This is a survival radio that transmits on either 121.5 or 243 MHz. It's KoreanConflict, Vietnam Era vintage and uses vacuum tubes.
The thing that's most noticable is that it weighs a lot (2lbs 13 oz without the battery or battery cable).
Movie credits: Ice Station Zebra, The Bridges at Toko-Ri, Bombers B-52, Flight from Ashiya, Battle Taxi
This is a Hoffman Radio Corp. RT-159A/URC-4 s/n: 31263
Both V3 & V4 are USAF 6147 pencil tubes.
RT-159A - the doubler tubes V3 & V4 changed from 5851 to USAF 6147 & wiring, resistor, bias and capacitor changes
RT-159B - JAN 2E32 used for V4 after s/n 16,000 CK6397 & JAN5678 used for V3 & V4.
BA-1264/U Mercury Battery
B+: 136/115 (replace at 120)
A: 1.3/1.18 (replace at 1.2)
Manual 5 Oct 1950 revised 5 May 1960
The Y1 crystal in the only crystal in the radio. It's in an axial lead machined cylindrical package and snaps into place just behind V1The MAY-1 UHF radio set come with the CY-591/U Crystal Case filled with CR-9/U (? is that the correct crystal designation) crystals that have this look and feel.
Marking engraved on crystal:
CR-24/U CAIJ 30.375 MC
Note: 4 * 30.375 = 121.5 MC
Note: 2* 121.5 = 243.0 MC
Examples of the CR-24/U crystal package:
2 each CZX 28.24000 MC
2 each CCSO 32.91250 MC
What do the letters CAIJ CZX and CCSO mean? Let me know.
|Fig 7 Schematic RT-159A
||Fig 8 Inside V1 at top
||Fig 9 Y1 Crystal
V1 in front of Y1, then V2, then V3 & V4 as a pair.
2866089 High-frequency radio transceiver, Maass Charles Frederick, Hoffman Electronics, 1958-12-23, 455/73; 455/336 -
2018569 Radio signaling apparatus, George W Pettengill, Carleton D Haigis, RCA, 1935-10-22, 455/85; 331/59; 455/78 -
2420740 Frequency-doubling device for highfrequency oscillations, Douma Tjiske, Priority: 1940-08-15, W.W.II, Pub: 1947-05-20, - for UHF (around 300 MHz)
2533493 Portable radio device, Donald H Mitchell, Motorola, Priority: 1942-02-20, W.W.II, Pub: 1950-12-12, 455/78; 315/95; 455/90.2 - See the BC-611
2535063 Communicating system, William S Halstead, Farnsworth Research, 1950-12-26, 455/83; 343/720; 381/111; 343/718; 367/903; 455/270, - single in-ear transducer for both talk and listen. See the EM200 combined Earphone and Mike.
2570840 Radio-frequency oscillator organization, John C O'brien, General Railway Signal Co, 1951-10-09, 331/139 - tube circuit to work at harmonics of a crystal
2613320 System for using overtone activity of piezoelectric crystals, Albert R Panetta, Electronic Research & Manf, 1952-10-07, 331/158; 331/164; 333/187 - tube circuit to work at harmonics of a crystal
2632812 Carrier-current intercommunication apparatus, John R Cooney, 1953-03-24, 455/73; 331/58; 455/335; 455/77 - intercom, not campus broadcast
2692943 Decituned transceiver, Reid John Drysdale, Avco Manufacturing, 1954-10-26, 455/87; 331/39; 455/77; 455/78- 2000 to 8990 kHz transceiver by push button tuning
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EE TImes - Retro wireless: Hoffman RT-159A/URC-4 survival radio - Dec. 2008 -
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