Question for anyone that is a radio tech or knowledgeable on this subject. I have noticed from watching both SDRTrunk and Pro96Com over the past few months that there seems to be several ways that the system allows you to establish a "patch" between two talk groups.
Can anyone shed some light on how patches are made in a Motorola P25 system and if there are multiple methods for doing this? Presumably there are limitations with each method? Is one method preferable over the other....
For example, GATRRS Travis County has Austin Fire FCOM N & FCOM S in a constant patch (same goes with FCOM E/W). This patch is visible on Pro96Com on the patches tab of that application. I will see ABI EM1 and ABI COM often patched together also - Same with Pflugerville PD patching their A and B channels together. If the Travis County Jail needs to broadcast a message to all of its talkgroups, I will see a patch initiated in Pro96Com that patches probably 6-8 talkgroups together for a few seconds while they transmit the broadcast. When Talkgroups patched together like this get transmitted on, it looks like from SDR and Pro96Com that only one actual frequency gets used and any radio that happens to be listening to any TG that the patch is applied to will tune in to that one specific freq.
OTOH, I almost never see Wilco doing a patch in this manner. Instead, when they patch two channels together, it does not show up as a patch on Pro96Com. From watching the display on Pro96Com, I see two frequencies being used, one for each talk group that has been "patched" together (which seems inefficient from a resource standpoint). From an architectural standpoint, this looks to me more like a simulcast and not a patch but that is not how they refer to it over the air.
Not to complicate the above, I also see some interesting stuff on Hays county and Bell county on how they will patch 2 talk groups into a third "temporary" Talk group (usually starts with 64xxx or 65xxx) for paging purposes. I presume this is to patch their P25 systems into either OpenSky (Hays County) or EDACS (Bell County). These patches are mostly annoying in that, if you want to listen in on the pages on the Broadcastify Calls platform, it only recognizes the 64xxx or 65xxx talk group (and not the talk groups being patched), and this temporary TG list is 100 talk groups that get selected in sequence, which is too many to plug into a Broadcastify Calls playlist (which is limited to 20). The other TGs getting patched are not recognized by the Calls platform so you end up never hearing the page/dispatch going out.
Anyone knowledgeable on this please chime in. Given our current fire weather forecast, patching across systems over the next few weeks is probably going to become a daily occurrence.
Can anyone shed some light on how patches are made in a Motorola P25 system and if there are multiple methods for doing this? Presumably there are limitations with each method? Is one method preferable over the other....
For example, GATRRS Travis County has Austin Fire FCOM N & FCOM S in a constant patch (same goes with FCOM E/W). This patch is visible on Pro96Com on the patches tab of that application. I will see ABI EM1 and ABI COM often patched together also - Same with Pflugerville PD patching their A and B channels together. If the Travis County Jail needs to broadcast a message to all of its talkgroups, I will see a patch initiated in Pro96Com that patches probably 6-8 talkgroups together for a few seconds while they transmit the broadcast. When Talkgroups patched together like this get transmitted on, it looks like from SDR and Pro96Com that only one actual frequency gets used and any radio that happens to be listening to any TG that the patch is applied to will tune in to that one specific freq.
OTOH, I almost never see Wilco doing a patch in this manner. Instead, when they patch two channels together, it does not show up as a patch on Pro96Com. From watching the display on Pro96Com, I see two frequencies being used, one for each talk group that has been "patched" together (which seems inefficient from a resource standpoint). From an architectural standpoint, this looks to me more like a simulcast and not a patch but that is not how they refer to it over the air.
Not to complicate the above, I also see some interesting stuff on Hays county and Bell county on how they will patch 2 talk groups into a third "temporary" Talk group (usually starts with 64xxx or 65xxx) for paging purposes. I presume this is to patch their P25 systems into either OpenSky (Hays County) or EDACS (Bell County). These patches are mostly annoying in that, if you want to listen in on the pages on the Broadcastify Calls platform, it only recognizes the 64xxx or 65xxx talk group (and not the talk groups being patched), and this temporary TG list is 100 talk groups that get selected in sequence, which is too many to plug into a Broadcastify Calls playlist (which is limited to 20). The other TGs getting patched are not recognized by the Calls platform so you end up never hearing the page/dispatch going out.
Anyone knowledgeable on this please chime in. Given our current fire weather forecast, patching across systems over the next few weeks is probably going to become a daily occurrence.