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P3 S meter variance

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Ai4PF

P3 S meter variance

Newly installed P3. Noticed S meter reading on K3 will be 2-3 units
higher than that displayed on P3. I've tried lengthening the signal
heights, but results are unsatisfactory:-( .

Is there another method for bringing the two more in balance?

73

Bill Wade, Ai4PF
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Don Wilhelm-4

Re: P3 S meter variance

Bill,

Alan may provide a better answer, but are you making that comparison on
the amplitude of a single signal that is substantially greater than the
ambient noise level?

If you are comparing the ambient noise level, the s-meter reading on the
K3 will vary by bandwidth, and will be lower at narrow bandwidths -
because the total noise depends on the bandwidth. For the P3, the
bandwidth of each sample is quite narrow, and the noise level will be
lower than shown on the K3.

The same phenomenon applies to a SSB signal, but to a lesser extent than
noise. The K3 is looking at the entire SSB signal where the P3 is
looking at smaller slices of the frequency spectrum contained in the
signal.

Bottom line, compare the two at a CW signal peak and they should agree
more closely. It is just the way the math works out.

73,
Don W3FPR

On 1/15/2011 11:16 PM, bill wade, sr. wrote:

> Newly installed P3. Noticed S meter reading on K3 will be 2-3 units
> higher than that displayed on P3. I've tried lengthening the signal
> heights, but results are unsatisfactory:-( .
>
> Is there another method for bringing the two more in balance?
>
> 73
>
> Bill Wade, Ai4PF
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
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>
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Matt Zilmer

Re: P3 S meter variance

In reply to this post by Ai4PF

What s/n is the K3 in question? Generally, I have the same issue
here. The K3 s-meter reads high compared to the P3.

BTW, there is an s-meter calibration procedure given in the K3 owner's
manual....

matt W6NIA
K3 s/n 24

--

On Sat, 15 Jan 2011 23:16:57 -0500, you wrote:

>Newly installed P3. Noticed S meter reading on K3 will be 2-3 units
>higher than that displayed on P3. I've tried lengthening the signal
>heights, but results are unsatisfactory:-( .
>
>Is there another method for bringing the two more in balance?
>
>73
>
>Bill Wade, Ai4PF
>______________________________________________________________
>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

Alan Bloom-2

Re: P3 S meter variance

In reply to this post by Ai4PF

There are a couple reasons why the K3's S meter and the P3 display may
show a different level.

As Don mentioned, the P3 will generally show a much lower level than the
K3 on noise. It's because the effective bandwidth of the P3 is
generally only one display pixel, about 1/450 of the span. Less
bandwidth means less noise power in each display point. The same thing
happens to some extent with an SSB signal.

Another issue is that the S meter reading on the K3 may change when you
turn the preamp or attenuator on or off. To prevent that happening, set
CONFIG:SMTR MD to "ABS".

If you do that and calibrate both the K3 S meter and the P3 amplitude,
then the two should closely agree when measuring a steady CW carrier.

Alan N1AL

On Sat, 2011-01-15 at 23:16 -0500, bill wade, sr. wrote:

Gary Gregory

Re: P3 S meter variance

Al,

Yes, this does work and even the SSB sigs match very closely to the K3 S-Meter.

Regards,
Gary

On Sun, Jan 16, 2011 at 3:20 PM, Alan Bloom <[hidden email]> wrote:

> There are a couple reasons why the K3's S meter and the P3 display may
> show a different level.
>
> As Don mentioned, the P3 will generally show a much lower level than the
> K3 on noise. It's because the effective bandwidth of the P3 is
> generally only one display pixel, about 1/450 of the span. Less
> bandwidth means less noise power in each display point. The same thing
> happens to some extent with an SSB signal.
>
> Another issue is that the S meter reading on the K3 may change when you
> turn the preamp or attenuator on or off. To prevent that happening, set
> CONFIG:SMTR MD to "ABS".
>
> If you do that and calibrate both the K3 S meter and the P3 amplitude,
> then the two should closely agree when measuring a steady CW carrier.
>
> Alan N1AL
>
>
> On Sat, 2011-01-15 at 23:16 -0500, bill wade, sr. wrote:
>> Newly installed P3. Noticed S meter reading on K3 will be 2-3 units
>> higher than that displayed on P3. I've tried lengthening the signal
>> heights, but results are unsatisfactory:-( .
>>
>> Is there another method for bringing the two more in balance?
>>
>> 73
>>
>> Bill Wade, Ai4PF
>> ______________________________________________________________
>> 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
>

--
Gary
VK4FD - Motorhome Mobile
http://www.qsl.net/vk4fd/
K3 #679, P3 #546
For everything else there's Mastercard!!!
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Don Wilhelm-4

Re: P3 S meter variance

In reply to this post by Alan Bloom-2

Alan,

I might add about the K3 CONFIG: SMTR MD = ABS, that the calibration
procedure indicated in the manual may (or may not) be the "proper" thing
to do.
The manual suggests that you calibrate the S-meter with the preamp ON.
If you do that, and set the S-meter to ABS, you will find that the
S-meter response is about 2 S-units lower than what you may expect. I
prefer to do the calibration with the S-meter off, and then the response
in SMTR ABS is more what I would expect.

Since everyone's expectations do not necessarily match mine (obviously,
I disagree with Wayne on this item), you can take your pick - do it the
way the manual says, or do it like I have. The choice is entirely
yours. Like all things S-meter reading related, there is a great
variation between receivers, The K3 has re-vitalized the old Collins 50
uV equal S-9 "standard". That standard is not a standard at all, and
many transceivers do it differently, but with the K3, you do have a
choice depending on how you want to set it up. If you cannot decide how
you want it, go with the manual instructions - they work and work quite
well. If you deviate, know why you are doing that deviation and know it
is for your own situation, others may or may not make the same choices.

73,
Don W3FPR

On 1/16/2011 12:20 AM, Alan Bloom wrote:

Alan Bloom-2

Re: P3 S meter variance

Don,

> The manual suggests that you calibrate the S-meter with the preamp ON.
> If you do that, and set the S-meter to ABS, you will find that the
> S-meter response is about 2 S-units lower than what you may expect.

Interesting. I assumed that in ABS mode it didn't matter if the preamp
was on or not. I sheepishly admit I have never bothered to calibrate my
K3 S meter. No excuse - I have an HP8656B signal generator sitting
right next to the K3 - I just never got around to it. I'd do it right
now but it's time to go to bed. :=)

> The K3 has re-vitalized the old Collins 50
> uV equal S-9 "standard". That standard is not a standard at all,

Actually IARU Region 1 has published Technical Recommendation R.1 which
specifies S9 = -73 dBm (50 uV into 50 ohms) and 6 dB per S-unit.
http://en.wikipedia.org/wiki/S_meter#IARU_Region_1_Technical_Recommendation_R.1

But you're right, that recommendation is more honored in the breach than
the observance. (Gosh, quoting Shakespeare on the reflector - what are
we coming to? :=)

Alan N1AL

On Sun, 2011-01-16 at 00:43 -0500, Don Wilhelm wrote:

> Alan,
>
> I might add about the K3 CONFIG: SMTR MD = ABS, that the calibration
> procedure indicated in the manual may (or may not) be the "proper" thing
> to do.
> The manual suggests that you calibrate the S-meter with the preamp ON.
> If you do that, and set the S-meter to ABS, you will find that the
> S-meter response is about 2 S-units lower than what you may expect. I
> prefer to do the calibration with the S-meter off, and then the response
> in SMTR ABS is more what I would expect.
>
> Since everyone's expectations do not necessarily match mine (obviously,
> I disagree with Wayne on this item), you can take your pick - do it the
> way the manual says, or do it like I have. The choice is entirely
> yours. Like all things S-meter reading related, there is a great
> variation between receivers, The K3 has re-vitalized the old Collins 50
> uV equal S-9 "standard". That standard is not a standard at all, and
> many transceivers do it differently, but with the K3, you do have a
> choice depending on how you want to set it up. If you cannot decide how
> you want it, go with the manual instructions - they work and work quite
> well. If you deviate, know why you are doing that deviation and know it
> is for your own situation, others may or may not make the same choices.
>
> 73,
> Don W3FPR
>
> On 1/16/2011 12:20 AM, Alan Bloom wrote:
> > There are a couple reasons why the K3's S meter and the P3 display may
> > show a different level.
> >
> > As Don mentioned, the P3 will generally show a much lower level than the
> > K3 on noise. It's because the effective bandwidth of the P3 is
> > generally only one display pixel, about 1/450 of the span. Less
> > bandwidth means less noise power in each display point. The same thing
> > happens to some extent with an SSB signal.
> >
> > Another issue is that the S meter reading on the K3 may change when you
> > turn the preamp or attenuator on or off. To prevent that happening, set
> > CONFIG:SMTR MD to "ABS".
> >
> > If you do that and calibrate both the K3 S meter and the P3 amplitude,
> > then the two should closely agree when measuring a steady CW carrier.
> >
> > Alan N1AL
> >

k6dgw

Re: P3 S meter variance

I have a service monitor, I could calibrate my S-meter if I really
understood the process, but haven't since I don't.

"For my part, it was Greek to me."
Youknowwho

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2011 Cal QSO Party 1-2 Oct 2011
- www.cqp.org

On 1/15/2011 10:20 PM, Alan Bloom wrote:

> Actually IARU Region 1 has published Technical Recommendation R.1 which
> specifies S9 = -73 dBm (50 uV into 50 ohms) and 6 dB per S-unit.
> http://en.wikipedia.org/wiki/S_meter#IARU_Region_1_Technical_Recommendation_R.1
>
> But you're right, that recommendation is more honored in the breach than
> the observance. (Gosh, quoting Shakespeare on the reflector - what are
> we coming to? :=)
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Nr4c

Re: P3 S meter variance

In reply to this post by Don Wilhelm-4

I just re-read my manual (rev D7), and it says on pg 51 for s-meter cal if
SMTR MD = NOR, set PREAMP ON. If SMTR MD = ABS, set PREAMP OFF.

...bc nr4c

-----Original Message-----
From: Don Wilhelm [mailto:[hidden email]]
Sent: Sunday, January 16, 2011 12:43 AM
To: [hidden email]
Cc: [hidden email]
Subject: Re: [Elecraft] P3 S meter variance

Alan,

I might add about the K3 CONFIG: SMTR MD = ABS, that the calibration
procedure indicated in the manual may (or may not) be the "proper" thing
to do.
The manual suggests that you calibrate the S-meter with the preamp ON.
If you do that, and set the S-meter to ABS, you will find that the
S-meter response is about 2 S-units lower than what you may expect. I
prefer to do the calibration with the S-meter off, and then the response
in SMTR ABS is more what I would expect.

Since everyone's expectations do not necessarily match mine (obviously,
I disagree with Wayne on this item), you can take your pick - do it the
way the manual says, or do it like I have. The choice is entirely
yours. Like all things S-meter reading related, there is a great
variation between receivers, The K3 has re-vitalized the old Collins 50
uV equal S-9 "standard". That standard is not a standard at all, and
many transceivers do it differently, but with the K3, you do have a
choice depending on how you want to set it up. If you cannot decide how
you want it, go with the manual instructions - they work and work quite
well. If you deviate, know why you are doing that deviation and know it
is for your own situation, others may or may not make the same choices.

73,
Don W3FPR

On 1/16/2011 12:20 AM, Alan Bloom wrote:

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Don Wilhelm-4

Re: P3 S meter variance

Bill,

I missed that recent update. It was not that way previously. We have
to keep up with the latest developments (and I failed). Wayne and I had
some discussion about this a while back, and I was not certain of the
outcome - Apparently we now agree.

73,
Don W3FPR

On 1/16/2011 1:46 AM, Bill Conkling wrote:

> I just re-read my manual (rev D7), and it says on pg 51 for s-meter cal if
> SMTR MD = NOR, set PREAMP ON. If SMTR MD = ABS, set PREAMP OFF.
>
> ...bc nr4c
>
> -----Original Message-----
> From: Don Wilhelm [mailto:[hidden email]]
> Sent: Sunday, January 16, 2011 12:43 AM
> To: [hidden email]
> Cc: [hidden email]
> Subject: Re: [Elecraft] P3 S meter variance
>
> Alan,
>
> I might add about the K3 CONFIG: SMTR MD = ABS, that the calibration
> procedure indicated in the manual may (or may not) be the "proper" thing
> to do.
> The manual suggests that you calibrate the S-meter with the preamp ON.
> If you do that, and set the S-meter to ABS, you will find that the
> S-meter response is about 2 S-units lower than what you may expect. I
> prefer to do the calibration with the S-meter off, and then the response
> in SMTR ABS is more what I would expect.
>
> Since everyone's expectations do not necessarily match mine (obviously,
> I disagree with Wayne on this item), you can take your pick - do it the
> way the manual says, or do it like I have. The choice is entirely
> yours. Like all things S-meter reading related, there is a great
> variation between receivers, The K3 has re-vitalized the old Collins 50
> uV equal S-9 "standard". That standard is not a standard at all, and
> many transceivers do it differently, but with the K3, you do have a
> choice depending on how you want to set it up. If you cannot decide how
> you want it, go with the manual instructions - they work and work quite
> well. If you deviate, know why you are doing that deviation and know it
> is for your own situation, others may or may not make the same choices.
>
> 73,
> Don W3FPR
>
> On 1/16/2011 12:20 AM, Alan Bloom wrote:
>> There are a couple reasons why the K3's S meter and the P3 display may
>> show a different level.
>>
>> As Don mentioned, the P3 will generally show a much lower level than the
>> K3 on noise. It's because the effective bandwidth of the P3 is
>> generally only one display pixel, about 1/450 of the span. Less
>> bandwidth means less noise power in each display point. The same thing
>> happens to some extent with an SSB signal.
>>
>> Another issue is that the S meter reading on the K3 may change when you
>> turn the preamp or attenuator on or off. To prevent that happening, set
>> CONFIG:SMTR MD to "ABS".
>>
>> If you do that and calibrate both the K3 S meter and the P3 amplitude,
>> then the two should closely agree when measuring a steady CW carrier.
>>
>> Alan N1AL
>>
> ______________________________________________________________
> 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
>

Don Wilhelm-4

Re: P3 S meter variance

In reply to this post by Alan Bloom-2

Alan,

WARNING - I am leading this thread Off-Topic. Delete immediately if you
object,- some parts are personal.

Quoting Shakespeare on the reflector may be as good or better than some
of the other "OT" posts that have appeared here in the past (no specific
examples cited nor intended).

I just might add a few of my favorite Mike Cross (and Tom Paxton) quotes
to the melay in due time!
(OK, you can Google if you are not familiar with those artists). The
humor and sentimentality of Mike Cross's songwriting helped me stay
grounded through 3 bouts with cancer - he gave me hope and a new
perspective on life, and I thouroughly enjoy the political satire that
Tom Paxton has provided me with both a laugh at politics and a deep
sorrow at the beauracracy that has developed.

From Mike Cross (who does not have an apparent active political agenda
-- the serious side is embodied in songs like "Red Tailed Hawk", while
the funny side is characterized by "Elma Turl",or "Granny's Milk Cartons".

Tom Paxton does have a political agenda, but has composed and performed
music ranging from "Ramblin' Boy" to "Lyndon Johnson told the Nation"
(use Google). Yes, this is stuff from the 1960s and the 1970s, and some
is anti-war., but the time of Lyndon Johnson and Vietnam are past, so
just enjoy the music and forget the politics that made that music so
close to home.

73,
Don W3FPR

.1/16/2011 1:20 AM, Alan Bloom wrote:

> Don,
>
>> The manual suggests that you calibrate the S-meter with the preamp ON.
>> If you do that, and set the S-meter to ABS, you will find that the
>> S-meter response is about 2 S-units lower than what you may expect.
> Interesting. I assumed that in ABS mode it didn't matter if the preamp
> was on or not. I sheepishly admit I have never bothered to calibrate my
> K3 S meter. No excuse - I have an HP8656B signal generator sitting
> right next to the K3 - I just never got around to it. I'd do it right
> now but it's time to go to bed. :=)
>
>> The K3 has re-vitalized the old Collins 50
>> uV equal S-9 "standard". That standard is not a standard at all,
> Actually IARU Region 1 has published Technical Recommendation R.1 which
> specifies S9 = -73 dBm (50 uV into 50 ohms) and 6 dB per S-unit.
> http://en.wikipedia.org/wiki/S_meter#IARU_Region_1_Technical_Recommendation_R.1
>
> But you're right, that recommendation is more honored in the breach than
> the observance. (Gosh, quoting Shakespeare on the reflector - what are
> we coming to? :=)
>
> Alan N1AL
>
>
>
> On Sun, 2011-01-16 at 00:43 -0500, Don Wilhelm wrote:
>> Alan,
>>
>> I might add about the K3 CONFIG: SMTR MD = ABS, that the calibration
>> procedure indicated in the manual may (or may not) be the "proper" thing
>> to do.
>> The manual suggests that you calibrate the S-meter with the preamp ON.
>> If you do that, and set the S-meter to ABS, you will find that the
>> S-meter response is about 2 S-units lower than what you may expect. I
>> prefer to do the calibration with the S-meter off, and then the response
>> in SMTR ABS is more what I would expect.
>>
>> Since everyone's expectations do not necessarily match mine (obviously,
>> I disagree with Wayne on this item), you can take your pick - do it the
>> way the manual says, or do it like I have. The choice is entirely
>> yours. Like all things S-meter reading related, there is a great
>> variation between receivers, The K3 has re-vitalized the old Collins 50
>> uV equal S-9 "standard". That standard is not a standard at all, and
>> many transceivers do it differently, but with the K3, you do have a
>> choice depending on how you want to set it up. If you cannot decide how
>> you want it, go with the manual instructions - they work and work quite
>> well. If you deviate, know why you are doing that deviation and know it
>> is for your own situation, others may or may not make the same choices.
>>
>> 73,
>> Don W3FPR
>>
>> On 1/16/2011 12:20 AM, Alan Bloom wrote:
>>> There are a couple reasons why the K3's S meter and the P3 display may
>>> show a different level.
>>>
>>> As Don mentioned, the P3 will generally show a much lower level than the
>>> K3 on noise. It's because the effective bandwidth of the P3 is
>>> generally only one display pixel, about 1/450 of the span. Less
>>> bandwidth means less noise power in each display point. The same thing
>>> happens to some extent with an SSB signal.
>>>
>>> Another issue is that the S meter reading on the K3 may change when you
>>> turn the preamp or attenuator on or off. To prevent that happening, set
>>> CONFIG:SMTR MD to "ABS".
>>>
>>> If you do that and calibrate both the K3 S meter and the P3 amplitude,
>>> then the two should closely agree when measuring a steady CW carrier.
>>>
>>> Alan N1AL
>>>
>
> ______________________________________________________________
> 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
>

kevinr@coho.net

Re: P3 S meter variance

I have quoted Shakespeare in my ECN notes as well as other authors. Many
times an apt quote can say what we cannot say. Or, more often, say it
much better than we ever could.
Kevin. KD5ONS

On Sat, 15 Jan 2011 23:32:58 -0800, Don Wilhelm <[hidden email]>
wrote:

> Alan,
>
> WARNING - I am leading this thread Off-Topic. Delete immediately if you
> object,- some parts are personal.
>
> Quoting Shakespeare on the reflector may be as good or better than some
> of the other "OT" posts that have appeared here in the past (no specific
> examples cited nor intended).
>
> I just might add a few of my favorite Mike Cross (and Tom Paxton) quotes
> to the melay in due time!
> (OK, you can Google if you are not familiar with those artists). The
> humor and sentimentality of Mike Cross's songwriting helped me stay
> grounded through 3 bouts with cancer - he gave me hope and a new
> perspective on life, and I thouroughly enjoy the political satire that
> Tom Paxton has provided me with both a laugh at politics and a deep
> sorrow at the beauracracy that has developed.
>
> From Mike Cross (who does not have an apparent active political agenda
> -- the serious side is embodied in songs like "Red Tailed Hawk", while
> the funny side is characterized by "Elma Turl",or "Granny's Milk
> Cartons".
>
> Tom Paxton does have a political agenda, but has composed and performed
> music ranging from "Ramblin' Boy" to "Lyndon Johnson told the Nation"
> (use Google). Yes, this is stuff from the 1960s and the 1970s, and some
> is anti-war., but the time of Lyndon Johnson and Vietnam are past, so
> just enjoy the music and forget the politics that made that music so
> close to home.
>
> 73,
> Don W3FPR
>
> .1/16/2011 1:20 AM, Alan Bloom wrote:
>> Don,
>>
>>> The manual suggests that you calibrate the S-meter with the preamp ON.
>>> If you do that, and set the S-meter to ABS, you will find that the
>>> S-meter response is about 2 S-units lower than what you may expect.
>> Interesting. I assumed that in ABS mode it didn't matter if the preamp
>> was on or not. I sheepishly admit I have never bothered to calibrate my
>> K3 S meter. No excuse - I have an HP8656B signal generator sitting
>> right next to the K3 - I just never got around to it. I'd do it right
>> now but it's time to go to bed. :=)
>>
>>> The K3 has re-vitalized the old Collins 50
>>> uV equal S-9 "standard". That standard is not a standard at all,
>> Actually IARU Region 1 has published Technical Recommendation R.1 which
>> specifies S9 = -73 dBm (50 uV into 50 ohms) and 6 dB per S-unit.
>> http://en.wikipedia.org/wiki/S_meter#IARU_Region_1_Technical_Recommendation_R.1
>>
>> But you're right, that recommendation is more honored in the breach than
>> the observance. (Gosh, quoting Shakespeare on the reflector - what are
>> we coming to? :=)
>>
>> Alan N1AL
>>
>>
>>
>> On Sun, 2011-01-16 at 00:43 -0500, Don Wilhelm wrote:
>>> Alan,
>>>
>>> I might add about the K3 CONFIG: SMTR MD = ABS, that the calibration
>>> procedure indicated in the manual may (or may not) be the "proper"
>>> thing
>>> to do.
>>> The manual suggests that you calibrate the S-meter with the preamp ON.
>>> If you do that, and set the S-meter to ABS, you will find that the
>>> S-meter response is about 2 S-units lower than what you may expect. I
>>> prefer to do the calibration with the S-meter off, and then the
>>> response
>>> in SMTR ABS is more what I would expect.
>>>
>>> Since everyone's expectations do not necessarily match mine (obviously,
>>> I disagree with Wayne on this item), you can take your pick - do it the
>>> way the manual says, or do it like I have. The choice is entirely
>>> yours. Like all things S-meter reading related, there is a great
>>> variation between receivers, The K3 has re-vitalized the old Collins
>>> 50
>>> uV equal S-9 "standard". That standard is not a standard at all, and
>>> many transceivers do it differently, but with the K3, you do have a
>>> choice depending on how you want to set it up. If you cannot decide
>>> how
>>> you want it, go with the manual instructions - they work and work quite
>>> well. If you deviate, know why you are doing that deviation and know
>>> it
>>> is for your own situation, others may or may not make the same choices.
>>>
>>> 73,
>>> Don W3FPR
>>>
>>> On 1/16/2011 12:20 AM, Alan Bloom wrote:
>>>> There are a couple reasons why the K3's S meter and the P3 display may
>>>> show a different level.
>>>>
>>>> As Don mentioned, the P3 will generally show a much lower level than
>>>> the
>>>> K3 on noise. It's because the effective bandwidth of the P3 is
>>>> generally only one display pixel, about 1/450 of the span. Less
>>>> bandwidth means less noise power in each display point. The same
>>>> thing
>>>> happens to some extent with an SSB signal.
>>>>
>>>> Another issue is that the S meter reading on the K3 may change when
>>>> you
>>>> turn the preamp or attenuator on or off. To prevent that happening,
>>>> set
>>>> CONFIG:SMTR MD to "ABS".
>>>>
>>>> If you do that and calibrate both the K3 S meter and the P3 amplitude,
>>>> then the two should closely agree when measuring a steady CW carrier.
>>>>
>>>> Alan N1AL
>>>>
>>
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Roy Morris-6

Re: P3 S meter variance

In reply to this post by Ai4PF

I have checked the calibration on both of my K3s with my XG-1, and the K3 S meter is miles apart from the P3 readings in S units. If this is going to be the case especially in SSB, just please say thats the way it going to be. There are a lot of us apparently who are perplexed by these incongruent readings. If this is normal, just say so. Thanks. Roy Morris W4WFB
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N5GE

Re: P3 S meter variance

Roy,

Did you calibrate the P3?

Tap the P3 MENU Button

Turn the knob until you see Lvl Cal

With the XG1 on the antenna connector of the K3 and turned on, adjust the level
to S-9.

Tap the knob.

73,

Tom Childers
Radio Amateur N5GE
Licensed since 1976
QCWA Life Member 35102
ARRL Life Member
Retired Professional
C# Software developer
http://www.n5ge.net

On Sun, 16 Jan 2011 12:04:54 -0500, "Roy Morris" <[hidden email]> wrote:

>I have checked the calibration on both of my K3s with my XG-1, and the K3 S meter is miles apart from the P3 readings in S units. If this is going to be the case especially in SSB, just please say thats the way it going to be. There are a lot of us apparently who are perplexed by these incongruent readings. If this is normal, just say so. Thanks. Roy Morris W4WFB
[snip]

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Amateur Radio Operator N5GE

k5oai

Re: P3 S meter variance

I have calibrated both my K3 (using ABS) and P3 by the manual with an XG2

the P3 Transfer gain (db): -12.1

In SSB or AM, if I want the P3's S meter reading to match the K3's S meter
I have to change the P3's Transfer gain (db) to -32.5 db

actually if I'm running 200khz span is should be about -30 db
if I am using 10khz span it should be about -35 db
so I have settled for -32.5 db as an average

feature request
is there some way the P3 could read the mode (bandwidth) of the k3

and then when running SSB or AM modes (bandwidths of 1.8khz to 6khz)
instruct the P3 to use transfer setting A (-xx db)

and then when running cw or data modes (bandwidths of around 400hz)
instruct the P3 to use transfer setting B (-xx db)

with user adjustable settings for A and B transfer settings

that way we could have the best of both worlds

(easy to say when I'm clueless as to what all
kinds of programing nightmares I just requested of Alan)

thank you to *ALL* the Elecraft staff for all the Elecraft mojo magic!

GB & 73
K5OAI
Sam Morgan

On 1/16/2011 12:24 PM, Amateur Radio Operator N5GE wrote:

>
> Roy,
>
> Did you calibrate the P3?
>
> Tap the P3 MENU Button
>
> Turn the knob until you see Lvl Cal
>
> With the XG1 on the antenna connector of the K3 and turned on, adjust the level
> to S-9.
>
> Tap the knob.
>
> 73,
>
> Tom Childers
> Radio Amateur N5GE
> Licensed since 1976
> QCWA Life Member 35102
> ARRL Life Member
> Retired Professional
> C# Software developer
> http://www.n5ge.net
>
>
>
> On Sun, 16 Jan 2011 12:04:54 -0500, "Roy Morris"<[hidden email]> wrote:
>
>> I have checked the calibration on both of my K3s with my XG-1, and the K3 S meter is miles apart from the P3 readings in S units. If this is going to be the case especially in SSB, just please say thats the way it going to be. There are a lot of us apparently who are perplexed by these incongruent readings. If this is normal, just say so. Thanks. Roy Morris W4WFB
> [snip]
>
> ______________________________________________________________
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>
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>

Vic K2VCO

Re: P3 S meter variance

In reply to this post by Roy Morris-6

Before assuming that you have a problem, you should

1) Calibrate the K3 RF gain using the procedure built into the K3 Utility.
2) Calibrate the K3 s-meter using the procedure explained in the K3 manual.
3) Adjust the P3 calibration using the Amplitude Calibration procedure in the latest P3
manual.

You need a signal source like an XG1 or XG2 to do these steps accurately.

On 1/16/2011 9:04 AM, Roy Morris wrote:

> I have checked the calibration on both of my K3s with my XG-1, and the K3 S meter is
> miles apart from the P3 readings in S units. If this is going to be the case
> especially in SSB, just please say thats the way it going to be. There are a lot of us
> apparently who are perplexed by these incongruent readings. If this is normal, just
> say so. Thanks. Roy Morris W4WFB
> ______________________________________________________________ Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft Help:
> http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email]
>
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> http://www.qsl.net/donate.html

--
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/
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Roy Morris-6

Re: P3 S meter variance

In reply to this post by Ai4PF

I have found that -8.9 LVL CAL (transfer gain) is the setting for an S9 reading on my P3 using my XG-1. The readings track right well as long as they are not stronger than S9+20. Signals over this on the K3 S meter are just not correct on my P3. If I change the LVL CAL (transfer gain) to around -27, the strong signals are then correct. This tells me there are no absolute settings that will make the P3 correct at all SSB signal strength levels. YMMV - Your LVL CAL settings will no doubt be different from mine. Roy Morris W4WFB
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alorona

Re: P3 S meter variance

An SSB signal that is S9 on the K3's S-meter is not going to measure S9 on the
P3.

The reason is that an SSB signal has bandwidth, and the sum of all of the signal
within that bandwidth is what the K3's S-meter reads.

You would have to add up all of the power of the SSB signal on the P3's display
to equal S9. This mathematical operation is called integration. The P3 does not
do integration.

Therefore, make all of your calibrations with CW signals, and live with the
apparent discrepancy on SSB.

Al W6LX

________________________________
From: Roy Morris <[hidden email]>
To: [hidden email]
Sent: Sun, January 16, 2011 3:28:53 PM
Subject: Re: [Elecraft] P3 S meter variance

I have found that -8.9 LVL CAL (transfer gain) is the setting for an S9 reading
on my P3 using my XG-1. The readings track right well as long as they are not
stronger than S9+20. Signals over this on the K3 S meter are just not correct
on my P3. If I change the LVL CAL (transfer gain) to around -27, the strong
signals are then correct. This tells me there are no absolute settings that
will make the P3 correct at all SSB signal strength levels. YMMV - Your LVL CAL
settings will no doubt be different from mine. Roy Morris W4WFB
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Mike Scott-7

Re: P3 S meter variance

In reply to this post by Ai4PF

My K3 S-meter and P-3 show identical S-9/S-3 readings at 50 uV and 1uV with
an XG-2 on 40M.

Sideband and particularly band noise are different as noted in previous
posts for obvious reasons.

If your readings are miles apart, time to check calibration of both units. I
went through the calibration procedure of the K3 and P3 long before the
change to S-meter scales and I find that the calibration of the P3 held when
shifting to S-meter scaling.

AE6WA

Mike Scott

Tarzana, CA

Roy wrote: I have checked the calibration on both of my K3s with my XG-1,
and the K3 S meter is miles apart from the P3 readings in S units. If this
is going to be the case especially in SSB, just please say thats the way it
going to be. There are a lot of us apparently who are perplexed by these
incongruent readings. If this is normal, just say so. Thanks. Roy Morris
W4WFB

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