[TowerTalk] TH7 puzzle

[Steve Lawrence]

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