Military Collector Group Post, Oct.20/97 Index: MILITARY TRADER RAG?? PRC-68 QUESTIONS; WW-II Vets In "Nam"; TCS & others JAPANESE TYPE 94-6 RADIOS; Bill Howard UXC-7 HELP; ********************************************************* MILITARY TRADER RAG?? Does anybody have an address, Email, or Snail mail for some Military Trader publication comming out of Texas? Might be called Hot Sheets or somethin like that. A phone number, voice or fax would also me nice. These people for some time have been running an add with my name, & address. Note, I don't know where they got this add material as I have never sent them any, nor do I even subscribe to their publication. I'd much like to put a stop to it. Thanks, Dennis ********************************************************* PRC-68 QUESTIONS; Dennis, After firing up this little rig and playing with it for a short time several questions have arisen. The radio will xmit and receive on all ten channels as well as unsquelch and be unsquelched. (150 hz tone squelch, haven't tried with carrier operated equipment) However, when channel 2 and 8 are selected they remain unsquelched all the time. Is this normal? When squelched out, regardless of listening on speaker mic or H-250, with the volume set at 1/2 or higher a slight putt-putt-putt can be heard on all channels except 2 and 8 which remain unsquelched. Is this normal? Is the Squelch Disable position on the function switch used as a monitor button like on some of the newer commercial VHF/UHF HT radios? Have you ever measured current draw at nominal battery voltage during receive squelch ops? receive unsquelch ops? xmit? I don't have a maintenance manual or another radio to compare mine against to know if it is normal.Any information you can provide regarding the above questions would be much appreciated. Sincerely, Doug. DJM-AIRCAP@juno.com -------------------------------------------------------------------------------------- Doug, The unsquelched operation on both channels 2 & 8 is most likely the result of stray RF from some external source, such as computer, TV, etc. The PRC-68 does not have 150cps tone squelch. In receive it has standard carrier squelch, which is adjusted via an internal trimmer resistor. This adjustment is very voltage sensitive, I/E if you adjust it with a real good battery in it, then said battery drains a little bit, the squelch will break. The best setting is sometimes tedious to find. In transmit, it has a 150cps tone oscillator so that compatibility with later model equipment can be maintained. The Squelch Disable position on the pwr switch simply defeats the radios internal squelch control. The slight Put-Put that your hear is the radio's battery save function. Non eccential sections of the radio are pulsed on & off to reduce the duty cycle, thus save battery drain until a signal is received. Another Put -Put noise symptom is that the VCO is out of lock, but as you say that it transmits & receives OK, this is not the case here. Trying to measure the current drain of the radio during squelched/unsquelched operation will not do you much good because of the pulsed supply when squelched, also if tried with a digital meter, it will tell you nothing. Dennis ********************************************************* WW-II Vets In "Nam"; TCS & others Dennis, Just had a conversation with co-worker and unrepentant RMC(retired) Gary Sinn KM6A. Part had to with multi-culturalism, he is using the CMI 26003A key I gave him with an Icom 706MK II. The rest had to do with TCS use in the '60s. Gary, aboard the USS Pollux AKS4, was part of a CW net operating in the Tonkin Gulf during Market Time. The main TX/RX he used was the TCS. The last tour Gary did on the Pollux ended in 66 but the WWII radio equipment was still in operation until decommisioning in approx 68. The other modern technology available on a support ship in the 'Nam era?? Main TX was a TBK backed by RBS and RBC receivers. LF/500KC was a TDE. TED/RED combos took care of UHF, no URC-9s or SRC-20/21 for these folks. A URC-32 came aboard with an R390 in '64 or so but the veteran equipment stayed in use with the R390 taking the TTY broadcast role from the unstable RBS and the URC-32 used mostly as an RX. Just before Gary left the ship got a WRT-2 TX. An added feature of the TBK was shack warming during winter in Yokosuka. I'm not sure when the oter sets were first brought on line but our buddy the TCS is approx '43 so thats 25 years in service right there. Ed Zeranski This is a private opinion or statement. home email: ezeran@cris.com ********************************************************* JAPANESE TYPE 94-6 RADIOS By: LTC William L. Howard In the period following WW I, considerable progress was made in the development of radios. The Japanese, especially the military, followed developments with a great deal of interest. In 1934, the Japanese ground forces adopted several radios as standard equipment. 1934 on the Basic Japanese calander was 2594, usually abbreviated as 94, hence the designation Type 94 - indicating it was adopted in 1934. The most commonly encountered sets are the Type 94-5 transmitters and receivers,(See Articles in the April 1994 and the Feb 1995 issues of ELECTRIC RADIO), the Type 94-3A and Type 94-3C transmitters and receivers, and the Type 94-6 transceiver. The Type 94-6 was a small compact set that used one tube, a double diode and a circuit that has been described as a "rush box". Power for reception came from a battery pack and power for transmitting came from a hand cranked generator. The earliest example found of one of these sets was manufactured in January 1935. It operated on one band, had one tuning capacitor, one filament rheostat and a regeneration control mounted on the top of the set in addition to a socket for connection of two headset/throat michrophones and an RF meter. Other controls were on the side and consisted of the transmit/receive switch which was a lever switch and a toggle switch which is the voice/tone switch and the built-in CW key. Below the key was a connection for the power cable from the generator which supplied the required 3 volts and 150 volts. On the opposite side was the power plug that connected the set to the battery pack for use during reception and supplied the required 3 volts and 135 volts. On what must be considered the front of the set as it hung down around the operators neck was another socket into which a special two prong plug fit. To this plug were fastened an antenna rod and a counterpoise rod. The set was housed in a thin walled metal case with a cover that could be opened to reveal access to the controls on the top as well as two charts, one for calibration and one which had a schematic diagram and parts list. This set was then carried in a leather case and hung from the operators neck when in use. After a number of years, experience showed that the one band was not enough to provide adequate coverage and the set was modified to cover three bands. This meant three coils instead of one and a band switch to move from band to band. Rather than develop a completly new radio, the Japanese re-designed the set to make maximum use of existing manufacturing processes. The filament rheostat was moved closer to the outside cover to make room for the band selector switch. The band selector switch was not a rotary switch but more on the order of lever switches controlled by a rotary cam. The next major problem was where to put two more coils. This was solved by moving the battery pack plug socket down to the bottom of the same side. One or two other parts were moved around and now there was room for the other two coils. See the photographs of the two sets side by side. It is this later version that was captured in some quantity by allied forces and became the subject of a U.S. Army technical manual and a very excellent article done by Dick Rollema, PAOSE, the Netherlands titled "Japan's Hush-Hush Rushbox" which appeared in the March 1986 issue of 73 for Radio Amateurs. According to Dick, his set was manufactured in June 1940. To determine the date of manufacture, the Japanese went to a different system, this time using the year of the Showa Reign. Emperor Hirohito ascended the throne in 1925 so anything made in 1926 would have a year of manufacture of 1. 1935 manufactured sets show the year as 10 and 1940 would show a manufacture year as 15. The months in Japan are the same as the rest of the world with January being shown as 1 and December being shown as 12. Usually the Japanese is written from right to left. Below is an extract from the U.S.Army technical manual showing a data plate and the translation. A SCHEMATIC DIAGRAM BELONGS HERE For further analysis of the set, one should read Dick's article or consult the U.S. Army Technical Manual on the Set. In addition to the earlier set, another item has surfaced and this is a canvas bag labled as Type 94-6 Wireless Set, Antenna Bag. All models had a leather case that housed the battery pack and also had a small pouch for the accessories, to include the headset/throat mike and power cords. Both the canvas bag and the leather accessory pack are rare items and seldom are found. When found, they are usually not with the radio. The metal and fibre board case that housed the batteries is also a rare item and I have never seen one of these. The three band version of the Type 94-6 is commonly found but very few of the earlier single band sets seem to have survived the war. If you should ever find one, try to obtain it as it is a rare set. Below is the schematic diagram of the set. Note that parts are numbered to facilitate repair of the sets. Below the schematic is a parts list with approximate values. ANOTHER SCHEMATIC BELONGS HERE Parts list for Japanese Type 94-6 three band set. 1 Antenna connection 17 Metal can capacitor 2 Counterpoise connector 18 250 ohm wire wound resistor 3 RF meter 19 Transformer 1:20 4 Mica capacitor 450 1500 20 Transformer 5 Coil 21 Mica capacitor 450 1500 6 Variable capacitor 22 CW key assembly 7 Mica capacitor 450 1500 23 Tone/Voice toggle switch 8 Mica Capacitor 450 1500 24 Headphones/mike socket 9 Coil 25 Generator power socket 10 Regeneration control 29K 26 Battery plugs connection 11 RFC 27 Mica capacitor 4500 1500 12 Mica capacitor 450 1500 28 Carbon resistor 13 Mica Capacitor 450 1500 29 Band switch 14 Tube socket 30 Coil 15 Transmit/receive switch 31 Coil (mounted on # 9) 16 Filament rheostat 32 Mica capacitor 450 1500 THE WILLIAM L. HOWARD ORDNANCE TECHNICAL INTELLIGENCE MUSEUM e-mail wlhoward@gte.net Telephone AC 813 585-7756 *********************************************** UXC-7 HELP; Hello everyone, We just aquired an AN/UXC-7 and we would like to run a test with it. The unit is new/boxed facsimile. We have the TM and it doesn't state if it works with any other units besides the UXC-7. Does anyone have some knowledge in this area? Thanks, Glen and Chuck. eldim@worldnet.att.net When finished reading use browser back button or go to http://www.prc68.com/MCGP/MCGP.html