[WriteLog] MMTTY and EXTFSK at 75 baud...

Don Hill AA5AU aa5au at bellsouth.net
Sun Jun 6 07:05:27 PDT 2010

Thanks for the valuable information Bob!  WriteLog users have an option available that does not use the MMTTY plug-in.

I have confirmed that the MMTTY Plug-in for WriteLog will not work on 75 Baud, this includes with or without using
Software-generated FSK.

However, you CAN use the Soundboard FSK (and Soundboard AFSK) option under TU Type in Rttyrite to transmit and receive 75 baud IF
you DON'T normally use Software-generated FSK.  Soundboard FSK (or Soundboard AFSK) is WriteLog's built-in soundboard decoder with
it's own tuning indicator.  I used this decoder for years before MMTTY came about and this decoder is very good.

I tested the Soundboard FSK generator using a standard legacy COM port to a homebrew transistor FSK interface and using a virtual
COM port with my Microham microkeyer and both appeared to transmit 75 baud fine.  This means that if you use a Rigblaster or any
other type of commercial interface to generate FSK on a standard legacy COM port, you can use the Soundboard FSK (or AFSK) TU option
in WriteLog.

But if you normally use Software-generated FSK with WriteLog to send RTTY, you will not be able to send 75 baud.  Software-generated
FSK was designed for 45 baud only.

I agree with Bob in that if you plan on participating in the 75 baud contests, try your alternative set up ahead of time.

Thanks again to Bob for bring this up.  I will update rttycontesting.com today with this information and maybe a tutorial on how to
use the Soundboard FSK (or AFSK) option with WriteLog.  But it's should work just fine.  Just go to the TU Type menu in Rttyrite and
choose "Soundboard FSK" (or AFSK if you are running AFSK).  I should be around today if you have any questions or concerns, shoot me
a direct reply.

73, Don AA5AU

-----Original Message-----
From: writelog-bounces at contesting.com [mailto:writelog-bounces at contesting.com] On Behalf Of Robert Chudek - K0RC
Sent: Saturday, June 05, 2010 11:04 AM
To: N1MMLogger at yahoogroups.com; cq-contest at contesting.com; rtty at contesting.com; writelog at contesting.com; MMTTY at yahoogroups.com
Subject: [WriteLog] MMTTY and EXTFSK at 75 baud...

This is a FYI message...

Operators planning to participate in the 75 Baud contests this weekend and next should be aware IF they are using the popular EXTFSK
driver, this driver is hard coded to transmit at 45.45 Baud. Typically this driver is used to generate FSK & PTT keying (not AFSK)
by RTTY software, MMTTY in particular.

Dave Bernstein, AA6YQ, verified this (documented) limitation. He maintains the MMTTY source code.

How do you know whether you are using the EXTFSK driver? Bring up your software configured for a RTTY contest. Look at the bottom of
the screen to see if there is an EXTFSK 1.05 button displayed on the Windows task bar. If it is shown, you are using the driver and
will only be able to transmit at 45.45 Baud.

There are many other RTTY packages that will allow 75 Baud TX speeds. If you were planning to participate in high speed RTTY, it
would be a good time to investigate other options if you are currently using the EXTFSK driver.

73 de Bob - KØRC in MN
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