[App_rpt-users] 12.5 kHz repeaters support

Ralph A. Schmid, dk5ras ralph at radio-link.net
Thu Mar 11 09:07:59 EST 2010


> I do understand, however because it has a commercial flat audio point does
> not mean it has the appropriate noise component for the software
> to detect .

It has, when switched to 25 KHz, but the filtering of course also narrows
audo bandwidth.

> The white noise we are talking about is in the audio band above
> 3khz.. up to
> maybe 6-7 khz.. you might sweep your receiver there for flat
> audio and watch
> that with a scope.. flat in band audio does not mean flat to 6khz...

6 KHz is to much fur 12.5 KHz, of course.

> The way to test that is see if the same radios align suitably in wideband
> mode assuming they can be programmed to test... If the URI cannot find an
> answer there.. it is most likely just a bad spot to pick noise from...

Like Jann already had mentioned, in wide band it is just fine. There can not
be very much additional filtering, as I can pass P25 and D-Star through this
output.

This leads to a topic that I at least dropped here for two times, but with
no response.
I would like to route the flat audio from DC level up to some KHz through
the PC, to allow P25 and D-Star through it. No codec, no DSP processing
(maybe even regenerating the digital signals in a later version), no
filtering. No LP, no HP. Nothing. Is there a possibility to enable this?
Maybe even to route this over the internet, to allow linking of multi mode
repeaters?  It would be a great feature to have all the asterisk features,
all the tone decoding stuff, DSP squelch - but without touching the audio.

> What I will also add is the level output is different on many radios (
> especially in 12k5) and in my case I had to play with external padding as
> well as the 20db gain/pad switch to get levels into a range the rx tuning
> software and hardware could deal with... The internal resistors of the URI
> are designed for a certain working range and load..

AFAIR the Motorolas are around 400 or 500 mV, but I am not sure.

> Doug
> KD8B

With best regards

Ralph.




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