Difficulties on 1 antenna
David O. Hachadorian
Sun, 22 Dec 1996 04:36:52 PST
On Sat, 21 Dec 1996 23:09:05 +0000 "Bill McFadden"
>This is going to sound really strange but I don't know where to go
>from here so I thought I would send it out on the reflector and see
>what other ideas may come up.
>I am having difficulty getting TRLOG to send CW on my 40M antenna. I
>have made up the box for the parallel port in the manual. It works
>fine on all other bands/antennas but my 40M half square.
>If I turn the power down to under 25 watts then the code goes out
>fine. With anything over 25 watts approx all I get is a steady mark
>(tone). If I use a different antenna and use my internal tuner on 7
>mhz the cw goes out fine.
>The SWR is fine on the half square and works fine with under 25
>The CW goes out fine on all other bands. The only thing that it could
>be is the antenna or the switch box (currently using a Ameritron 4
>positon remote coax switch.
>Any crazy ideas? I know I would believe it unless I saw it and
>believe me I am seeing it.
Sounds like rf getting into the lpt port on the keying line.
Try rf chokes on both ends of the keying line. Try disconnecting
all the other antennas except the half square. Sometimes the
rf comes down the outside of the shield on an unused antenna and
gets into the shack. Try different grounding schemes.
You mention that you have "made up the box." I generally build
these little circuits inside the metal shell of the 9 or 25 pin
connector. Maybe if you do that, the lead lengths will be smaller
and it will work better.
I have found that serial ports are generally less sensitive to rf
than parallel ports, so you may want to try that option if all else
fails. Good luck.