Where Does Your Antenna Analyzer Go?

[@vladtepes481]

You are correct that measuring SWR etc at the antenna can be physically difficult but it the best place to understand the antenna. The ARRL antenna book (recent editions) have a piece of software included called TLW that can estimate the the SWR at the antenna from a measurement taken at the end of a piece of coax of known type and length. The SWR at the end of the COAX will be lower than that measured at the antenna due to losses at the cable. The SWR at the antenna determines the cable losses due to SWR on the cable. For example an antenna with Z= 200 -50j impedance at 28MHz connected to a radio with 200 feet of RG-174 will have an SWR at the antenna of 4.23 but at the radio of only 1.08. The return signal is mostly lost in the cable. The line loss here will be about 14 db including 2 db due to the elevated SWR at the antenna. Your signal will also be down be down by 14dB

[@tristan4777]

Nicely put. If the performance of the antenna and your analyzer readings don't match up, (low SWR but poor performance) then you may need to check at both ends of the coax to account for losses.

[@MM0OPXFieldRadio]

Mike, on the SWR measuring. I agree in practice but only to a point. Measurements should always be at the antenna feedpoint to know exactly what's going on as with a non resonant antenna the coax will affect the match. There are 2 easier ways to do this. Use an electrical half wavelength of coax for the specified frequency and which will be "invisible" to the analyser/meter. To have an accurate half wavelength length of coax an analyser ideally needs to be used to cut it. The 2nd way is to "null" out the coax by doing an open/short/load calibration at the far end of your coax. Any Rigexpert or NanoVNA will do this. This is my preferred method and this is how you check at a feedpoint high up. Once you tune your antenna the lengths of coax used should not matter but in practice the SWR will likely go lower due to losses etc. For commercial antennas dont bother and just check at the end of the coax. For antenna building then the former is pretty critical, for example on my 5/8 verticals L/C match. 73 👍

[@chuckk5358]

I picked up a couple of the ICOM band plans at a hamfest and took them to Office Depot and had them laminate them with 6 mil (I think) laminate. Came out pretty nice.

[@bryceettwell9537]

Mike, what you say about connecting your antenna analyzer at or as close to your transceiver does make sense in that the whole idea of a low VSWR is to provide a match to your radio. And as you also state your feedline is part of your antenna system. However, I feel that you should check your antenna system at the antenna so as you can see what your antenna is doing and how it is behaving thus giving you the opportunity to correct any mistakes before attaching your feedline. I feel that if you only check your antenna system performance where you attach it to your radio, and there is a problem, you then have to determine where the problem is (IE is there something amiss in the antenna or is there something amiss in the feedline). You could spend a lot of time messing with your feedline rather than fixing the problem with the antenna and vice versa. Now, something of a tip (most owners of a Rig Expert will know this) with a Rig Expert you can attach the analyzer at your radio and "NULL OUT" the feedline, IE the analyzer shows you what is happening at the antenna. For me at least, it is a lot easier to change a feedline than change an antenna. I hope this makes sense. Luv your videos, keep up the great work!! 73's DE Bryce VK3NBI

[@1shARyn3]

Common problem with SWR on the DX Commander is capactive shorting of the elements. Have the guy change the orientation of the elements ---- move the 20m element to the opposite of the pole and try that.

[@BMCTackle]

SWRs & DX Commander - My Experience: The only time when the SWRs are affected on my DX Commander Rapide, and a 40 mono band dipole I have on my roof, is when it snows. Once the element plate gets snow on it, or worst, gets covered up, SWRs go to infinite. Solution, dusting snow off periodically, yup time to get motivated walk through snow and start dusting. Dusting snow from antennas does build character over a winter season. LOL Today I cleaned up the element plate, and gobbed it up with a heavy coat of Vaseline on all the bolts & wire connections. Vaseline will not freeze at the temps we have here in Heber City UT, so I will let you know if that works or not, but it is looking very good since I cleaned it all up this AM. Come Spring I am building a 2nd Rapide with the 40 element and the coil wrap on the mast. I am building a 12 in diamter UV stabile black plastic spreader that will sit about an inch above the element plate to avoid snow accumulation. Other than snow issue, the SWRs on my Rapide stay put, all the bands are resonant at 14.25, 7.20, 18.148, 21.34, 24.960. & 28.470. So my SWRs are ideal for the SSB portions of the bands. My DX commander is a permanent install with a concrete base, so I never move it, stays put. I replaced all my coax from TImes LMR 400 to M&P Extraflex Bury 10. NO TUNER. I use the SWR meter on the 7300, a Nano VNA, and a Rig Expert to measure my SWRs. All three instruments reproduce the same SWR ranges. The measurement devices we use in Ham Radio have no controls, and no real way to evaluate the measured results, therefore the only way to assure I have quality results from any and all the analyzers and watt meters I use in the shack is reproducibility of the measurements across all instruments/analyzers. Louis WW7GBA

[@k9eihamradio]

Two things about measuring SWR at the antenna: 1. Antennas do not have standing waves, or SWR. When you use an antenna analyzer to check an antenna you are checking the complex impedance for resonance and the feed point resistance in ohms. 2. Feedlines have SWR. Especially IF their is a difference between the Antenna feed point impedance and the 50 ohm coax you are connecting it to. The "imbalance" between the 2 impedances is the mismatch and creates reflecting waves to travel down the coax towards the transmitter thus creating the infamous standing wave ratio (SWR).

[@BusDriverRFI]

On a centerfed dipole antenna, ideally the current is maximum in the middle and minimum at the ends. The voltage is maximum at the ends and minimum at the middle. That, my friend, is the definition of "standing waves". What we don't want to get is "reflected signals". Let's not forget the difference between "reflected signals" and "standing waves".

[@k9eihamradio]

Standing waves are created by impedance mismatch and are introduced when you terminate a 50 coax to a 73 ohm dipole. The “reflections” are produced from the mismatch and create standing waves. So the reflections and standing waves are one and the same.

[@BusDriverRFI]

@@k9eihamradio I see a difference between reflected waves and standing waves. Reflected waves. Like I said. Ideally we have standing waves on the antenna. Ideally, we don't have standing waves on the coax or feedline.

[@Klaatu-ij9uz]

"Out-of-the-Park"⚾ episode! Also, that high SWR on 20-meters is a problem on several different radio systems I'm told. Something hokey is definitely going on there......and it's not just one single "fix" to alleviate the problem.

[@ryank5tar]

Thanks for helping me learn things.

[@HamRadioWithKE0MAD]

Ryan, Mike is a great Teacher and Master Debater.

[@davidsradioroom9678]

Good questions. Great answers. Thanks!

[@ronross4288]

KF5MCJ Tulsa, handle Ron. Just retired at 68 now. I am working on my HF station and a few other Ham projects. Purchased and installed two used HF antennas. One, Hy-Gain AV-14AVQ and the other is a Gap Challenger DX-8. Both test bad at the switch on the outside of my home. Bad, means no resonate frequency with MFJ-259B on any band. Underground PCV conduit to each antenna. I took a 2-meter antenna that dipped at 146mhz and disconnected the HF vertical and screwed in the 2-meter antenna. Went back to the home and both dipped at around 146 mhz, the cable is good, and the antenna is bad. I will re-run the test on the vertical at the antenna before title base it down and replacing it. My MFJ is old and I just purchased a Comet CAA 500 to re-test. My father was a ham radio operator for seventy years, now a silent key. Do you have any of his hand made QSL cards, W5OQA Grove Okla.

[@BusDriverRFI]

"How are you going to measure a 40m dipole a half wave up?" Use a NanoVNA. Get your coax that you will use, Run the calibration procedure at the far end of the coax, Raise the antenna into place, Then with your calibrated VNA, analyze the antenna as if your unit was 60 feet in the air but it's in your hand.

[@randymclain4195]

Check the tension on DXcommander wires. After overlooking important instructions from Cullum, I had problems when the mast slipped a little the the 20m wire got loose enough to wrap around wire element next to it.

[@Ammed_KN6STX]

Yes, the orientation of the elements need to be placed as they show in the instructions.

[@johnsalisbury7664]

Good stuff Mike, really enjoyed the antenna talk.

[@KeepEvery1Guessing]

On band plans: first recognize that there is what the FCC regulations require, which is what the ARRL chart shows, and everything else is by "gentlemen's agreement. That iCom chart is pretty good. On the DX Commander 20m intermittent issue: One additional possibility is that something near this (installed in a fixed position) antenna is sometimes resonant near 20m. For example, house wiring for a light that is resonant near 20m or not depending on whether the switch is on or off. Gutters or metal siding components that connect or not depending on weather conditions. But the first thing I would try is replacing the 20m element with a new one, since a bad crimp/solder job on the fork connector, or maybe a break in the conductor inside the insulation seem most likely to me. You can start with just plain wire and no fork connector to see if the issue disappears, before building an element that will stand up to time and weather. On where too measure SWR, first figure out why you care. 1. You want your transmitter's finals to be happy (and, related, you want received signal to, as much as possible, go into the receiver front end, rather than being reflected). If you fix this with a tuner (including the one that may be built into your rig), realize that tuners have some losses, and those losses probably increase with the amount of impedance transformation required. 2. Coax loss increases with SWR, but if the coax is short (coax loss is given per unit length) and/or low loss at the frequencies of interest, this isn't a big deal, and could even me less than the losses in that cheap matching coil on the base of your vertical. Coax loss also hides SWR, than is, the SWR at the shack end is less than at the antenna end (signals in both directions are attenuated, so the difference between forward and reflected power is larger at the transmitter end, meaning lower SWR). 3. You being in the antenna's "near field" will definitely effect the tuning, and thus SWR. While you may not have the ambition to go in and out of the house while tuning, you can connect an alternate coax to the antenna to let you get reasonably far from it while measuring. But finally check again at the transmitter end to make sure that the final coax is OK. 4. SWR at the feed point really doesn't matter, per se, but can indicate that you have misstuned the antenna (though you can see this from the transmitter end to. SWR an the input to a matching network that you have placed at the feed point does matter, since the whole point of that network is to reduce SWR on the coax. Mike, you have a great cat, and those old cat food commercials featuring the finicky tabby Morris were cute. But the man's name isn't Morris, it's Morse, and that rhymes with horse, of course.

[@tkflanagan4449]

You are so good..... I understand You and you ARE helpful my friend I'm 70 and need all the help I can get !!! I just wish you lived in Mass🍀🍀

[@barndweller4573]

Wow I love that band plan from Icom, Thanks!

[@hamradiotube]

So much better isn't it?

[@chrissewell1608]

After finally getting a SWR meter, I learned that tuning an antenna has a lot to do with the co-ax you are using! The antenna and coax together, act as a system. I my opinion, its best to test that System (at the radio), as you plan to use it, to tune it correctly. Because even a later change in the coax's length will give you a different SWR. Its symbiotic! (BIG WORD, like Aluminum! 😅) And your ultimate goals are Not Fry the radio 🔥, get efficient power in your output ⚡️, and clear receiption 🔊.

[@gartnl]

The length of coax will not change the SWR other than through a change in losses. Take a look at a smith chart: the coax length rotates the impedance in a circle but the resulting SWR is the same. If adding 1 meter of coax changes the SWR than there is something wrong with your setup, most likely common-mode current.

[@StealthGTI]

Checking SWR in my mobile setup is more convenient at the antenna (for some of them). By "checking," I mean while troubleshooting a high SWR issue. If my check at the antenna is good, then I go to any inline switches or the back of the radio. The backs of my radios are buried. So, I'm thankful if I find the issue before I have to unpack the car to access the radios. HAHA. With that said, if the goal is to tune or measure ultimate system SWR, then measuring the feedline AND antenna, "what the radio sees," is the way to go. Just my $0.02, minus inflation and other diminishing factors. 😉 73! -Scott, KE4WMF

[@Davidjb37721]

Thanks for your input 😊😊

[@black75powder]

Thank you Mike for the more complex band plan. That helps. I’m still a little worried about interfering with nets,Maritime, ect.

[@chrissewell1608]

An active Net you will hear as you cruise the band width, or they will tell you to move on, as you are on there channel! Marine frequencies are already set up, just know what they are and avoid them. Just do some general research, in your area, before cruiseing the air waves! Ie. If you live in Montana, you won't hear much VHF Marine traffic!

[@battlestarone]

Use a halfwave tuned feeder,,,the analyser only input about 6mw to the antenna so the physical interaction will be low,,,but you can also calibrate analizers to take into account coax

[@robertmeyer4744]

with the DX commander antenna SWR. check all bands and if just one band check that element . start with the wire is crimp at fork terminal . did that come loose did you solder it after crimp . I would start at coax make Shure that good them make way threw the antenna. also check ground side as well. if that SO-239 comes loose on bottom plate will cause SWR jump. 73's

[@HamRadioWithKE0MAD]

Definitely agree with using the Icom bandplan.

[@W9HJBill]

Interesting that this video just came out. Ironically, W6LG Jim just did a video on the subject as to where to analyze things and how the type of coax can give a wrong SWR reading.

[@ShaneKA5GSS]

I thought the exact same thing Both make sense I guess

[@rafaelgcpp]

EE here. I'll try to explain it without equations.... If you had lossless transmission line (a perfect coaxial cable), then the SWR at each end would be the same, hence, the antenna analyzer could be a thousand miles away, and the SWR would be exactly the same as the one at the feedpoint of the antenna. If you are familiar with the Smith chart, the perfect coaxial would make a perfect circle on it, while the lossy spirals torward the center. As real coaxial cables have losses, the reflected power at the tx side of the cable is attenuated just as much as the transmitted power that gets to the feedpoint. Since you have less reflected power and more forward power at the TX end, the SWR not only seems lower, it IS lower! But that won't help you with tuning the antenna! On contrary, it might hinder you of doing a good match if you are not aware of that. It is not a lost cause, since as you close to 50ohm resistive, the SWR deviation gets smaller. Some antenna analyzers have a calibration feature, where you place a 50ohm load at the antenna end and it will compensate for the coaxial lenght and loss, pretty much as a VNA does. I consider that an excelent feature to have. If you don't have this feature, you might have to so some guesswork till you get closer to the 50 ohm impedance. BTW, that loss in the coaxial is the same reason you should try to place the ATU as closer to the feedpoint as possible!

[@randymclain4195]

The "sad hams" will let you know about the band plan.

[@hamradiotube]

lol!

[@stelluspereira]

ICOM products seems be expensive compared to Yeasu in similar capabilities(TranRecevers 50-100W ranges) to best of my knowledge If you were given a choice which will be your preference for a long term Perhaps can give why you prefer the one you choose

[@AlvinMcManus]

Roger that on the coax antenna connection (pun intended). Just for that reason I have my EFHW on 55 ft of RG8x.

[@BusDriverRFI]

We never rely on the coax to be a counterpoise. A counterpoise is just "the rest of the antenna".

[@ShaneKA5GSS]

Great video Thx for sharing 73

[@DellFargus]

Digressing from the video a lot here... You kind of went off on a quick tangent about EFHW counterpoises. I use them, because I was getting RFI sickness - after 20 minutes of FT8 (under 100W) on higher bands (10,12,15), I would feel like I just woke up after heavily drinking tequila until last call the night before. The counterpoise made the RFI go away - no more 10m FT8 hangovers.

[@hamradiotube]

interesting study. I'd be curious to learn more about this.

[@peterdekeles.]

I had to replace the so-239 on the antenna. The threads were not long enough to make a good connection. All is well now

[@jameski5oeb668]

I put a BNC on my DX Commander Classic. The center of the female UHF connector was broken by me at some point and I only had the female BNC to replace it. Works great now!

[@gartnl]

With an analyser what I want to measure is the performance of the antenna, not the SWR of the total system. Having a good SWR at your TX does not mean the antenna is working.

[@ShaneKA5GSS]

I use a tuner with my Dx commander so I can use all of 80 meters It is only resonate in a small window. Also some of the other bands the swr climbs on certain ends of the bands

[@hamradiotube]

Great point. Tuners sure do have their place, and they're especially good when you want to just work those frequencies that are not resonant on your antenna. Not gonna lie, I do it all the time.

[@Sonicgott]

As far as the 20 meter antenna getting 25:1, I’m thinking something is damaged. I’d inspect the entire element.

[@earlwithmore9065]

Antenna EF question. I had 10g stranded 160ft that I used on my Icom, Setup, Coax 20ft from icom 718 to icom ah4 tuner that is 15ft high, and under the eve. from the tuner, the 160ft / 10g stranded again from tuner at 15ft to a tree 90ft. Well, the line going through the pulley snaped after 3 years, so do it came. Now, I tried to send a new line over the tree, and even tried to hire someone to climb the tree but no go. So, instead of 90ft, its only 20 ft. now having 160ft 15ft to 20ft high. I feel this will kick me in the ass. Any thoughts?

[@Philip-KA4KOE]

Thats a personal question ... 😅

[@nekrorakas]

Would swr measure be lower at antenna connector of the radio because of reflected waves have been atennuated by the coax lenght?

[@hamradiotube]

Yes, Depending on the length of the coax, the type, and the frequency, SWR measurements could give a false indication of a good SWR due to losses. Particularly at higher frequencies.

[@BusDriverRFI]

It could show lower or higher. The coax will change the reading.

[@ab2679011]

I enjoy your videos. However, the music is distracting?

[@justawfulgamer7738]

Why is the dx window only available to amature exras 😢?

[@NgakpaW]

DX stations sometimes operate at the high end of the extra band so they can be heard (less QRM). They may “listen up” into the general band. You may hear CQ CQ DE CALL UP which means they are listening to a higher frequency, and don’t want to be called on their frequency

[@justawfulgamer7738]

@@NgakpaW I learned something new today. Thanks!

[@NgakpaW]

@@justawfulgamer7738 Glad to be of help. Looking at my answer, I had one thought. CQ CQ (their call) UP. Just to clarify. You learn to hear ..- .-. as one sound.

[@kylefreemason]

Sob didn’t answer my question 🙋‍♂️ haha

[@TheREALJosephTurner]

40-160 LSB, EXCEPT for 60 meters.