[WriteLog] CW PTT

[Clive Whelan]

Thanks to all for the explanation, which makes perfect sense.

It is thus interesting that the delay in software is virtually the same on
two different rigs, but no matter if RTS solves the problem, ca ne faire
rien!


73


Clive
GW3NJW




-----Original Message-----
From: writelog-bounces at contesting.com
[mailto:writelog-bounces at contesting.com]On Behalf Of Mike McCarthy
Sent: 16 June 2005 19:30
To: Clive Whelan; writelog at contesting.com
Subject: Re: [WriteLog] CW PTT


"Command on COM port" means that a message is sent over the radio interface
to turn TX on or off.  It is subject to delays depending on the port speed
to the radio and if the radio is busy.

"COM RTS" means use the hardware RTS signal to do PTT.  There is negligible
delay.

Mike, W1NR

----- Original Message -----
From: "Clive Whelan" <clive.whelan at btinternet.com>
To: <writelog at contesting.com>
Sent: Thursday, June 16, 2005 3:24 PM
Subject: [WriteLog] CW PTT


> Hi list
>
> I seem to have solved a problem which has bothered me for some time.
>
>
> Rather than use QSK when running SO2R and wear out the relay to no good
> effect, I set CW/PTT to command on COM port, but have always been troubled
> by a delay in returning to receive, which sometimes truncated the first
> character on a quick responder. I thought  that perhaps this was a
> characteristic of my transceiver ( TS870 for reference), but on switching
> for test purposes to an IC7400 the same problem was experienced. I then
> changed the PTT method from "command on COM port" to " On lpt pin 16/ COM
> RTS" . So in both cases the command is going via the COM port, but in the
> first case there is a finite delay of a part of a dot, not in the second.
> so
> the problem is apparently solved, but being electronically challenged I am
> puzzled as to why.
>
> Is there a simple explanation perhaps?
>
> 73
>
> Clive
> GW3NJW
>
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