K4 S-meter characteristics

[wayne burdick]

We've been making some final changes to firmware associated with the S-meters. Seemed like a good time to summarize how they work.

The S-meters in the K4 have been upgraded from the K3/K3S:

- separate, color-coded S-meters for VFO A and B

- higher resolution (twice as many bars)

- calibration maintained over a wide range of input signals

The two S-meters are calibrated at S9 = -73 dBm (50 uV). As you change receiver front-end gain settings (preamp off/1/2, attenautor 0 to 21 dB) the S-meter level remains virtually constant. Calibration also takes into account the main/sub receiver -3 dB splitters (if engaged) and any slight variations in per-band BPF loss. The upshot is that you get a very accurate signal level indication.

In addition to the S-meters, the K4 provides a convenient way to see signal levels directly in dB (relative). Typically you'd zero the reference level on band noise, then tune into a signal to get the dB increase (S+N / N). This is useful for comparison tests. The numeric values for dB, both main and sub, are shown in the status area of the display, so they don't overwrite VFO B as on the K3/K3S.

In conjunction with these changes, we're updating the "SMH" remote-control command (high-resolution S-meter read) so that it reads directly in dBm.

The S-meters can also be tapped to show the "mini-pan," the K4's high-resolution tuning aid.

Wayne
N6KR

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[cbscholl]

I do not believe that I saw in any demonstrations but was any thought ever
given to include traditional type meter faces rather than the horizontal
meters used in the past elecraft products?

Barney
K3LA



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[wayne burdick]

Simulation of traditional analog meters is possible, though not in the works at present.

The advantage of the K4's present high-resolution bar graphs is especially apparent in transmit mode, where we simultaneously show forward power, SWR, ALC, and compression. We've found this to be extremely effective, and [speaking personally] it would be hard to go back to a single-parameter meter movement. That said, as with other wish-list items, we'll keep track of demand for this and could add it in the future.

73,
Wayne
N6KR

> On Apr 23, 2020, at 12:20 PM, cbscholl <[hidden email]> wrote:
>
> I do not believe that I saw in any demonstrations but was any thought ever
> given to include traditional type meter faces rather than the horizontal
> meters used in the past elecraft products?
>
> Barney
> K3LA
>
>
>
> --
> Sent from: http://elecraft.365791.n2.nabble.com/
> ______________________________________________________________
> 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
> Message delivered to [hidden email]

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[cbscholl]

The question was more an understanding of the reasoning, which you answered,
rather than a request, since other manufacturers include such faces. Just
thinking, if auto makers included bar graphs they could fit more on a given
screen but might take our eyes off the road longer. Enough of these
thoughts.

73 Barney K3LA

-----Original Message-----
From: Wayne Burdick [mailto:[hidden email]]
Sent: Thursday, April 23, 2020 3:30 PM
To: cbscholl <[hidden email]>
Cc: Elecraft Reflector <[hidden email]>
Subject: Re: [Elecraft] K4 S-meter characteristics

Simulation of traditional analog meters is possible, though not in the works
at present.

The advantage of the K4's present high-resolution bar graphs is especially
apparent in transmit mode, where we simultaneously show forward power, SWR,
ALC, and compression. We've found this to be extremely effective, and
[speaking personally] it would be hard to go back to a single-parameter
meter movement. That said, as with other wish-list items, we'll keep track
of demand for this and could add it in the future.

73,
Wayne
N6KR

> On Apr 23, 2020, at 12:20 PM, cbscholl <[hidden email]> wrote:
>
> I do not believe that I saw in any demonstrations but was any thought
> ever given to include traditional type meter faces rather than the
> horizontal meters used in the past elecraft products?
>
> Barney
> K3LA
>
>
>
> --
> Sent from: http://elecraft.365791.n2.nabble.com/
> ______________________________________________________________
> 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 Message delivered to
> [hidden email]

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[Bob Wilson, N6TV]

On Thu, Apr 23, 2020 at 10:01 AM Wayne Burdick <[hidden email]> wrote:

> The two S-meters are calibrated at S9 = -73 dBm (50 uV).


Will the K4 S-meter be calibrated at *6 dB per S-unit* as per the ITU
Recommendation
<https://en.wikipedia.org/wiki/S_meter#IARU_Region_1_Technical_Recommendation_R.1>,
or 5 dB per S-unit, like the K3?

FYI, the P3 uses 6 dB per S-unit.

I hope the K4 will also use 6 dB, even if it means "breaking tradition"
with the legendary K3.

73,
Bob, N6TV
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[Greg Troxel-2]

Wayne Burdick <[hidden email]> writes:

Thanks for the note.  I am a fan of radios being able to serve as test
equipment, when that's a reasonable approach.

> In addition to the S-meters, the K4 provides a convenient way to see
> signal levels directly in dB (relative). Typically you'd zero the
> reference level on band noise, then tune into a signal to get the dB
> increase (S+N / N). This is useful for comparison tests. The numeric
> values for dB, both main and sub, are shown in the status area of the
> display, so they don't overwrite VFO B as on the K3/K3S.

I am not sure how popular this request will be, but I would like to be
able to see signal levels in dBm.  Given what you said, that's just a
different labeling, similar to how the PX3 can label in dBm or S units.
But without seeing it, I realize that it could be awkward to have lots
of large negative numbers, and if "S1" really means -73 - 8 * 6 = -121
dBm, as it seems to on the PX3, there's no real need.  Probably, it's
enough to see this in the "P4" section, and to use the SHM interface
command.

I think you are intending to stick to -73 dBm for 6m as well.  There is
a notion of using 5 uV for VHF, but I think that's more confusing than
helpful, so I am in favor of -73 dBm for S9 always.

It would also be nice for the KX3 to finally get the long-discussed
absolute S-meter mode.

73 de n1dam
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