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On 7/25/11 7:59 PM, Tim Sawyer wrote:
<blockquote cite="mid:0969FDAB-9FFB-4F5F-90DB-178760BF8485@me.com"
type="cite"><base href="x-msg://60/">Lu Venci,
<div><br>
</div>
<div>I found the same issue thought I did not measure it as you
have. I reverted to good-old Micor squelch and P/L reeds because
I did not feel that app_rpt DSP did as well as the Micor in
either case. Sometimes 40 year old technology is still best. <br>
</div>
</blockquote>
<br>
I'm doing a hybrid of what you're doing, Tim; Scott Z built my 220
Micor bringing out both the COR signal and the discriminator audio;
I use the Micor squelch circuit high for COR, and the DSP to decode
the tone. In my mind, one is a go/no go, the other is something
that can be inferred from simple signal processing. <br>
<br>
carrierfrom=usb<br>
ctcssfrom=dsp<br>
<br>
Gives me the best of both worlds (Micor squelch, as you say, thought
40+ years old, is the tops), and the flexibility to change tone
without having to search out reeds (for testing, lid removal, etc.).<br>
<br>
I have an issue to throw out...which kind of got me scratching my
head....occasionally (and non-repeatably), when keying up the
repeater...I'll get a building in volume rushing noise (think raster
noise like on an unoccupied TV channel that increases in volume)
that peaks and then goes quiet. Incoming audio is there all the
time...I was thinking it was desensing, but it is not every time I
key up the machine, I've gone thru the duplexers to tweak them to
>90db of notch (after cleaning up the caps and polishing the
copper-to-copper mating surfaces for the coil/cap assembly...I'll
send a photo if anyone is interested...) and am running only about
55w into the xmt side. <br>
<br>
Coax is 1/2" superflex out to the polyphaser, (I'm not going to
admit I have some other non-recommended from the polyphaser up the
pole, ok? It's in the plan to replace, I have 140' of LDF4 ready to
go...just have to get up on the roof...), SWR from the radio to the
amp is <1.2, from the amp to the duplexer is <1.2, loss thru
the cans is 1.7db, swr out of the cans into the superflex is
1.2...all audio paths are shielded (but not ground looped, I know
how to build audio channels...), no connector adapters, all
silver/gold/teflon, etc. <br>
<br>
Has me scratching my head. That it's not repeatable, but happens
randomly has me thinking that it's static discharge? Pole and
tripod are bonded and grounded, antenna is a stationmaster-type
(tram 1494 cut to length, lock screws in the center radiator are
tight and lock-tighted, and it's a dc ground design, albeit with a
fiberglass radome. <br>
<br>
Thinking static build up/discharge? Something else? Anyone else
run into this? We can take this offline, but, seeing as we're all
repeater geeks here...thought I'd throw it out for consideration. <br>
<br>
Thanks all...<br>
<br>
<pre class="moz-signature" cols="72">--
Bryan
In this world, you must be oh so smart or oh so pleasant.
Well, for years I was smart. I recommend pleasant.
You may quote me. </pre>
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