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All,
I am not at all new to radio, but my monitoring is mostly HF. And when I do VHF and up monitoring it tends to be analog, or it had been until not too long ago. I do have digital scanners, like the Uniden BCD536HP, but I just punch the database into them and let them go. That has worked for what little public service is digital around here.
A few years back the local Navy base moved their local comms from analog VHF FM to P25 on the same (or near same) VHF freqs. Now, I know the guys in the comm shop there, and they told me not only were they P25, but they were encrypted as well, so I never really tried to do any monitoring beyond occasionally tuning across a freq and hearing the digital signal.
But recently, after getting the Icom R8600, I was playing around with the modes and tuned to a couple of those Navy freqs. Whenever a transmission came on the R8600 displayed to me things like "1432 -> 1000 (GRP) NAC:064" and such. I have no idea what that means (OK, I can guess, maybe, source TX, destination group, and some kind of ID). But it was intriguing that occasionally a station would come through with voice also, although most transmissions did not, so at least some of the traffic is not encrypted.
So I need to learn more about P25, but starting at the very basic level.
Can a single node/system carry both encrypted and in-the-clear traffic seemlessly?
Is P25 trunked? Is there a control channel?
Can I learn anything about the system from the displayed information?
What questions don't I know to ask?
Is there a good resource on how P25 works and what things mean aimed at casual listeners out there?
Thanks,
T!
I am not at all new to radio, but my monitoring is mostly HF. And when I do VHF and up monitoring it tends to be analog, or it had been until not too long ago. I do have digital scanners, like the Uniden BCD536HP, but I just punch the database into them and let them go. That has worked for what little public service is digital around here.
A few years back the local Navy base moved their local comms from analog VHF FM to P25 on the same (or near same) VHF freqs. Now, I know the guys in the comm shop there, and they told me not only were they P25, but they were encrypted as well, so I never really tried to do any monitoring beyond occasionally tuning across a freq and hearing the digital signal.
But recently, after getting the Icom R8600, I was playing around with the modes and tuned to a couple of those Navy freqs. Whenever a transmission came on the R8600 displayed to me things like "1432 -> 1000 (GRP) NAC:064" and such. I have no idea what that means (OK, I can guess, maybe, source TX, destination group, and some kind of ID). But it was intriguing that occasionally a station would come through with voice also, although most transmissions did not, so at least some of the traffic is not encrypted.
So I need to learn more about P25, but starting at the very basic level.
Can a single node/system carry both encrypted and in-the-clear traffic seemlessly?
Is P25 trunked? Is there a control channel?
Can I learn anything about the system from the displayed information?
What questions don't I know to ask?
Is there a good resource on how P25 works and what things mean aimed at casual listeners out there?
Thanks,
T!