perhaps we have written this up before - lets do it again history of public safety radio in usa
starting around 1910 or 1920 - shortwave radios were used - channels near 1 Mhz perhaps - maybe all AM radios 1930 - maybe newer channels began to be used at 35 mhz with fm radios - cities and towns each had 1 channel - mostly for police - counties might have 1 channel also (for larger sheriff depts) - state police maybe had short wave radios and 35 mhz radios 1940 perhaps - 150 mhz radios used - first in big cities - police and fire started to get different channels from each other 1950s - police and fire had their own channels - countywide channels at 33 mhz and 46 mhz and 154 mhz for fire - countywide police channels at 37 mhz and 39 mhz and 45 mhz and 154 mhz for police - larger cities and towns and villages had their own radio channels - and they were often on different bands than the surrounding suburban or rural agencies - FDs had home alert radios and tone activated sirens 1960s - the first handheld portable radios started to come into use - rechargeable nicad batteries were used to replace alkaline batteries - UHF radio appeared (453 mhz and 460 mhz) - more radios had PL - microwave started to be used to link transmit sites - smaller pagers were able to be carried on hip belts - UHF channels were usually repeaterized 1980s - first 800 mhz radios went into use and first trunked radios systems went on the air - trunked radios were used in major cities and some larger counties 1990s - first P25 digital radios appeared - more units were equipped with mobile date terminals 2000s - synchronized simulcast became more prevalent for base stations - internet began to be used to link radio sites 2020s - 700 mhz trs becoming more common - FirstNet is trying to get started using cellular radio bands who can make corrections to this? -- You received this message because you are subscribed to the Google Groups "massfire" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/massfire/CAFXWwKavKY%3DGeqXjV9zD5prdBWCKAHsyNH05MMd_0gJOCbn3BQ%40mail.gmail.com.
