At 12:20 PM 3/30/2014, you wrote:
With all the Winlink and RM-11708 talk going around, I have a question.
When I contest especially on 80M RTTY band (also occurs other bands,
but most frequently on 80M RTTY band, may be weighted by the fact
that I like 80M the most!) I am often QRM'ed by some sort of
automatic digital mode.
This auto mode is characterized by two sides chirping at each other,
one side typically is "longer" than the other. The short chirps are
just a second or so, the longer chirps are several seconds.
Bandwidth is similar or broader than RTTY but it is not RTTY.
I think this is some sort of ALE mode or HF packet, but don't know
if it's Winlink.
It most frequently comes up on me after I've been running on a freq
for 10 or 20 minutes or even more.
I know that this auto mode "sees me" because if I pause, it switches
from "short chirps", to the long chirps. So clearly this auto mode
sees me on the frequency and knows the frequency isn't clear, but is
trying to carry on nevertheless.
Does this sound familiar? I am on east coast US and I'm pretty sure
this is some sort of ALE mode (unsure which one) and I'm 100% sure
there's no human at either end.
Tim N3QE
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A guess: The long chirps when you pause probably means that it could
not transfer data while you were txing, but took advantage of your
stopping to transfer it. I suspect it would give up after a few
minutes if it could not complete the transfer, but i might be wrong.
If the rx station doesn't receive valid data, it requests a repeat
(the short chirp). the tx station then tries again with the long
chirp. When you went qrt, the rx station received all OK, and stopped
requesting repeats. Don't know what mode.
Jerry W4UK
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