100 without adjusting the rings and no higher than 1.4 from 25.800 to 28.000, and just as you have said over here in the UK the price as doubled so will not be getting another new one. Looking at the Sirio 2016 as the guy's love them over here and are only 2/3 the price of the Imax and well built with high power handling. Keep up the good work! :)

[@heffptbo]

@@markcarrington2358 my max 2000 sucks. Can't tune properly. I will be taking mine down soon and going back to the a99. So much for the upgrade!

[@Tcnj80]

I’m looking to set up a base station after being out of the hobby for 20 years. Was going to put up a IMAX. Aside from a metal antenna what alternative should I consider?

[@brianr555]

The I Max 2000 is made for 10m and 11m, so the “capacitor” is for shortening the antenna for the 10m portion. I could be wrong, but thats my best guess. For a simple travel antenna (for ham radio) i built a endfed wire antenna and a 49:1 torroid transformer to match it, no radials required. I use one as a perminant 80m antenna. Shoot it up in a tree with a slingshot or lead wt etc. Use a length of wire for specific bands or use a tuner for multi band use. If your radio has a built in tuner you might get by cutting it for the center of the 11m band. Of course test equipment is highly recommended (your RigExpert). Travel setup with transmit radios i found can be a challenge, but fun!

[@flash001USA]

No I think you're correct about the inline cap. I was surprised when I found that in the antenna. You normally expect to find coils in an antenna but not that often caps. I too built up the 49:1 torrid transformer and used that on my horizontal long wire and it did a good job of matching. I'm just intrigued by the broad-banded matching setup in the Imax so this is why I decided to take this little project on.

[@justme-n-gracie]

"no radials required" only because the outside of the coax is the "radial" or return path for the RF current. All antenna require a "mirror image reflector". It's simple physics.

[@brianr555]

@@justme-n-gracie my feed point is approximately 8”-10” off the ground, with 8’ of the coax laying on the ground. It works best in this configuration.

[@jimkeappock7558]

Good video! So, is the IMAX 2000 still a good antenna, you demonstrated how it is constructed. Does that construction differ from any other Fiberglass antenna.

[@flash001USA]

The Antron-99 is built on the same design but it's only a 1/2 wave antenna. I'm not sure if the Antron-99 has the 10pF series cap in the mid section or not but the loading coil design is almost identical. As far as other fiberglass antennas go, I haven't checked out any other fiberglass antennas. I did sit down and build the I-MAX 2000 from what I learned and you may find this video to be interesting. kzbin.info/www/bejne/eJCzXp6LdrOmq9E

[@jamesvw769]

There junk. Get a real antenna not this cheap gimick.

[@shartne]

I have the bottom part of the I Max and then Im using a antron 99 middle part that is not 8 ft long so I bought a 22 Inch Stainless Steel Antenna Shaft With Two Shaft Nuts then put a 102" stainless steel whip on top the whole thing is 24 foot long. Hope it works? LOL I am going to buy an antenna tunner too just to make sure it has a good match but I may try it first before I buy a antenna tunner. Antron 99 part in the middle I have no idea what it has inside I just tested it for continuity. this is exciting wonder what will happen. I have a antron 99 ground plane I might try that later? I have made zeplin antennas from a 12 gauge wire that worked pretty nice. The antron 99 worked good too. This is going to be the same length as the I max 2.000 but I dont know what it will do? I thinking it wont get low enough SWR but that is nothing a antenna tuner wont fix. the band width may be off too far who knows?

[@coldandaloof7166]

I love my Max 2000. I talk to Europe and the west coast regularly when the conditions are right and do so on relatively low wattage. I've even used it on 10m to make contacts world-wide. Running old school stuff. A Galaxy Saturn and a Yaesu FT 101EE with a Maverick 250 amp for 10m of course. It's on a 60ft tower and I am blessed to live on top a high ridge in Ohio. "Ranger 332" aka KE8WLS.

[@randyreynolds986]

I wonder what effect it would have if you replaced the top section with a 102" steel whip?

[@flash001USA]

If the steel whip is the same length as the original fiberglass top piece it won't change a thing. The issue is you can get away with trimming the antenna shorter for higher bands but adding length to it doesn't have the desired effect. From what I've learned disassembling and rebuilding this antenna if you want to lengthen it for lower frequencies you would need to do it by adding length to the mid section BEFORE the internal 10pF cap that's in the mid section. You may find this video interesting. I was able to do a working design on this antenna based on what I learned disassembling this antenna. kzbin.info/www/bejne/eJCzXp6LdrOmq9E

[@randyreynolds986]

@@flash001USA Thanks for the info

[@billyjoejimbob75]

I cut a 102SS down after the threads stripped on the original for mine. Didn't consider the added weight. It did last a couple more years though before the center section broke inside.

[@CBPunisher1900]

the extra 6 inches over the 8ft whip will lower your swr for cb .

[@justme-n-gracie]

@@flash001USA sorry but the same length would change the resonant point of that portion of the antennabecause the orignal whip has fiberglass coating this is a dialectric and changes the velocity factor of the radiator.

[@jaceizzonn877]

Very nicely done. You present a very clear and easy to follow dissection analysis. A full length 5/8 at 27.185mhz would calculate out to be 22' 6.75'' so it appears your measurement shows it's about 6'' too short, however, the top 96'' fiberglass whip section of my Imax works perfectly as a 1/4 wave whip on the vehicle, same tuning as my 102'' stainless steel whip, so apparently the velocity factor of the copper wire inside the fiberglass is low enough for it to act (electrically) 6'' longer. 96''÷102'' = 94% velocity factor of the top whip. You're using 1KΩ but I believe a 5/8 is only about 200Ω at it's bottom end-fed feed point. I wonder what a 200Ω in your circuit might read?

[@flash001USA]

The way I came up with the reference test resistor value was to try a few different "ballpark" values that I expected the range to fall into. Keep in mind that there was also a lot of stray inductance and capacitance the way I did this but this was just to be used as a diamond in the rough reference for a quick go/no go test. When it comes to length, there are two things I need to point out here. I made a mistake in the video where my brain was thinking of a 1/2 wave end fed antenna but the very early I Max antennas from 20+ years ago radiating element were around 22.5 feet. This does not include the mounting bracket. The more recent ones measure 22.0 feet from their radiating element. They did this to please the HAMS and they knew the antenna would still function in the 11 meter band. The older antennas would center tune almost dead center of 27.18500 Mhz where these newer ones like in this video can be tuned at best to resonate around 27.600 or 27.700 Mhz. When I purchased this antenna years ago to replace one that was struck by lightning I couldn't understand why it didn't tune dead center of the 11 meter band and after some research I was able to figure it out. The newer I Max antennas can be modified to resonate dead center of the 11 meter band but the extra length has to be added between the 1st and the 2nd section! If you try to add length past the 10pF series cap in the second section you will mess up the lobe and it still won't tune correctly. Before I forget to mention it, I did finally do a knock-off build and it kicked ass. If you haven't seen that video you can find it on the channel. Thank you for your feedback.

[@CrawldaBeast]

I would venture to say if the upper capacitor was removed you would find this antenna much closer to a half wave. That being said, I'm willing to bet something closer 1.5k ohm might be a better match. That being said, I think duplicating Sirio GPS 27 feed coil would give a more robust feed system without all the Jedi capacitor tricks. That way it's a true DC shunt fed with the antenna at the same DC potential as the mast.

[@billyjoejimbob75]

Is it my imagination or did you switch the caps around in the "portable antenna project" video?

[@flash001USA]

Not sure which caps you are making reference to. The one that's inline with the antenna or the coupling and matching cap on the matching coil side?

[@billyjoejimbob75]

Are they both double capacitors? I thought the one at the bottom was just a single.

[@flash001USA]

@@billyjoejimbob75 Yeah it is basically two capacitors that share a common plate if that makes sense.

[@billyjoejimbob75]

Totally makes sense. I probably just wasn't paying enough attention.

[@unclequack5445]

All I want to know is if its a good antenna OR NOT???

[@flash001USA]

If you're asking about the IMax-2000 the earlier antennas were great. They changed the center tune on the later ones to accommodate the 10 meter band and it still works on 11 meters but the lowest frequency you can get a good SWR on the newer IMax-2000's is around 27.500 Mhz

[@unclequack5445]

@@flash001USA So not a good choice for 27 mhz and ssb?

[@flash001USA]

@@unclequack5445 Their earlier antennas were great until they changed the sweet spot on the antennas. They felt there was more of a market for the HAM operators then there was for CB but they still work for CB. I had an earlier one and that thing talked like a million bucks until it was taken out by a lightning strike. The one in this video was my replacement and when I set it up I couldn't understand why it wouldn't tune like the first one did until I did a bunch of research and realized they screwed with the formula. In my opinion you would be better off with something different. I'm using a Sirio Tornado 27 and it's a great talking antenna but they have one that's a bit better than the Tornado called the Sirio 827 and it's built like a battle ship. I have one in the box but I won't set it up until spring. For now while the weather is cold and damp I'll stick with the Tornado 27. Here is the link to both antennas just in case you are interested in looking at them. www.sirio.store/index.php?main_page=product_info&cPath=2_18&products_id=185 www.sirio.store/index.php?main_page=product_info&cPath=2_18&products_id=417

[@unclequack5445]

@@flash001USA Yo Flash Thanks' for that I'm looking for a replacement for my A-99 the top mast looks crooked from the ground it's not straight all the way up it bothers me every time I look at it I will get by with it for now I should have got a different one.

[@flash001USA]

@@unclequack5445 You're welcome. I owned a A-99 1/2 wave antenna when they first came onto the market. They're ok but once you switch over to a 5/8 wave antenna you'll wonder why you didn't do it sooner. The A-99 won't touch the 5/8 wave antennas on performance and you'll notice it on both RX and TX.

[@9PAT508]

DO not forget. this antenna was made for 11m but can be used on 20 with antenna tuner. It could be the reason why this antenna is longer in compasaison to an antron 99

[@flash001USA]

Thanks for the feedback. The Antron 99 is a 1/2 wave antenna which is why it's around 18 feet in length. The IMax-2000 is a 5/8 wave antenna so it measures around 22 feet in length. Most of your 5/8 wave antennas will almost always be much longer than the 1/2 wave antennas.

[@waynegordon6629]

The Imax-2000 is 24 ft long. Not 22ft. You can see the top end on yours has been changed. I-Max 2000 has three 8 ft sections. They are a good antenna. They are also a lighting rod. 2 of us here have had lightning strike ours. I have 2 antennas up. One Aluminum and one Fiberglass. Lightning went for the Fiberglass

[@flash001USA]

I can see how you would see the top and think the top section was trimmed down by a few feet but it wasn't. Originally I had planned on cleaning and resealing this antenna but decided to do a break down for this video instead. I also said the antenna was 18 feet in length which was just a mistake on my end because my brain was thinking of a 1/2 wavelength antenna which I not only corrected in a second video but I also corrected it when I measure it in this video. Yeah that was my mistake. The odd thing was when I was making this video I kept thinking and remembering my first antenna being 24 feet in length but it had been so many years since I put the first IMAX-2000 up that I thought that I was imagining 24 feet. Later I did the research and figured out what in the hell was actually going on! Are you aware that Solarcon was making changes on these antennas and the end users (That would be us) were clueless unless you were somehow made aware of the changes? In their later revisions which is what I have in this video, they decided to cater this antenna to the HAMS for the 10 meter band thinking that because the antenna had such a wide bandwidth that people wanting to use it on 11 meters wouldn't notice it. They were WRONG and now their new IMAX-2000 antennas ship with 4 sections and you can now set it up for 10 or 11 meters depending on which section you choose to use. I guess they figured out very quickly that they were losing out on sales for CB operators. Now with that said, My first IMAX-2000 that I purchased which was one of their earlier builds more than likely was 24 feet in length. That antenna worked great and it tuned dead center of the 11 meter band. When that antenna was sent to antenna Heaven thanks to a direct lightning strike, I replaced it with what I thought was purchasing the same antenna but when I ran the antenna analyzer on it, the antenna appeared to be better suited for the 10 meter band and I thought at first that I was doing something wrong on my end. If my memory is correct, I think that at best I was only able to get this second IMAX-2000 in this video to resonate at 27.500 Mhz which is why I went with a different antenna because I couldn't get the sweet spot to resonate any lower with this IMAX-2000 in the video. I even tried to add a few inches to the top of the antenna to lower it's resonace spot which is probably why you thought it had been modified. Besides the tape that I later put on the top section to seal it that you see in the video I tried to add 2 extra inches of length to the top of the antenna which made ZERO difference on the SWR. Later I was to find out that you have to lengthen it between the lower and mid section to lower the antenna's frequency or it's resonate spot because of the inline capacitor they placed in the mid section. The outer tuning rings will affect the resonate spot some but they really play more into fine tuning the 50 ohm match on the loading coil more than fooling the antenna into thinking it's either electrically longer or shorter. From what I figured out and by Solorcon's own actions of adding the 11 meter extension kit to their new IMAX-2000 antennas they sell, I was right on what I was seeing on this second antenna not resonating in the 11 meter band like their earlier builds. I hope this makes sense.

[@CBPunisher1900]

@@flash001USA i got the new one also but u dont need the new peace u can use a 102 inch whip as the top part and that extra 6 inches over the 8ft whip will give u flat swr on cb no extra forth peace needed u can also just snip the top whip and wrap a 6 inch peach of metal guy wire or hanger even to make up the missing few inches if your cheap and will work just as good.

[@justme-n-gracie]

the bottom of the bottom section is not part of the radiator.

[@brazenbull636]

Does somebody know the lock washer sizes offhand? I just set mine with the gpk and decided ima take it down and replace them with stainless..

[@snippits75]

1/2 inch and 3/8. Buy real galvanized split washers...not zinc coated that will be rusted in less than six months.

[@gregestee9099]

Does anyone know if adding the Max ground plane kit is worth it.???

[@flash001USA]

I personally don't think it helps. I purchased a ground plane kit and I didn't see any difference in the performance of the antenna. Maybe there are others who will say otherwise but for me I didn't see any noticeable difference on transmit or receive or any difference in the SWR either.

[@gregestee9099]

@@flash001USA much appreciated. Thank you for your time and talent.

[@CBPunisher1900]

yes it is

[@josephriffle124]

Great video, thanks for taking the time to make it. This explains why they get hit by lighting more so than aluminum DC grounded antennas. The caps holding static charge...

[@justme-n-gracie]

LOL no. Having a radiator dc isolated allows static charge to build up in/on the radiator... lightning just amplifies this effect. If this static charge discharges to the coax and everything connected to it... it can destroy the rf amp and 1st mixer. An ungrounded radiator/antenna is also usually noisier. A DC grounded antenna is nothing more than a simple lightning rod....

[@izzzzzz6]

Great info. More in those than I thought. I have a "President" version that I don't use much but I think it would be half decent if it had at least 3 or 4 x 104" groundplanes. I found some alloy rings that clamp to 30mm tube or many different sizes 40mm etc. I plan to tap in some M10 holes and screw in those stainless telescopic antennas as ground planes. They are quite strong and light. They can extend up to 5.6M anyway these rings if you get the ones that have the split can be quite chunky and a good basis for a ground plane system if you size them correctly. I would like to know more about those loading coils / tank coils out of phase. I am making my version of a Maco V5000. I made 2 rings because i coiled the 1st one clockwise but now I'm thinking to experiment and add two rings by sliding in the backwards one in upside down just above the main one. I made them in the same form as the ally one on a Maco V58 or 5000. Looks really cool in copper pipe. Teflon insulators and more stuff coming soon. I think that cap in the 2000 puts the top section out of phase causing it to act like a 2nd antenna in a stacked co phase array configuration. This should lower the radiation pattern. I can't get over the fact that there is no electrical connection other than that chunky capacitor in brass. That's impressive.

[@flash001USA]

I know in the I-max write-up I stumbled across they said the coils being out of phase helped get rid of unnecessary peak and null points which gave the antenna a somewhat smoother and wider bandwidth. Yeah the inline series capacitor plays a few roles or at least that's what I read. It can be a 1/2 wave with a 1/4 wave stacked over it or it makes the top section appear electrically shorter but correcting the phase as you mentioned sounds reasonable too. Doesn't do any good if the antenna is cancelling out in places. Kind of defeats the purpose of the extra bit of antenna length. As to the series capacitor, I honestly don't know how that behaves over a 2 Mhz or 3 Mhz span. Only the shadow knows.

[@justme-n-gracie]

"I can't get over the fact that there is no electrical connection other than that chunky capacitor in brass." Research "critical coupling of resonant circuits/radiators".

[@justme-n-gracie]

@@flash001USA The Shadow knows that it's called "critical coupling" loi

[@izzzzzz6]

@@flash001USA once you have what is seen as stacked antenna it's a type of array well, an array of 2. It will add gain to the radiation pattern just as co phasing two antenna would but a different radiation pattern. A co phase pair at the same height would show a stronger pattern 90 degrees to the line between the two. I believe one stacked above the other will squish the radiation pattern lower and penetrate further but in all directions depending on surrounding objects

[@izzzzzz6]

@@justme-n-gracie Yes. Capacitors pass AC which is what a radio signal is essentially, also they can delay a signal or tune an antennas reactive inductance over capacitance depending on weather it's being seen as too long or too short for the band. Adding or subtracting either inductance or capacitance will tune the antenna and radio to different bands within the scope of the antenna being used for those bands. Some antenna work better than others over multiple bands but then one must use a tuner. All too often people talk about antenna, baluns, tuners etc without distinguishing between multi band and mono band antenna etc. Some cool experiments you can try with high voltage capacitors and inductor coils. A capacitance hat is another example but it is usually near to the top of the antenna to either broaden the band usage, adapt the antenna length or to change the radiation pattern. Recently I built a copy of the Maco V5000 and the lowest section is a capacitor. about 8cm overlap with a 3,5mm space all the way around. I used teflon as an insulator by wrapping 3mm thick walled teflon tube around and around the 2nd lowest section then slid it into the lowest section. There is an inductor tuning ring between them.

[@Fox250R]

Any idea where I could find an imax 2000 these days ? Thanks

[@flash001USA]

Yeah they still sell them. Go to Google and type something like purchase a I Max 2000 antenna. You should see a lot of companies and retailers pop up and then you just go through the list and find the best price that you can get it for. I hope that helps.

[@Fox250R]

@@flash001USA The problem is I’ve been told and heard that the newer I max2000 are smaller than 24 feet and they now come in 4 piece sections due to making them easier to ship I guess. I’m looking for an old school one that’s still 24 feet. If you have and ideas again I’d very much appreciate it! Thank you 🙏

[@flash001USA]

@@Fox250R You could go with a Sirio 827 but it looks like they are out of stock. They also have a Sirio 2008 antenna that is in stock and this too would be a great antenna that would actually be a step above the Tornado 27 antenna I have by them now. Here is the link. www.sirio.store/index.php?main_page=product_info&cPath=2_18&products_id=21

[@Fox250R]

@@flash001USA sweet I’ll check it out thank you!

[@timmack2415]

No! The formula for a 1/2 wave antenna is 468/frequency in MHz. Making a 1/2 wave antenna about 17.5 feet. The formula for a 5/8 wave antenna is 585/freq in MHz or about 21.7 feet. There is nothing remarkable about the length of the IMAX. It is the same size as other 5/8 wave antennas for 27 MHz. The amount of inductance required (L) is equal to the amount of capacitance (C) in the antenna. So, first you need to know the capacitive reactance (Xc) of the antenna, then you can calculate the inductance (coils) based on L = XL/2pi*f. The center capacitor is to add capacitance to the radiating element to give more bandwidth. The original IMAX exposed was wrong about many things. My guess is that it was a nod to the manufacturer with plenty of smoke and mirrors and just plain nonsense. I might add that in almost all situations, a 5/8 wave antenna needs a ground plane to work against and coupling to nearby conductive media, like the mast, u-bolts, etc. is an issue without radials. A 1/2 wave, like the A-99 doesn't need radials and are generally a waste of money except in some very rare mounting situations.

[@flash001USA]

Thank you for your reply and feedback. You would be correct that when I mentioned 18 feet that I made reference to a 1/2 wavelength antenna and I did that by accident and didn't pick up on it until a few days later. The I-Max length specs are 22.5 feet. My first ground plane antenna was a MACO v5/8 and it had been a while back since I assembled it but I did assemble it by their frequency chart and at 26.0 Mhz they specified a length of 249 inches. At 27.0 Mhz they specified a length of 248 inches and at 28.0 Mhz they specified a length a bit over 232.5 inches length. This is what was in the back of my mind when I was making this video. Even at 26.0 Mhz center frequency for the MACO their actual chart length for the antenna was 20.75 feet and for a center frequency of 27.0 Mhz the chart gave you a measurement of 248 inches which is only 1 inch longer from 26.0 Mhz to 27.0 Mhz. They state "an overall length" so these numbers are only to get you in the ballpark but I know you are aware of that. The physical length difference with the I-Max and the MACO is just a bit under a 2 foot difference length with the I-MAX being the longer of the antennas. When I assembled my first I-MAX and laid it next to the MACO I was replacing I remembered the length difference which made me decide to go look at the MACO pdf file where I got the actual numbers before I did this video. I'm not sure why the MACO is physically shorter than the I-MAX but it definitely is and a almost 2 foot difference is a lot. As far as crunching the numbers they are apparently different for a real world 5/8 wave MACO. That probably could apply to other 5/8 wave ground plane antennas but don't hold me to that. I also know that Solorcon the builders of the I-MAX claim to fame was that it was a much longer antenna than most of the 5/8 wave ground plane antennas on the market and comparing it to a MACO they would be correct. I was having a Biden moment when I mentioned a 4 foot difference between the I-MAX and other 5/8 wave antennas because my mind for some reason made reference to a 1/2 wave antenna and as mentioned, I didn't pick up on it until a few days later. That was my bad. Still even with opening mouth and accidentally inserting foot my main goal for this video was to show people how the matching network was designed in the I-MAX and to build my own a wide-band roll-up bug out antenna based on the I-MAX 2000 antenna. I'm decent at what I do and I understand antennas but antenna theory isn't one of my strong points which is why I was asking for any knowledgeable people watching this to hopefully help out and fill in the blanks as to how they made this antenna so broad banded like they did. My first I-MAX was set at a center frequency of 27.0 Mhz and it covered from 26.0Mhz all the way up to 28.0Mhz with a most excellent SWR across a 2 Mhz span. Both the MACO and the Sirio I run now are only good for a 600 Khz bandwidth at best before you need a tuner. Once again, thank you for your feedback.

[@flash001USA]

Almost forgot.... The main snafu I picked up from the I-MAX 2000 exposed website was the spark gap. I tried to point that out in the video.

[@timmack2415]

@@flash001USA I have lots of Joe Biden moments myself and increasing as I age. LoL Well, the formula assumes 14awg wire. If you went with larger diameter, say even 10 AWG, the antenna would be physically shorter because of increased efficiency. Going to tubing, like the Maco gives you far more surface area, better efficiency and at, say 12-15 times more surface area than a 14 gauge wire, a much shorter antenna. (also because of lower radiation resistance and velocity factor, but that's way too much to get into on a post, much less the chapter in a book) As far as the center capacitor in the IMAX, it serves two, but related purposes. One it to increase bandwidth and the other is to add capacitance to the radiating element so the antenna will "look like" a 50 ohm load without the use of radials. But adding extra capacitance lowers the efficiency by introducing energy loss. The IMAX is a "compromise" antenna. You trade better bandwidth for less efficiency. If bandwidth is your goal over better radiation, it's a good choice. I've viewed the IMAX using two antenna modeling programs. In the original "IMAX exposed" article, he claimed it has .8DB over a half-wave dipole. However, when you add Q-factor into the equation (real life) and the center capacitor, the IMAX has about -1.6 to -1.8 DB loss over a 1/2 wave, wire dipole! I know that you're familiar with electronic and Q-factor (efficiency) is governed by the laws of physics (unchangeable). You can make an extremely efficient antenna that will radiate extremely well, with very little loss over a more narrow frequency range. But you can never get something without sacrificing another. Modeling the IMAX 2000 with ZELAND IE3D (probably the best antenna modeling software I'm aware of) shows a very interesting thing. Since the IMAX uses the coax shield (and consequently the mast, u bolts, etc) as a "counterpoise" (in place of radials), I can model the antenna mounted in 10 scenarios and yield 10 different radiation patterns. I'm an electrical engineer, but not an 'expert' in antennas, however, basic principles apply. I have a 10 meter beacon (@ 3 watts) and use a direct-fed, 1/2 wave vertical dipole and I have 10's thousands of reception reports from all over the the US and 59 countries. It's uses no coils (which introduce loss), no capacitors (which introduce loss) as a tuning network isn't needed, nor is a counterpoise or radials as "both halves" of the antenna are already present. If it were me, I'd use a half-wave, center fed vertical wire, or even two 102" whip antennas, center fed, as an option. Either will outperform an IMAX in every scenario I've tried to model. Not that it's relevant to the IMAX, but I have an A99 on my roof at 35 feet (yeah, I can hear the groans) and my wire dipole at 20 feet. Never, not even once, did I ever have a better signal report or a single received signal that was better on the A-99.

[@flash001USA]

@@timmack2415 Yeah after I replied to you last night it hit me about the antenna wire diameter that the larger the diameter the shorter the antenna can be to some extent. You're also correct about the Q factor and that also applies to broad banding coils in transmitters and receiver circuits. When I was designing diplex filters for the cable industry those had bandwidths starting from 50 Mhz all the way up to 1.2 Ghz and trying to control the roll-off and insertion losses was a pain in the backside that required top shelf hi quality inductors, capacitors and a really smart board layout along with a bit of tilt EQ'ing thrown into the mix so with just with that experience I understand the trade-off with losses vs bandwidth. Years ago I used to broadband off the shelf CB radios for customers when I did channel expansions and it worked but the trade-off was reduced sensitivity on the receive so I can understand how that would also translate over to a antenna. When my I-MAX was set up I talked all over the world (under the right conditions) with no more than 100 watts and even if the antenna was a bit lossey it was worth it for the wide coverage for me. Somewhere in my saved documents I have a design for an ultra narrow band antenna that can be set up to be tunable even on a mast and the claim was it would give you a very clean low noise rejection to the adjacent channels along with a good gain in a smaller package. One of these days I may try that build. Anyhow once again thanks for your feedback. Take care, Mike

[@flash001USA]

@Greg Webb Here is a good online calculator that also gives you explanations of everything. www.omnicalculator.com/physics/dipole#how-is-dipole-antenna-length-calculated

[@nasanction]

About 8 years ago, I wanted an antenna I could just hoist up a tree with a slingshot line. I cut away all the fiberglass and original antenna wire. I then connected my own measured wire with a more flexible one. It still hangs from a giant oak in my yard and remains my staple omnidirectional antenna to this day. The only thing I had to add was a shroud (2 liter bottle) to protect from rain. I saw the innards when I did this, but left them intact.

[@flash001USA]

I thought of doing the same thing too. I've always wanted to reverse engineer their design but I couldn't justify dishing out that kind of money for the project. The I-Max-2000 now cost around $185. When I purchased my first one it was less than $70! The day I did the swap I knew I was eventually going to make this video. I plan on building this and once I get it worked out I'll do a "how to" follow-up video and share this.

[@nasanction]

@@flash001USA I'm interested in what your design will be. I built my gasifier from your design, and it worked first time producing the "Halloween Orange" flame. I find your attention to detail refreshing, and I look forward to your backpack Antenna design.

[@stevenhitt6954]

When it comes to the capacitor up on the antenna, I have modeled it in the past and its effects on the current distribution is significant. You are correct, it "electrically shortens" the antenna in the exact same way that an inductor (or coil) electrically lengthens mobile antennas. In this regard, when modeling the Imax antenna and adding the capacitor, all of the currents along the antenna are in phase with each other. This is one of two 5/8 wavelength CB antennas that have all of their currents along the length of the antenna in phase. Aside from said two CB antennas, all other 5/8 wavelength CB antennas have a part of the antenna where out of phase currents flow. Said out of phase currents have negative effects on the antenna pattern, although no one seems to know or care about said effects, that goes beyond the scope of this post. Another thing the capacitor does, or more specifically is caused by the capacitor's change in the current distribution, is also a change in feed point impedance. In this case, the feed point impedance is the same or similar to that of an end fed half wavelength antenna, such as the a99. You will notice that the matching circuits of the a99 and Imax 2000 are very close if not the same. This change the capacitor causes in the antenna's current distribution is why it is possible to even use such a matching circuit on this antenna. When it comes to the two coils in the matching circuit, these should not be represented as two separate coils, but instead as a single transformer. Factoring in the rings which affect only the inductance of the outside coil by capacitvely coupling to them, making this a variable unbalanced to unbalanced impedance transformer. In fact looking at your (and the other) schematic, this is a classic unun design, and similar designs are widely used elsewhere when matching various other antennas. I don't know why no has ever noticed this, but this is how unun's are made and used, always has been. And finally the bandwidth of this antenna. Its actually not that complicated. Two different things come together here. Every electrical 1/4 wavelength multiple tends to have a naturally wider bandwidth, especially the electrical 1/2 wavelength multiples. However, the points in between these electrical 1/4 wavelength points (such as the electrical 5/8 wavelength point) have a very narrow natural bandwidth, aka the Maco V5/8 and V5000 antennas as an example. Adding to that almost all matching circuits used have the effect of narrowing said bandwidth further. The few matching devices that don't narrow an antenna's bandwidth are baluns and ununs. Both baluns and ununs, properly used, have the effect of maintaining an antenna's natural bandwidth while transforming the antenna's feed point impedance closer to that of the feed line.. The thing about baluns and ununs, for them to work like this, the antenna needs to be at or near resonance. Naturally resonant lengths are 1/4 wavelength multiples, including the 1/2 wavelength length, and as the Imax is near a physical 5/8 wavelength, so it needs something to compensate for this electrically... One way this is done is by adding a load of some sort of load to the antenna, like a capacitor... Wait, didn't I talk about the capacitor already?

[@flash001USA]

That's the "BEST" damned description I think I've ever heard someone explain this antenna! The center capacitor does somewhat make the antenna act as if it is electrically shorter and I proved that to myself just by experimenting and tinkering with the design. I like how you broke down the explanation of the outer tuning rings and that makes sense too. You mentioned the matching coil and although they overlap the coil onto itself they do it out of phase by turning the coils opposite of each other and according to the manufacturer, they claim this helps with the reactance which helps achieve the clean smooth wide bandwidth. I can tell you for a hard core fact that the capacitor in the center of the antenna plays a BIG factor in the wide bandwidth too. Have you seen the video where I built this antenna? I was able to fine tune the antenna for a near perfect mirrored response from the center tune of the antenna to the lowest to the highest frequency spread of the 2 Mhz bandwidth this antenna has. I demonstrate this on an antenna analyzer. Here is a link to the video. kzbin.info/www/bejne/eJCzXp6LdrOmq9E

[@SoonDumpingAllGmailAccounts]

Yes but if it behaves as a Halfwave - or similarly with the A99 - it shouldn't require any 1/4 wave counterpoise, *but the Imax does,* and I have tested this by wrapping a 5T choke in the coax directly beneath the connector so the shield could not act as a counterpoise and the SWR increased from 1.2:1 up to 3:1 - until I added a 1/4 wave counterpoise radial at the top of the U-bolt area, which caused it to once again provide a low 1.2:1 SWR. EDIT: The Imax 2000 was mounted on a wooden 4x4 mast.

[@stevenhitt6954]

@@SoonDumpingAllGmailAccounts I haven't told anyone to put a choke at the feed point of this this antenna in a long time, the a99 either. It is simply not effective there, and often does more harm than good, as you found out. I have been telling people to put said choke seven to eight feet down from the feed point. This, with the foot or so of coax that is inside the antenna should come out to a familiar length... and it is the best place for said choke for both of these antennas. This is also why you had better results with the so called "counterpoise" wire. For it to be effective, you have to put a choke where the current is, and on the a99 and Imax antennas, that is actually not at the feed point, which by the nature of said antenna designs is a current null. Sure, in some cases, depending on the length of the feed line and how it was run it might appear to do some good, but that will not be the case in every situation. That air choke you used is reactive by nature, not resistive (i.e using ferrite beads make resistive chokes). As they are reactive, how they are used and where they are placed is very important, yet no one ever considers this, people just assume that they have to go at the same place on every antenna and that is it. Again, as you found out, they can be double edge swords...

[@SoonDumpingAllGmailAccounts]

@@stevenhitt6954 Agreed, and the reason I tested it was to prove to a friend who told me & others that an Imax doesn't require any counterpoise, so I proved it does and that it typically uses the coax & mast for it's counterpoise. How I got the best performance from my Imax years ago was to install it on a solid 6' fiberglass rod atop the 5-section Tv push-up mast and wrap a 5T x 4.5" dia choke around the fiberglass rod and right below the connector, then I attached 3 102" wires from the top U-bolt downward at a fairly steep diagonal angle - maybe 60° - 70°. It added a full S-unit to the signal up into the mountains about 90 miles from here. How would you find the right size specs to build a 10pf cap utilizing 1" or so dia aluminum tubing - and to handle at least 10KW?

[@SoonDumpingAllGmailAccounts]

@@stevenhitt6954 Also, thank you for taking time from your busy career to help out youtubers. Maybe soon we'll be able to QSO on 20m or 40m from here in Cali to MO(?).

[@frankovision1]

The Max2000 is not quite the same as the original Imax2000 which is no longer available. The original Imax2000 was 26' long and the ones made today are made in china so they found a way to shorten the antenna for shipping to 22' I'm not sure if it makes a difference but when my Imax2000 match went to 3.5 on the SWR I was going to purchase a new one but someone told me that the problem was the top whip and that I could use a 102" stainless steel whip in place of the fiberglass which I did and now my 12 year old Imax works excellent and the band width is amazing and is 1.5 or less thru 11 meter and 10meter. I can use my antenna tuner for 12,15,20 and 40 meters. If I need to someday I may buy the new one but after they started making them in china I have no confidence in the material and workmanship.

[@flash001USA]

I don't blame you. I wouldn't trust an I Max 2000 made in China either. I could only imagine the shortcuts they would gladly pull to get the antenna out the door.

[@snippits75]

No they are not made in China. Still made in the USA. Stop spreading lies.

[@aquatekt1402]

I replaced my top section with a light weight 102” whip. Less wind load and brought resonance down from 29 MHz to 28 MHz. Now 12 and 15 have acceptable / good swr. 17m has fairly high swr but still seems to work ok. Most of the time this antenna works better than the 2 element Yagi mounted just below it.

[@CBPunisher1900]

@@aquatekt1402 i did that also and got a flat swr on channal 38 after a retune .

[@shaknit]

Looks kind of like a double tank circuit.

[@flash001USA]

To me the interesting part of the design is the way they configured the two coils out of phase. I also like the way they used the brass sleeve as two separate capacitors.

[@trailbossx2]

,,,,,,,,,you,,,,,,you,,,,,,mean there aint no santy claus???????,,,,,,lol,,,,de NV1H

[@flash001USA]

Lol, Let's not spoil it for any of the kiddies out there that may be reading these replies.

[@Brenda-jf2pe]

I added to the top a 102 inch Wilson fiberglass car bumper Whip , now I can tune up on 20 meters ! Go figure this Antenna is a Sleeper!! KJ7TBR

[@calescapee9642]

The Original video was called Antron 99 Exposed.

[@flash001USA]

That's possible. I was only aware of the I-Max 2000 antenna exposed website. They also talked about the Antron-99 antenna too. I know that both antennas are pretty much based on the same matching circuit. Here is a link to the I-Max 2000 if you would like to check it out. cbradiomagazine.com/the-imax-2000-exposed/

[@jacianmcgurk7424]

Hi Flash, great video, like everyone on here I have been thru loads of antennae, currently have a max 2000 up and for bandwidth its great but for me it struggles to beat my old 5/8 wave silver rod. All knowledge is good my friend. Take care and all the best from the west coast of Scotland.

[@ericdee6802]

Isnt that nothing more than a 1/2 wave end fed dipole?. Wish my Father was around. He was Lockheeds highest paid radar engineer for 24 years, He and Kelly Johnson were big buddies back in the day. He was also a extra class ham operator, he would have that joker figured out in a second.

[@flash001USA]

The Antron-99 is a 1/2 wave antenna but the IMAX-2000 is a 5/8 wave antenna with a few mods to allow the antenna to be a bit longer and they accomplished this by adding a 10pF series cap in the mid section of the antenna to make the lobe stay lower in the antenna so that it had less RF energy radiated into space.

[@justme-n-gracie]

yes it is more than a simple 1/2 wave end fed antenna.

[@fitzwater504]

I came to see this video today.With the exact same thinking as yourself. I would like to build a homemade version myself. Using Small copper tubing inner elements & pvc outside. My main concern is loss/resistance... I've A99 Antron or Solarcon A99 as my goal build. But, also have in mind 1/2 wave vs. 5/8 wave to. Subscribed Love your details of your videos.Can't wait to see more. 20-yrs. of cb knowledge myself. Thanks for your video.

[@flash001USA]

Since this video I have done the build. Here's the video link if you would like to see the build. kzbin.info/www/bejne/eJCzXp6LdrOmq9E

[@flash001USA]

@Shotgun Cat The Sirio Gain Master antenna will handle a 500 watt RMS continuous carrier and 1000 watts for short transmissions. For the average person this is probably more antenna they will really need unless you are wanting to join the Channel 6 Super Bowl. The Sirio Gain Master is a "Kick-Ass" antenna and whenever you go from a 1/2 wave antenna to a 5/8 wave will almost always be a win-win for the station. The IMAX is unique in it's design because of it's design with the 10pF series cap in it's mid section of the antenna. it's the magic bullet to the IMAX. which helps to reduce a lot of wasted RF going into space by keeping it's pattern close to the earth and this is where it differs from a lot of antennas. I've tried many vertical antennas and the IMAX has had the best ears and some of the best reports from stations over the other antennas I've used. Going back to the Sirio antennas, one of the better Sirio antennas that's even better over the Sirio Gain Master is their Sirio 827. I have one but I have not set it up yet. What makes this antenna a winner is it uses 8 radials instead of the usual 4 radials you see on most ground-plane antennas which gives this antenna great ears and a very good and uniform TX pattern. You may want to take a look at this antenna. It's rated at 1000 watts continuous RF carrier and a 3000 watt short time transmit use. The peak rating will be much higher. Here's the link for you if you would like to check it out. www.sirio.store/index.php?main_page=product_info&cPath=2_88&products_id=444

[@flash001USA]

@Shotgun Cat That's interesting that you mentioned the thick wall antenna material. Right now I'm running a Sirio Tornado 27 which is a 5/8 wave antenna and It's really a great antenna for the money but there are two things I can point out about the antenna that I don't like. (1) The Sirio antenna bandwidth is narrower than my old IMAX-2000 (2) The loading coil is not DC grounded which I prefer because it helps control random static buildup on the antenna coax by grounding it out before it gets to the radio but other than that the antenna has served me well. Going back to my last reply to you, the Sirio 827 is built like you are describing with very thick walls for the antenna. They barely flex in the wind and they are also DC grounded. They also addressed an issue with the Tornado 27 by really beefing up the insulator spacer at the bottom of the antenna with a thick solid fiberglass rod that then has a PVC jacket over it so it's technically stronger than the actual antenna that it's supporting. I'll check out the Mr. Coiley Build you mentioned because I'm always looking at antennas. Thanks for the tip.

[@9PAT508]

it's not a 5/8 but a .64

[@flash001USA]

Yes/No Yes/No Yes and no all at the same time. Technically it will only operate as a .64 wave on a small handful of channels above and below the center tuned sweet spot. This same remark will also apply to 5/8 wave antennas too.

[@justme-n-gracie]

it is both. it is a 3/4 on 11M and a 5/8 on 10M

[@blugrassdave]

It's an idea from a ham radio antenna called CCD or controlled current distribution

[@jakemichael8586]

1/4 vs 5/8 is a max 3db over most ground but factor in loss of matching section it is only about 1-2 db! if you get a 1/4 wave up the right above ground it will have about 2dbi gane or about 7dbi if you factor ground reflection! dipole is 2.15 dbi or 8 dbi with right hight with ground reflection! now for 5/8 it has a lot of reactence at the feed point the resistive is around 70 ohms. the coil and capacetance makes it as if it is 3/4 wave for a 50 ohm no reactive match. the 5/8 wave is more feel good than real #. now if you have a short wave set the 5/8 can work as a ok receve antena as it is long but it is not perfect but will work. I take a 1/4 wave over 5/8 and add extra hight to the 1/4! take care 73 \/

[@flash001USA]

I have run 1/4 wave, 1/2 wave and 5/8 wave antennas and from what I've seen is the following: the 1/4 wave and the 1/2 wave antenna are pretty close to performance both on TX and RX at about 50 feet up in the air. You can take both the 1/4 wave and the 1/2 wave and run them low to the ground and get great ground wave performances with them and they will shoot skip quite well when the conditions are right. The 5/8 will work close to the ground too but I'm not sure if it's performance is the same low to the ground. When you put any of these antennas up around 50 feet up in the air, there is a noticeable difference in performance on a 5/8 end fed antenna compared to a 1/4 wave or even a 1/2 wave up at the same height and this is where you WILL notice the difference on the both the TX and the RX performance. The 5/8 will almost always have better RX and TX with your locals you speak to. I have run and tested the following antennas all in the same day where I built an automatic keyer that would key my base station up for 3 seconds on with a 6 second rest so that I could read the TX signal from the base in the mobile and I had strategic open areas such as parking lots etc where I recorded the results and while I was doing this I had a video camera recording the base radio RX meter so I could see the difference on how it received from the mobile and around 6 or 7 miles there was a very noticeable difference on signal strength from the base to the mobile and visa versa from the mobile back to the base. I did this test with low power around 5 watts from the base. I also had a few locals who joined in and they seen the same results. The locals were in the range of the closest being around 12 miles and the furthest being around 22 miles away. The antennas under test were the following: Star duster or M-400 (1/4 wave) Antron-99 (1/2 wave) and the IMax-2000 (5/8 wave). Both the TX and the RX was noticeably better with the 5/8 wave including the audible S/N ratio compared to both the 1/4 wave and the 1/2 wave as signals dropped. Right now I'm running a 1/4 wave star duster on top of the shop that's only 20 feet in the air and it will shoot skip quite well with a barefoot radio, talking into NY or Texas with no problem but the locals who are used to my base station can tell the difference from the home base to the shop base signals. When it comes to RF, antennas and lobe patterns or performance in the real world compared to technical specs it's like practicing voodoo. It's all about your location, your radio and your equipment and the height you choose to run your antenna.

[@radioatividadepx]

youtube.com/@estacaoradioatividadepx?si=vPglXcfyf8Cmnb0v Poderia verificar a descrição da antena na aba COMUNIDADE do meu canal, onde há informações importantes sobre a antena de cabo coaxial 75 ohms com transformador de impedância para 50 ohms, gostaria de saber qual é o lóbulo de irradiação de campo dessa minha antena é também qual é o ganho dessa antena.

[@shaknit]

I wonder if it could be re engineered for 2.4 ghz.

[@flash001USA]

Not sure if that would work with that high of a frequency. It would be tiny for sure.

[@nasanction]

Any antenna is simply the length of the element cut to the frequency you wish to use. Most antenna's like the I-Max-2000 use some sort of circuit to broaden the range of the frequencies to be used. 1/4 wave 1/2 wave 5/8 wave are just the length cut in a smaller segment to shorten the antenna. This in turn reduces it's ability. Ideally a full wave is optimal but not practical as the length becomes unusable with frequencies like CB. Most 2.4ghz antenna's are rather small in that frequency range, and can be made in a wide range of configurations. I made a directional helix design about 15 years ago and had a line of site range of over 50 miles. it was only 2 feet long. ;)

[@flash001USA]

@@nasanction If you look at the MACO v/58 it is around 248 inches for the 11 meter band. That applies to most of your basic 5/8 wave antennas. The I Max is 270 inches in total length according to the specs. I still think by them using the inline series cap they are making the antenna electrically shorter so they can add more element into the air but I'm not sure. That's interesting about the 2.4ghz setup you made. I haven't worked with any hi frequency stuff like that other than using my cellphone lol.

[@nasanction]

@@flash001USA I still have that 2.4ghz helix antenna somewhere, If I run across it I'll take some photo's for you. The backside was simply an 8" aluminum pie pan and the element was copper wire coiled around a 1" pvc in a helix pattern around 2 ft. long. It's been a long time, so I don't remember the actual spec's.

[@flash001USA]

@@nasanction What you're describing I think I have actually seen something like that somewhere along the line. It seems like I read somewhere where people were making homemade directional internet extender antennas.

[@ericdee6802]

Outstanding explanation of that antenna. I believe the "Big stick" from way back when was the founding Father of the fiberglass base antennas!. Iam definately subscribing!!!

[@flash001USA]

Thank you for the reply. This is a follow-up to this video that you may find interesting. kzbin.info/www/bejne/eJCzXp6LdrOmq9E

[@robworrall6832]

Glad I found your channel, very interesting indeed to look inside this antenna as it's not your average vertical is it? I understand most of the basics but wouldn't have understood the purpose of the capacitor and the transformer coils (if that's what you call them). Great reverse engineering there - which I know a little about in basic electronics but to reverse engineer antennas and RF circuits gets a lot of respect from me. I remember thre names of many of these legendary antennas and used to fantasize over them when I was a youngster on the CB in the late '80's :-)

[@danieljohnson8437]

Excellent ,thank you for taking me along.

[@GaryLordsWayMinistry]

Now if you do not put that series capacitance back in the bug out antenna it will need a new poper loading coil that is designed to electrically match the new antenna length of the long wire; or you going to have to make up the difference of the series capacitance in the length of wire to compensate for the missing capacitor that the loading coil is used to seeing inline with it. Or change the total capacitance in the new loading coil to compensate for the missing capacitance further on down the line. If that makes sense at all to ya. On your schematic drawing you should have used 3/4 and 1/2 for the O.D. size of the inductors and their values (uH or pH or what it tested out to be) with the proper coils turns on the schematic for others to follow your designs. As well as Capacitance values on the schematics as well. KI5UHA Rogers, AR. But overall nice video and looking forward to seeing the next video on this subject matter.

[@flash001USA]

Thank you for your feedback. As to the series capacitor, if you remove the series capacitor all bets are off and the antenna will not tune. You could probably cut it down to a 1/2 wave end fed antenna and make it work but it won't load correctly as the 5/8 wave design it was intended for. In the video and the drawings I could have done a few things differently but the video itself allows people to see first-hand how the antenna was built. I used drill bits as my coil forms because they are going to be spot on as far as their diameters go.The I.D. will be what I stated in the video but you would be correct that the O.D. will be larger in diameter. In other words, the O.D. will be the diameter of the coil form + the diameter of the wire itself added together. I took the I-Max 2000 and did what I haven't seen anyone else online do which was not only to dissect the antenna but I tinkered and tested everything with the antenna to learn what affected what. In the end I was actually able to build a custom design that resonated dead center of the 11 meter band with both the lower and the upper ends of the SWR balanced out. On a ending note I can tell you what I did miss in the video and what others who have dissected this antenna missed too and that would be pointing out that the tuning rings are technically closed loop coils that couple to the loading coils to rubberize them which allows you to fine tune the antenna as a whole. The tuning rings can only shift the resonance of the antenna by 5 or 6 channels or better yet, 50Khz or 60Khz tops. From what I figured out, the tuning rings really serve more of a purpose of truing or fin tuning the 50 Ohm resonance point of the antenna's length. I did build a follow-up to this video with an actual working bug-out antenna based on this design that worked quite well.

[@n0vty873]

.64 wave

[@flash001USA]

.64 wave at and around it's resonant frequency for sure.

[@gmcc5709]

Tagra bt-104 was and is the best antenna

[@flash001USA]

I've heard a lot of good things on this antenna and this design in general.

[@gmcc5709]

@@flash001USA yes sigma 4 style but gold in colour, had clamps instead of jubilee clips and gamma rod never came out was a beautiful antenna think it was 7/8

[@flash001USA]

@@gmcc5709 I looked it up after reading your comment and it is a 7/8 wave antenna. I'm always interested in in topics like this so thanks for the info.

[@GustavoGomez-kk7ob]

Hi , thanks very well done and explained crystal clear . Nice to see the inner working . Alright 😀👍

[@zzxxenith]

Excellent work thank you.

[@keystonecountryboy]

I just run aluminum anymore less dc static

[@flash001USA]

To be honest I prefer aluminum over the fiberglass myself. Don't get me wrong because a good fiberglass antenna will talk just as good as an aluminum antenna provided it's set up correctly but then again that goes with any antenna. With my fiberglass antenna I used to notice the static sound whenever a rainstorm would come over and it would be a sizzling sound every time rain drops would hit the antenna and that would be followed with a buzzing sound going up and down in pitch once the rain went from a sprinkle to a steady rain. It was definitely strange. What's weird is I thought that was something that was only unique with fiberglass antennas but I'm hearing those same sounds with the aluminum antenna when a rainstorm comes over. There doesn't even have to be lightning or thunder. It's as if the raindrops themselves have a static charge built up on them when they hit the antenna. It doesn't do it all the time so I'm not sure if it's something to do with atmospheric conditions or what. Have you ever experienced what I'm talking about?

[@justme-n-gracie]

The only reason a bare aluminum antenna would have less static is all in the feedpoint. A matching network that is DC grounded/DC grounded at the radiator dissipates the static charge that builds up on any and all bare metal antennas. Not having a DC ground at the feedpoint and connected to the radiator allows static to build up... caused by wind and sometimes lightning.... the discharge of the static can kill the rf amp in the front end of thereceiver... sometimes the first mixer as well. Any coating or covering on the radiating element will prevent this... from paint to fiberglass or pvc tube... as long as the wind/air does not tough the radiator.

[@oswaldorodriguez7047]

D Momento zona.

[@billmyers262]

Genius