Question from visitor

[natedawg1604]

Hey there, today I happened to be driving through Northern NM for the first time, and I'm probably gonna be posting several questions on here. For now, my first question is simply this: while in Santa Fe I wasn't hearing any traffic on the NMSP D1 vhf frequencies. (I had heard lots of activity on the D7 frequencies).

Are all the District 1 cars using the 700 MHz system? Just as I'm posting this I started hearing 2-way traffic from the D1 and D5 dispatch talkgroups on 700, and it doesn't sound like they have any vhf patches setup. So have all the District 1 and/or District 5 cars migrated to the new 700 system? That would explain why I'm not hearing traffic on the D1 frequencies (I'm pretty sure I'm too far away to hear 2-way traffic from the D-5 vhf freqs). But I've never been here before so I just wanted to see what the local experts had to say. Any input is greatly appreciated, thanks!!!

 

[natedawg1604]

Hey there, today I happened to be driving through Northern NM for the first time, and I'm probably gonna be posting several questions on here. For now, my first question is simply this: while in Santa Fe I wasn't hearing any traffic on the NMSP D1 vhf frequencies. (I had heard lots of activity on the D7 frequencies).

Are all the District 1 cars using the 700 MHz system? Just as I'm posting this I started hearing 2-way traffic from the D1 and D5 dispatch talkgroups on 700, and it doesn't sound like they have any vhf patches setup. So have all the District 1 and/or District 5 cars migrated to the new 700 system? That would explain why I'm not hearing traffic on the D1 frequencies (I'm pretty sure I'm too far away to hear 2-way traffic from the D-5 vhf freqs). But I've never been here before so I just wanted to see what the local experts had to say. Any input is greatly appreciated, thanks!!!

UPDATE: After a bit of further monitoring it appears when I hear traffic on the D1 Dispatch talkgroup, I hear the same traffic from the dispatch side only on 155.565, 127.3 PL. What's weird it it doesn't sound patched, it almost like the dispatcher has 2 different microphones feeding 2 radios or something. Very interesting, I may have to come back after updating my XTS so I can listen to vhf and 700 and at the same time.

 

[abqscan]

The NMSP do not use a full duplex repeater system like you are used to monitoring. On VHF, you must monitor both the frequencies and if the vehicle is too far from your location, you will miss the traffic. I've heard that the dispatchers must know what repeater to talk on based on the location of the vehicle. Once a district upgrades to 700, it will definitely make the dispatchers job easier.

 

[Giddyuptd]

NMSP can use VHF or the 700. Dual band mobiles. As said above they arent full duplex and there is some VHF repeaters but 99 percent of time are turned off.

Think of the LASD 400 system. Similar but different.

 

[Giddyuptd]

Fwiw 9 out of 10 times units will not monitor the car to state input, only state to car output and thus on the old vhf you hear the dispatch basically repeat what last unit had transmitted in. If the units want to talk to another they use state car. By default on old vhf system ch 4 is the pre set emergency depress channel where emergency traffic will go. On 700, ch 4 it is encrypted.