17 Dec
2012
17 Dec
'12
2:26 p.m.
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(a)yopmail.com>
To: op25-dev(a)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(a)yahoogroups.com, "ikj1234i" <ikj1234i@...> wrote:
--- In op25-dev(a)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