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Peaking L34 (IF amplifier)

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David C Dawson-2

Peaking L34 (IF amplifier)

Hi,
First, I took Don Wilhelm;s advice about checking soldering and re-did
anything I could find that looked dubious.

Now, I've come to peak the IF amplifier.
It seems to me that a signal just gets louder when I turn the slug
counter-clockwise until it hits the stop and quieter turning the slug
clockwise. If there was a peak, it was a really shallow one.

I followed the instructions and could hear the internal birdie quite
well, so peaking should not have been difficult.

Any suggestions, please?
Thanks.
--
David Dawson

A strong conviction that something must be done is the parent of many
bad measures.
-- Daniel Webster

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Don Wilhelm-3

RE: Peaking L34 (IF amplifier)

David,

Yes, the peak is VERY broad. You may have to connect an AC voltmeter across
the speaker connector to find the peak if you cannot discern it by ear. The
peak is normally 1 to 1 1/2 turns down from the top of the can. Be certain
you are using CW mode. If your peak is right at the top of the can, check
the value of C182.

73,
Don W3FPR

> -----Original Message-----
> First, I took Don Wilhelm;s advice about checking soldering and re-did
> anything I could find that looked dubious.
>
> Now, I've come to peak the IF amplifier.
> It seems to me that a signal just gets louder when I turn the slug
> counter-clockwise until it hits the stop and quieter turning the slug
> clockwise. If there was a peak, it was a really shallow one.
>
> I followed the instructions and could hear the internal birdie quite
> well, so peaking should not have been difficult.
>
> Any suggestions, please?
> Thanks.
> --
> David Dawson
>

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David C Dawson-2

Re: Peaking L34 (IF amplifier)

On Sat, Nov 18, 2006 at 07:32:44AM -0500, Don Wilhelm wrote:
> David,
>
> Yes, the peak is VERY broad. You may have to connect an AC voltmeter across
> the speaker connector to find the peak if you cannot discern it by ear. The
> peak is normally 1 to 1 1/2 turns down from the top of the can. Be certain
> you are using CW mode. If your peak is right at the top of the can, check
> the value of C182.
C182 is a fairly big yellow disk ceramic marked '181', if that is
correct, then I guess I don't have a problem?

I have a software audio analyser (xanalyser) which I could use to find
the peak and I have a DMM which should measure audio frequencies just
fine (It has a range of 0 - 4MHz as a frequency counter).

Which would be preferable?

>
> 73,
> Don W3FPR
>
> > -----Original Message-----
> > First, I took Don Wilhelm;s advice about checking soldering and re-did
> > anything I could find that looked dubious.
> >
> > Now, I've come to peak the IF amplifier.
> > It seems to me that a signal just gets louder when I turn the slug
> > counter-clockwise until it hits the stop and quieter turning the slug
> > clockwise. If there was a peak, it was a really shallow one.
> >
> > I followed the instructions and could hear the internal birdie quite
> > well, so peaking should not have been difficult.
> >
> > Any suggestions, please?
> > Thanks.
> > --
> > David Dawson
> >
>

Don Wilhelm-3

RE: Peaking L34 (IF amplifier)

David,

It sounds like either will work fine - use the one that is more convenient
and does the job.

73,
Don W3FPR

> -----Original Message-----
>
> I have a software audio analyser (xanalyser) which I could use to find
> the peak and I have a DMM which should measure audio frequencies just
> fine (It has a range of 0 - 4MHz as a frequency counter).
>
> Which would be preferable?
> >
>

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Ron D'Eau Claire-2

RE: Peaking L34 (IF amplifier)

In reply to this post by David C Dawson-2

It's important to remember that the effect of L34 on the performance of the
K2 is as subtle as the peak. That is, the effect on receiver performance is
negligible as long as L34 is set somewhere in the general vicinity of the
"peak".

Ron AC7AC

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of David C Dawson
Sent: Saturday, November 18, 2006 3:44 PM
To: [hidden email]
Subject: Re: [Elecraft] Peaking L34 (IF amplifier)

On Sat, Nov 18, 2006 at 07:32:44AM -0500, Don Wilhelm wrote:
> David,
>
> Yes, the peak is VERY broad. You may have to connect an AC voltmeter
> across the speaker connector to find the peak if you cannot discern it
> by ear. The peak is normally 1 to 1 1/2 turns down from the top of
> the can. Be certain you are using CW mode. If your peak is right at
> the top of the can, check the value of C182.
C182 is a fairly big yellow disk ceramic marked '181', if that is correct,
then I guess I don't have a problem?

I have a software audio analyser (xanalyser) which I could use to find the
peak and I have a DMM which should measure audio frequencies just fine (It
has a range of 0 - 4MHz as a frequency counter).

Which would be preferable?

>
> 73,
> Don W3FPR
>
> > -----Original Message-----
> > First, I took Don Wilhelm;s advice about checking soldering and
> > re-did anything I could find that looked dubious.
> >
> > Now, I've come to peak the IF amplifier.
> > It seems to me that a signal just gets louder when I turn the slug
> > counter-clockwise until it hits the stop and quieter turning the
> > slug clockwise. If there was a peak, it was a really shallow one.
> >
> > I followed the instructions and could hear the internal birdie quite
> > well, so peaking should not have been difficult.
> >
> > Any suggestions, please?
> > Thanks.
> > --
> > David Dawson
> >
>

--
David Dawson

A strong conviction that something must be done is the parent of many bad
measures.
-- Daniel Webster

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Don Wilhelm-3

RE: Peaking L34 (IF amplifier)

Ron is quite correct. If no peak can be discerned, just set the slug 1 to 1
1/2 turns in from the top of the can and be satisfied - alternately, as Ron
stated, 'in the general vicinity of the peak'.

73,
Don W3FPR

> -----Original Message-----
>
> It's important to remember that the effect of L34 on the
> performance of the
> K2 is as subtle as the peak. That is, the effect on receiver
> performance is
> negligible as long as L34 is set somewhere in the general vicinity of the
> "peak".
>
> Ron AC7AC
>

David C Dawson-2

Re: Peaking L34 (IF amplifier)

In reply to this post by David C Dawson-2

On Sat, Nov 18, 2006 at 10:55:12PM -0600, Tom Hammond wrote:
> David:
>
> For finding the peak, either will work, however, for finding the best
> Signal-to-noise ratio, the xanalyser will probably be better because
> it should allow you to see both the signal AND the background noise,
> so you can tell when he background noise is dropping faster than the signal.
That's what I thought.
That should be fairly easy for me to set up.
Thanks.
>
> 73,
>
> Tom N0SS

--
David Dawson

A strong conviction that something must be done is the parent of many
bad measures.
-- Daniel Webster

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David C Dawson-2

Re: Peaking L34 (IF amplifier)

On Sun, Nov 19, 2006 at 09:19:34AM -0600, Tom Hammond wrote:

> David:
>
> >> For finding the peak, either will work, however, for finding the best
> >> Signal-to-noise ratio, the xanalyser will probably be better because
> >> it should allow you to see both the signal AND the background noise,
> >> so you can tell when he background noise is dropping faster than
> >the signal.
> >
> >That's what I thought.
> >That should be fairly easy for me to set up.
>
> The s/n ratio setting is usually only about 1/2-3/4 turn in from the
> point of max received signal. Run thru it a few times, to make sue
> you're seeing what you think you're seeing... and if you can't see
> it, try to hit the point of max. rx sig and then turn the slug in
> about 1/2 turn.

Yes, that is what I did.
Thanks.
>
> 73,
>
> Tom
>

--
David Dawson

A strong conviction that something must be done is the parent of many
bad measures.
-- Daniel Webster

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Post to: [hidden email]
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David C Dawson-2

Re: Peaking L34 (IF amplifier)

In reply to this post by Don Wilhelm-3

It is done.
Thanks.
On Sat, Nov 18, 2006 at 08:09:35PM -0500, Don Wilhelm wrote:

> Ron is quite correct. If no peak can be discerned, just set the slug 1 to 1
> 1/2 turns in from the top of the can and be satisfied - alternately, as Ron
> stated, 'in the general vicinity of the peak'.
>
> 73,
> Don W3FPR
>
> > -----Original Message-----
> >
> > It's important to remember that the effect of L34 on the
> > performance of the
> > K2 is as subtle as the peak. That is, the effect on receiver
> > performance is
> > negligible as long as L34 is set somewhere in the general vicinity of the
> > "peak".
> >
> > Ron AC7AC
> >
>
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> Elecraft mailing list
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> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
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>
> Help: http://mailman.qth.net/subscribers.htm
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David C Dawson-2

Re: Peaking L34 (IF amplifier)

On Mon, Nov 20, 2006 at 07:46:19AM -0600, Tom Hammond wrote:
> David:
>
> Did it go pretty much as we had described? Any problems?
I used Xanalyser and just cranked it counterclockwise until it hit the
top of the can and then backed it off. It is possible there was a broad
peak, but it was hard to see indeed.
Thanks.

>
> Cheers,
>
> Tom N0SS
>
> At 12:54 AM 11/20/2006, you wrote:
> >It is done.
> >Thanks.
> >On Sat, Nov 18, 2006 at 08:09:35PM -0500, Don Wilhelm wrote:
> >> Ron is quite correct. If no peak can be discerned, just set the
> >slug 1 to 1
> >> 1/2 turns in from the top of the can and be satisfied - alternately, as
> >Ron
> >> stated, 'in the general vicinity of the peak'.
>

David C Dawson-2

Re: Peaking L34 (IF amplifier)

In reply to this post by David C Dawson-2

On Mon, Nov 20, 2006 at 07:46:19AM -0600, Tom Hammond wrote:
> David:
>
> Did it go pretty much as we had described? Any problems?
I was not feeling well this morning and so didn't think so fast.
I understand the point about s/n and it wouldn't hurt to take another
look at the situation, although I don't think I need to adjust it much.

Anyway it is an easy procedure.
Thanks.