weird antenna matching proble.

[WA1GFZ]

HELP......I calculated my antenna matching with the handy calculator some fine perfson posted.
My 160 meter vee with 75 feet of 400 ohm line into the shack. ( I used 450 ohm in the program) at 1.9 MHz I got 162.6 Ohms +J613. I figured the network was wrong so changed the input to a coax Balun using RG393 and ripped out the 1:2 BB step up transformer.
Now the match is even worse. The only clue I have is in the old configuration I got close to a match if I cut the feed line shorter. I can cut a few more feet off but it appears I'm in one of those weird lenghts that doesn't want to match. The ant is 125 feet on a leg at 60 degree angle. The program says R and J drop if I cut the feeders shorter. I'm thinking of flipping the L networks around around since it looks like I'm really looking into a low z. It sucks not being able to measure the real deal....might have to invest in a mfj. Any suggestions. I can't get the antenna to work on 1885 but seems better higher. I also cant get a match on 75 either and would assume ant plus feedline is a low z. Everything worked fine when the feed line was 125 feet long. DA

[W2VW]

Assuming you have the balanced low pass deal. Have you tried exchanging the position of the tuning cap to the other side of the ganged coil pair?
If so and no workie then try a roller inductor opposite position of the tuning cap. Cap across feeders put roller inductor at balanced side of BalUn. Reverse them both if you don't get a match. With this setup you will be able to match cast iron patio furniture. My tuner at home uses a fixed copper coil across junction of BalUn output and each coil of the matched pair on 160. To go to 75 I unhook the extra coil and retune the cap across the feeders a little. The K3L tuner pictured on this site has the capability to use the extra roller inductor and that thing has been used to match some stuff which would not work with other tuners. It takes a long time to find a match with all these unknowns so an MFJ might be a good idea.

[WA1GFZ]

Dave,
I headed down to the shack ready to try both configurations then I remembered your extra inductor. This morning I noticed a couple twigs across the feeders and thought they may have been shorting across in last night's rain. Anyway the antenna tuned right up tonight and I was able to QSY to 1885 with no problems. I tuned up last night with a 10 dB pad at the RX input tuning for maximum noise. this usually gets me pretty close. Last night I heard the background noise jumping around like there was a short or open. This made me think about the twigs. I just raised the antenna last weekend and the feeders were in the tips of the branches.
It won't take much to QRO them out of the way. I do get a better match with the coax balun since the input z is low. I guess I could swap the network around but I will try 75 meters first. I used 1/2 inch Teflon RG393 so it will take a lot of power before it warms up. fc

[Tim WA1HnyLR]

Frank, I wrote out a detailed reply but hit a wrong key and lost 45 minutes of work I am pissed talk to me on the radio . It is more simple.Basic and does not blow away communication. I find this method of communicating  interesting but slow and very frustrating. Catch you on 75/80 M fone. Tim WA1HnyLR

[WA1GFZ]

Tim,
Hope to catch you on the air this week. Taking a large dose of ham radio this week.
The antenna problem was simple. A couple of wet twigs across the feeders shorting the line.
A bit of 160 meter QRO fixed the problem. I had a 1:2 step up BB transformer into the network and only needed 1:1. It works great now. the shorter feed line dropped the feed Z.
When I put the high dipole back up I may have to switch back to 1:2. cul