On the rare occasions that I have operated my Omni VI in SSB mode I have
received excellent TX audio reports. I use a Ten-Tec 705 microphone,
with the MIC gain control set at about 11:00 (40%). I speak directly
into the microphone, with my mouth about two to three inches from the
microphone. When I used the speech PROCESSOR I set it also to about
11:00. I have not made any modifications to the rig, which I purchased
used from another ham. To my knowledge it has not been modified.
What different mics have you tried? Have you tried a Ten-Tec 705? What
do you mean by "upgraded" Omni VI? Maybe the "upgrades" are part of the
problem.
Can you look at the audio input levels of your two tone test source
(that looks good on a RF monitor scope and spectrum analyzer) with an
oscilloscope and compare that with the level you are getting from the
microphone? The TX audio path circuitry from the rear panel audio
input connector is identical to the circuitry from the mic connector,
so levels that work at the rear connector should work from the mic
connector too.
DE N6KB
Fraser Robertson wrote:
Hi all, is possible to transmit good quality SSB from this rig? I get
reports of muffled audio. Listening on another RX I know what they mean.
I've re-aligned the driver & pa bias, carrier oscillators etc. I've
isolated the mic ground as by design it shares the PTT ground and
digital noise was getting into the mic amp.
With a two tone test the signal looks ok on a scope and spectrum
analyser (products 26dB and 38dB down).
I've tried different power supplies, different mics and audio sources.
It sounds reasonable on receive, to me anyway, and works well on CW.
The rig has the stock filters fitted. A friend has the Inrad SSB
filter and says he gets muffled audio reports too.
I've ruled out RF feedback and am running out of ideas. Any advice
would be appreciated. The audio is readable but not crisp clear
quality. (The rig is an upgraded Omni6).
Thanks / 73 Fraser G4BJM
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