It is a bit difficult for JT65/JT9 to generate "noise" on demand.
Those protocols will only start transmitting at one second after
the top of a minute. A RTTY contester who tunes on a frequency at
xx:yy:50 is not going to hear anything for 10 seconds and by then
he has pushed F1.
It is *still* important to know what activity is generally found
in a given range and adjust one's behavior accordingly. In the
case of Joe Taylor's modes that means listening "on the minute of
*both* odd and even minutes" before one can assume a frequency is
free.
73,
... Joe, W4TV
On 2015-01-05 9:16 PM, Jeff Stai wrote:
On Mon, Jan 5, 2015 at 5:41 PM, Joe Subich, W4TV <lists@subich.com> wrote:
Neither JT65, JT9, PSK31, PSK63, nor PSK125 sound like "random noise".
All have a distinctive "sound" and are clearly identifiable on a
waterfall or spectrum display. It should even be possible to make an
informed guess as to the mode just based on the frequency - the
"center of activity" for each digital mode is published just about
everywhere except in the contest rules.
My point exactly.
1. If it sounds like something, it probably is something.
2. If you send QRL? and you hear something, assume it means "in use".
3. If you are using a frequency, and you hear something, assume it is a
QRL? and make a sound.
That should handle most cases and doesn't require knowing a bandplan or
center of activity. Just good manners.
jeff wk6i
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