In article ,
Cecil Moore wrote:

dansawyeror wrote:
I am trying to install a trapped 40m dipole in the attic, the antenna is
in place however it is short and resonates at about 7.7 MHz. I decided
to try it by using a tuner close to the transmitter in the shack. The
feedline is 50 ohm coax. On low power the tuner creates a very low SWR.
The transmitter is a solid state 100 watt Heathkit.

However when I transmit according to the SWR Watt meter the system
appears to transmit well over 200 watts. It pined the meter on a 200
watt range. I repeated the test twice and then stopped. When it is
transmitting the SWR reads about 1.1 to 1. The meter works very well and
does not exhibit strange readings on other setups.

My questions a What is happening? What is causing it?



two things pop into mind could be your antenna is radiating towards
and into or near your radio and causing some feedback that might effect
the radio and or the meter

there is also the possibility that you have some bad (common mode? etc)
current flowing back down the coax which could also wreck havock


just my guess and double check the above and grounds

put a dummy load into your tuner see if you get proper readings