Icom-746 NON PRO, SignaLink USB and MMTTY issue??

[N2KYX]

I am using an Icom 746 (non pro) and a SignaLink USB and I'm trying to do RTTY using MMTTY software.

My problem is that the 746 will do FSK and the SignaLInk will only do AFSK. The IC-746 has a button on the panel to select RTTY, latter models had the digital mode selection availible, but not the 746 non pro.

The SignaLink will not do FSK but it will do AFSK. I can decode RTTY perfectly when I select the RTTY button on the rig but cannot transmit with that setup.I am using the 8 pin ACC Data port on the IC-746

When I try and decode using SSB, either USB or LSB, it doesn't work very well. I've tried numerous settings in MMTTY but to no avail.

I am wondering if any else has used the IC-746 with a SignaLInk and MMTTY for RTTY? What settings do I need for MMTTY for the signaLink to work properly? or is it not possible?

Any suggestions would be greatly appreciated.
s, Mitch N2KYX

[KB6HOH]

Mitch,

        As you said the Signalink USB will NOT do FSK RTTY and as pointed out by Tigertonics:
Does the SignaLink USB support FSK?

None of our SignaLink products support FSK operation.  However, except among a small group of "FSK purists", this is not an issue because FSK is no longer the preferred method of operating RTTY.  FSK used to be preferred because radios we're not very linear in operation on Transmit, and the only way to access your "good" RTTY filter was with the radio set to the RTTY mode.  Today's modern radios provide excellent AFSK performance in both Transmit and Receive, and most provide complete control over all filtering, so you can still select the "good" RTTY filter while in a digital AFSK mode.  AFSK is also preferred over FSK because every other modern digital mode (PSK31, MT63, SSTV, etc.) uses AFSK, and on most radios, switching to FSK would require a completely different cable connection. 

Now they make this statement: switching to FSK would require a completely different cable connection.

It leads one to believe that it is possible with a different cable.

Now almost ALL Digital Modes today are on USB (Upper Sideband). I am guessing you want to use the RTTY Filter when in the RTTY Mode on the 746(non-pro).  Now do you have anyother Filters on the 746 other than what came with it when on SSB you can kick them in?

FYI:
Now this has been hashed out on the Yahoo User Group: http://groups.yahoo.com/group/TigertronicsSignaLink
Have you joined this Group?

Here is the link that I pulled up regarding the 746/(pro):
http://groups.yahoo.com/group/TigertronicsSignaLink/msearch?query=icom+746+fsk+rtty&submit=Search&charset=UTF-8

I wish I could give you better answers !

                                  73 de Steve KB6HOH

[VA7CPC]

If you want to use a SignaLink with MMTTY, the easiest way to do it is:

. . . Set the rig up for PACKET operation (the non-PRO probably supports that - check the manual, see what
. . .        MODE the rig should be in to use it)

. . . Use MMTTY in AFSK mode (which uses the same signal path as PACKET)


Your problem is then:

. . . . How to get the rig to use a _narrow_ filter in its PACKET mode, if you have a narrow filter (350 Hz is good) installed.

But it will _work_ using the standard SSB filter bandwidth.  That's not ideal for RTTY contests, but it works OK at any other time.

There's no difference between using MMTTY in AFSK mode, and using any PSK31 software to do PSK31 on the rig.  I'm sure that "PSK31 / SignaLink / IC-746 non-PRO" is a "solved problem".

If you can't get it working, and you can point me to an online copy of the IC-746 non-PRO manual, I'll take a look at it.

.                  Charles

PS -- if the rig has a "6-pin mini-DIN" DATA port on the back (the manual will talk about connecting a TNC to that port), and that's what you're using for the SignaLink, you should be able to get this working with no hardware changes or 'special cables'.  It should be plug-and-play.

[N2KYX]

All,
Thanks everyone for the responses to my problem, which I am now happy to say is resolved.
After re-loading MMTTY and starting from scratch again I found that I had a setting wrong in my previous version.
Under View, FFT sensitivity, I had selected "highest". I should have selected "lower". Once I got that right I then tried LSB first, but that did not work.
I then proceeded to put the radio in USB and selected the Rev. button, which to my surprize worked. I am now able to copy RTTY.
Next step is to transmit. I don't beleive that transmitting will be an issue.

Again I want to say thanks to everyone who gave me input to this issue. THANKS 

73's Mitch N2KYX

[AD6KA]

Once I got that right I then tried LSB first, but that did not work.
I then proceeded to put the radio in USB and selected the Rev. button, which to my surprize worked. I am now able to copy RTTY.

That is strange.
AFSK RTTY is sent LSB.
I wonder why USB->Rev worked when LSB did not.
Ken  AD6KA

[N1ZZZ]

I have used an Icom 746 for digital for years, including AFSK RTTY using both MCP's and MixW via a soundcard interface.  I have a 500 hz filter in there and just lie to the rig telling it that's it is a SSB filter.  You just adjust the passband. with the rig selected to SSB, so that it is listening to the segment of the bandwidth that you transit on and all works well.  I do the same thing on my Icom 706 MK2G.

73
Jeremy N1ZZZ