2 METER ANTENNA TUNER , ONE EVENING 2 METER TUNER PROJECT,

Checking out an Icom 746PRO on 2 meters using a copper J-pole antenna
on the tower I found the SWR of the J-pole was 3.5 to 1.0 quite high . We had high winds this winter and the J-pole was bent . Its to cold to do the repair now and I got the idea to make a quick little 2 meter antenna tuner
as a one evening project . The construction is shown in the video it is a standard PI network tuner both variable capacitors are grounded to the case the number 14 wire goes from one coax connector (SO239 ) directly to the stator of the first variable capacitor then continues as the 2 turn 5/8th inch coil connected directly to the stator of variable capacitor number 2 then directly to the second coax connector (SO239) very simple . The tuner coil is 2 turns of number 14 wire 5/8ths of an inch diameter I wound it on the smooth end of a 5/8ths inch drill bit and left 3 inches of #14 wire on each end to connect to the coax connectors . Anything that is close to that 5/8ths inch diameter should work winding the 2 turn coil part . It took 2 hours from start to finish to make and test it was an enjoyable project that works good and I will use here . Projects like this for me help with the Cabin fever we are experiencing here with that nasty virus going around . 73 Bob

[@soulrongang]

Thanks OM Bob...
I'm not climbing my tower til I feel more up to it, and this did the trick for me. I raided my junk box and put together one with what I had on hand. I needed to make the coil smaller, using my MFJ antenna analyzer to measure SWR. Right on! it does the job like you say it would. Big Up from 4X1MK.

[@Warndog9]

Cool stuff! Thanks

[@SKYHAWK0115]

Very nice project to create. So these were 50 Pico farad air capacitors ? Maybe other ones with more plates would also work. I have a tuner that has electronic circuitry. Yet if something as simple as this works, then that's a plus. Good video. It would be good if you could actually put a video together on a new project slowing the build in progress. Thanks Billy. Albq N.M. 2 / 15 / 2023

[@acestudioscouk-Ace-G0ACE]

Nicely done, thank-you.

[@happydog4929]

Thanks for the video.
could you draw up a little sketch of the tuner.
Is it a pi circuit?
Thanks

[@Cardassiaprime]

Hey there Robert, I’ll say that 2metre tuners are as rare as hens teeth, for the reasons you gave. Yours is the only other one I know of - I have one made by LAR ( Leeds Amateur Radio) a club in the North of England, they made a few and sold them in the 80’s. And they look the same as yours inside, though the caps are a tad smaller.
Bottom line though Robert is, if ya need one ya need one, great work thank for Sharing.
Barnie. 73 de M7PBX.

[@tomsworkshop5856]

Now this is something I want to build... I wonder if I'd be able to tune my HF random wire to 2 meter? Hmm....

[@jeromeGrzelak]

Yep built mine 4 70 cm tnx bob kg6mn

[@josephroblesjr.8944]

It’s is a cool project! I might try something like this
-ki5tlz

[@elmakednos]

Show us how it works with a swr meter.

[@edschaff6291]

Built one. I had some caps with 17 plates (your had 9) tried 3 different coils about 3/4 inch diameter and cant dip below 2.5 to 1 anywhere in the 2 meter band. Suggestions.. Ed W6AOA Pensacola

[@crazyham]

Maybe try it in a T match configuration and see how that goes.

[@bigguyprepper]

Is it a T match? Also curious about your inductor in the back of the tuner

[@modellerdesign]

Pi network

[@ronaldsmith4027]

100 mfd seems high is this correct?

[@guyt6329]

Agreed.seems too high by six orders of magnitude. I think he might mean 100 pF

[@SportsStream365]

Great video Bob, thanks. Where can I find some adjustable caps like that? What the proper name for them so I can try to search them ?

[@josephroblesjr.8944]

Air gap variable capacitors

[@SportsStream365]

@@josephroblesjr.8944 ok. Thank you. I can’t seem to find those anywhere

[@robertsumption1243]

They are standard 50 PF maximum capacity capacitors single hole mounting with 1/4 inch shaft . I recommend Ebay to find them or one of the internet radio suppliers who sell old time parts . I also look for such parts at hamfests or ask other hams at the local amateur radio club . Bob

[@johnsandoval347]

How often are two capacitors needed? With low voltage on an antenna that has come partially out of tune could you just use a T-Net one capacitor only?

[@palmtopman24]

I'm looking for 2M ATU that would get the SWR down when operating at 169MHz with a 144MHz antenna, would this ATU work? Thanks

[@crazyham]

It probably would work but you may lose a lot of power due to coax losses at a high swr even with the ATU at VHF. Would be ok to get you on the air but inefficient.

[@edschaff6291]

Also was PI configuration both caps grounded.

[@crazyham]

Both Caps would have shared the chassy ground.🙏

[@stephenpadley6684]

Is that the earth clip next to the connectors.

[@jeffsmythe3038]

could you draw up a little sketch of the tuner

[@jeromeGrzelak]

it is a pie network

[@JCCB11360]

How many turns for 11 meters? , thanks.

[@crazyham]

Trial and Error maybe or make a coil with multi taps so you can select how many turns and then it will be a broader range Tuner.

[@_rmb.official1494]

skema

[@herla84]

Simple itu, cuman pake konfigurasi Phi

[@noslidemais]

[@crazyham]

Nice Work Mate 🙏
I hope u managed to correct the antenna Problem
as you would get a lot of coaxial loss
at VHF with excess 3:1 swr
but that's a great solution in the meantime.
I haven't built a VHF ATU before.
Did you also try a T match config?
if so, did it also work just as well ?
Again, Nice Work & Thnx So Much for Sharing.
73 de VK3VKe 🙏