Welcome to the DMR Group of the Bay Area Communications Society, a technical group of experimenters and builders of amateur radio systems, including Digital Mobile Radio, located in the San Francisco Bay Area. We use our 5 Baycom UHF DMR repeaters in a Brandmeister cluster, on ‘Baycom Talk Group 97150’ Time Slot 2, mainly for communication while building our other projects, including complex remote HF stations (K6MTU), 8 mountain top IP/VoIP distribution networks, Video IP systems, Gigabit microwave VPN and L2 Pseudowire networks, a large MPLS network,  the NCDX Beacon, FlightRadar24 ADS-B receivers, MarineTraffic AIS receivers, NASA DeepSky Fireball Network Meteor Cameras, Redwood Seismic Network seismographs, Air Quality monitors on Mt Umunhum, McQueen Ridge and Empire Grade, as well as a professional Weather station to NOAA specs on Mt Umunhum. Future air quality monitors installations are planned for Mt Allison, Mt Toro and Mt Vaca.

Operating Tips and Requests

We are open to all, yet we do have a few (gently) suggested tips to make your (and our) lives easier. We’d appreciate your cooperation.

  • We politely request that Timeslot 2 be kept as free as possible, other than for Baycom TG 97150
  • We also kindly request that Linking and Reflector use be performed on TS 1 only.
  • We time out Dynamic TG’s after 10 min. This is in order to allow other Dynamics to have a chance, due to several limitations of DMR for ham use, namely a lack of TG prioritization, fine grain scheduling, or multiple QoS levels. It’s almost a trunked radio system, but not quite. Quite frustrating, to put it mildly.
  • We discourage the use of Private Calls, as other hams can’t usually see/hear them and can’t figure out why they can’t access the Time Slots and become frustrated.
  • We really urge folks sending location data (LRRP/APRS) GPS updates to crank down the update frequency to maybe 1 per 5 min to conserve bandwidth, as they eat both TDMA slots with these data frames. So how far are you going to go in 5 min ? Same with sending SMS, since it uses the whole 12.5kHz, please be aware you are eating the bandwidth of both slots.
  • Last, if you want to yack with the folks from the old country, why not buy an OpenSpot, a ZumSpot or a MMDVM RaspPi and have at it, there are loads of ways to set up a hotspot at home. Be courteous to your ham neighbors and don’t eat up their RF air time, IP network time is free. If you don’t know how to set it up, we’ll help you, glad to be of service.

We monitor our repeaters with RTL-SDRs, Cubic SDR, Gqrx, DSD+FastTrack for the DMR RF data side of things and Wireshark, TCPdump, Pingplotter, some MOS Score (ITU P.861) VoIP quality testing s/w for the network side, along with the usual gaggle of network tools recommended by our friends at SLAC. We also monitor, graph and alarm Network trends and events using Raspi3b+ based Network Management systems employing LibreNMS, Nagios, pnp4nagios, smokeping, routers2.cgi, NagiosQL, MRTG.We use the tools to decode traffic, including Group calls, Private calls, LOCN-LRRP-APRS, SMS, data only frames, IP Site Connect data and beacons, but also radios which are misbehaving, in order to help folks out, not to be a pain ! You’d be surprised how easy it is to misconfigure a DMR radio and cause group problems for everyone. Ever been talking to someone and they just “go away” ? Ever try to get on a TS and you can’t, but there’s no activity you can see or hear (and it drives you crazy) ? We can help, give us a shout, we’re glad to help.

Baycom Frequencies and Talk Groups

The Baycom DMR System consists of 4 Motorola UHF XPR-8400 ver R02.40.20 firmware repeaters linked to the USA-West Brandmeister server 3103 and are located around the San Francisco Bay Area and Santa Cruz California USA, they include:

Mt Umunhum

WA6YCZ 442.5375 Mhz+ CC1  above San Jose, elevation 3509 ft,  37.160999 N -121.910040 W (decimal DD.mmssss for Google Earth)

Black Mountain

K6OTR 441.85 MHz+ CC1 above Palo Alto, Monte Bello Ridge, elevation 2812 ft,  37.320348 N -122.142594 W

Mt San Bruno

N6AMG 440.500 MHz+ CC1 above SFO Airport, elevation 1319 ft,  37.687439 N -122.435547 W

Mt Allison

WA6KPX 443.400 MHz+ CC1 above Milpitas East Bay, elevation 2657 ft,  37.5000 N  -121.837001 W

Bonny Doon (Destroyed by the Aug 2020 by Lightning Fire)

WB6ECE 440.5875 MHz+ CC2 Northwest of Santa Cruz,  elevation 1476 ft,  37.100254 N -122.141869 W

                                                               Baycom System Static Talk Groups


                                                                    TS 1 – Common to all Machines

TG 93North America3106California 10 Min limit31065DMR AllStars, 31075BayNet31606 – Call Zone 6 , 310604 CARLA

                                                          TS – 1 Unique to Geographic region machines

WA6YCZ – 31064 Santa Clara County by request

K6OTR – 91 Worldwide net from 0830 PST-1100 PST hrs every Sat 

N6AMG – 31062 Mountain West

                                                                     TS 2 – Common to all Machines

TG 97150Baycom   

TG 31062 – Mountain West                

TG 31068 – Norcal to TS 2 per request of several NorCal users.