[WriteLog] BARTG 75 setup

[Joe Subich, W4TV]

> In the second clone window running XMMT.ocx and MMTTY with the AA6YQ
> profile I have set the Mode to 75 baud in RttyRite and in its MMTTY
> instance. However, the decoding in this clone window is still not
> perfect.

Don't even think abut using the AA6YQ profile for 75 baud.  The filters
are simply too narrow for the added bandwidth.  You are seeing the
effects of inter-symbol interference from channel (Mark/Space) filters
that are close to optimum for 45.45 baud but have far too much delay
for 75 baud.

The AA6YQ profile has *two* cascaded 512 tap filters in each decoder
channel - the "Dual Peak filter" as a bandpass filter and a second
512 tap FIR resonator for each channel.  Each of those resonators is
35 Hz wide - far too narrow for 75 baud.

I'd copy the AA6YQ profile ... *uncheck* the Dual Peak filter on the
Demodulator tab, change the TAP in the Discriminator box to 386 and
increase the FW setting in the Pre-Filter/BPF to 150 as a starting
point for 75 baud work.   In addition, I would enable ATC (AFC/ATC
tab) and set sweep to .3

73,

    ... Joe, W4TV


On 4/25/2013 12:41 AM, Gary AL9A wrote:
> Thanks for the help Joe.  I followed the new WriteLog and MK II setup
> instructions at the support page and I can now send 75 baud using
> XMMT.ocx using MMTTY per the instructions.  I'm not sure what changed in
> the setup I was already using, but obviously something got reset.
>
> So now my situation is this.  I can send at 75 baud in the main RttyRite
> window and what I'm sending decodes correctly in the blue italic font.
> In the clone 2Tone window Setup is set to 75 baud and the RttyRite
> window has the Mode set to 75 baud.  When I send a macro at 75 baud
> 2Tone decodes it properly in that clone window.  In the second clone
> window running XMMT.ocx and MMTTY with the AA6YQ profile I have set the
> Mode to 75 baud in RttyRite and in its MMTTY instance.  However, the
> decoding in this clone window is still not perfect.  I can see some of
> my macro message decoding, but many of the characters are still
> garbled.  I'm not sure what will happen with this window under "live"
> receive at 75 baud when on the air signals are coming in.
>
> I will continue to try various things with the second RttyRite clone
> window and see if I can get it to decode better.  Perhaps a different
> profile other than the AA6YQ one?
>
> 73,
> Gary AL9A
>
>
>
>
> ----- Original Message ----- From: "Joe Subich, W4TV" <lists at subich.com>
> To: <writelog at contesting.com>; "Gary AL9A" <al9a at mtaonline.net>; "DONALD
> A HILL" <aa5au at bellsouth.net>
> Sent: April 24, 2013 6:41 PM
> Subject: Re: [WriteLog] BARTG 75 setup
>
>
>>
>>
>>
>> On 4/24/2013 9:53 PM, Gary AL9A wrote:
>>>
>>> So unless I am missing something here, when using the XMMT.ocx interface
>>> it will not be possible to achieve 75 baud unless you use Hardware
>>> generated FSK.  But Hardware generated FSK with XMMT.ocx will produce
>>> the buffer timing speed issue that is unacceptable.  So now my thinking
>>> is that in order to run 75 baud for the BARTG 75 I must go back and
>>> reinstall the MMTTY plug-in and use that for the RttyRite transmit
>>> window at 75 baud  instead of XMMT.ocx?  As I am typing this my mind is
>>> now asking should I delete all my RttyRite sections in the ini file an
>>> let WL rebuild those too?  Life ain't simple out here on the bleeding
>>> edge!
>>
>> Gary,
>>
>> Go to the MK II area at www.microHAM-USA.com/Support.html, download the
>> updated configuration for Writelog and MK II *and follow it* for the
>> SM6SRW MMTTY Plug-in for Writelog or the XMMT.ocx interface using FSK.
>>
>> I have just checked and *both* work perfectly at 75 baud.  I was able
>> to transmit at 75 baud and receive on a different system at 75 baud in
>> either 2Tone or MMTTY (using WinWarbler) as well as the decoder built
>> into the K3.
>>
>> You *must* use MMTTY to generate the FSK - *DO NOT* attempt to use the
>> WriteLog software (or hardware) generated FSK.  It appears that one can
>> not select 75 baud with *hardware* generated FSK and the SM6SRW MMTTY
>> Plug-in for WriteLog (although it is possible to use Hardware generated
>> FSK at 75 baud with XMMT.ocx).
>>
>> It will be necessary to set the baud rate in MMTTY (Options | Setup
>> MMTTY | Decode tab) ... I recommend defining a "Profile" for 75 baud
>> so you can return to it quickly.  Also make sure "Fixes 45.45" is *NOT*
>> checked in HAM Default or every time you chick "HAM" the data rate will
>> be reset to 45.45 baud.
>>
>> Software Generated FSK is 45.45 baud only and can not be used for this
>> contest.
>>
>>
>> 73,
>>
>>    ... Joe, W4TV
>>
>
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