Portable Ham Radio Antenna Project - 20/40 Meter Linked Dipole for POTA

[@James_Bowie]

Rather than cut a few inches off for trimming -- and risk overdoing it -- just fold and twist the extra wire along each leg. This works fine as long as the folded back length isn't excessive.

[@1crazynordlander]

So if you connect only one side and leave the other open do you have an off center fed dipole for 30 meters? Full watch and like!

[@hamradiotube]

I just bought that same .88 cent cutting board from Walmart the other day to make some guy rings for my portable mast! What a coincidence.

[@SevenFortyOne]

If all of us ham radio guys keep buying them Walmart is going to raise the price on us! I look forward to seeing what you do with yours.

[@cqarizona4461]

Enjoyed this video Rob..Heard our contact at 9:38 in video. Appreciate the link for the wire. Antennas are great to build and field test. Good luck with POTA..de W7TY Scott in Idaho.

[@rs4425]

This video inspires me. Success!

[@davidsradioroom9678]

Great antenna for POTA and EmComm. I like your instructions on it. They were very clear and concise. Great job!

[@JnJTrueOutdoorAdventures]

Great video Rob!! I was working on an antenna today (August 25, 2019) when I worked your POTA activation of K-3101. I made a 9:1 Unun and had a 35.5 foot radiator up about 20 feet as a sloper, and I had a 13 foot ground radial. I was using a Yaesu FT-817ND and 5 watts. I am getting ready to start POTA activations here in WV. I have found several parks here in WV that are on the list but have never been activated. Hope to work you again. My KZbin channel is more about hunting in WV, but I have reloading, leather work, knife making, drone flying and ham radio videos. Built a couple kits, a QRP-Labs QCX40 and a uBitx and a Bitx40. Again thanks for the contact. Juddie WD8WV

[@SevenFortyOne]

I'll check it out when I get home to CT...lousy cell service here in the VT mountains. 73 and thanks for the contact!

[@twwtb]

I noticed that your painter pole is upside-down. Was it necessary to keep the metel part away from the antenna elements?

[@SevenFortyOne]

No, I just oriented it that way so I could use the hole in the Handel to mount the antenna insulator to it.

[@kylearea2227]

Iowa license plate at the start of the video and Mass at the end? Thanks - great video!

[@matthewshank73]

Found your video for 40/20 linked dipole. Just finished making a QRPGUYS 1:1 balun and will use that as center point. Building a linked dipole for POTA activations 20 gauge wire & banana plugs for the link connectors. I seen Pack Antenna loop back or element wire with a carabiner clip to take the stress. Will have to experiment on that. Just subscribed to your channel. Did the SWR change when hanging higher?

[@SevenFortyOne]

Sounds like good projects! The swr did improve a bit when the antenna is put higher.

[@normandavis6569]

WB4BKO Ned Davis I have two questions: 1. did you prestretch the zip cord before building the antenna. Being soft drawn copper the wire tends to lengthen over time. 2. I observed you did not use a balun or coax wound around a piece of PVC pipe, which can also act as the center insulator. Anyway, being out in the parks or summits, you aren't going to interfere with anyone's electrical devices. I'm surprised you were able to work in to Europe and Caribbean with an antenna which for all intensive purposes is NVIS. But you were in the right place at the right time

[@SevenFortyOne]

1 - No...this is a temporary install so if the wire stretches, the next time the antenna is installed it can be tension-ed accordingly. I suppose over time that may affect SWR a little, but again, since this is a portable antenna I wouldn't worry too much about it or trim if needed. 2-Again, since this is a temporary antenna a balun isn't strictly necessary although this point could be argued. Since I wasn't having any problems tuning the antenna or getting RF coupling onto the feed line I decided not to use one.

[@miker1473]

I think what George meant was, why not use power-pole connections on the 20/40 link, in the antenna element. I thought the same, by the way. N4ZN

[@SevenFortyOne]

I'm not a huge fan of power poles so I don't tend to use them unless I have to. I don't have anything against them really, I just tend not to use them unless there is a need to. In this application, the 1/4 -20 hardware seems to do just fine.

[@K2CTC]

I really liked this video. I've been wondering how to make a multi-band 40/20/10 and this gave me some ideas. I'm going to put it up 35-50 feet so not sure about switching to different bands this way. Well done.

[@322doug]

Ok subscribed, just come home after 20 years in the US military, great video, but wow bro BUY AMERICAN! Im planning on spending the bulk of my retirement years trveling the US and doing POTA. GOD bless the USA. and 73s NS9T!

[@georgeroberts3849]

The only question I have is why didn’t you use something like a Anderson power pole or a Banana plug for a easier connection? But I certainly did enjoy your video. 73 George

[@SevenFortyOne]

I have power poles on the power cord in the motorcycle. I'd have to watch this back to see what you are talking about I guess. The radio had ring terminals on the power cord but I switched them to power poles...but maybe I did that after shooting this. I had just gotten the radio a day or so before shooting this video.

[@georgeroberts3849]

The power poles or the banana plugs for the antenna jumper connection?

[@SevenFortyOne]

@@georgeroberts3849 Oh i understand now. I have the coax "pigtail" connected to the center insulator - it is about 6" long with a PL-259 on the other end. I use a barrel connector to connect from that to the main coax run. I can disconnect the coax and the pigtail stays with the antenna so it's pretty quick and easy to disconnect that way. I show it better in the video I made on the prototype version of this antenna.

[@sirhaugen1025]

Question... Why didnt you just tune the antenna for 20m first, then link it and tune for 40m? :) Thats the way I did it and it was way easier, and quicker... Other than that, great video :) 73 LB6CI

[@SevenFortyOne]

This antenna actually started out as something else and turned into a linked dipole otherwise I would have built it from shortest to longest as you suggested

[@1958johndeere620]

I heard the islands on the air, but did not get a chance to work any. I built a 20 meter speaker wire inverted V and I have the wolf river coil with a 102 and 213 inch whips for portable work. ( of which I have not had the chance to do ) . Somehow work keeps getting in the way. LOL! Hope to work portable soon.

[@SevenFortyOne]

Same here....work is always getting in the way of playing radio an other fun things. If you do get out with the wolf river antenna let me know what you think about it and how it works for you. They look like nice units, I may pick one up at some point.

[@1958johndeere620]

@@SevenFortyOne I have had the WRC in the yard twice just messing with it. Did some DX one time, then the other no luck. Crap conditions. The inverted v worked great when I threw it in a tree like it would be deployed in the field. I think both will be winners. I have worked K8MRD while he was POTA with his WRC.

[@brianfields4479]

very nice video, and your ant works very well indeed, well done.

[@SevenFortyOne]

Thanks! Glad you enjoyed this

[@appalachianoutdoors5355]

Curious if you could put a link or description of the wire off amazon. Thanks for the Video. KE8GDD

[@SevenFortyOne]

There is a link in the description already...but I'm going to warn you that I've had problems with it breaking. I just got done switching it out for 14ga wire from home Depot. It's really only good for light duty work.

[@appalachianoutdoors5355]

@@SevenFortyOne Thanks for the warning and sorry i forgot to click show more in the description. I will be purchasing some wire for POTA and general portable operations when I am camping.So I am trying to find a decent wire that will pack away well and be good quality. Thanks again for the response. hope to work you down the log. KE8GDD

[@TI2GBB]

Hi Rob @SevenFortyOne , I hope you're well, so just to see if I understood, basically you need to calculate the leght of the dipole first using the formula, then you divide the leght to get the elements of the dipole, my question is, if I want to use it in 10 -20 -40m I need first start to calculate 10m then I can move to calculate 20m and ( question #2) when I'm calculating the 20m I need to add more cable or subtract the cable of the end point of the10m measure to adjust the measure of a full dipole calculated to 20m ( imagining that the 20m dipole is already linked) Let me know if I'm correct, I want to try this antenna on the bands mentioned here in Costa Rica. Thanks at lot! 73s

[@SevenFortyOne]

I'm working on a new video where I built a 6 band version of this antenna and explain how I did the construction. Its going to be a few weeks before I post it though. To answer your questions: Answer 1 is Yes - start with the highest frequency (shortest antenna legs) and work toward the lower frequencies. Answer 2: subtract the length of wire from the 10 meter section and add the difference to the end to make the 20 meter dipole. I went to Costa Rica in 2009 and found it to be a very beautiful country. I'm hoping to go back again someday. 73!

[@TI2GBB]

​@@SevenFortyOne ​ Thanks for the response Rob! I can't wait to see that video! Thanks to share another good explanation soon, I did google research about this linked antenna ( there is not much information on the web btw) I found this link www.sotamaps.org/extras they have a antenna calculator, I think it will nice to check it if the measures are correct. pD: Glad to know that you visited my country, I hope you can return someday soon! I can prepare some tours and why not? We can make Radio in a mountain/beach/National Park! Take care and stay safe! PURA VIDA!

[@normjacques6853]

Wow! Nice bunch of contacts! Your latest video got me curious about POTA, so I began checking out your videos on the subject....then came across this one. The antenna sure seems to get the job done. Do you find any difference in performance using different wire gauges? Also, do you find that a balun helps (or perhaps even harms!)? Does an impedance mismatch (on a dipole) make achieving decent SWR more difficult? Thanks, and 73! :-)

[@SevenFortyOne]

Fatter wire only helps insomuch as it makes the antenna slightly more broad-banded. Otherwise, there isn't much difference electrically. The thicker wire is mechanically stronger but harder to wind up for storage. There are arguments on both sides of the balun fence. I've run antennas with and without them and noticed no performance difference. Having said that, a balun is good in situations where you need to prevent RF from getting on to the feed line or you need to match and impedance.

[@buzzsah]

I run the 891 w/ fc50 in my van. Nice job on the wire.

[@SevenFortyOne]

Thanks Buzz - I've wanted an 891 ever since seeing yours and finally bought one from a local ham...its a fun little radio.

[@dr4710]

What’s 741 reference?

[@SevenFortyOne]

Is a tribute to my late father

[@dr4710]

@@SevenFortyOne very cool....thanks!

[@hamrad88]

Thumbs up and thanks for sharing.

[@leemonaco5377]

Thanks!

[@abelgarcia1190]

Why do you own like 50 cars with tags from all 48 states? Lol

[@SevenFortyOne]

I like to keep people guessing

[@abelgarcia1190]

@@SevenFortyOne you know I follow you because of how soft spoken and well explained your videos are im a truck driver myself I own 3 cbs and one handheld cb radio been wanting to install one in my car and my room