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MMTTY FSK

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Brett Howard

MMTTY FSK

Ok so I've never done RTTY via true FSK only audio modes... I have to
put in a fence this weekend so I won't be able to play this weekend but
I'm trying to get ready for FD...

So I've made an interface that consists of a couple opto couplers (one
for FSK and one for PTT)... I've got the radio all setup and shorting
the FSK_IN pin to GND makes the radio switch tones as it should...

However I'm having issues getting MMTTY to open the COM port. I'm using
an FTDI based USB->RS232 converter. The MMTTY settings have the USB
button right there and they tell me to click on the last 3 options.
I've tried all 3 but in all 3 modes I get the unable to open COM3
error...

I'm going to be googling and seeing if anyone else has had this issue
with me but I figured I'd pose here in the event someone here has
already run into this issue.

~Brett (N7MG)

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Iain MacDonnell - N6ML-2

Re: MMTTY FSK

Hi Brett,

You might want to look at EXTFSK/COMFSK ... it's generally known to
work well with USB adapters...

http://mmhamsoft.amateur-radio.ca/pages/mmtty/ext-fsk.php

Also make sure no other application has the COM port open, and that
your FTDI adapter really is COM3!

~Iain / N6ML

On Fri, Jun 11, 2010 at 10:54 PM, Brett Howard <[hidden email]> wrote:

> Ok so I've never done RTTY via true FSK only audio modes... I have to
> put in a fence this weekend so I won't be able to play this weekend but
> I'm trying to get ready for FD...
>
> So I've made an interface that consists of a couple opto couplers (one
> for FSK and one for PTT)... I've got the radio all setup and shorting
> the FSK_IN pin to GND makes the radio switch tones as it should...
>
> However I'm having issues getting MMTTY to open the COM port. I'm using
> an FTDI based USB->RS232 converter. The MMTTY settings have the USB
> button right there and they tell me to click on the last 3 options.
> I've tried all 3 but in all 3 modes I get the unable to open COM3
> error...
>
> I'm going to be googling and seeing if anyone else has had this issue
> with me but I figured I'd pose here in the event someone here has
> already run into this issue.
>
> ~Brett (N7MG)
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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Mike Reublin

Re: MMTTY FSK

In reply to this post by Brett Howard

When I got my K3, I was hot to get it set up on FSK. Somebody here
convinced me to try AFSK, and I was blown away by how simple it is, and
less complicated to set up. AFAICT, FSK offers no advantage.

73, Mike NF4L

Brett Howard wrote:

Greg - AB7R

Re: MMTTY FSK

In reply to this post by Brett Howard

Brett

Go into device manager and change the COM number to something unused and
other than "3". As you know, many computers reserve or use COM3 in the
background for such things as modems.

73
Greg
AB7R

On 6/11/2010 3:54 PM, Brett Howard wrote:

Brett Howard

Re: MMTTY FSK

Iain actually pointed me in the direction of using the EXTFSK .dll
interface as the FTDI interfaces don't support any speeds less than 300
bps. EXTFSK uses the media timers to generate the baud rates at slower
speeds. Kinda stinks that you've gotta use windows timers as that was
the main reason why I had to buy the K1EL keyer because the Windows
timing was junk... However the K3 is already ready to rock and roll
doing things via AFSK or FSK so I can easily switch between the two
methods in the field with no trouble what-so-ever.

~Brett

On Fri, 2010-06-11 at 16:56 -0700, Greg wrote:

> Brett
>
> Go into device manager and change the COM number to something unused and
> other than "3". As you know, many computers reserve or use COM3 in the
> background for such things as modems.
>
> 73
> Greg
> AB7R
>
>
> On 6/11/2010 3:54 PM, Brett Howard wrote:
> > Ok so I've never done RTTY via true FSK only audio modes... I have to
> > put in a fence this weekend so I won't be able to play this weekend but
> > I'm trying to get ready for FD...
> >
> > So I've made an interface that consists of a couple opto couplers (one
> > for FSK and one for PTT)... I've got the radio all setup and shorting
> > the FSK_IN pin to GND makes the radio switch tones as it should...
> >
> > However I'm having issues getting MMTTY to open the COM port. I'm using
> > an FTDI based USB->RS232 converter. The MMTTY settings have the USB
> > button right there and they tell me to click on the last 3 options.
> > I've tried all 3 but in all 3 modes I get the unable to open COM3
> > error...
> >
> > I'm going to be googling and seeing if anyone else has had this issue
> > with me but I figured I'd pose here in the event someone here has
> > already run into this issue.
> >
> > ~Brett (N7MG)
> >
> > ______________________________________________________________
> > 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
> >
> >
> ______________________________________________________________
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> Post: mailto:[hidden email]
>
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Brett Howard

Re: MMTTY FSK

In reply to this post by Mike Reublin

I'm one of those guys that is a glutton for punishment... To me the
fact that FSK is more complicated and I've not done it before is the
actual advantage. I do see FSK as a method that is slightly less prone
to TX distortions. I built my interface using opto couplers and then
put in a few jumpers to allow for several grounding situations. Turned
out that 100% disconnect between all grounds is working very well.

~Brett (N7MG)

On Fri, 2010-06-11 at 19:28 -0400, Mike wrote:

> When I got my K3, I was hot to get it set up on FSK. Somebody here
> convinced me to try AFSK, and I was blown away by how simple it is, and
> less complicated to set up. AFAICT, FSK offers no advantage.
>
> 73, Mike NF4L
>
> Brett Howard wrote:
> > Ok so I've never done RTTY via true FSK only audio modes... I have to
> > put in a fence this weekend so I won't be able to play this weekend but
> > I'm trying to get ready for FD...
> >
> > So I've made an interface that consists of a couple opto couplers (one
> > for FSK and one for PTT)... I've got the radio all setup and shorting
> > the FSK_IN pin to GND makes the radio switch tones as it should...
> >
> > However I'm having issues getting MMTTY to open the COM port. I'm using
> > an FTDI based USB->RS232 converter. The MMTTY settings have the USB
> > button right there and they tell me to click on the last 3 options.
> > I've tried all 3 but in all 3 modes I get the unable to open COM3
> > error...
> >
> > I'm going to be googling and seeing if anyone else has had this issue
> > with me but I figured I'd pose here in the event someone here has
> > already run into this issue.
> >
> > ~Brett (N7MG)
> >
> > ______________________________________________________________
> > 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
> >
> >
>
>

Mike Reublin

Re: MMTTY FSK

Fair enough.

Mike NF4L

Brett Howard wrote:

> I'm one of those guys that is a glutton for punishment... To me the
> fact that FSK is more complicated and I've not done it before is the
> actual advantage. I do see FSK as a method that is slightly less prone
> to TX distortions. I built my interface using opto couplers and then
> put in a few jumpers to allow for several grounding situations. Turned
> out that 100% disconnect between all grounds is working very well.
>
> ~Brett (N7MG)
>
> On Fri, 2010-06-11 at 19:28 -0400, Mike wrote:
>
>> When I got my K3, I was hot to get it set up on FSK. Somebody here
>> convinced me to try AFSK, and I was blown away by how simple it is, and
>> less complicated to set up. AFAICT, FSK offers no advantage.
>>
>> 73, Mike NF4L
>>
>> Brett Howard wrote:
>>
>>> Ok so I've never done RTTY via true FSK only audio modes... I have to
>>> put in a fence this weekend so I won't be able to play this weekend but
>>> I'm trying to get ready for FD...
>>>
>>> So I've made an interface that consists of a couple opto couplers (one
>>> for FSK and one for PTT)... I've got the radio all setup and shorting
>>> the FSK_IN pin to GND makes the radio switch tones as it should...
>>>
>>> However I'm having issues getting MMTTY to open the COM port. I'm using
>>> an FTDI based USB->RS232 converter. The MMTTY settings have the USB
>>> button right there and they tell me to click on the last 3 options.
>>> I've tried all 3 but in all 3 modes I get the unable to open COM3
>>> error...
>>>
>>> I'm going to be googling and seeing if anyone else has had this issue
>>> with me but I figured I'd pose here in the event someone here has
>>> already run into this issue.
>>>
>>> ~Brett (N7MG)
>>>
>>> ______________________________________________________________
>>> 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
>>>
>>>
>>>
>>
>
>
>
>

Richard Ferch

Re: MMTTY FSK

In reply to this post by Brett Howard

Brett Howard wrote:
> I do see FSK as a method that is slightly less prone
> to TX distortions.

You might be surprised. In my setup I can switch back and forth
instantly between FSK and AFSK. I have done some testing with a second
receiver, and my K3's RTTY signal seems to be cleaner in AFSK than FSK
(lower odd-order sidebands). My guess is that this is due to keying
transients in FSK. I assume the AFSK from MMTTY uses some form of
waveform shaping or phase-coherent transitions between the two tones,
resulting in lower keying transients.

73,
Rich VE3KI
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Bob Naumann W5OV

Re: MMTTY FSK

In reply to this post by Mike Reublin

Where did the idea that FSK is more difficult come from?

FSK requires no setting of transmit audio levels or concerns about sound
card settings - for transmission.

To me, this cuts the difficulty in half.

Using a RigExpert or MicroHam (or their equivalent) Interface it's basically
automatic and requires no fiddling with levels.

100% FSK RTTY here. Zero problems.

73,

Bob W5OV

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Mike
Sent: Saturday, June 12, 2010 6:37 AM
To: Brett Howard
Cc: elecraft
Subject: Re: [Elecraft] MMTTY FSK

Fair enough.

Mike NF4L

Brett Howard wrote:

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KK7P

Re: MMTTY FSK

In reply to this post by Richard Ferch

> ...In my setup I can switch back and forth
> instantly between FSK and AFSK. I have done some testing with a second
> receiver, and my K3's RTTY signal seems to be cleaner in AFSK than FSK
> (lower odd-order sidebands).

The K3 uses continuous-phase switching between the IF (and AF monitor)
tones, but no shaping, in FSK. The Tx signal passes through the 2.7 (or
2.8) kHz IF filter, of course.

During AFSK operation, the audio passes through some AF filtering as
well as IF filtering.

The K3 also has an AFSK Tx Filter that can optionally be switched in
(CONFIG:AFSK TX FIL ON|OFF, default is OFF) which provides a much
narrower AF filter centered on the RTTY tones (using the FSK PITCH
control). If you choose to use this filter, be sure your software is
set up in a fixed pitch mode, and not "click the waterfall" or "AFC ON"
where your Tx tones could be anywhere in the wider audio passband as
defined by the waterfall display.

73,

Lyle KK7P

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Brett Howard

Re: MMTTY FSK

In reply to this post by Bob Naumann W5OV

Its not more difficult just more fun cause I got to pull out the screwdriver
and soldering iron. That and it was harder for me cause that method I'd not
used before. I like using fsk and made a few contacts with it last night so
I can now say Ive make both ways work successfully.

~Brett (N7MG)

On Jun 12, 2010 5:14 AM, "Bob Naumann" <[hidden email]> wrote:
Where did the idea that FSK is more difficult come from?

FSK requires no setting of transmit audio levels or concerns about sound
card settings - for transmission.

To me, this cuts the difficulty in half.

Using a RigExpert or MicroHam (or their equivalent) Interface it's basically
automatic and requires no fiddling with levels.

100% FSK RTTY here. Zero problems.

73,

Bob W5OV

-----Original Message-----
From: [hidden email]
[mailto:elecraft-bounces@mailman....
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Kok Chen

Re: MMTTY FSK

In reply to this post by Richard Ferch

On Jun 12, 2010, at 6/12 5:09 AM, Richard Ferch wrote:

> Brett Howard wrote:
>> I do see FSK as a method that is slightly less prone
>> to TX distortions.
>
> I have done some testing with a second
> receiver, and my K3's RTTY signal seems to be cleaner in AFSK than FSK
> (lower odd-order sidebands).

That is indeed correct. AFSK can potentially produce cleaner signals
than FSK, as long the transmit IMD is good. Take a look at the last
two figures on this page:

http://homepage.mac.com/chen/Technical/K3/Digital/digital.html

cocoaModem applies a filter to reduce the keying sidebands. Except
for having two tones, the result is similar to what Alex VE3NEA had
described in his CW keying experiments article in QEX a couple of
years ago.

The difference between FSK and AFSK can be even greater than what I'd
measured if the K3 transmitter were cleaner. Waveshaping the keying
signal created albeit small, temporal overlap between the two RTTY
tones, whereas an unwaveshaped FSK signal has no overlap and can be
used even with class C amplifiers.

You can indeed see the low level IMD spikes from the in the last
screen capture.

73
Chen, W7AY

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Rick Prather-2

Re: MMTTY FSK

Chen,

Very interesting. Thanks for your link.

Have you looked at the waveform with the AFSK TX Filter turned on?

Rick
K6LE

On 6/12/2010, at 9:09 , Kok Chen wrote:

> On Jun 12, 2010, at 6/12 5:09 AM, Richard Ferch wrote:
>
>> Brett Howard wrote:
>>> I do see FSK as a method that is slightly less prone
>>> to TX distortions.
>>
>> I have done some testing with a second
>> receiver, and my K3's RTTY signal seems to be cleaner in AFSK than FSK
>> (lower odd-order sidebands).
>
> That is indeed correct. AFSK can potentially produce cleaner signals
> than FSK, as long the transmit IMD is good. Take a look at the last
> two figures on this page:
>
> http://homepage.mac.com/chen/Technical/K3/Digital/digital.html
>
> cocoaModem applies a filter to reduce the keying sidebands. Except
> for having two tones, the result is similar to what Alex VE3NEA had
> described in his CW keying experiments article in QEX a couple of
> years ago.
>
> The difference between FSK and AFSK can be even greater than what I'd
> measured if the K3 transmitter were cleaner. Waveshaping the keying
> signal created albeit small, temporal overlap between the two RTTY
> tones, whereas an unwaveshaped FSK signal has no overlap and can be
> used even with class C amplifiers.
>
> You can indeed see the low level IMD spikes from the in the last
> screen capture.
>
> 73
> Chen, W7AY
>

Mike Reublin

Re: MMTTY FSK

In reply to this post by Bob Naumann W5OV

Not more difficult, just more equipment involved (and $$).... unless
you're doing it all from the K3, not using any external interface.

73, Mike NF4L

Bob Naumann wrote:

> Where did the idea that FSK is more difficult come from?
>
> FSK requires no setting of transmit audio levels or concerns about sound
> card settings - for transmission.
>
> To me, this cuts the difficulty in half.
>
> Using a RigExpert or MicroHam (or their equivalent) Interface it's basically
> automatic and requires no fiddling with levels.
>
> 100% FSK RTTY here. Zero problems.
>
> 73,
>
> Bob W5OV
>
> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of Mike
> Sent: Saturday, June 12, 2010 6:37 AM
> To: Brett Howard
> Cc: elecraft
> Subject: Re: [Elecraft] MMTTY FSK
>
> Fair enough.
>
> Mike NF4L
>
> Brett Howard wrote:
>
>> I'm one of those guys that is a glutton for punishment... To me the
>> fact that FSK is more complicated and I've not done it before is the
>> actual advantage. I do see FSK as a method that is slightly less prone
>> to TX distortions. I built my interface using opto couplers and then
>> put in a few jumpers to allow for several grounding situations. Turned
>> out that 100% disconnect between all grounds is working very well.
>>
>> ~Brett (N7MG)
>>
>> On Fri, 2010-06-11 at 19:28 -0400, Mike wrote:
>>
>>
>>> When I got my K3, I was hot to get it set up on FSK. Somebody here
>>> convinced me to try AFSK, and I was blown away by how simple it is, and
>>> less complicated to set up. AFAICT, FSK offers no advantage.
>>>
>>> 73, Mike NF4L
>>>
>>> Brett Howard wrote:
>>>
>>>
>>>> Ok so I've never done RTTY via true FSK only audio modes... I have to
>>>> put in a fence this weekend so I won't be able to play this weekend but
>>>> I'm trying to get ready for FD...
>>>>
>>>> So I've made an interface that consists of a couple opto couplers (one
>>>> for FSK and one for PTT)... I've got the radio all setup and shorting
>>>> the FSK_IN pin to GND makes the radio switch tones as it should...
>>>>
>>>> However I'm having issues getting MMTTY to open the COM port. I'm using
>>>> an FTDI based USB->RS232 converter. The MMTTY settings have the USB
>>>> button right there and they tell me to click on the last 3 options.
>>>> I've tried all 3 but in all 3 modes I get the unable to open COM3
>>>> error...
>>>>
>>>> I'm going to be googling and seeing if anyone else has had this issue
>>>> with me but I figured I'd pose here in the event someone here has
>>>> already run into this issue.
>>>>
>>>> ~Brett (N7MG)
>>>>
>>>> ______________________________________________________________
>>>> 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
>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>
>>
>>
>
>
> ______________________________________________________________
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>
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> ______________________________________________________________
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> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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>
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>
>

John_N1JM

Re: MMTTY FSK

In reply to this post by Kok Chen

In real world operating, has anyone really experienced a difference or could tell a difference?

k6dgw

Re: MMTTY FSK

N1JM wrote:
> In real world operating, has anyone really experienced a difference or could
> tell a difference?

If AFSK is working right, I don't think it is possible to tell the
difference between it and FSK by listening [unless the two audio tones
aren't clean sine waves]. I think the real difference between FSK and
AFSK is that the interface in FSK has some hardware involved but is
pretty straight forward in MMTTY config, while AFSK requires only a
couple of audio cables but you have to make sure the K3 Pitch and MMTTY
mark frequency are set to the same values.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2010 Cal QSO Party 2-3 Oct 2010
- www.cqp.org

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Kok Chen

Re: MMTTY FSK

In reply to this post by John_N1JM

On Jun 13, 2010, at 2:07 PM, N1JM wrote:
> In real world operating, has anyone really experienced a difference or could
> tell a difference?

When you are a weak station looking for holes in between loud stations to put yourself in, yes, it will matter how wide those stations are.

(It is like asking if wide CW keying sidebands (keyclicks) bothers anybody.)

But my original response was really to document that fact that AFSK from a K3 can indeed be cleaner than FSK, in support of VE3KI's statement which responded to an earlier posting by someone else that said:

> I do see FSK as a method that is slightly less prone to TX distortions.

The K3's transmit IMD, although not stellar, is already good enough that you can produce an AFSK signal which is cleaner than the internally produced FSK for now. (If Elecraft can waveshape the CW signal, they probably can also do it to an FSK signal, thus the "for now" in the previous sentence.)

What the K3 is very good at is how easy it is to adjust for the AFSK levels, and that VOX is available for use in digital modes (not true in many other rigs). It makes AFSK simpler and cheaper to set up than many other rigs.

Cleaner signal, simpler setup, and cheaper... what is there not to like?

To make it any simpler for digital mode users, the K3 would need an integrated USB sound card.

73
Chen, W7AY

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John_N1JM

Re: MMTTY FSK

As in the past, I suppose this convrsation could go on, but my setup is very simple- 2 cables: data out from the radio the line in on the PC and fsk out from a PC comport(simple transistor keyer inside serial cable housing) to radio fsk in. No audio levels to adjust, no vox to adjust. But as they say DSFDF

. Yes, and if the FSK wave shape could be cleaner( and each tone output could be equal as I have asked Elecraft in the past and should be on their list of to dos).
73, John N1JM

Mike Cox

Re: MMTTY FSK

In reply to this post by John_N1JM

The only real difference I've heard is that on some strong signals you
can occasionally hear the unwanted sideband mirroring the intended AFSK
signal. This signal is at a level reduced by the unwanted sideband
suppression characteristics of the transmitter involved and separated by
twice the modulating tone frequencies. This might put the two signals
over 4 KHz apart, making it not apparent who the culprit is. It's pretty
easy to see the problem with a panadapter. Note that some current radios
(for example. IC756ProIII) only rate their transmitted unwanted sideband
suppression at -40 dB (K3 is -50 dB). Some older radios are much worse.
An unwanted sideband of -40 dB from a 1.5Kw signal would be 150 mW. I've
worked DX with less.

On 6/13/2010 17:07 PM, N1JM wrote:
> In real world operating, has anyone really experienced a difference or could
> tell a difference?
>
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Alan Bloom

Re: MMTTY FSK

In reply to this post by k6dgw

Theoretically FSK should be cleaner than AFSK. With the latter you can
get the following spurious signals:

- Incompletely-suppressed carrier
- Unwanted sideband
- Audio harmonics of the AFSK tones

None of those unwanted signals occur with true FSK.

With either FSK or AFSK you can get switching transients when
transitioning from one frequency to the other. If you just use two
free-running oscillators, there will be horrible transients as you
switch from one to the other. The K3 apparently uses phase-continuous
switching, which eliminates that problem. However you really should
transition gradually from one frequency to the other to limit the
transmitted bandwidth. I believe the K3 addresses that problem by
running the FSK signal through the 2.7 kHz crystal filter.

Al N1AL

On Sun, 2010-06-13 at 14:24 -0700, Fred Jensen wrote:

> N1JM wrote:
> > In real world operating, has anyone really experienced a difference or could
> > tell a difference?
>
> If AFSK is working right, I don't think it is possible to tell the
> difference between it and FSK by listening [unless the two audio tones
> aren't clean sine waves]. I think the real difference between FSK and
> AFSK is that the interface in FSK has some hardware involved but is
> pretty straight forward in MMTTY config, while AFSK requires only a
> couple of audio cables but you have to make sure the K3 Pitch and MMTTY
> mark frequency are set to the same values.
>
> 73,
>
> Fred K6DGW
> - Northern California Contest Club
> - CU in the 2010 Cal QSO Party 2-3 Oct 2010
> - www.cqp.org
>
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