Then I started my career in Public Safety. Starting out I was a Dispatcher. So, I used a radio a lot. But, it was push the button on the console or activate the foot switch, no real interaction with turning knobs and dials. However, all the radios have vacuum tubes in them. One of the base radios that worked in the 40MHz range was a five foot tall cabinet. That cabinet generated a lot of heat.
Then I went into the field division and had a little more interaction with the radio. We had a squelch control (now squelch control is mostly programmed into the radio), turn the switch to change frequencies and the switch to choose which repeater that you wanted. The mobile radios at this time were a “hybrid” in that the receiver was all solid state, but the transmitter still had one tube (though not a glass envelope tube) in the final Power Amplifier. The unit fit in the trunk and was large and heavy. Of course, some of the cars still had radios in the trunk that required a dynamo to run. When you keyed the microphone (held PTT switch) the dynamo started, and it sounded like a jet taking off. After the dynamo hit peak, you could transmit.
Then we got fully solid-state radios. Not much smaller in the trunk, the control heads were larger but that was because the siren\Public Address board was part of the control head. We still had a squelch control and the knob to change frequencies and push buttons to choose the repeater that you wanted. These radios still had crystals in them that were “cut” to the proper frequency. The crystals were housed in metal heater containers to make sure that they would work at the proper frequency.
As time went on, I got acquainted with a gentleman that ran the radio repair shop for a large construction company doing work in the area. He had been in law enforcement, and volunteered with the local EMS and volunteer Fire Departments. He was not into Amateur (ham) radio, just commercial and Public Safety. From him I learned a lot about radios. With his guidance I took several radios that had been donated by a federal agency to the local search and rescue organization and replaced the crystals with new ones and retuned them to work in the public safety band area. I learned how repeaters worked, that a frequency split was necessary, that most were activated with a CTCSS tone. That changing or adding a new repeater or changing the CTCSS tone on a repeater meant a lot of work, as all the radios that accessed that repeater had to be modified. I even started my own sideline business of installing radios in Public Safety vehicles. It was not unusual to see an ambulance, police car or fire truck in our carport while I spent days or weeks installing radios. A lot of the installations had to have control heads or at least microphones in the front and back of the vehicle. I learned a lot.
Then a promotion came, and I was assigned to administration. Part of that job was management of the radio system and the fleet. It was about time to change the radio equipment. It was getting a little ancient and though it still worked well it was time to upgrade. So, with all the background and knowledge gathered through all the years of radio interaction, we redesigned the system. We relocated repeater sites, added a few and made the conversion to synthesized radios. No more crystals. We used a computer to change the frequencies. We also added Digital Voice Protection, or scrambling to the system. This was a headache as the code had to be created and then loaded into each radio. But, it worked well.
A change of jobs led me to yet another radio adventure. This time it was to assist in the planning and implementation of a county wide narrow band VHF simulcast system. This system would carry traffic for numerous law enforcement, fire and ems agencies. What a project.