[RTTY] TX and RX not on same frequency

[Bob Darlington]

And a little more to this.  Talking to Tom (Win4k3Suite author), I think we
may have narrowed down the issue and I don't think it's necessarily
software at this point.  I think it's the crystal filter offset setting of
"-0.94"    If I set this to zero the jumping on the waterfall disappears,
my rtty tracks for tx and rx coincide.  It may be his software isn't
compensating for this offset with the 5 pole Elecraft filters.  That's to
be determined. Either way, we're on the right track and my rtty setup
appears to be working fb.   Thanks again everyone.

-Bob N3XKB

On Fri, Dec 23, 2016 at 2:41 PM, Bob Darlington <rdarlington at gmail.com>
wrote:

> I double checked these settings, all looked okay.  Turns out there is an
> option in the radio to flip what the fsk line does and that was set the
> wrong way.    The clue was the jibberish coming in to fldigi.  Flipped it
> and that was good to go.
>
> The problem with the tx being offset from rx is an artifact (aka, bug) in
> my software.  If I set my filter width to the native width of 400Hz, it's
> wrong on the waterfall.  450Hz done through the DSP and everything is lined
> up as you'd expect.  I'll email Tom (VA2FSQ.com) about it so he can get it
> updated in the next version of Win4k3Suite.
>
> Thanks all!
>
> -Bob N3XKB
>
> On Thu, Dec 22, 2016 at 2:21 PM, Bob Darlington <rdarlington at gmail.com>
> wrote:
>
>> Dave, thank you.   This makes sense, and it jives with what I just read
>> in the manual.  I've been trying to figure this out for the last several
>> days, off and on, and just came across a topic in the manual, "I transmit
>> on a different frequency from my receive frequency when I operate FSK".
>> Yep, sounds like my problem indeed.
>>
>> Much thanks,
>> Bob
>>
>>
>>
>> On Thu, Dec 22, 2016 at 2:17 PM, Dave Hachadorian <k6ll.dave at gmail.com>
>> wrote:
>>
>>> With K3 in RTTY mode, hold PITCH button, and observe the mark
>>> frequency.  In MMTTY options/setup/demodulator tab, choose the exact same
>>> mark frequency. Turn off MMTTY AFC.
>>>
>>>
>>> Dave Hachadorian, K6LL
>>> Yuma, Arizona
>>>
>>>
>>> -----Original Message----- From: Bob Darlington
>>> Sent: Thursday, December 22, 2016 1:49 PM
>>> To: RTTY Reflector
>>> Subject: [RTTY] TX and RX not on same frequency
>>>
>>>
>>> Hi guys,
>>>
>>> I'm new to RTTY when it comes to using an FSK interface.  AFSK, easy
>>> peasy
>>> and I've done it off and on for years.
>>>
>>> I recently purchased a W3YY interface board, soldered it up, got it
>>> mounted
>>> in a box and then cabled to my rig.
>>>
>>> I'm running an Elecraft K3S radio using MMTTY software (either by itself
>>> or
>>> through N1MM+).
>>>
>>> In addition to this I'm running Win4k3Suite for the panadapter display.
>>>
>>> What I see is that I can decode rtty just fine.  If I try to respond to a
>>> CQ my transmitted signal is next off by a bit.  I can see it on the
>>> panadapter that I'm not in the same column, so to say, but instead off by
>>> several tens of Hz or more.
>>>
>>> This gap seems to depend on the filter setting in the rig.   I'm using
>>> FSK
>>> D (data) mode for all these tests.   I just can't seem to get it to work
>>> right.   I randomly found a webpage that said to push the "HAM" button to
>>> get the tx and rx to align.  I don't know why these would drift apart,
>>> but
>>> I bit and saw no improvement.  It did snap the mark frequency back to
>>> 2125.
>>>   I figured I should turn off AFC.  I still have this problem, but the
>>> mark frequency doesn't drift around as the software tries to figure out
>>> the
>>> rtty signal frequency.
>>>
>>> What am I doing wrong?   I feel like the little waterfall display and
>>> band
>>> scope in MMTTY is just off by a bit and don't know how to correct this.
>>> It's listening to the wrong frequency I think, but am unsure how a filter
>>> change on the rig would change this.  I'm not attempting to use the
>>> double
>>> peak rtty filter, although when I have tried, it doesn't seem to make any
>>> difference.
>>>
>>>
>>> All that said, I also see that I am MUCH faster at pouncing on signals
>>> using fldigi with AFSK signalling so may participate in the RTTY Roundup
>>> that way.
>>>
>>> Thanks for any suggestions,
>>> Bob - N3XKB
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>>
>>
>