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P3 TX Mon: FEATURE REQUEST - Monitoring of RTTY Waveform

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Lu Romero - W4LT

P3 TX Mon: FEATURE REQUEST - Monitoring of RTTY Waveform

Hello Elecraft folk:

Just installed my new P3 TX Monitor board that I ordered at Dayton (!). I
have been waiting for this capability for the P3 since 2010, so as to enable
me to monitor transmitter waveforms accurately like I did in my Heath
SB-401/SB303 station with the SB610 in ancient times (the late '70's).

So now my O'Scope can go back to the bench where it belongs. Since I already
had an accurate dual meter peak reading Wattmeter (Autek WM-1), the bundled
SWR/Wattmeter capability is not important to me. A good, full featured
visual transmitted waveform monitor was what I was looking for.

However, a big feature is missing from the TX Monitor option: Accurate
monitoring of the direct FSK signal for RTTY. All that is visible on RTTY
transmissions is a solid envelope that fills the screen, just like sampling
RF using my bench 'scope.

True, RTTY is a full carrier FM signal, so the display is showing me the
"correct" interpretation for an envelope sampler, but I was hoping to at
least see the same display we see on RTTY receive: Two pulses with a valley
in between. If both pulses are equal, there is no passband ripple. If
there are single peaks and the fall to the valley is smooth and sinusoidal,
all is well and the transmitter is not being overdriven.

My preference, however, would be to see a traditional crossed ellipsis
display like on my old SB610 and the simulated one on software RTTY apps
(that are NOT real transmitted waveforms!), but I can live with the above.
Neither mode is available on the simple envelope sampler add on that
comprises the TX Monitor today.

I don't use AM here, but the a "Trapezoid" display would also be helpful to
set amplifier linearity and peak modulation.

These features would make a P3 with the TX Mon option a real, full featured,
transmission monitor, which was my assumption that it was to be. Right now,
it's a simple envelope sampler which, while helpful (and cute to show off to
guests), doesn't do what a true full featured transmission monitoring tool
*should* do, especially for RTTY and AM, and especially for its price. I can
do most of what it does with a chunk of wire and any o'scope.

Am I out of line with my expectation? Are these features in the works for a
future software update? If not, they should be!

Lu Romero - W4LT

K-Line

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Al Gulseth-2

Re: P3 TX Mon: FEATURE REQUEST - Monitoring of RTTY Waveform

Lu,

Without addressing what any hardware/software changes needed might entail, I'd
say that you are _not_ "out of line with [your] expectation...." Any request
for features intended help the operator adjust his equipment for a cleaner
transmitted signal is valid in my opinion. In fact, I tip my hat to you: one
doesn't have to listen around very much to hear "crud" on the bands coming
from ops who either don't know and/or don't care about how to adjust things
properly, so by contrast it's refreshing to find someone who is concerned
about his signal quality. (I'm sure there are many others on this list who
also share your desire to strive for the cleanest signal possible.)

73, Al

On Sun September 13 2015 3:29:13 pm Luis V. Romero wrote:

> Hello Elecraft folk:
>
>
>
> Just installed my new P3 TX Monitor board that I ordered at Dayton (!). I
> have been waiting for this capability for the P3 since 2010, so as to
> enable me to monitor transmitter waveforms accurately like I did in my
> Heath SB-401/SB303 station with the SB610 in ancient times (the late
> '70's).
>
>
>
> So now my O'Scope can go back to the bench where it belongs. Since I
> already had an accurate dual meter peak reading Wattmeter (Autek WM-1), the
> bundled SWR/Wattmeter capability is not important to me. A good, full
> featured visual transmitted waveform monitor was what I was looking for.
>
>
>
> However, a big feature is missing from the TX Monitor option: Accurate
> monitoring of the direct FSK signal for RTTY. All that is visible on RTTY
> transmissions is a solid envelope that fills the screen, just like sampling
> RF using my bench 'scope.
>
>
>
> True, RTTY is a full carrier FM signal, so the display is showing me the
> "correct" interpretation for an envelope sampler, but I was hoping to at
> least see the same display we see on RTTY receive: Two pulses with a
> valley in between. If both pulses are equal, there is no passband ripple.
> If there are single peaks and the fall to the valley is smooth and
> sinusoidal, all is well and the transmitter is not being overdriven.
>
>
>
> My preference, however, would be to see a traditional crossed ellipsis
> display like on my old SB610 and the simulated one on software RTTY apps
> (that are NOT real transmitted waveforms!), but I can live with the above.
> Neither mode is available on the simple envelope sampler add on that
> comprises the TX Monitor today.
>
>
>
> I don't use AM here, but the a "Trapezoid" display would also be helpful to
> set amplifier linearity and peak modulation.
>
>
>
> These features would make a P3 with the TX Mon option a real, full
> featured, transmission monitor, which was my assumption that it was to be.
> Right now, it's a simple envelope sampler which, while helpful (and cute to
> show off to guests), doesn't do what a true full featured transmission
> monitoring tool *should* do, especially for RTTY and AM, and especially for
> its price. I can do most of what it does with a chunk of wire and any
> o'scope.
>
>
>
> Am I out of line with my expectation? Are these features in the works for
> a future software update? If not, they should be!
>
>
>
> Lu Romero - W4LT
>
> K-Line
>
>
>
>
>
> ______________________________________________________________
> 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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Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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Alan Bloom

Re: P3 TX Mon: FEATURE REQUEST - Monitoring of RTTY Waveform

In reply to this post by Lu Romero - W4LT

Hi Luis,

As you mentioned, monitoring the amplitude of a properly-functioning
RTTY transmitter is not very interesting. Since FSK is a
constant-amplitude modulation mode, all you see is a constant-amplitude
envelope on the screen. It gets more interesting if there is a problem
in the RTTY transmitter that causes the two tones to come out at
different amplitudes, which would be easy to see on the screen.

The traditional "plus sign" (crossed ellipses) display is normally used
in the FSK receiving demodulator as a tuning aid. As you tune the
receiver the ellipses change their angle. When you see the "plus sign"
then the receiver is tuned correctly.

You can also see if the transmitter has the wrong (or at least
different) frequency shift. In that case the ellipses don't make a
right angle with each other even when the receiver is tuned correctly.
That might be useful in a transmit monitor, but it can't be done using
an RF coupler because it only detects the amplitude, not the frequency.

A "trapezoid" display would be interesting, but it requires two RF
coupler/detectors, one at the input of the amplifier and one at the
output. Any non-linearity in the transmitter shows up as a
non-linearity in the trapezoid. An alternative that serves the same
purpose is a "triangle" display, in which the RF signal ramps up and
down from zero to PEP and back. You feed the mic input of the SSB
transmitter with a (say) 1500-Hz sine wave that is modulated with a
(say) 100 Hz triangle. The P3 TX monitor would then show any
non-linearity in a manner similar to a trapezoid.

Alan N1AL

On 09/13/2015 01:29 PM, Luis V. Romero wrote:

> Hello Elecraft folk:
>
>
>
> Just installed my new P3 TX Monitor board that I ordered at Dayton (!). I
> have been waiting for this capability for the P3 since 2010, so as to enable
> me to monitor transmitter waveforms accurately like I did in my Heath
> SB-401/SB303 station with the SB610 in ancient times (the late '70's).
>
>
>
> So now my O'Scope can go back to the bench where it belongs. Since I already
> had an accurate dual meter peak reading Wattmeter (Autek WM-1), the bundled
> SWR/Wattmeter capability is not important to me. A good, full featured
> visual transmitted waveform monitor was what I was looking for.
>
>
>
> However, a big feature is missing from the TX Monitor option: Accurate
> monitoring of the direct FSK signal for RTTY. All that is visible on RTTY
> transmissions is a solid envelope that fills the screen, just like sampling
> RF using my bench 'scope.
>
>
>
> True, RTTY is a full carrier FM signal, so the display is showing me the
> "correct" interpretation for an envelope sampler, but I was hoping to at
> least see the same display we see on RTTY receive: Two pulses with a valley
> in between. If both pulses are equal, there is no passband ripple. If
> there are single peaks and the fall to the valley is smooth and sinusoidal,
> all is well and the transmitter is not being overdriven.
>
>
>
> My preference, however, would be to see a traditional crossed ellipsis
> display like on my old SB610 and the simulated one on software RTTY apps
> (that are NOT real transmitted waveforms!), but I can live with the above.
> Neither mode is available on the simple envelope sampler add on that
> comprises the TX Monitor today.
>
>
>
> I don't use AM here, but the a "Trapezoid" display would also be helpful to
> set amplifier linearity and peak modulation.
>
>
>
> These features would make a P3 with the TX Mon option a real, full featured,
> transmission monitor, which was my assumption that it was to be. Right now,
> it's a simple envelope sampler which, while helpful (and cute to show off to
> guests), doesn't do what a true full featured transmission monitoring tool
> *should* do, especially for RTTY and AM, and especially for its price. I can
> do most of what it does with a chunk of wire and any o'scope.
>
>
>
> Am I out of line with my expectation? Are these features in the works for a
> future software update? If not, they should be!
>
>
>
> Lu Romero - W4LT
>
> K-Line
>

Grant Youngman

Re: P3 TX Mon: FEATURE REQUEST - Monitoring of RTTY Waveform

In reply to this post by Al Gulseth-2

But certainly it isn't necessary to wait around for Elecraft to provide. There are all kinds of tried and true and well documented ways to do all of the things.

We've apparently come to the point where we expect our radio vendor to do EVERYTHING for us, instead if just doing it for ourselves. Why does our radio have to do all of it? It isn't always just a few more lines of code, after all.

So E'craft doesn't provide a trapezoid or RTTY cross display or turn on the coffee pot? So?

Grant NQ5T
Just feeling contrary -- as usual ;)

Sent from my iPhone

> On Sep 13, 2015, at 6:05 PM, Al Gulseth <[hidden email]> wrote:
>
> Lu,
>
> Without addressing what any hardware/software changes needed might entail, I'd
> say that you are _not_ "out of line with [your] expectation...."
______________________________________________________________
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Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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Gary Gregory-2

Re: P3 TX Mon: FEATURE REQUEST - Monitoring of RTTYWaveform

Grant,

Your not the only one who thinks the same way you do.

Gary

-----Original Message-----
From: "Grant Youngman" <[hidden email]>
Sent: ‎14/‎09/‎2015 2:15 PM
To: "[hidden email]" <[hidden email]>
Subject: Re: [Elecraft] P3 TX Mon: FEATURE REQUEST - Monitoring of RTTYWaveform

But certainly it isn't necessary to wait around for Elecraft to provide. There are all kinds of tried and true and well documented ways to do all of the things.

We've apparently come to the point where we expect our radio vendor to do EVERYTHING for us, instead if just doing it for ourselves. Why does our radio have to do all of it? It isn't always just a few more lines of code, after all.

So E'craft doesn't provide a trapezoid or RTTY cross display or turn on the coffee pot? So?

Grant NQ5T
Just feeling contrary -- as usual ;)

Sent from my iPhone

> On Sep 13, 2015, at 6:05 PM, Al Gulseth <[hidden email]> wrote:
>
> Lu,
>
> Without addressing what any hardware/software changes needed might entail, I'd
> say that you are _not_ "out of line with [your] expectation...."
______________________________________________________________
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]
______________________________________________________________
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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Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Lu Romero - W4LT

Re: P3 TX Mon: FEATURE REQUEST - Monitoring of RTTY Waveform

In reply to this post by Lu Romero - W4LT

Alan:

You wrote:

It gets more interesting if there is a problem

in the RTTY transmitter that causes the two tones to come out at

different amplitudes, which would be easy to see on the screen.

In your example, you would see ripple in the flat waveform on the screen,
true enough. The Ripple would increase with the amount of the different
amplitudes of the two tones.

However, I can't monitor other issues that can rear their ugly heads in
RTTY, be it modulated by FSK or AFSK with the existing functionality
available: The reason I was looking for a better visual representation of
these issues in this tool is explained in an excellent article by Andy
Flowers, K0SM.

http://frontiernet.net/~aflowers/k3rtty/k3rtty.html

Gee, it would be nice not to have to buy a Flex rig just to monitor my K3's
output. And I already have an SDR receiver sitting inside the P3 box, locked
to my transmitter frequency.

You wrote:

The traditional "plus sign" (crossed ellipses) display is normally used

in the FSK receiving demodulator as a tuning aid. As you tune the

receiver the ellipses change their angle. When you see the "plus sign"

then the receiver is tuned correctly.

Not just for receive, but in transmit as well. Especially in tone modulated
RTTY (pseudo FSK) using AFSK "tone" modulation. If one tone is off, it
would be shown in the transmission ellipsoid representation as well. When
you see a "plus sign", both tones are in phase and in quadrature. But if
one tone is out of quadrature? Then you see an ellipse. We deal with this
daily in the representation of Trellis modulation artifacts in ATV
transmitters. There we call it "The Eye Pattern". Same display principle.

While the dual ellipse waveform would be ideal, there are alternatives, In
receive, we can see similar information in the two tone demodulation
"envelope" showing two peaks with a valley in between using a single
envelope detector as described bu K0SM. Why not avail us of at least that
waveform, since you already can show it on receive in the P3
hardware/software? With some handles on the display for gain, width, slope
and maybe a synthetic "mask", it solves this requirement!

You wrote:

You can also see if the transmitter has the wrong (or at least

different) frequency shift. In that case the ellipses don't make a

right angle with each other even when the receiver is tuned correctly.

True and correct. And I agree.

You wrote:

That might be useful in a transmit monitor, but it can't be done using

An RF coupler because it only detects the amplitude, not the frequency.

True: Not the *quadrature* (two ellipsoids) display. But you *can* show the
dual peak/valley display. You already show it on receive! It is an
equivalent 2-D representation that can be used in addition to the flat
envelope display. But, alas, I can't see it in transmit (yes, I could
unplug the control cable to see IF "bleedthrough", but what a pain!). The
way it is now, I can only tell folks I am receiving that they are having
problems. I can't proactively solve my own problems before I transmit with
my monitoring tool!

I don't know. Maybe I'm just old fashioned, but I'm really disappointed to
have waited 5 years and paid $200 for this simple envelope sampler
functionality using a repurposed WM2 sampling bridge. I sort of expected
more. Maybe not in hardware, but in the application software, as all
hardware for this type of measurement is synthesized in apps anymore. For
$200 more I could have gotten a Wavenode WN-2, but then I have wasted the
wattmeter again and I would need another PC to run the app software. But
the funniest thing is that the P3 can display an equivalent waveform today
in receive that does what I need for transmission monitoring!

I'm still no better off and $200 poorer than where I was with my Bench
Oscilloscope and a 17 inch piece of hook up wire, and that is the issue.
It's the first time I have been disappointed by an Elecraft product.

Lu - W4LT

______________________________________________________________
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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Joe Subich, W4TV-4

Re: P3 TX Mon: FEATURE REQUEST - Monitoring of RTTY Waveform

On 9/14/2015 2:55 PM, Luis V. Romero wrote:
>
> However, I can't monitor other issues that can rear their ugly heads
> in RTTY, be it modulated by FSK or AFSK with the existing
> functionality available: The reason I was looking for a better visual
> representation of these issues in this tool is explained in an
> excellent article by Andy Flowers, K0SM.
>
> http://frontiernet.net/~aflowers/k3rtty/k3rtty.html

The displays generated by K0SM are frequency domain ... TX MON is
strictly a time domain (amplitude) display. TX Mon uses a amplitude
detector driven by a directional coupler. To do what you desire would
require an SDR tuned by frequency data (TX frequency) from the K3.

The difference between an envelope (diode) detector and a tracking SDR
is a couple of orders of magnitude in both cost and complexity.

73,

... Joe, W4TV

On 9/14/2015 2:55 PM, Luis V. Romero wrote:

> Alan:
>
>
>
> You wrote:
>
> It gets more interesting if there is a problem
>
> in the RTTY transmitter that causes the two tones to come out at
>
> different amplitudes, which would be easy to see on the screen.
>
>
>
> In your example, you would see ripple in the flat waveform on the screen,
> true enough. The Ripple would increase with the amount of the different
> amplitudes of the two tones.
>
>
>
> However, I can't monitor other issues that can rear their ugly heads in
> RTTY, be it modulated by FSK or AFSK with the existing functionality
> available: The reason I was looking for a better visual representation of
> these issues in this tool is explained in an excellent article by Andy
> Flowers, K0SM.
>
>
>
> http://frontiernet.net/~aflowers/k3rtty/k3rtty.html
>
>
>
> Gee, it would be nice not to have to buy a Flex rig just to monitor my K3's
> output. And I already have an SDR receiver sitting inside the P3 box, locked
> to my transmitter frequency.
>
>
>
> You wrote:
>
> The traditional "plus sign" (crossed ellipses) display is normally used
>
> in the FSK receiving demodulator as a tuning aid. As you tune the
>
> receiver the ellipses change their angle. When you see the "plus sign"
>
> then the receiver is tuned correctly.
>
>
>
> Not just for receive, but in transmit as well. Especially in tone modulated
> RTTY (pseudo FSK) using AFSK "tone" modulation. If one tone is off, it
> would be shown in the transmission ellipsoid representation as well. When
> you see a "plus sign", both tones are in phase and in quadrature. But if
> one tone is out of quadrature? Then you see an ellipse. We deal with this
> daily in the representation of Trellis modulation artifacts in ATV
> transmitters. There we call it "The Eye Pattern". Same display principle.
>
>
>
> While the dual ellipse waveform would be ideal, there are alternatives, In
> receive, we can see similar information in the two tone demodulation
> "envelope" showing two peaks with a valley in between using a single
> envelope detector as described bu K0SM. Why not avail us of at least that
> waveform, since you already can show it on receive in the P3
> hardware/software? With some handles on the display for gain, width, slope
> and maybe a synthetic "mask", it solves this requirement!
>
>
>
> You wrote:
>
> You can also see if the transmitter has the wrong (or at least
>
> different) frequency shift. In that case the ellipses don't make a
>
> right angle with each other even when the receiver is tuned correctly.
>
>
>
> True and correct. And I agree.
>
>
>
> You wrote:
>
> That might be useful in a transmit monitor, but it can't be done using
>
> An RF coupler because it only detects the amplitude, not the frequency.
>
>
>
> True: Not the *quadrature* (two ellipsoids) display. But you *can* show the
> dual peak/valley display. You already show it on receive! It is an
> equivalent 2-D representation that can be used in addition to the flat
> envelope display. But, alas, I can't see it in transmit (yes, I could
> unplug the control cable to see IF "bleedthrough", but what a pain!). The
> way it is now, I can only tell folks I am receiving that they are having
> problems. I can't proactively solve my own problems before I transmit with
> my monitoring tool!
>
>
>
> I don't know. Maybe I'm just old fashioned, but I'm really disappointed to
> have waited 5 years and paid $200 for this simple envelope sampler
> functionality using a repurposed WM2 sampling bridge. I sort of expected
> more. Maybe not in hardware, but in the application software, as all
> hardware for this type of measurement is synthesized in apps anymore. For
> $200 more I could have gotten a Wavenode WN-2, but then I have wasted the
> wattmeter again and I would need another PC to run the app software. But
> the funniest thing is that the P3 can display an equivalent waveform today
> in receive that does what I need for transmission monitoring!
>
>
>
> I'm still no better off and $200 poorer than where I was with my Bench
> Oscilloscope and a 17 inch piece of hook up wire, and that is the issue.
> It's the first time I have been disappointed by an Elecraft product.
>
>
>
>
>
> Lu - W4LT
>
>
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>