[op25-dev] Re: P25 Transmission

ikjtel ikj1234i at yahoo.com
Mon Dec 17 13:26:05 UTC 2012



tried - the email bounced

My address is ikj1234i at yahoo dot com - you can send email to that addr

Best

Max

p.s. apols to the list for the OT


________________________________
 From: fredofaiduvelo <rostard at yopmail.com>
To: op25-dev at yahoogroups.com 
Sent: Friday, December 14, 2012 9:52 PM
Subject: [op25-dev] Re: P25 Transmission
 

  
Hi Max,

Could you send out to me an e-mail at my e-mail @. We are looking for talent for an ambitious project.

Regards,
Fred

--- In op25-dev at yahoogroups.com, "ikj1234i" <ikj1234i at ...> wrote:
>
> 
> 
> --- In op25-dev at yahoogroups.com, "rosin.f@" <rosin.f@> wrote:
> 
> > - Why is the channel spacing arbitrarily 25 kHz (just a SW limitation ?)
> 
> No reason for this, it's just behavior inherited from the previous iteration of the p25 transmitter.  Would be simple to add code to transmit on specific, discrete frequencies (the selected frequencies would have to fall within the USRP limits, of course).
> 
> Please note that the transmitter also supports the use of external hardware to do the actual transmission (that is, standard NBFM transmitter hardware), although this is a difficult problem and we don't have a lot of experience with it.   Nonetheless in that case the frequencies would be determined by the external hardware, not the software.
> 
> > - Are you transmitting the P25 air interface for voice ?
> > 
> 
> Nominally yes, the transmissions should be compliant with the P25 Common Air Interface (CAI).  Early testers found a few nitpicks though, most notably the bit settings for the MI fields weren't being set properly to indicate the proper alg ID.  In addition we don't currently prepend HDU's to each transmission. 
> 
> All of the above are minor omissions and would not take a lot of effort to add.
> 
> In addition although we might say that nominally it's transmitting the CAI it has never been certified or even tested for any regulatory compliance, etc...
> 
> Best
> 
> Max
>


 
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