[App_rpt-users] Deviation settings for narrow band

hwstar at rodgers.sdcoxmail.com hwstar at rodgers.sdcoxmail.com
Tue May 19 15:01:30 EDT 2009


> 
> From: "Mark Hergesheimer" <mark at hergesheimer.com>
> Date: 2009/05/19 Tue AM 10:34:27 PDT
> To: <app_rpt-users at qrvc.com>
> Subject: [App_rpt-users] Deviation settings for narrow band
> 
> I'm using a 12.5 KHz narrow band system with 2.5 KHz of deviation so when
> setting up the URI,  I referred to Steve's post "Adjusting Audio Levels"
> using the URI. I also made the assumption that if a 1 KHZ tone set to 3 KHz
> of deviation was correct for a 5KHz system then 1.5KHz would be correct for
> my 2.5KHz system. So I set rxvoice to 1.5KHz and rxtone to .6KHz then with
> txtone set to 0, I set txvoice to 1.5KHz and txtone to .6KHz.  However when
> this was complete I had low audio through the repeater and only 1.85KHz of
> dev out. So I went back with the service monitor in duplex mode and adjusted
> the txvoice up until I got my 2.5KHZ out and the repeater sounds very good
> as a standalone.
> 
>  
> 
> I have 2 questions and a comment,  first, what are the correct numbers for
> setting up a 2.5KHz system using the URI's? and why?
> 
> Second, What would the best way to add a 5KHz node and keep the levels even
> across the system?
> 
> Comment: We recorded some voice announcements for repeater ID through our
> Asterisk phone system at work to produce the wav files and the audio is
> really great, as a matter of fact I'm very impressed with this whole app_rpt
> deal !!!  Thanks
> 
>  
> 
> Mark
> 
>  
> 
> 
>
Mark,

I've never deployed a 2.5 KHz radio on a node so the values are somewhat unknown.  If you don't mind collecting some data, I'd like you to try the following with 2 nodes:

1. Configure and adjust a node with a 5KHz radio connected
using the standard procedure. Don't worry about txtone and set it to 0 before adjusting txvoice. 

2. Configure and adjust a node with a 2.5 KHz radio using
your procedure of setting 1.5KHz for rxvoice, and txvoice.
Don't worry about txtone and set it to 0 before adjusting txvoice. 

3. Using your service monitor in duplex mode on the 5 KHz radio, see if you get 3.0KHz dev. on the TX while driving the RX with 3.0KHz  of dev. on the input. Note the value.

4. Using your service monitor in duplex mode on the 2.5 KHz radio, see if you get 1.5KHz dev. on the TX while driving the RX with 1.5KHz  of dev. on the input. Note the value.

5. Link the two nodes (using the adpcm or ulaw codec only, and not GSM!!), and check the audio transfer ratio between the two systems using a 1KHz tone at 1.5KHz dev. on the 2.5 KHz radio and a 1KHz tone at 3.0KHz dev. on the 5KHz radio (RX to 5KHz tx and 5KHZ rx to 2.5KHz tx). We would like to know what comes out of the 5KHz radio Note the values.

6. Report all the noted values back to this list.

Steve
WA6ZFT
 
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