[aprssig] Xastir Internet->RF configuration

Keith VE7GDH ve7gdh at rac.ca
Tue Apr 7 19:42:41 EDT 2009

Curt WE7U wrote...

> Probably most WIDEn-N digi's, yea, but what about home fill-in
> digi's and what about igates? What about people picking you up
> direct who might be running with squelch and so never decode your
> packets?

It's probably more important for the digis to run open squelch than the
IGates, but when you are heard direct by an IGate, having an open
squelch on the IGate radio could help out a marginal signal. Of course,
if the IGate heard the mobile, it will probably hear another copy a
moment later via a digi.

> Also:  Are you _sure_ you're running 5ms, or is it like most TNC's
> where "5" really means 50ms?

The KPC3+ is like that... TXDelay = n * 10 ms. I think I mentioned
that my quick test was with a T2-301. That's really a Tracker 2 (OT2m)
built into a 5W transceiver. Setting TXDelay from a command prompt
accepts values between zero and 255. In the GUI (otwincfg.exe) the
TXDelay is shown in actual milliseconds. TXD 1 in a terminal program (or
set from a Nuvi 250) translates to 5 ms in the GUI. TXD 5 translates to
20 ms in the GUI. Guess I'm trusting Scott's math and the algorithm he
created in the T2 for the accuracy of those figures. Going by ear, I
sure couldn't hear any flags at the beginning. When I set it to 100 ms,
that's easily long enough to tell by ear that there is some transmit
delay. The 5 and 20 ms are certainly the shortest transmit delays I've 
ever used with any success. Just because my own digi sitting right 
beside me (FT-1500 & KPC3+) could decode it doesn't mean that everyone 
else could. For general use, I'll probably stick with 100 ms, but 
sitting in the shack the current 20 ms setting is working for me.

73 es cul - Keith VE7GDH
"I may be lost, but I know exactly where I am!"

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