[TowerTalk] HELP - Hy-Gain TH-3JRS

[Gary Mayfield]

We had a much better day today. We removed the hairpin, and the choke and fed the antenna with split coax and got the same results as before. --- Has to be a trap...

The traps all measure as dead shorts at DC (expected), but while measuring one of the traps with an ohmmeter a sweep of the antenna shows dips (off frequency) in the SWR (not just flat bad).

We took that trap apart and it looked great, but we did get two tiny drops of dirty water. It was damp, but not wet. We cleaned it and put it back together and presto - three nice dips, pretty much on frequency.

We reconnected the hairpin and the in band SWR went from around 3 to 1 in each band to around 1.2 to 1 on each band (hey it really does help match the antenna).  We added the choke and it didn't have any SWR impact, but we are quite pleased and Rich's new antenna is on the air. The lift can be returned in the morning. If you hear Rich ke0epy (originally wn0vzp) on the air - say howdy!

Thanks to all the folks who provided input. This reflector is a great sounding board!

73,
Joe n0sd

-----Original Message-----
From: TowerTalk <towertalk-bounces at contesting.com> On Behalf Of Gary Mayfield
Sent: Saturday, May 17, 2025 8:04 PM
To: 'towertalk at contesting.com' <towertalk at contesting.com>
Subject: [TowerTalk] HELP - Hy-Gain TH-3JRS

Hello - We had a frustrating afternoon today trying to put up a Hy-Gain TH-3JRS at the QTH of Rich, KE0EPY.

The antenna is previously owned, and we replaced the broken aluminum matching wire (beta match) with one made of copper. We have also added a balun made from type 31 ferrite material. Other than that, the antenna seems to be all original. A few days ago, we tested the antenna on top of an 8-foot fiberglass ladder, and it had three nice SWR dips right where you would expect for 20, 15 and 10 meters. Today before taking the antenna up the tower, we checked it all again, by pointing it lifting it a couple feet and pointing it straight up. Again, we saw 3 nice dips where they were expected.

Once we mounted it on the tower the SWR went very high and only showed one small dip just below 15 meters at 20.8 MHz. Thinking the coax had been damaged we took a small jumper up in the lift and connected directly to the balun but got the same results. Then we bypassed the balun - same results. We removed the beta match and connected straight to the driven element and got the same results. With the beta match removed the two sides of the driven element are not shorted to each other or the boom.

We have the lift for another day. Any ideas/thought/suggestions will be greatly appreciated!!

Thanks, and 73,
Joe - n0sd
_______________________________________________



_______________________________________________
TowerTalk mailing list
TowerTalk at contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk