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| Siglent SSA 3021X... Ooops |
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| Joel_l:
Mine is a little different than that, I have 4 more diodes where the signal enters the first switch. So I think I found two things going on, one really muddied the other. Looks like my attenuator is bad and is causing the high SWR on my TX. This does not explain the initial high SWR with my antenna analyzer, I did not use my attenuator with that. I went back and looked with my signal generator again. I fed a -20dBm signal in and went through the SA attenuator settings. The reading never changed from -20dBm only the noise floor moved up and down, the SA always measured -20dBm. Those switches are not very expensive. I think I will just replace those. I hope the programable attenuator at the end is OK, not as easy to find. |
| tautech:
--- Quote from: Joel_l on April 28, 2024, 03:10:33 pm ---Something very strange happened. When I did the sweep, the SA barked at me with an overload. I need to look at this more and make sure I'm not chasing bad data. --- End quote --- Good. After a Preset all previous settings are set to factory and the analyzer attempts to protect itself. Some wrongly use Manual attenuation to correct for external attenuation when instead they should shift the Ref Offset for Markers to display the correct level. When set to Manual the analyzer is locked out from automatically managing its internal attenuation that varies with settings used. |
| Joel_l:
Except that when using the antenna analyzer, I made no changes to any SA setting. As far as what the SA is reading, thinking about it, it's all good. The SA knows what the attenuation is set to, so can always display the power being applied to the input port. I did test my external attenuator and it is indeed bad. The only potential issue left is why when using the antenna analyzer did I initially get several high SWR readings, when I tried the Smith chart I got the overload warning, then things worked fine. I did not change any SA settings during these tests with the antenna analyzer. The SA still acts odd sometimes, so I think I will still replace those switches. |
| tautech:
Have you considered working through some of the performance verification steps in the service manual ? |
| Joel_l:
Looking at it, there are a couple I think I can do, though I have always wanted a power meter.... Problem is still the flakey nature of it, might pass this time and not the next. I will do the ones I can for a baseline. I always thought the noise floor on mine seemed high, so that will be a good one to go through. Thanks |
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