+++ AA6YQ responses below
-----Original Message-----
From: digitalradio@yahoogroups.com [mailto:digitalra...@yahoogroups.com]on
Behalf Of Alan Barrow
Sent: Wednesday, November 25, 2009 8:12 AM
To: digitalradio@yahoogroups.com
Subject: Re: [digitalradio] Digital busy detect
Dave AA6YQ wrote:
>
>
> To be clear, an attended station need not wait for 5 minutes of clear
> frequency before transmitting; 30 seconds of no signals (meaning no
> automatic station is QRV) followed by a "QRL?" sent "in mode" with no
> response should be sufficient.
What does "in mode" mean on shared frequencies? The interfering station
could be packet, pactor 2-3, ALE, whatever.
+++If you're about to send CQ in PSK, you send "QRL?" in PSK; if you're
about to send CQ in RTTY, you send "QRL?" in RTTY.
This concept demonstrably does not work even in attended mode ops, like in
PSK. RTTY ops do not honor a QRL in psk, same for CW.
+++If an operator sends "QRL?" in PSK on a frequency being used by a RTTY
QSO that he or she did not hear beforehand, one or both participants of that
RTTY QSO can ask you to move by sending "QRL QRL" in CW; the participants
don't need to know what the operator sent, they just need to respond with
"QRL QRL" in CW.
+++If an operator sends "QRL?" in PSK on a frequency being used by an
unattended automatic station that he or she did not hear beforehand, the
automatic station will respond by sending "QRL QRL" in CW (rule #1 from my
previous post).
+++In both cases, the operator should QSY on hearing the "QRL QRL".
Cross mode is the majority of the issue. Most of the protocols will hold
off for their mode already.
You are asking some modes to solve a problem that has not been addressed
even in attended mode. (CW x PSK, RTTY x PSK, etc)
+++ Listening for a clear frequency before transmitting "QRL?" has long been
the recommended practice before calling CQ; sending "QRL" in-mode to a
station that appears on your frequency mid-QSO is also standard practice. I
agree that there has been no concerted effort to address cross-mode
scenarios, but the use of "QRL QRL" in CW is quite straightforward. Yes,
digital ops that didn't learn CW will have to recognize this signal, though
"if you call CQ in a digital mode and hear CW in response, the frequency is
in use" is all we'd really need to broadly syndicate. As I said before, I'd
be happy to drive this effort.
73,
Dave, AA6YQ
