Jim B. wrote: > By way of PWF: > <http://www.k6ccc.org/k6ccc-r.html>
Neat Jim. I've been playing around with P-25 via a borrowed radio. Very interesting stuff. On this repeater: http://www.rmrl.org/rmrl_news/rmrl_goes_digital.htm Your web page mentioned "still debating about analog ID's"? Why? Your web page also doesn't mention if your users are typically monitoring a particular talk group? The group above uses $FFFF. Locally here anyway, we're ID'ing in digital, can't see any reason to change emission type to ID -- if someone were monitoring, they'd have to change receiver types too, which seems counter-productive. P-25 is an open standard, anyone that needs to copy the ID certainly can. (i.e. FCC) Hams can't run with the encryption features enabled, either, of course. The repeater also ID's via MCW over the digital channel when someone's using it in digital mode, which sounds really odd, but is copyable. (GRIN) Kinda like a CW operator with a generator that can't quite keep up with his amp. Heh. The repeater above turns off CTCSS when transmitting in digital mode, but some local users still run without CTCSS decode on analog, so there have been some questions once in a while about "what's that horrible white noise blasting the repeater at 45 minutes after the hour?!". Heh heh. Yes Virginia, that would be the digital ID going by... The most interesting aspect of digital so far is of course that "static" simply doesn't exist. Instead your ear becomes tuned to what the vocoder does when it's erroring... Sometimes the "Max Headroom" effect... repeated syllables. Sometimes the audio gets "raspy" as the vocoder struggles to replace lost bits. But no "noise" per-se. You can get pretty good at it and tell when someone's starting to get marginal, from my limited playing with it, if you know they're headed out of range of the system. If you DON'T know they're headed into a dead spot they'll just be gone... bye... heh. On the flip side, the S/N gains of digital are real -- places where the system is 50-60% or more white noise, the digital sounds fine with a few digital "artifacts". In my office at work where I'm surrounded by PC's that throw RF hash, analog copy on just about any local repeater is horrible... the digital systems sound perfect. Interesting stuff. Still expensive but coming down in price rapidly. Rumor is that Motorola will be to the $400 price range on the HT's by next year-end perhaps? We'll see. The closed IMBE CODEC in P-25 is the hobbling issue for REAL experimentation, unfortunately. There *ARE* smart enough people in the ham community to hack on DSP code these days -- but it'd be worthless without the source for the CODEC. Mmmmmm... Digital Toys! Nate WY0X Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
