Stewart G3RXQ wrote:
>
> Having run a quick test switching between USB and LSB on a quiet
> band 10m, I noticed an appreciable difference in the tone of the
> noise spectrum.
>
> I dug out my noise generator and examined the audio response using
> Spectrum Lab. I set the DSP B/W to the maximum as what I wanted to
> see was the 2.7KHz SSB roofing filter response.
>
> On USB the trace was substantially flat with the -3dB points at
> 430Hz and 2.77KHz. Not too bad and could probably be improved by
> moving the carrier offset frequency.
>
> On LSB, however the trace was far from flat having a slope from
> audio LF to HF of about 6dB. Not very good at all...
>
> I tried adjusting the FL FRQ, but all this did was shift the
> overall position of the sloping trace.
>
>
Stuart the thing I find curious is that, in fact, there is physically only
one 2.7 kHz filter...not 2 separate ones for USB and and LSB. This makes me
wonder if something else is going on in your unit since the responses you
are reporting are so different. I might try re-calibrating the synthesizer
and checking again. Also check that you have no offset in PBT (or HI and LO
if you use that), EQ set to flat, etc. You can also check the 2.7k in CW
(on both sidebands) which might give some additional clues.
73, Bill W4ZV
--
View this message in context:
http://www.nabble.com/K3-SSB----Is-the-5-pole-filter-good-enough-tp15664900p15669386.html
Sent from the Elecraft mailing list archive at Nabble.com.
_______________________________________________
Elecraft mailing list
Post to: Elecraft@mailman.qth.net
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com
