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![]() 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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What would cause the SWR to go up drastically when I turn my amp on? | Equipment |