Making dual band (2m/70cm) antenna elements from welding rod
Вставка
- Опубліковано 16 бер 2017
- I show how to use stainless steel TIG welding rods (can be done with other materials as well) to make antenna elements for home built 2m / 70cm antennae such as the ones in my videos (three versions available so far).
The lengths, measured from the outside of the bottom bend, are:
6 1/4" for the 70cm side
18 5/8" for the 2m side - Наука та технологія
Greetings from Sweden 🇸🇪
Great channel!
You just got yourself a new subscriber 🤖
Well thank you, please tell your friends. And listen for me during major SSB contests
Thank you for the videos,,, I will build this antenna, and I will test it.
Sounds good. Be sure to let us know how it goes.
It works great....
@@andymattson That's good to hear. Be sure to show all your HAM friends and send them to this channel.
Have you Been able to make any contacts with this antenna? Please share your experience
I've used it for repeaters and simplex. I have one at 12.5 feet high and can make the repeater 30 miles away (straight line) with 2 watts on a Baofeng. The 4 watt setting is better audio but 2 will do it.
I also have one for my RV. At 15 feet above ground I was able to make it 102 straight line miles from the central valley of Calif into a mountain repeater in Dunsmuir.....using 50 watts.
It works quite well. There is a slight null in it that I occasionally find but it's mostly omni directional.
Just for clarification purposes. Those are not two antennas (the 2m long, and 70cm short). The parallel part of the antenna is actually a open wire matching stub. The antenna does not radiate there, it is effectively a feedline. Both bands radiate from the long single section rising above the matching stub. It just so happens that 70cm is 3X the fo of 2m, so it is resonant there too. Just a little antenna theory from KQ6UP
I've wondered about this myself. It seems to me that it could be either way with the 70cm RF departing from whichever is THE MOST RESONANT. The most resonant element will result in the RF radiating from that point wouldn't it? It doesn't radiate all along a traditional HF dipole for instance. It radiates at the point of resonance.
So on these antennae elements, if the long piece is off a bit and the short piece is perfectly cut, wouldn't signal resonate from the shorter one?
Could you use a zip tie to align them to be horizontal and stay in place with some “spring” resistance?
I'm not sure what you're suggesting. I use these elements in vertical dipole configuration and there is no need for anything to hold them apart other than the two elements of the dipole being electrically insulated
I guess I was thinking to get them vertical you could click down the zip ties until they were vertical and the resistance of the opposing horizontal pieces would be applying outward pressure to hold them parallel. Versus trying to get them perfectly aligned and they could move and get out of alignment. Just a thought.
@@neeko7878 I've been running these antennae for several years and never had a problem. The first one I built (the one with the un needed choke) sits in one of the boxes of my utility bed truck with mast sections, coax, etc. and has been knocking around in there for a year and a half without any issues.
So we are crossing threads here sorry, I’m not referring to the durability... in the beginning of your videos... you were saying that it takes awhile and some finagling to get the two horizontals parallel to each other. Couldn’t you just add the approximate bend curvature to the welding rod but leave them in a slight “V” to one another and slide over a couple of zip ties to “click them” down until the two rods are parallel to one another. You would achieve the same thing you did however... there would then also be slight spring tension against the zip ties to keep them parallel and not wobble around once mounted. I love your antenna, just curious if that would be a good way to keep them always parallel to one another. The other thought was to add a spacer of the correct size between the two rods and zip tie those in between to keep the spacing. Just thoughts I had while watching and I was curious of your thoughts about my ideas.
I wonder which welding rod type are most corrosion resistant ? I heard 316 stainless steel rod is most corrosion resistant. I am thinking of making simple vertical antenna for 144MHz AG6JU
316 stainless is good
Hi, could you please tell the exact length's of shorter and longer rod of the antenna measuring from the bottom of the U bend (so including the diameter of the rod). I assume it will be close to 49cm and 16 cm.
On some other diy antenna video someone told that in practice the length should be circa 6-7% longer than calculated for given frequency and recommended 53 cm and 17.5 - however he was talking about pig tails most of the time so I am not sure if what he said is true only for pig tails or in general for all the antennas.
Anyway yours is nicely measured and I trust SWR chart more than this pig tail guy.
Thanks for your question. I didn't realize I hadn't put the actual measurements in any of the videos except the review of the first build. They'll be added in the comments section.
The lengths, measured from the outside of the bottom bend, are:
6 1/4" for the 70cm side
18 5/8" for the 2m side
KG7TUO
@@kg7tuo999 What are those size's in CM?
@@damianverhoeks3544 I have no idea but a simple google search will provide any number of conversion calculators. Or you can download a conversion app on your Android or Apple phone
Greetings, I have a question. You said that you tested the elements, how?
I put them on the antenna being built and use an antenna analyzer. You could also use and swr meter but an analyzer is quicker and easier.
diameter of TIG = ? mm (2,4 or 3,2)
1/8 inch. There are converters online as well as phone apps. It's not super critical at VHF/UHF frequencies. Just get close.
TABA VIVA LA ALAMBRRE