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Re: [RTTY] TX and RX not on same frequency

To: Dave Hachadorian <k6ll.dave@gmail.com>
Subject: Re: [RTTY] TX and RX not on same frequency
From: Bob Darlington <rdarlington@gmail.com>
Date: Thu, 22 Dec 2016 14:21:33 -0700
List-post: <rtty@contesting.com">mailto:rtty@contesting.com>
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@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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