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using an HP 8405A to measure SWR ?
"dansawyeror" wrote in message . .. Owen, Yes, you are right. The single coupler doesn't isolate the channels. Putting a 10 dbm attenuator between the tee and the coupler changes the 50 Ohm reading. I think a dual directional coupler is required. I will have to put this on hold until that problem is solved. Thanks - Dan Dan Are you open to trying to assemble something to measure the reflection coefficient rather than to put the project on hold? The HP 41952A Transmission/Reflection Test Set uses only one directional coupler. It uses a power splitter at the input with a pad to level the outputs from the "Fwd" and "Rev" ports. I can scan some info from the HP 41952 and E-mail them to you if you have interest in building something. I would think it would be fairly easy to build devices for HF if you already have a decent directional coupler. Jerry |
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using an HP 8405A to measure SWR ?
Jerry,
Thanks, the antenna handbook has a design for a bi-directional coupler that looks like it will work. At this point I think the next step is to separate the input to the A port from the reflected signal. Putting a pad in the circuit to increase isolation affected the reflected reading. I am also sorting through those readings. Dan Jerry Martes wrote: "dansawyeror" wrote in message . .. Owen, Yes, you are right. The single coupler doesn't isolate the channels. Putting a 10 dbm attenuator between the tee and the coupler changes the 50 Ohm reading. I think a dual directional coupler is required. I will have to put this on hold until that problem is solved. Thanks - Dan Dan Are you open to trying to assemble something to measure the reflection coefficient rather than to put the project on hold? The HP 41952A Transmission/Reflection Test Set uses only one directional coupler. It uses a power splitter at the input with a pad to level the outputs from the "Fwd" and "Rev" ports. I can scan some info from the HP 41952 and E-mail them to you if you have interest in building something. I would think it would be fairly easy to build devices for HF if you already have a decent directional coupler. Jerry |
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