Re: 8566 to measure 100W FM transmitter
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First of all you must be very strong. The 8566 A or B is somewhat over 100 pounds and very bulky, if you have to take it to the transmitter. I have one of each and try to never move them.
I would keep the input power below one half watt on the 8566 input, to be safe. Never put in zero dB attenuator on the analyzer!
You will either need a large 50 ohm attenuator of at least 40 dB, with an additional low power 10 dB attenuator to sample the transmitter and protect the spectrum analyzer. That is what I have on the bench.
The other way to measure the transmitter is to use a high power directional coupler in addition to a small attenuator on the forward coupled arm, for insurance.
I routinely measure two 21 kW FM transmitter, but they have a built-in 55 dB directional coupler. However, I always use an additional attenuator at the spectrum analyzer, just in case.
If you are just looking at a SSB transmitter, at a very narrow dispersion, you probably can use just a test lead. If you are just interested in relative readings, such as close-in distortion, carrier or unwanted sideband suppression in a Single Sideband transmitter, that will work well.
Stuart K6YAZ
Los Angeles, California
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