Another question about L34 adjustment IF Amp.

[Gary D Krause]

After reading another post about adjusting L34 for the IF amplifier, I have
another question.  I've wondered about this since completing my K2.  The
manual was a bit confusing and from what I can remember, it said to adjust L34
for the strongest signal and lowest background noise.  It also said that a DMM
could be used across the speaker output to get a more accurate reading.  Well,
my question at the time was how can you get the strongest signal and lowest
background noise with only one adjustment.  So, I figured it would be a
compromise between the two.  I adjusted L34 but, not exactly to it's highest
volume or loudest signal.

Now I've learned that it should be adjusted for the loudest signal and that
includes the background noise.  So, can I now go back and readjust L34 for
maximum volume and if so what else will I have to align?  I assume that I
would only have to re-calibrate the bar-graph, is that correct?

Thanks,
Gary, N7HTS



_______________________________________________
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]

Gary,

That is correct, CAL S Lo and CAL S Hi may have to be adjusted a small
amount, but no other adjustments should be necessary.

73,
Don W3FPR

Gary D Krause wrote:

>
> Now I've learned that it should be adjusted for the loudest signal and
> that includes the background noise.  So, can I now go back and readjust
> L34 for maximum volume and if so what else will I have to align?  I
> assume that I would only have to re-calibrate the bar-graph, is that
> correct?
_______________________________________________
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

[Tom Hammond-2]

Hi Gary:

There's a tuning point, just below the point on L34 where you DO
achieve max. received signal, where the background noise will drop
off faster than the received signal. It's (if I recall) about 1/2 to
1 full turn DOWN from the point of max RX sig.

If you have Spectrogram installed, you can actually see it on the
spectral display... it's NOT a terribly dramatic effect, but it is
observable... you WILL lose a bit of received signal strength, BUT
it's more than compensated for by the fact that the signal-to-noise
ratio has been improved, so to signal seems to 'stand out' a bit
better, even though it may be a couple dB lower in level.

73,

Tom Hammond    N0SS


At 10:33 06/28/2007, Gary D Krause wrote:

>After reading another post about adjusting L34 for the IF amplifier,
>I have another question.  I've wondered about this since completing
>my K2.  The manual was a bit confusing and from what I can remember,
>it said to adjust L34 for the strongest signal and lowest background
>noise.  It also said that a DMM could be used across the speaker
>output to get a more accurate reading.  Well, my question at the
>time was how can you get the strongest signal and lowest background
>noise with only one adjustment.  So, I figured it would be a
>compromise between the two.  I adjusted L34 but, not exactly to it's
>highest volume or loudest signal.
>
>Now I've learned that it should be adjusted for the loudest signal
>and that includes the background noise.  So, can I now go back and
>readjust L34 for maximum volume and if so what else will I have to
>align?  I assume that I would only have to re-calibrate the
>bar-graph, is that correct?
>
>Thanks,
>Gary, N7HTS
>
>
>
>_______________________________________________
>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

_______________________________________________
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

[Gary D Krause]

Thanks Tom, that's what I was thinking when I adjusted it by ear.  I have also
thought about using Spectrogram to get a "visual" of the signal to noise.  I
might have it adjusted pretty close because, that's what I was listening for
when I adjusted it.  I'll use Spectrogram to look at it when I readjust it.
 The confusing part to me was the suggestion of using a DMM to adjust it since
it cannot differentiate between the signal and noise.  I live in a noisy area
and my antenna is a quarter wave vertical so, the last thing I need is noise.
:-)

Gary, N7HTS


On Thu, 28 Jun 2007 12:24:02 -0500
  Tom Hammond <[hidden email]> wrote:

> Hi Gary:
>
> There's a tuning point, just below the point on L34 where you DO achieve
>max. received signal, where the background noise will drop off faster than
>the received signal. It's (if I recall) about 1/2 to 1 full turn DOWN from
>the point of max RX sig.
>
> If you have Spectrogram installed, you can actually see it on the spectral
>display... it's NOT a terribly dramatic effect, but it is observable... you
>WILL lose a bit of received signal strength, BUT it's more than compensated
>for by the fact that the signal-to-noise ratio has been improved, so to
>signal seems to 'stand out' a bit better, even though it may be a couple dB
>lower in level.
>
> 73,
>
> Tom Hammond    N0SS
>
>
> At 10:33 06/28/2007, Gary D Krause wrote:
>>After reading another post about adjusting L34 for the IF amplifier, I have
>>another question.  I've wondered about this since completing my K2.  The
>>manual was a bit confusing and from what I can remember, it said to adjust
>>L34 for the strongest signal and lowest background noise.  It also said that
>>a DMM could be used across the speaker output to get a more accurate reading.
>> Well, my question at the time was how can you get the strongest signal and
>>lowest background noise with only one adjustment.  So, I figured it would be
>>a compromise between the two.  I adjusted L34 but, not exactly to it's
>>highest volume or loudest signal.
>>
>>Now I've learned that it should be adjusted for the loudest signal and that
>>includes the background noise.  So, can I now go back and readjust L34 for
>>maximum volume and if so what else will I have to align?  I assume that I
>>would only have to re-calibrate the bar-graph, is that correct?
>>
>>Thanks,
>>Gary, N7HTS
>>
>>
>>
>>_______________________________________________
>>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
>

_______________________________________________
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