San Bernardino county Mercy Air Dispatch.

[avdrummerboy]

Hey all, just curious if anyone else has noticed what appears to be some sort of digital (NXDN maybe?) noise on the Air Methods Mercy Air channel for Southern California, 155.220, PL 127.2 Hz. All I hear anymore is static sounding noise and I don't have anything that receives any digital other than P25.

 

[Randyk4661]

If it were NXDN I believe it would have a RAN code.
I will have to give the frequency a listen later today and see if I can hear it in Orange county.
There is also a bus company that uses the frequency and tone in Los Angeles.

 

[techman210]

I haven’t heard them on their VHF frequencies (FM and AM airband) for a very long time.

They are probably on the encrypted EMS talkgroups - or their own - on the SB County system.

 

[f40ph]

155.220 was only used in the desert 131.675 AM was used in the valley areas. This info goes WAY back. 155.220 was also shared with the Adelanto School district. Definitely want to filter the PL tone so you "only" hear Mercy. I wonder if they're still using it at all?

I know they use the P25 COMCTR channel to talk with Comm Center regarding scene call dispatching. However, I still think they need to talk to the company to update them when going on interfacility calls.

 

[techman210]

It is my understanding that the 131.675 radio was at Santiago peak, so that makes sense.

 

[f40ph]

That's correct. They used to have Santiago and a local tower in Fontana on that freq when dispatch was in Fontana.

 

[Randyk4661]

Going through the FCC database, they are license for pagers on this channel.
That's probably what you are hearing.

 

[f40ph]

Hey all, just curious if anyone else has noticed what appears to be some sort of digital (NXDN maybe?) noise on the Air Methods Mercy Air channel for Southern California, 155.220, PL 127.2 Hz. All I hear anymore is static sounding noise and I don't have anything that receives any digital other than P25.

Have you listened to 156.2175? It shows narrowband FM, not NXDN. Looking at their license I see this for Quartzite.

 

[Randyk4661]

It seems like this was discussed before. I think it was determined this is a two-way paging system for the flight crews.
Call information will be sent to the pager at time of dispatch. Crews can also respond with questions through this system to keep PII off the air. Actual air to ground comms are on a AM air frequency.

 

[f40ph]

Deleted.
Better information below...
Thanks

 

[littona]

155.22 is conventional FM. Nothing special going on there. Transmitter is on Onyx Peak.
156.2175 is our newer freq for Quartzite. Conventional FM as well.
131.675 AM at Santiago Peak is recently back online after a LONG outage.
Our newest aircraft radios are built off the Motorola APX platform, so NXDN is out of the question.
Randyk4661... you're right about pagers, but they've also gone one step beyond. All aircrews now have iPads to do everything from weight/balance to risk assessments.

 

[avdrummerboy]

So is 155.22 still in general use? Up to maybe a year ago I heard the Mercy crews updating life com on that channel with flight information. But then all of a sudden nothing and there was occasional digital sounding noise on the channel. I'll add the other two frequencies to my scanners and see what I hear on there as well. Thanks for the info.

 

[littona]

So is 155.22 still in general use? Up to maybe a year ago I heard the Mercy crews updating life com on that channel with flight information. But then all of a sudden nothing and there was occasional digital sounding noise on the channel. I'll add the other two frequencies to my scanners and see what I hear on there as well. Thanks for the info.

Yes, but it's been down for a few days. Should be back online tomorrow afternoon.