My first job in the business was as a service tech for an RCC. We had a GE IMTS terminal with hand wired 5th Selector Level stroger switches on the direct inward dial trunks complete with sleeve lead control. There were 4 selector switches, and one block on 1000 numbers. In addition to the GE IMTS terminal there was also a Motorola LO9DAL dial access paging terminal that used code plan 'S' The code plan determined which 2 groups of tones were used in two tone sequential. The pagers were Bell and Howell and KEL - that used either alkaline or mercury batteries.
The IMTS system had about 20 T1433AE full duplex FACTS (fully automated car telephone system) radios and control heads. (there were fewer than 50 pagers in Temple, TX in 1975). Drew about 2 amperes while idle. Took a channel element like you described (radio was similar to a Mocom 70) and ran it up to about 40 watts VHF before it hit the varactor tripler and the duplexer. There was one Moto base station and one GE PRO series station - (we had only 3 channels to start with) I never will forget the day when it got so hot at the site in Temple - south of Waco abt 30 miles that the plastic relay covers on the Moto melted and kept the TX from keying - no isulation or anything - just a tin shed on a hill top in a corn field. When the stations were keyed via remote control phone line, the station would change the load resistance to tell the terminal that it had come up to full power, else there was a remote fail indicator at the terminal. Next came the customer owned and maintained units - Moto Pulsars and GE / Secode Mark 5 heads. We also has some Secode DID1 terminals and VP1 control heads, but these were on VHF with the TLD1100's. Interesting, the TLD1100 also drew 2 amperes in standby, due to the 5894 PA and driver tubes, not like the T1433AE with the all PNP transistor supervisory logic pack. All this for just $3.50 an hour just out of tech school. 1/2 a day Saturdays at overtime....you could almost make a living. When I left the RCC in 1981 for a microwave / T1 transmission job at Centel in 1981 there were 600 pagers and 40 some odd mobile phones. We implemented metered service in 1979 - cost went from $72.60 per month unlimited to the same plus $0.20 per minute or portion there of. I remember seeing some $300 phone bills - we got about 1/2 the rental phones back - and continued to make the same revenue with 1/2 the equipment in the field. Tone and voice pagers were running $15 per month, and tone only were $9 per month. Those were the days. Steve NU5D We On 3/26/07, Milt <[EMAIL PROTECTED]> wrote:
If it was a copper colored square channel element, then the radio should have been about 2ft long, 6"high, and 15" wide and weighed enough to eliminate the need for the extra couple of sandbags in the trunk in the winter. TLD-1100 comes to mind but that was the VHF version. Based on a Motrac, the VHF units still used 3 tubes to get up to 50 watts before the duplexing filter. The UHF was solid state and ran about 18-20 watts out. They were very popular with the telephone company folks around MD.
-- Ham Radio Spoken Here.....NU5D Visit the Temple Ham Club Website http://www.tarc.org www.yahoogroups.com/group/Temple_arc www.yahoogroups.com/group/60meter
