2/08/2010

BWT-133 15W SSB Transceiver (TBR-131)



BWT-133 is the second field portable SSB device sees large scale deployment in infantry units. It is the third generation short ware SSB transceivers developed after TBR-130/10 W Frequency Syntheses SSB. The requirement was given in 1978 and samples were sent to troop in late 80s and certified in early 90s. It is the major division/regiment level transceivers in 90s and up until recently. It is being replaced by TBR-134 20W full digital frequency agile SSB device.



The BWT-133 Frequency Syntheses SSB transceiver is designed to replace Type 81 Compact in infantry units, and formal code name was given as TBR-131 in mid 90s when new military equipment naming convention was introduced, however, most people still call it BWT-133 and even manufactory still uses BWT-133 on the radio’s name plate. There are two major versions; the early version is LSB only device plus an AM compatible mode, the later version could operate in both LSB and USB modes plus an AM compatible mode. This device covers 1.600 to 29.999 Mhz with 28400 possible channels, controlled by a full digital Frequency Syntheses device.



The radio itself weights 7 kg and the system (including antenna, headset, carrying harness and battery) weights 14 kg, and the radio itself measures 286x98x262mm and radio plus battery measure 286X98X353mm. In addition to backpack configuration, BWT-133 could also be a vehicle mount device. In this configuration, it usually works with a 100W output power amplifier and a 12V DC power regulator.



This device is powered by 25 V/3 A DC power with full working condition when the power source is within 21.6 and 28 V. The power source could be a detachable 24V rechargeable battery unit, hand-crank 24 V DC power generator, or any external 24 V/3 A power source. The output power has two level in SSB mode, 15 W and 4.5 W. The output power for AM compatible mode is 4.5 W. It uses 3 meter rod type antenna, 20 meter wire antenna or 44 meter bipolar antenna (I only have the 3 meter antenna).



Comparing to 10W SSB’s three power switches, BWT-133 has only one power switch built into the volume control. Comparing to Type 81, operation is much simpler, but not as simple as a modern transceiver. The receiving part is very simple, one just needs to set the frequency, turn on the receiver, and that is it. To transmit, you need first set the frequency using the six frequency setting knobs, then turn the mode switch to Adjustment and antenna adjustment dials (two) until the output power reach it peak, as indicated in the small meter on left side of the control panel. After that, you could turn to oen of the voice modes (high output SSB, low output SSB or AM) or CW mode and begin communication. The tricky part is that you need to adjust two antenna adjustment dials (rough and fine).



My sample is an early LSB device in near NOS condition. I got the radio in 2009 but all the accessories in much early time. My sample was made in 1993 with serial number of 930497. It is made by Fen Huo Wireless Manufactory (Works No. 769) in Baoji, Shanxi.
When I first turned my set on, there is no output, nil. I opened it up and saw nothing wrong and put them together again. Then it started to work fine. No idea what was going on with this baby.



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