Sounds like you have a bad connection somewhere in the antenna or coax
to the antenna. Probably some oxidation. Your amp is putting out
enough voltage to clear the oxidation and "weld" a connection, much the
same kind of thing you see happen with Christmas lights. Same thing will
happen with open frame relays used for antenna switching. After you make
a good connection using the amp, it is OK for a while until the
oxidation builds up again, and everything starts over.
Jerry, K4SAV
Steve Lawrence wrote:
>TH7 Puzzle:
>
>I have an FT1000D driving a legal limit amp to a TH7DX. The FT1KD
>tuner is left off when driving the amp. Occasionally, the FT's Hi SWR
>light will flicker or stay on but only when the amp is off line. The
>FT's power setting can be anywhere from the 3 watt minimum to full.
>This happens only on 20m, not 15m or 10m and not all of the time. If
>I put the amp on, the antenna takes the full legal limit without any
>problems. Immediately after that, if I put the amp on standby, the
>rig's Hi SWR light no longer reacts and there is no indication of
>reflected power.
>
>I can make the light go out when I have the Hi SWR indication and the
>amp is off line by switching the FT's tuner in but I'll still see the
>same reflected power as if the Hi SWR light is on.
>
>I have connected the FT directly to a dummy load and the Hi SWR light
>remains off. Connecting the TH7 directly - no switches, power meters,
>coax elbows, no amp in standby - and the light comes on. This is
>repeatable. Unless I run the amp and then everything is normal until
>some time passes - hours, days or not for some time.
>
>Best guess is that there something going on with the TH7. Loose
>hardware? Critters in traps? But why only 20m and why would high
>power clear it but not blow it out.
>
>Experiences and thoughts appreciated.
>
>73 - Steve WB6RSE
>_______________________________________________
>
>See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
>Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
>questions and ask for Sherman, W2FLA.
>
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>
>
>
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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