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Calibration

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Chester Alderman

Calibration

I just completed the RF Gain and S-Meter calibration on my K3 (4521) and all
went smooth. However I am left with a question (of course!). If I leave SMTR
MD in NOR, changing PRE or ATT, the affect will be seen on the S-Meter. If I
leave SMTR MD in ABS, the S-Meter does not respond to any change in PRE or
ATT.
What is the advantage of leaving SMTR MD set to ABS since I would guess it
would be meaningful to the operator to actually see the effects of using PRE
and/or ATT?
Tom - W4BQF

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n7ws

Re: Calibration

If the intent of the S-meter is to give an indication of the signal level at the antenna spigot, then having the indication change when the attenuator and/or preamp is engaged is counterproductive. A 50 uV (or whatever) signal should give the same reading no matter what. In that case, "ABS" is the answer.

Wes N7WS

--- On Wed, 12/15/10, Tommy Alderman <[hidden email]> wrote:

> I just completed the RF Gain and
> S-Meter calibration on my K3 (4521) and all
> went smooth. However I am left with a question (of
> course!). If I leave SMTR
> MD in NOR, changing PRE or ATT, the affect will be seen on
> the S-Meter. If I
> leave SMTR MD in ABS, the S-Meter does not respond to any
> change in PRE or
> ATT.
> What is the advantage of leaving SMTR MD set to ABS since I
> would guess it
> would be meaningful to the operator to actually see the
> effects of using PRE
> and/or ATT?
> Tom - W4BQF

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KK7P

Re: Calibration

In reply to this post by Chester Alderman

Some people want to see the S meter move with PRE and ATT.

Others think that the signal level at the antenna connector is what is
important, and PRE and ATT have no effect on that. Looking at it
another way, if S9 = 50 uV into 50 ohms, and if I apply a 50 uV signal
to my K3, the S Meter should read S9 regardless of PRE or ATT settings
(ABS mode).

Take your pick :-)

73,

Lyle KK7P (who only uses ABS mode)

> ...TR MD in ABS, the S-Meter does not respond to any change in PRE or
> ATT.

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Chester Alderman

Re: Calibration

In reply to this post by Chester Alderman

OK - thanks for the good answers! Now I know!
73,

Tom - W4BQF

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Tommy Alderman
Sent: Wednesday, December 15, 2010 5:04 PM
To: [hidden email]
Subject: [Elecraft] Calibration

I just completed the RF Gain and S-Meter calibration on my K3 (4521) and all
went smooth. However I am left with a question (of course!). If I leave SMTR
MD in NOR, changing PRE or ATT, the affect will be seen on the S-Meter. If I
leave SMTR MD in ABS, the S-Meter does not respond to any change in PRE or
ATT.
What is the advantage of leaving SMTR MD set to ABS since I would guess it
would be meaningful to the operator to actually see the effects of using PRE
and/or ATT?
Tom - W4BQF

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k6rb

Re: Calibration

In reply to this post by Chester Alderman

I would add that I don't need to see the s-meter jump when I kick in PRE
or fall when I kick in ATT. With my old FT-1000, there were differences in
S levels when I did either, and so for consistency sake, if someone asked
for a signal report, I would cancel either PRE or ATT. With ABS, that's
not necessary. I can hear the difference, don't need to see it :-).

Rob K6RB

> I just completed the RF Gain and S-Meter calibration on my K3 (4521) and
> all
> went smooth. However I am left with a question (of course!). If I leave
> SMTR
> MD in NOR, changing PRE or ATT, the affect will be seen on the S-Meter. If
> I
> leave SMTR MD in ABS, the S-Meter does not respond to any change in PRE or
> ATT.
> What is the advantage of leaving SMTR MD set to ABS since I would guess it
> would be meaningful to the operator to actually see the effects of using
> PRE
> and/or ATT?
> Tom - W4BQF
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

Guy, K2AV

Re: Calibration

Setting PRE or ATT causing the S-meter go up and down is how analog
radios have worked forever. The S meter was reading the voltage off
the AGC bus which usually controlled the gain of half a dozen tube
stages. Some folks WANT their digital radio to behave like their
previous analog radios and view every divergent behavior as something
potentially wrong with their K3. They'll take the better performance,
but they don't want to learn a new paradigm to use it. Hence a lot of
dual personality items in the K3.

But having the input absolute is indeed useful. In this mode PRE and
ATT are just a range switch for RF gain. Like LOW, MED and HIGH.

Using ABS and calibrated, seeing a 40 over S9 indication (five
MILLIVOLTS or more) on an Italian 40 meter ham signal tells me
something. Like should I REALLY bother trying to override him, or is
he going to SO LOUD in EU, I might as well go find another run
frequency.

73, Guy.

On Wed, Dec 15, 2010 at 6:38 PM, <[hidden email]> wrote:

> I would add that I don't need to see the s-meter jump when I kick in PRE
> or fall when I kick in ATT. With my old FT-1000, there were differences in
> S levels when I did either, and so for consistency sake, if someone asked
> for a signal report, I would cancel either PRE or ATT. With ABS, that's
> not necessary. I can hear the difference, don't need to see it :-).
>
> Rob K6RB
>
>> I just completed the RF Gain and S-Meter calibration on my K3 (4521) and
>> all
>> went smooth. However I am left with a question (of course!). If I leave
>> SMTR
>> MD in NOR, changing PRE or ATT, the affect will be seen on the S-Meter. If
>> I
>> leave SMTR MD in ABS, the S-Meter does not respond to any change in PRE or
>> ATT.
>> What is the advantage of leaving SMTR MD set to ABS since I would guess it
>> would be meaningful to the operator to actually see the effects of using
>> PRE
>> and/or ATT?
>> Tom - W4BQF
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

AC7AC

Re: Calibration

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