Los Angeles City Fire Department Radio History
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General Timeline
1930s - maybe AM - maybe near 500 kc
1946 - 38.70 in San Pedro area - (previously LAFD used the LAPD radio system)
1947 - FM on 35.58
1947 - Coldwater Dispatch started operations, at Fire Sta 108, using callsign KMA706 on 33.90
1949 - FM on 33.90
1949 to ?1979? - several more 33 Mhz channels were added
late 1960s - low band portable radios were introduced
1965 - Watts Riots after action report mentions that 4 radio channels were used : Westlake + Coldwater + San Pedro + Command
late 60s early 70s - Valley Dispatch changed from 33.90 to 33.82
1972 ? - added 6 channels at 506 mhz
?1972? - "Digicom" status buttons were added in apparatus (?on low band?)
1981 - use 6 radio transmit sites and 8 radio receiver sites - Ch 7 to Ch 14 are on VHF Low Band - Ch 1 to Ch 6 are on UHF - Ch 1 is 506.3125 R with 509.3125 as input - HEAR 1 and HEAR 2 are on VHF high band and used for ambulance to hospital communications - UHF mobiles transmit at 40 watts - low band mobiles transmit at 60 watts - portable radios transmit at 2 or 4 watts depending on model
1985 123.175 AM for helicopters
1991 - moved to 18 channels at 800 Mhz - all onduty firefighters now have portable radios
? 1992? - (for a while some radio traffic from ?800? mhz was patched onto some lowband channels - I remember hearing patched traffic on 33.60 here in Massachusetts)
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Sources of Information
https://www.fireengineering.com/leadership/department-operations-speeded-by-2-way-fm-radiotelephone/#gref - 1947 - article in Fire Engineering Magazine - LAFD has 3 main radio sites with 250 watt FM radios - plus 60 FM 2 way mobile radios - frequency is 35.58
https://worldradiohistory.com/Archive-FM-Magazine/FM-1949-07.pdf - 1949 - per FM TV Magazine - LAFD has radio licenses on 33.90
https://archive.is/Yff6s - 1991 - per LAFD radio document - 7 channels on 33 Mhz band - 2 channels on 155 Mhz band (HEAR 1 and HEAR 2 - ? 155.34 ? and ? 155.28 ? - maybe ambulances and hospitals only) - 6 channels on 506 Mhz band - moving to 18 channels at 800 Mhz in 1991/1992
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further info
https://sites.google.com/site/losangelescitycalifpubsafety/home/lafd/feb-4-2002-post-about-old-radio-channels - more misc info here - Marnell page at archive.org has 800 mhz channels from lafd website circa 2010 maybe
https://www.govinfo.gov/content/pkg/FR-1971-02-04/pdf/FR-1971-02-04.pdf - the FCC first made former TV channels available for land mobile use at 506 Mhz approx 1968 to 1972 - this narrows down the time range for when LAFD could have first started to use their UHF channels
the 1990 visiting fireman has low band and uhf band freqs for lafd - ch 1 - div 1 fg - 506.3125 - ch 2 - div 2 fg - 506.5375 - ch 3 - div 3 fg - 506.9125 - ch 4 - metro rescue amb - 507.1375 - ch 5 - special ops - 506.6375 - ch 6 - special ops - 506.0125 - ch 7 - metro fire ops - 33.70 - ch 8 - san fernando valley ops - 33.82 - ch 9 - special ops - 33.94 - ch 11 - command for chiefs - 33.60 - ch 12 - chiefs cars only - 33.56 - ch 13 - chiefs, car / car - 33.52
from 1979 "Visiting Fireman" - Los Angeles City FD radio channels
Ch 1 - 506.3125
Ch 2 - 506.5375
Ch 3 - 506.9125
Ch 4 - 507.1375
Ch 5 - 506.6375
Ch 6 - 507.0125
Ch 7 - Central / West / South - 33.70
Ch 9 - Valley - 33.90
Ch 11 - Command - 33.60