hmmmm, that's not been my experience at all Richard.
I use a FT1000MP which has a menu bug. You have to set the menu to 'reverse' for it to
send FSK right side up.
Now I do use MMTTY, both stand alone and as the decoder in Writelog.
The only way I can see for it to get out of whack is if you accidentally (or
intentionally) click on the Reverse Button.
Please correct me but I've thought that MMTTY reverse button changes BOTH transmit and
recieve.
At least when I'd had to use it to connect with someone who was inverted, I THOUGHT it
did.
----- Original Message -----
From: "Richard Ferch" <ve3iay@rac.ca>
To: <rtty@contesting.com>
Sent: Saturday, October 16, 2004 8:20 AM
Subject: Re: [RTTY] DESREVER
I agree with everything Bill, Chen and Goetz have just posted, and would like to add one
more comment:
AFAIK, by far the easiest way to get your TX and RX out of whack with each other is to
use FSK with a sound-card program like MMTTY. This is because in this situation the
software sets the receive polarity ("right side up" vs. "upside down") but it's your
transmitter that sets the transmit polarity. Since they are two different devices
programmed by two different people, it's easy for them to be out of sync. In particular,
I believe recent Kenwood and Yaesu radios assume the opposite polarity to the one
assumed by JE3HHT in MMTTY, so on these radios you have to change one of the radio's
menu items. On my TS-850, this is power on function no. 11, "FSK transmission key short:
OFF(SPACE)/ON (MARK)". The default from the factory is OFF, but for MMTTY (and before
that, for my old MFJ-1278 TU) you have to change this setting to ON. If I have
understood correctly the postings I have read on this, FT-1000 series radios have a
similar issue.
In AFSK, the transmit and receive polarities are set in the same place, so it is hard
(indeed, with most software it may even be impossible) to get them out of whack with
each other. It is, of course, easy to get them upside down compared to everyone else,
but that's also easy to correct with one click of a mouse button.
Please note: I am NOT saying that AFSK is better than FSK. I am just saying that when
you set up for FSK, you CANNOT assume that the polarities will be correct or in sync,
you have to try it out and adjust until you get them coordinated. You don't have to
worry about this in AFSK; in AFSK if you are receiving the right way you will
automatically be transmitting the right way too. On the other hand, in AFSK you MUST NOT
assume that your levels will come out right every time - you have to adjust your volume
settings in the sound card and on the radio until you get a clean signal. In FSK, you
can forget about level adjustments.
Getting the polarity right is, in the end, a one-time job which is usually easier to do
than ensuring your signal is as clean as it can (or should) be. It's also harder to get
it wrong subsequently by an accidental misadjustment (or simply by changing bands!). So
from that point of view FSK is preferable because you only have to get it right once,
not (in principle) every time you transmit.
73,
Rich VE3IAY
_______________________________________________
RTTY mailing list
RTTY@contesting.com
http://lists.contesting.com/mailman/listinfo/rtty
_______________________________________________
RTTY mailing list
RTTY@contesting.com
http://lists.contesting.com/mailman/listinfo/rtty
|