Can someone please explain the difference between a P25 One-Frequency Trunk system and a P25 conventional channel?
Does the 1 Tr system have a control channel?
That's what I thought as well - I have heard that the TSA does that with the numerous simplex channels that they have in their portables - multiple channels with the same frequency, but different NAC & talkgroups assigned to each...
That's my situation exactly. I have 3 TSA freqs (with a known NAC on one that is 001) programmed in my Pro-106. But I'll only get about 2 or 3 hits a day if I leave the radio in hold mode on the frequency.
I've just acquired a 996XT and I'm wondering how to program those freqs into the radio; as a conventional P25 or a P25 1 freq trunk system?
I could try both ways to see witch way works when they transmit, but only if I sat in front of the radio all day. Not sure if 'Auto Search and Store' would catch it correctly.
I'm about 4 miles from the airport and when I do get a hit it's loud and clear-voice.
Maybe if I just spent a few hours at the airport I'd get more hits.
ecps92 mentioned that they may use analog and digital on the same channel. If you have the channel programmed with a NAC, or if it is programmed as a single-frequency trunked system, then I believe you will not pick up an analog transmissions on that channel.
APCO 25 also allows for conventional talk-groups. It is very similiar to having a muti-tone ctcss panel in an analog repeater. I have programmed APCO25 radios to do this in conventional and it does work as the users on a different talk-group doesn't hear the traffic, but someone in conventional listening to in digital carrier squelch will hear everything.
APCO 25 also allows for conventional talk-groups. It is very similiar to having a muti-tone ctcss panel in an analog repeater. I have programmed APCO25 radios to do this in conventional and it does work as the users on a different talk-group doesn't hear the traffic, but someone in conventional listening to in digital carrier squelch will hear everything.
No, you shouldn't need a Syskey to program CONVENTIONAL P25 Talkgroups.Do you still need a system key to program Astro25 radios this way?
No, you shouldn't need a Syskey to program CONVENTIONAL P25 Talkgroups.
Good point. I'll set the channel to 'All'.
BTW, went to the airport with the freqs programmed as conv P25 and that works.
Can someone please explain the difference between a P25 One-Frequency Trunk system and a P25 conventional channel?
Does the 1 Tr system have a control channel?
There is also a talkgroup field in P25 Voice signals. In true trunking its used to transmit the current talkgroup (like the old sub-audible data in SmartZone) However it can be used in the same way a NAC is used on a conventional channel to create logical user groups.
Let me make a simple statement. You don't have a trunked system with only one channel. You need a control channel to have a P25 trunked system. Then the control channel will assign the talkgroups to a voice channel for the conversations. Generally you won't see a trunked system with less than 4 channels. One for the control channel and then 3 for voice.
With that said, you can have a P25 conventional channel where the voice is in the digital mode. Motorola normally calls this "Astro" mode. You can have a NAC and different talkgroups in this type of operation. I expect that this digital conventional mode is what your trying to describe.
Do you still need a system key to program Astro25 radios this way?