Elecraft

Bad LSB audio

Classic

List

Threaded

3 messages Options

Neal Campbell

Bad LSB audio

Hi all,

Not being a particularly active ham on SSB, I have toyed with it a bit on K2
4490 but bought the MD-2 mic and figured I would 'tune' the BFO to give me
decent audio. I got a couple of 'horrible audio' reports which also drove
the decision.

I tested the BFO setting using an Orion fed into my computer so I could
record and listen to myself as I tuned. I had to remove the coax and set the
attenuator on the orion to keep the signal under S9 (I do have a K2/100).

Trying to adjust the LSB setting on 40m, I honestly could not find a setting
that was not very hollow and a bit tinny. It was very interesting seeing how
senstive the audio was to theBFO setting, a slight adjustment could really
mean a big difference. After achieving unsatisfactory result, I glumly did
the USB setting on 20 meters. Oddly enough, it was almost spot on with the
original setting and I believe yields decent (if not great) audio.

I also noticed (without any scientific basis!) that I had to tune about
300-400 Hz low on LSB to achieve the best audio while on 20m it was again
spot on with the frequency display of the K2.

Any clues as to what could cause LSB to sound pretty bad while USB sound
decent?

Thanks
Neal k3nc
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
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

Don Wilhelm-3

RE: Bad LSB audio

Neal,

It may be that your LSB BFO is not currently set anywhere close to the
correct setting, and your efforts are being confounded by that situation.

I recommend that you first re-do the LSB BFO setting in receive using
Spectrogram and a noise generator. If your OP1 filter width is the older
2.1 kHz, set markers (pointers) at 300 and 2300 Hz and center the passband
between them - if you have the newer 2.4 kHz width, use markers at 300 and
2600 Hz.

After that, proceed with your "on the air" testing to improve it if
possible - and move the BFO only a small bit at a time - and do not move the
VFO on the K2 or the Orion while doing this procedure - just set the
frequencies to match - assuming your K2 dial frequency is properly
calibrated, check that by zeroing 10 MHz (or 15 MHz) WWV and see if the
frequency display is correct.

73,
Don W3FPR

> -----Original Message-----
>
> Not being a particularly active ham on SSB, I have toyed with it
> a bit on K2
> 4490 but bought the MD-2 mic and figured I would 'tune' the BFO to give me
> decent audio. I got a couple of 'horrible audio' reports which also drove
> the decision.
>
> I tested the BFO setting using an Orion fed into my computer so I could
> record and listen to myself as I tuned. I had to remove the coax
> and set the
> attenuator on the orion to keep the signal under S9 (I do have a K2/100).
>
> Trying to adjust the LSB setting on 40m, I honestly could not
> find a setting
> that was not very hollow and a bit tinny. It was very interesting
> seeing how
> senstive the audio was to theBFO setting, a slight adjustment could really
> mean a big difference. After achieving unsatisfactory result, I glumly did
> the USB setting on 20 meters. Oddly enough, it was almost spot on with the
> original setting and I believe yields decent (if not great) audio.
>
> I also noticed (without any scientific basis!) that I had to tune about
> 300-400 Hz low on LSB to achieve the best audio while on 20m it was again
> spot on with the frequency display of the K2.
>
> Any clues as to what could cause LSB to sound pretty bad while USB sound
> decent?
>
> Thanks
> Neal k3nc
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> 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
> --
> No virus found in this incoming message.
> Checked by AVG Anti-Virus.
> Version: 7.0.322 / Virus Database: 267.4.1 - Release Date: 6/2/2005
>

--
No virus found in this outgoing message.
Checked by AVG Anti-Virus.
Version: 7.0.322 / Virus Database: 267.4.1 - Release Date: 6/2/2005

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
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

Neal Campbell

RE: Bad LSB audio

Problem solved by Dr. Don's recommendation. I also found that using
spectrogram to set the tx bfo was helpful, you can really see where your
signal is. Next frontier is rtty, but that will have to wait.

Neal
-----Original Message-----
From: W3FPR - Don Wilhelm [mailto:[hidden email]]
Sent: Thursday, June 02, 2005 11:35 PM
To: Neal Campbell; [hidden email]
Subject: RE: [Elecraft] Bad LSB audio

Neal,

It may be that your LSB BFO is not currently set anywhere close to the
correct setting, and your efforts are being confounded by that situation.

I recommend that you first re-do the LSB BFO setting in receive using
Spectrogram and a noise generator. If your OP1 filter width is the older
2.1 kHz, set markers (pointers) at 300 and 2300 Hz and center the passband
between them - if you have the newer 2.4 kHz width, use markers at 300 and
2600 Hz.

After that, proceed with your "on the air" testing to improve it if possible
- and move the BFO only a small bit at a time - and do not move the VFO on
the K2 or the Orion while doing this procedure - just set the frequencies to
match - assuming your K2 dial frequency is properly calibrated, check that
by zeroing 10 MHz (or 15 MHz) WWV and see if the frequency display is
correct.

73,
Don W3FPR

> -----Original Message-----
>
> Not being a particularly active ham on SSB, I have toyed with it a bit
> on K2 4490 but bought the MD-2 mic and figured I would 'tune' the BFO
> to give me decent audio. I got a couple of 'horrible audio' reports
> which also drove the decision.
>
> I tested the BFO setting using an Orion fed into my computer so I
> could record and listen to myself as I tuned. I had to remove the coax
> and set the attenuator on the orion to keep the signal under S9 (I do
> have a K2/100).
>
> Trying to adjust the LSB setting on 40m, I honestly could not find a
> setting that was not very hollow and a bit tinny. It was very
> interesting seeing how senstive the audio was to theBFO setting, a
> slight adjustment could really mean a big difference. After achieving
> unsatisfactory result, I glumly did the USB setting on 20 meters.
> Oddly enough, it was almost spot on with the original setting and I
> believe yields decent (if not great) audio.
>
> I also noticed (without any scientific basis!) that I had to tune
> about 300-400 Hz low on LSB to achieve the best audio while on 20m it
> was again spot on with the frequency display of the K2.
>
> Any clues as to what could cause LSB to sound pretty bad while USB
> sound decent?
>
> Thanks
> Neal k3nc
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> 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
> --
> No virus found in this incoming message.
> Checked by AVG Anti-Virus.
> Version: 7.0.322 / Virus Database: 267.4.1 - Release Date: 6/2/2005
>