The_B_Chief said:
There is a lot of history behind Tac-1 isn't there? Was it not one of the first frequencies used when LA went from one -way radio to two-way radio?
There's a fair amount of history behind Tac 1, but it doesn't go back quite that far. LAPD started using one-way radio in 1931, and began regular use of two-way in 1938, with the mobiles transmitting on five frequencies in the VHF low band, 35.10, 35.22, 37.22, 37.78, and 39.38 mHz. They received the dispatchers on 1712 kHz (changed to 1730 kHz about 1940). Everything was AM.
In 1947 and 1948 they got their first nine VHF-High frequencies, including 154.83, which were FM from the get-go, but many cars continued to use the low-band AM transmitters into the mid 1950s. Old-timer radio techs from the 50s, the few that are still around, tell about the hodge-podge of radios and combinations they had to maintain during that decade: Older cars had 6-volt systems, but newer models had 12-volts, some radios transmitted on low-band AM, while others had high-band FM, and while most cars had 1730 mHz receivers, the 158 & 159 mHz FM dispatch frequencies were starting to go online as well.
Anyway, at some point in the 50s, 154.83 "Frequency 9" became a car-to-car detective and "crowd control" frequency, but its use was restricted to command officers and some selected detective units for surveillance and stuff like that. Chief Parker (1950-1966) was adamantly opposed to patrol officers being able to communicate with each other without going through the RTOs (RadioTelephone Operators) at Communications Division. As his successor, Tom Reddin related it to me years later, "Old Parker was scared to death he'd lose control of his men if he let them talk to each other on the radio." Even the communications nightmares that complicated the handling of the 1965 Watts riots didn't sway him.
Parker died the following year, though, and in 1967 Chief Reddin (who had previously been the commander of Technical Services Bureau) ordered installation of 4-channel radios in patrol cars, with two semi-duplex dispatch frequency pairs, and two simplex tactical frequencies, 154.83 (Tac 1 / Freq 9) and 154.77 (Tac 2 / Freq 6). It took several years for all the cars to get them. In general, Tac 1 was reserved for detectives and Tac 2 for patrol, but there were plenty of exceptions to that.
As far as broadcasting the "hotshot" calls on a tac frequency, that didn't begin until about 1972 or 1973, and was mainly for the benefit of the air units, so they could receive the calls on a single frequency no matter where over the city they were flying. At first they used Tac 2, though, since it was the "patrol" tac frequency. Unfortunately Tac 2, 154.77, was immediately adjacent to the Van Nuys Div mobile freq 20, 154.785, one of the 15-kHz-split frequencies LAPD had received about 1968. Even with PL protection, very often the hotshot broadcasts would blast into the Van Nuys RTOs' ears with tremendous bursts of static. This went on for many months despite the complaints from Valley Communications - not only was it
literally hurting the operators' ears, but whenever downtown communications was transmitting, the Van Nuys units couldn't be heard by their dispatcher. Finally they moved the hotshots to Tac 1, but sure enough, within a couple months Van Nuys got a "new" frequency, 155.07, freq 8. It was the same mobile frequency used by Harbor Div cars, but receiver location and PL tones kept interference to a minimum. The UHF ROVER frequencies were to come along in just a couple years anyway.
