Posted May 1, 2005 by atlaspete
Long before the advent of 800 mhz full duplex mobile telephones there were vhf and uhf full duplex mobile telephones available. Many companies involved with 2way radio manufactured these. Motorola, GE, Aerotron, Harris, Spilsbury, Glenayre, NEC, and possibly a few more I have missed. These had limited channels available. SOme were crystal controlled , some were synthesized. They were higher power 20 to 40 watts of transmitter power. 152 and 454 mhz receive and 157 and 459 mhz transmit.
WIth the advent of poorly shielded RF noisy computers in automobiles in the late 70s and early 80s the Vhf full duplex mobile telephones and 2 way radios suffered greatly. The mobile phones were never advertised by the large telephone companies since their terminals and the limited number of channels allotted could only handle a limited number of mobile IDs. It was never a marketing concern, just word of mouth . Some radio common carriers got involved and made a go of it in the US. Glenayre a canadian company was one of the last players in the vhf/uhf mobile telephone manufacturing game.
The Motorola DynaTac was one of teh first 800 mhz full duplex mobile telephones available for use in teh huge 800 mhz channel allotment with 45 mhz tx/rx duplex splits. Before thus Motorola had a Pulsar full duplex mobile telephone. It weighed approximately 20 to 30 pounds and was usually mounted in teh trunk of a car.
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