9/15 Team Meeting

Thanks to everyone who attended our September 15th Team Zoom meeting.

We discussed our participation in and the results of the HEAR test  from earlier in the day, recapped our first in person meeting at the end of August and had a general discussion about the upcoming OCRACES drill on October 2nd. 

The meeting was rather short, but full of good information. 

Enjoy the replay.


Orange county maintains several analog FM channels aside from the 800 mHz digital trunking system as emergency backup and mutual aid use, so agencies from outside the county can communicate with county dispatchers.  These channels should be programmed into normal amateur VHF-UHF transceivers or scanners, and could become very active during emergencies.  It would be a good idea for all OCHEART members to have these channels programmed to monitor.

Item #3, the HEAR frequency is the test that was discussed during our September meeting.

1) Sheriff-police mutual aid channels.

These channels provide a analog FM way to contact the sheriff dispatcher on Loma Ridge.  Under normal conditions, will not be active, except to broadcast traffic issues, like SIGALERTS.  During times of public disturbance—riots, large protests, etc, they could become active.  There is one channel for each public service band:

      • VHF—151.085
      • UHF—460.525
      • 800 MHZ—821.0125

2) Orange County Fire Authority Mutual aid channel

The OCFA maintains a mutual aid channel used particularly on large wildfires, where many agencies may be providing personnel.  If a large wildfire is occurring in the county, this would be a good channel to monitor.

      • VHF—151.01

3) H.E.A.R. radio.

The Hospital Emergency Administrative Radio service was established by the FCC many years ago to provide hospitals and ambulances a backup radio channel to contact each other when their normal communications are down.  It consists of two simplex FM frequencies: 155.28 and 155.34.  Locally, it has been decided that Orange County will use 155.28 and Los Angeles County uses 155.34, as their primaries.  In Orange County, the Redinet company installs and maintains the HEAR radios in the hospital emergency departments.  Hospitals may be using 155.28 in emergencies. The county could be giving hospitals general emergency bulletins over HEAR.  Communication is only by line-of-sight, no repeaters.  Loma Ridge, of course, is on a high point, so has good line-of-sight to hospitals.

 4) UHF MED radio.

The UHF MED system was set up by the FCC more recently than HEAR radio, and is designed to be used through repeaters. It is intended to be used by both hospitals and ambulance-paramedics.  The entire system has at least 10 channels available for dispatching, voice traffic, and even EKG transmission.   Every county in the country will implement this system to one degree or another.  In Orange County, it was decided only to implement the dispatch channel, channel 9, which is 462.95 MHz.  LA County implements UHF-MED more extensively.

Orange County requires all ambulances operating in the county to be equipped with a MED 9 radio, to communicate with each other, including other ambulance companies, or ambulances coming from out of county that do not have 800 MHz radios.  Hospitals can equip themselves with MED-9 if they wish.  The advantage of MED 9 over HEAR is that it is repeated and therefore has more range around the county, especially tight places..

Users on HEAR and MED 9 are cautioned to not put specific patient data on these channels that would violate HIPAA restrictions, as we should also not do on amateur frequencies.

Keep in mind all these channels are for emergency use and won’t be active under routine conditions.

You can download this information as a handy PDF here

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