Hi to all in the group!
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I'm close to the end of repairing an FT-301D transceiver and trying to get the transmitted audio quality sounding anything like 'nice'. It's proving surprisingly challenging.
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Looking at the transmitted RF spectrum, one issue would seem to be that the SSB filter response is very narrow - more like 2.0 kHz rather than the supposed 2.4 kHz. I've tried moving the carrier point around and different microphones, all with no real improvement. This morning, I grabbed a Filter Unit from my spare radio and tried that. No real improvement:-(
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I imagine it's possible that the crystals in both SSB filters I have tried have aged the same way and their responses have degraded. If that is the case, then I'm stuck with the problem. I do have a minVNA and could remove the filter to test it, but it would be nice not to have to. The receive audio response with either filter sounds generally OK.
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I'm wondering whether aged coupling capacitors in the mic. amp. could also be a factor. I've not looked into that as yet.
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Any experience out there of this issue?
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Regards,
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Mark, G4FPH.
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