n5jrn
Newbie
I’ve been attempting to get OP25 to receive my local Customs and Border Patrol frequencies, with limited success. I have found the frequencies just fine (the control frequency on 167.2375 was pretty obvious in gqrx, and it agreed with the RadioReference data for my area). I’m seeing talkgroups become active and inactive (and the TG’s I see make sense for my area), but it only seems like maybe 1 to 5 percent of traffic gets successfully demodulated to audio in my PC’s speaker.
Part of the problem has been an evident lack of documentation about what’s getting displayed in the terminal window. The top line is obviously data pertaining to the control channel. Then come a bunch of lines summarizing what was heard on the various trunking frequencies. The lower left corner displays the frequency currently being monitored, and the lower-right corner the ID of the radio doing the transmission and possibly some other transmission-related information (such as whether or not the traffic is encrypted).
When a frequency is received, first the talk group and frequency are displayed, then as more information becomes available the radio ID and other status information get displayed. A marginal signal might well reault in the frequency and TG getting displayed, but never any further data in the lower-right corner.
Is this understanding basically correct?
If it’s correct, one of the problems that seems to be happening is that eventually OP25 gets “stuck” on a very weak signal that it can’t decode (or even, it appears, successfully recognize when it goes away), and so never comes back to the main control channel but instead becomes permanently silent. The FFT plot shows at best a very weak signal and the constellation plot shows nothing being successfully interpreted into dibits, just a disorganized cloud.
When this happens, hitting the s (skip) key seems to get OP25 unstuck, but apparently at the cost of forever deafening it to the frequency in question (which sometimes has meaningful, strong signals).
Part of the problem has been an evident lack of documentation about what’s getting displayed in the terminal window. The top line is obviously data pertaining to the control channel. Then come a bunch of lines summarizing what was heard on the various trunking frequencies. The lower left corner displays the frequency currently being monitored, and the lower-right corner the ID of the radio doing the transmission and possibly some other transmission-related information (such as whether or not the traffic is encrypted).
When a frequency is received, first the talk group and frequency are displayed, then as more information becomes available the radio ID and other status information get displayed. A marginal signal might well reault in the frequency and TG getting displayed, but never any further data in the lower-right corner.
Is this understanding basically correct?
If it’s correct, one of the problems that seems to be happening is that eventually OP25 gets “stuck” on a very weak signal that it can’t decode (or even, it appears, successfully recognize when it goes away), and so never comes back to the main control channel but instead becomes permanently silent. The FFT plot shows at best a very weak signal and the constellation plot shows nothing being successfully interpreted into dibits, just a disorganized cloud.
When this happens, hitting the s (skip) key seems to get OP25 unstuck, but apparently at the cost of forever deafening it to the frequency in question (which sometimes has meaningful, strong signals).
