P25 Emission Designation

[Tim]

Hi Folks,

What is the emission designator for a P25 narrow band channel system? We want
to try some mixed mode, and need to get our license modified.

We haven't gone narrowband yet, but I understand from reading that there's
about a 3dB loss in coverage when narrowbanding, but could get 6 back if we went digital.

Gee, why do I smell a rat in this???

Thanks,

Tim

[Astro Spectra]

P25 digital voice: 8K10F1E
P25 signalling: 8K10F1D

People don't normally separately identify the P25 signalling component and simply put 8K10F1E down. Splitting hairs, there is actually a tiny data component multiplexed in with the voice but let's not attempt to go there as no one else does.

If you wish to include the optional characteristics the designations become 8K10F1EJN and 8K10F1DDN. But I always have a problem with this as the ITU system is a bit silly in that while there is a means to properly designate 4FSK in the case of data (DDN) you are traditionally meant to identify the transmission of voice as EJN when in fact is digital voice carried using 4FSK and therefore should be EDN.

Always happy to be corrected ...

[jmr061]

P25 Phase 1 Voice should be 8K10F1E.

Be prepared that modifying this will require frequency coordination which will cost some cash.

Jason

[Tim]

Thanks all, just what I wanted to know.

I knew it would cost some $, but that's not a problem. Was more worried
that they would try and hit us for an ERP reduction... just ran into that
problem with an existing system that we had to re-do the location of the
antenna. (coordinates on the license were different than where the tower
really was).

Since it was in a different place, it required a new contour, and since the
department isn't quite ready to go narrowband, they have a ERP reduction
on their wideband until they convert. Guess that's an incentive?!

Thanks again,

Tim

[escomm]

If the licensee is a government agency at least you'll get the FCC filing fees waived.

[jmr061]

Speaking of freq coordination for something like this, who would be the cheapest freq. coordination service (fcc accepted) for changing just an emissions designator to P25? If anyone knows.

Thanks

Jason

[kt2728]

Check with federal radio licensing out in california. they seemed to be pretty cheap on some stuff i checked on for a guy i know at a local rail road.