Ham Radio Basics--Dipole Antenna Center Insulator

Jim, W6LG shows the PVC plumbing parts, coax connector and screw eyes to make a dipole center insulator.

[@rcbrush99]

Jim, You make me want to explore amateur radio deeper every time I watch your videos. Thanks so much for taking the time to share. 73s, Bob

[@ham-radio]

Wow, thank you! Have fun doing exactly that; exploring. 73, Jim W6LG

[@peschpit]

Thank you Jim for all the hard work you put in making all these videos! They are always informative.

[@wrxs1781]

Well done Jim, I enjoyed your video which gave me some fresh ideas.

[@doctypo]

Thank you for that easy to remember calculation trick.

[@MichaeLDeBiaseSF]

Definitely going to try this Jim eventually when u get a chance for qrp or portable use and i will let you know and film it. Thanks 73s

[@chuckkb8yit859]

Great video Jim, made one a few years ago they work great.

[@ham-radio]

Good to know Chuck. Thanks. 73, Jim W6LG

[@alphasxsignal]

Fan dipoles are great to make for all the bands off one coax. I have used them for many years.

[@billvia3137]

An dipoles are great. Relatively omnidirectional.

[@billvia3137]

Inverted V dipoles in a fan configuration is what I meant. (It’s late in the day) 😁 love your videos. In Utah now but lived in east Sac years ago.

[@billvia3137]

K7VIA

[@GroundControl204]

I have a solid aluminum constructed dipole, made by sirio. Sirio SD27 dipole on the flat side and I love it. great vid by the way. 73's

[@ham-radio]

Nice! 73, Jim W6LG

[@glennstevenson6242]

Thanks mate, great advice as usual. Regards Glenn form VK

[@ham-radio]

Thanks Glenn. 73 from 39N! W6LG

[@Winstonsdad1956]

I would love to see a close up of how you soldered the wires to the inside 239 connector.

[@NX8T-JIM]

great video Jim. I use 3 different dipole antennas a 20, 17, and 40. I can also use my 40 meter wire on 15 meter. they all work great for dx. Not sure if everyone knows about the 3rd and fifth harmonics. ..tnx again Jim Jim...KB8YBG

[@ham-radio]

Excellent! You are correct. I should have mentioned that. Those odd harmonics are helpful to getting an extra band with no effort. Like well all did as Novices using a 40 meter dipole on 15 meters. Thanks Jim. 73, W6LG

[@DonDegidio]

Jim, Another fine video. Only addition I would make is to use some liquid tape to seal the copper braid and solder connection after soldering the radiating elements. 73 WB3BJU

[@ham-radio]

Good point. Braid is good at sucking up water. Thanks Don! 73, Jim W6LG

[@bmmrrr]

as usual...a great straight logical make...

[@HamRadioAdventures]

1,2,3,4 I love it!

[@BEdmonson85]

I learn something new every time I watch one of your videos! I don't know why I haven't subscribed before now, just always notice your new uploads and never thought about it. It's about time I hit that button. :) There's no way I could possibly forget how to calculate the length of a dipole now, such an easy way to remember! Thanks, Jim. 73, -Brian KM4MLS P.S. How's it coming with your PE? You're absolutely right about needing to get up and move around. I had a similar problem about 2 years ago. (Dec'14 - Jan'15) I was hospitalized with a MRSA infection and pneumonia. It had progressed without treatment (thought I just had the flu) for so long I became septic (blood poisoning). Had to be intubated and put into a medically induced coma for 3 weeks. Because I was laying there asleep for so long I developed a pulmonary embolism. That kept me in the hospital an extra 2 weeks before they let me go and I was on blood thinners for 6 months afterwards. I hope things are getting better with you. Take care.

[@ham-radio]

Oh my! I had a friend die recently from septic (septus?). He did not have MRSA. Last week I fired my doctor and got a new one about an hours drive. There are few doctors here in the foothills that are taking new patients. So, I have a concierge doctor. So far he has been great. I am at 6 months and maybe, just beginning to feel stronger. It has been a long recovery. I am still on the blood thinning, expensive medication. Part of my lethargy may be from another drug that my previous doctor prescribed at 50% over the max recommended. It is for Parkinson's that I don't have. What I do have is RLS that is pretty bad without the meds. The new doctor is going to change to another med. Hopefully, I can turn the corner. I am trying to walk everyday. The weather has been a problem. My jaw dropped when I read your message. You have an amazing story of survival from MRSA, septus and PE. Any one of those is enough but to have all three! Thanks for sharing. 73, Jim W6LG

[@BEdmonson85]

Yeah it was a pretty scary experience. I spent all of that December in a quarantined hospital room unable to really interact with my family during the holidays. All the hospital staff were on edge because this was during the same time frame as everyone was freaking out about the Ebola virus. Sepsis is the term you were looking for. Septic is the adjective. Basically the doctors described it to me as when an infection local to a specific part of the body spreads into the blood stream and starts attacking your whole body (including major organs). I made it through ok. I later found out that the most likely place I picked up the infection in the first place was about two weeks earlier I had visited my grandfather who has Alzheimer's in the hospital; it most likely came from a door handle or hand rail. Moral of the story? Always wash your hands very well with a good anti-bacterial soap after any visit to a hospital even if you're just visiting. And if you're admitted, be sure the person/people charged with cleaning your room does it thoroughly and properly. MRSA kills, and older folks are especially susceptible. I'm sorry this has gotten so long. I hope your new doctor works out for you. Keep yourself educated. Oh and about expensive meds, it never hurts to ask if your doc has some samples available to help curb some of the cost. The answer may be "no", but it never hurts to ask. I was really lucky to have a doctor that I believe really cares and knows his stuff. The blood thinners they had me on never costed me a penny because they were all sample packs. Have a great day, Jim. 73, -Brian KM4MLS

[@dheller777]

I have a 4 band end fed antenna. It seems to be very noisy with the noise level! running 5-7 on my S meter all the time. Is this type of dipole as noisy as end feds seem to be?

[@roxannkosmicki6259]

Hi Jim! KZ0IMO here. I am super new to the HAM world! Love you videos. In particular I like this design. Being new I am only on 2m currently. In the video you said that you were going to wrap the wire around the eye hooks and solder on. Will you the attach something to those or is that all you need to do?

[@nickjaxe]

Hi Jim...everybody tells me I need a Balun when I construct my half wave dipole fed with 50 ohm coax....you mention fitting ferite beads...is this just as good as a commercial Balun....if so could you tell me me more about the correct type of beads....sound a lot less expensive than a commercial unit. Nick.

[@Laborkei]

Hello Jim... Still using my High Sierra Antennas. de K4KAL

[@briancallam2279]

Hi Jim, Would there be an adverse effects of soldering the two braid wires to the eye hooks on the inside of the insulator housing rather than running then outside, wrapping them around your antenna wire, and then soldering them? From thinking about it, my only concern would be that the signal wouldn't conduct through the eyehook very well for some reason. 73, Brian KE4CLY

[@ham-radio]

The signal will go through the eye with absolutely no loss. The metal is way too short to amount to anything. Your idea is good and I did do that with 3 of the devices. It was just harder to build. Thanks Brian. 73, Jim

[@seanyunt]

thanks Jim. what benefits would use a 4:1 current balun have - assuming the dipole is cut to resonant frequency where you plan to operate? aside from the wound toroid, you almost built all the balun hardware

[@ham-radio]

It would depend on the impedance of the antenna and the feedline; as you know. So, if you used ladder line and transformed to some lower impedance for the dipole, you would not have the usual line losses. Those feedline losses can be huge. So, a balun (balanced to unbalanced) can increase you signal strength when it is done correctly. The impedance of the dipole will vary with its length and height. 73, Jim

[@alanhughes1262]

Great video Jim, i was thinking to use stainless steel cable instead of copper as i can get it straight , dont know if stainless works ok as a conductor.

[@ham-radio]

I did that and it worked fine. I think the length was shorted by about 10% because of the resistance. The antenna had a relatively low SWR as you might think. Build it and have fun! 73, Jim W6LG

[@bushmaster777]

Hello Jim. I am VU3EQF from India. I am new to this hobby although i have handled HF sets in the Navy. I watch your videos regularly. I have heard two different reasons for using a balun with a dipole. The first one says it is for mitigating the common mode currents. The second version says that its needed to balance the antenna and induce current in the pole connected to the shield as in a coax it is grounded and without a balun the limb will just act like a ground with no flow of current. can you elaborate on this here or through a video perhaps.

[@Captainhairyass]

Hi Jim, how does this apply for a dipole used for television viewing?

[@HewesNews]

How much power can you put through this type of center insulator?

[@paulshaffer9674]

Use the screw on the flange of the SO 239 for the negative side of the dipole. It is easier to connect to.

[@ham-radio]

rrr Thank you and 73, Jim W6LG

[@darrellcollins877]

Hey Jim, I made a 2 meter dipole not long ago to practice before I made a larger version. I could not get the swr low enough to use it. I then researched more about dipoles on the internet and most everything led to a dipole is said to be a balanced load and coax you feed it with is unbalanced, therefore a 4:1 balun must be installed. The information on making a 4:1 balun is so varied its hard to know which way is right, my dipole projects were put on hold. I will trust in your experience over internet info, so you use a dipole in this manner without the use of a balun and can get good swr ? Can you show that on a video ? Thanks

[@AndrejaKostic]

+1 for the idea! I too started with 2 m (balunless) dipoles and then moved on to 70 cm dipoles and quad loops. While I could tune my dipoles, I found them to be very susceptible to things in the near field of the antenna as well as things close to the coaxial cable. The latter made me believe that there's current on the cable and that balun could be needed or at least helpful. When I started researching, just like you did, I found tons of info claiming both that a balun is needed and that at the same time, a balun is not needed. This, perhaps a bit tricky, subject could definitely fit in the "Ham Radio Basics" title. Let's just hope that Jim does VHF too! 73 de YU1NKA/DM1NKA

[@ham-radio]

Hi, You are right. Maybe we should not call it a balun at all. Maybe it is just an RF choke for common mode currents on the shield of the coax. So, you choke the shield with beads. It is still an unbalance feedline connected to a balanced antenna (a dipole). Or, you can coil some coax to form an RF choke. I believe it is better to have some kind of choke since the feedline is coax. How does that sound to you? 73, Jim

[@darrellcollins877]

i tried that and it did not change the swr, mind you I have not tried it with a larger antenna than a 2 meter. From what ive learned, a RF choke is to keep rf out of the shack. A balun is a current or voltage transformer that matches a mismatched system, coax being 50 ohm, and i thought ive read a dipole is 200 ohms in the middle. But im unsure of it all due to so much conflicting information. Was wondering what you experiences were. Apparently you have not had to use a 4:1 balun to match a dipole to coax.

[@jamesk0ua]

Harley, you would NOT want a 4 to 1 Balun for a center fed dipole, Its impedence would be close to 72 ohms or so depending on height and ground factors, but NOT 200 ohms. You would want a 1 to 1 balun. On an OCFD or Off Center Fed Dipole if fed at the 1/3 point it will be closer to 200 ohms and a 4 to 1 balun would be called for. Again this will depend on height and ground factors. . I hope this helped. James K0UA

[@beekeeper8474]

So a$hole destroyed my fan dipole and mast. I temporarily deployed in my front yard as I was putting together my ham room and was waiting on the coax to run to the backyard. Now I got to start all over

[@gama45]

Another great video Jim! I assume this would be a 1:1 balun? 73, Gary W6FH

[@DonDegidio]

Gary, Not a balun, just a dipole center insulator. WB3BJU

[@gama45]

Thanks Donald.

[@ham-radio]

Hi Gary! Thanks Don! You can clip ferrite beads onto the coax as a common mode choke. This is a real simple solution. 73, Jim W6LG

[@davelucht2895]

Question, where did you solder to the S0-239,? One to the center and one to the ground?

[@josephboyd5440]

Dave Lucht from looking at other diy dipole center insulators one wire is to the center pin and one to the ground. 73 De Joseph VO1BYD

[@NX8T-JIM]

quick question Jim. I am ready to purchase my new yagi and just want to know why you don't run a triband beam. I understand you love 20 meter but do you not have any interest in 15 or 17? I value your opinion, thanks for your input. KB8YBG JIM

[@ham-radio]

Hi, I am at a different part of the experience. I am experimenting on 20 meters with 2 yagis in phase. For you, some kind of multiband beam makes sense. It may be 5 years before 10 meters is good again. So get that antenna and have lots of fun learning about propagation. 73, Jim W6LG

[@philthompson3499]

Thanks Jim.

[@ham-radio]

Thanks Phil. I hope to see you soon. 73, Jim

[@a.v.stechs9398]

Dear sir I understand but I have question Is wattage value for dipole antenna For example I have 500watt amp for 20 meter band So how could I select wire Mostly video uses 18awg wire Will it enough for 500watt amp

[@ali.salsuwaidi6072]

Thanks :).

[@ham-radio]

Thank you Ali! I hope to hear you on 20 meters. 73, Jim W6LG

[@624radicalham]

Jesus I noticed that the antenna tuner in the background is larger than his torso, and that the Icom is enormous. Instantly wanted to know the model numbers to have this impressive looking equipment, then I realized its all a disproportionate green screen

[@ham-radio]

Hi, The large antenna tuner was very big. The NyeViking is about 15 x 7 inches. The Dake amps are 8 inches tall. I am not sure what Icom you are seeing. 73, Jim W6LG

[@624radicalham]

@@ham-radio My goodness I thought it was a green screen and that in fact you weren't standing in your shack. Something about the depth perception made everything behind you seem unnatural! Merry Christmas this 2018 and thank you for your amazing videos which have helped me on HF more than you can imagine.

[@billyogilisbie5865]

what about 11 meters up down to 26.0000

[@johnlew5972]

Saw all the parts but not how to make it????

[@polishpicl]

Please go one more step and show hooking up the end wires to the pig tails you already showed..need to see yours please..Ron K3RJW. 73

[@jaybats7865]

This is obviously for ham experts because we could not see up close any of the elements

[@bobahlberg6360]

good job that's how I do it.thanks for sharing bob/k0taz

[@ham-radio]

Thanks Bob. I had a few failures along the way. Using braid made things a lot simpler. Thanks again! 73, Jim

[@bobahlberg6360]

I agree braid is the only way to go 73bob/k0taz

[@TheJkilla11]

I F********** love you JIM!, j/k your pretty cool tho!

[@ham-radio]

thanks Justin! 73, Jim

[@tomw5vlt119]

Sorry, Jim. This says basics, but you lost me right from the beginning with a ton of jargon not explained. Like your videos, you’re a pro... but this is one of many where I was quickly left behind, on a video saying “basics”. Antennas are a real weak spot for this new operator, and I’m really looking for (unsuccessfully) a video that walks through an antenna build like a dipole from the beginning with no stone left unturned with respect to basics, jargon explained ... everything explained. Not sure why it’s so hard to find.