[RTTY] REV polarity

[Bill Turner]

On Thu, 5 Sep 2002 11:28:36 -0000, Dez in Cyprus wrote:

>Hi,
>
>Just installed MMTTY it is working fb on RX.
>
>I'm using FSK, but seem to be TX-ing reverse polarity. Everything is =
>decoding fine on RX.
>Is there a way I can reverse my TX polarity within MMTTY that does not =
>affect the RX side of things?
>
>73
>
>Dez

_________________________________________________________

I don't think you can do it within MMTTY, but there are a couple
of workarounds:

1.  Some rigs have a menu setting that allows you to reverse the
TX polarity, so check the manual.  On a TS-870S, it's menu # 63.

2.  If you are using the typical one-transistor drive circuit
running from a com port, swap the base and emitter leads.  I know
it looks weird driving the emitter instead of the base, but it
should work.  You might have to vary the value of the current
limiting resistor at the input, depending on your transistor's
gain.

73, Bill W7TI