Date: Tue, 05 May 2009 17:25:49 +0200
To: rsgb_lf_group@blacksheep.org
From: Rik Strobbe <rik.strobbe@fys.kuleuven.be>
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Subject: RE: LF: RE: rtty test
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Gary, LF,

I just had a look at MMTTY and it seems pretty easy to set it to 50Hz 
shift and 22Bd baudrate.
The way I did it:
1. As a start select 23Hz RTTY (in "Profiles")
2. In "Options" select "Setup MMTTY"
3. In the tab "Demodulator" change "Shift" from 23 tot 50 (it is not 
a standard option, but you can just type 50 into the field)
4. In the tab "Demodulator" change "Mark" to a suitable value (that 
is the audio frequency you get)
5. In the tab "Demodulator" change "Discriminator Type" from VCO to FIR BPF
6. In the tab "Demodulator" change "Tap" from 72 to 256
7. In the tab "Demodulator" click on "OK"
8. In the tab "Decode" change "BaudRate" from 45 tot 22 and click "OK"
Steps 5-7 set demodulator type, the values above are the result of 
some brief dry tests and can most likely still be optimized. You can 
do that in the main screen.

If WX permits (no rain) I intend to run some tests between 20:30 and 
21:30 UTC on 503.5kHz in mode USB (so if you listen in LSB don't 
forget to select reverse mode).
I will announce the exact hours later this evening.
Between transmissions I will listen on the same frequency.

All reports (or replies) are welcome.

73, Rik  ON7YD - OR7T

At 14:14 5/05/2009, you wrote:
>Hello Gary,
>
>I had a closer look at the 23Hz shift option of MMTTY and it seems 
>to run at 45Bd what is on the edge regarding the shift/baudrate 
>ratio. That is most likely the reason why it is not so robust.
>Using 45Bd at 85Hz shift would exceed the 100Hz bandwidth limit.
>I guess the best option for RTTY would be a shift around 50Hz and a 
>lower baudrate (say 20Bd) what would well fit within the 100Hz 
>bandwidth and would have a sufficient shift/baudrate ratio to 
>provide a robust signal.
>I will see if I can get such signal out of MMTTY and - if time 
>permits - run some tests tonight.
>
>73, Rik  ON7YD - OR7T
>
>At 12:22 5/05/2009, you wrote:
>>Hi Rik,
>>
>>You have experienced the same as I did with 23Hz shift, the signal needs to
>>be very strong to decode. It was in the last 2 minutes that I got the
>>partial decode.
>>
>>A much better shift to use is the 85Hz which will fit into your spec.
>>
>>I have had good QSO's with Chris G3XIZ in Biggleswade both of us using 85Hz.
>>
>>Give that a try next time & I believe I will get a much better decode
>>judging by the strength of your signal.
>>
>>73
>>
>>Gary - G4WGT.
>>
>>-----Original Message-----
>>From: owner-rsgb_lf_group@blacksheep.org
>>[mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Rik Strobbe
>>Sent: 04 May 2009 22:37
>>To: rsgb_lf_group@blacksheep.org
>>Subject: Re: LF: RE: rtty test
>>
>>Hello Gary,
>>
>>call the is almost right, locator completely.
>>But not really impressive for 500mW ERP.
>>I could see my signal on your grabber, some slow QSB but strong for
>>the last 2 minutes or so.
>>I used MTTY with the profile "23Hz RTTY (MTTY)" without any further
>>changes, not sure that this is the best mode.
>>So any advice is welcome.
>>I have also installed MultiPSK, but am still overwhelmed by the colors
>>and options.
>>I am allowed to use any digital mode as long as I stick to max. 100Hz
>>bandwidth.
>>
>>73, Rik  ON7YD - OR7T
>>
>>
>>
>>Quoting Gary - G4WGT <g4wgt@tiscali.co.uk>:
>>
>> > Hi Rik,
>> >
>> > This is the best I could do, it looks like almost your call sign & locator
>> > :-
>> >
>> > RHTQHTST DE TC(TIOJ7T OR1T JO20IX
>> >
>> > 73
>> >
>> > Gary - G4WGT.
>> >
>> > -----Original Message-----
>> > From: owner-rsgb_lf_group@blacksheep.org
>> > [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Rik Strobbe
>> > Sent: 04 May 2009 21:10
>> > To: rsgb_lf_group@blacksheep.org
>> > Subject: LF: rtty test
>> >
>> > dear all,
>> >
>> > I will run a short (10 minute) rtty test (23Hz shift) on 503.500 at 21UTC
>> > Reports and/or reply welcome.
>> >
>> > 73, Rik  ON7YD - OR7T
>> >
>> >
>> >
>