Your transistor amp is putting out garbage; transmitting harmonics that your
SWR Meter is responding to. You need tuning/lowpass filters on both input
and output.
"Joeseph" wrote in message
...
This is a very screwy problem. First lets get the set-up of my
radio equipment;
The amp puts out about 100 watts on HF.
RADIO-----2 TRANSISTOR AMP-----SWR METER------ ANTENNA
Note the SWR meter comes AFTER the 2 transistor amp.
Ok, when I check the SWR on my antenna it shows 1.1. When I turn the
amp on it shows over 3.x SWR. The antenna is rated at 5 KW. The amp
only puts out about 100 watts.
Hmmm.....Ok lets see what happens when I use my 1 KW oil filled dummy
load.
RADIO----- 2 TRANSISTOR AMP----SWR METER-------1 KW DUMMY LOAD
Same thing. The SWR is about 1.5 in to the dummy load, but as soon as
I turn the amp on the SWR meter shows 3.x plus.
Ok, Maybe my SWR meter is screwy, so lets use my Dentron MT3000
tuner with a built in 200 watt dry dummy load and built in SWR meter.
RADIO ----2 TRANSISTOR AMP----DENTRON MT3000
Same thing. The SWR is low without the amp on and goes high when the
amp gets turned on.
Ok, Lets see what happens when I use my Drake L-4B amp instead of the
2 transistor amp.
RADIO-----Drake L-4B-----SWR METER-------Dummy load
Now the SWR stays low when I turn on the Drake L-4B for both the 1 KW
dummy load and the external antenna.
The transistor uses MRF455 transistors. Why would the SWR meter go up
significantly when I turn on the 2 transisor amp, but stay low when I
turn on a Drake L-4B.
I've duplicated this scenario with three different SWR meters, and
different patch cables. Lets me say for the record the SWR meter
comes after the amp, so I'm not looking at a high SWR on the input
side of the amp. This is on the output side of the amp.
?????
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