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MYSTERY RADIOS;(22 pages) Index: MYSTERY RADIO; The PRC-88, by Dennis Starks MEMBERS WRITE; Delco/PRC-88? From Jim Karlow A Real PRC-88! More PRC-88 Proof, Experimental PRC-88, -68, PRT-4's, URC-68, & More FS-5000, From Mike Murphy MYSTERY RADIO; The PRC-28. by Dennis Starks PRC-28, AND 2 CENTS; Lenox Carruth, and Dennis Starks MYSTERY RADIO; The Navy RBZ, by Dennis Starks MYSTERY RADIO; Navy AMA, by Dennis Starks MORE ON GRAY SIGNAL CORPS RADIOS; MYSTERY RADIO; the PRR-15, by Dennis Starks, & Bill Howard MYSTERY RADIO; GRR-5 by Dennis Starks

   MYSTERY RADIO; The PRC-88 As with the PRC-28, the first place that I ever saw reference to a PRC-88 was in The "Can Communicate With" section of a PRC-25 manual, near 20 years ago. Since that time I've been diligently searching for the truth about it's existence, or non-existence. Below are several conflicting descriptions of the set, as taken from Ref.#1, among others. PRC-88; Handheld VHF, FM transceiver. Developed for the US Marine Corps out of dissatisfaction with the recently adopted combination PRT-4 & PRR-9 radio set, which was intended(in part)to replace the PRC-6, circa 1964. Three conflicting physical descriptions exist from both official & non official but informed sources. #1,The PRC-88 is a repackaged PRT-4 & PRR-9 radio set into a single common handheld cabinet, Ref.#14, #26. #2,The PRC-88 is simply the possession of both the PRT-4 & PRR-9, (normally a PRR-9 would be issued to each member of a squad, while only the squad leader was issued both the PRR-9 & PRT-4). #3,The PRC-88 never existed in physical form, but only on paper. Ops 47-54mc, on one xtal control channel(2 chan on transmitter), with an RF power output of 450mw. Requires 5v(rec), 12-15v(trans). I/E the operational parameters are the same as for the PRT-4 & PRR-9. Ref.#14, #26, various PRC-25/77, PRT-4 & PRR-9 manuals. In defense of description #1, In Ref.#1(printed in 1976), the author describes the radio in some detail, it's PRT-4/PRR-9 lineage, and the Marine Corps connection. To fully understand the growing pains of the Squad Radio during this time period(1951-65), interested parties must read the reference material. But in short, though all prospective users of these new squad radios were consulted during most of the development of the PRT-4, and PRR-9. Their input as to what the optimal squad radio should be was largely ignored. And comments from the Marine Corps particularly so. With the adoption of the PRT-4, and PRR-9, the Marine Corps, now thoroughly pissed off, and having no further interest in any more joint services development, did two things. As the official account goes, they had the PRT-4 and PRR-9 re-packaged into a single unit as an expedient until their own version of the optimal squad radio could be developed. And at this same time, initiated the development of this new optimal squad radio that would later become the PRC-68. Of these two acts, at least the later is unrefutable historic fact. In defense of description #2, In Ref.#2, under "System Applications" the PRT-4, and PRR-9 are list separately with an addenda at the end of the chart that reads,"As a pair, these radios are identified as Radio Set AN/PRC-88". Over the years I've interviewed numerous Vietnam veterans, and questioned them on the radios they used. All named the PRC-25 and 77, and a few mentioned the PRC-88. When I asked them to describe the PRC-88, their description was that of the PRT-4 and PRR-9. But for the most part, these were mainly Army Vets, the Marine Corps Vets could remember neither the PRC-88 or the PRT-4/PRR-9. A couple years ago, I was offered a PRC-88 from a supposed collector in trade for a BC-312. I quizzed him repeatedly to insure that the set he was offering was indeed a PRC-88. He assured me that the radio was a single unit, with a data plate that read PRC-88. So I consented to a trade. He replied that he had sold the radio to a local law enforcement officer that collected communications equipment. Needless to say, I was pissed! Personally I think the PRC-88 did exist, though very possibly in a limited production, experimental, or simi-experimental form. Our lack of a physical example, or historical references is not an indication to the contrary, as this is typical of most equipment used by the Navy/Marine Corps dating back to WW-II, and this has been pointed out in numerous previous articles. Dennis Starks; MILITARY RADIO COLLECTOR/HISTORIAN References: #1. MILITARY RADIO DATA, VOLUME I, PRC Designated Radio Equipment, by Dennis Starks (copies available from the author) #2. TM11-5820-398-12, Nov. 1965, Radio Set PRC-25, Operator and Orginizational Maint. #14. ECOM 4451, Nov. 1976, History of the Squad Radio. (reproductions available from W7FG Vintage Manuals) ****************************************
    MEMBERS WRITE; Delco/PRC-88? From Jim Karlow Dennis - I may actually have had the unit you describe as the PRC-88. After graduating from college, I went to work for Delco Radio in 1977, shortly afterwords they were disbanding their military radio group and I picked up several items. One item was a unit without a tag on it but containing a PRT 4a transmitter circuit board and a PRR-11 receiver circuit board. the unit had outside dimensions about the size of a BC-611. It had no built in mike or speaker unit. The unit had a clip on battery box on the bottom, which I believe contained 2 PRT-4 batteries. These batteries would operate both the receiver and transmitter. On the top, the unit had 2 PRR-11 antennas mounted diagonally across from each other, one was for transmit and the other receive. The unit also had a military handset connector on the top. The only switch was also mounted on the top and it was marked off-on-retrans. The operating frequency was 51.0 Mhz crystal controlled. The second transmit channel was not accessable by the operator. The unit would work as a standalone 2 way radio with a handset. I was told that the radio could be bound to the side if a PRC-25/77 to provide retransmit capability. I remember that the radio was as tall as a PRC-25/77 but only 1/4th as wide. The case had the appropriate indents on one side to conform to the side of the PRC-25/77 case. With no label on it, I never was sure what it was. I used it on 51.0 for awhile and later either traded it or sold it at a hamfest in Indiana. I sold the unit about 15 years ago and don't remember who got it. My guess is that it still exists in someone's basement somewhere. By the way I also had a Delco 6800, which was an updated version of the PRC-64. This unit had a tuneable receiver and a small 2-10 MHz synthesized transmitter. It was mounted in a box just slightly larger than the PRC-64 box. All the best, Jim Karlow ed)The thing you had sounds like it was more intended for use as a portable repeater. Motorola built some prototypes along that line, one had everything in a single PRC-25 cabinet. That was a PRR-9, not PRR-11 that was inside the unit you had. ----------------------------------------------------------------- MEMBERS WRITE; A Real PRC-88! DENNIS GOT TO SEE A REAL PRC-88 TODAY!!!!!! WENT TO *********'S HOUSE HE HIS THE OWNER OF THE ********* SIGNAL CORPS MUESEUM.HE HAS ONE ITS LOOKS JUST LIKE A PRT-4 BUT IS WIDER AND HAS THE PRR-9 SPEAKER ATACHED TO THE BACK.WILL GET PICTURES OF THIS TO SHARE WITH THE GROUP.ALSO WILL GET NSN NUMBER OFF OF THIS RADIO. DAVID DAVIDSON ed) I have long held, in the face of extreme adversity, that a physical example of a REAL PRC-88 existed. Even if only in an experimental form. Now the proof! I want me one! Check out the serial number too, and whether or not the model number is followed by an (EX), or (EC). Pete McCollum, in his usual diligence, has also just discovered a here-to-fore unknown PRC built by AVCO. Maybe he'll write something up on it for us before long. Hint! -----------------------------------------------------------------
     More PRC-88 Proof, Dennis, I was up on a japanese collector site: And saw he had a picture of the 'prc-88'. The long debatted combo of prr-9 and prt-4. The picture looks like a wider prt-4 with prr-9 speaker mounted to the back of it, speaker horn coming around the left side of radio (behind the regular prt-4 antenna). Some switch is mounted below the mike/freq switch on the prt-4. The prr-9 earphone jack is mounted on the lower right hand of prt-4. A separate photo shows a label clearly indicated PRC-88. However, it isnt in standard black foil type they normally use. I have the jpeg if anyone wants me to email it to them. Ralph Hogan WB4TUR Huntsville, AL. ed) You all know I have long argued for the existence of a true PRC-88. Now we have found two physical examples in the last three months. It's tough always being right! Now to find one for myself. Experimental PRC-88, -68, PRT-4's, URC-68, & More FS-5000, DENNIS: FYI: I HAD SOME OF THE PRC-88 SETS ( ALL PROTOTYPES) THEY ALSO AHD A BATTERY BOX THAT HELD 3 OF THE BA-399/PRT-4 IN PARALLEL, AND A RF AMP MODULE THAT FIT ON THE TOP ( WORKED ON THE PRT-4 ALONE ALSO) THAT SEEMED TO BOOST THE POWER TO ABOUT 3 W. THERE WERE LOTS OF VARIATIONS OF THE SETS, I ALSO HAD A PRR-9 THAT WAS ALL MODULAR, WITH BLADE ANTENNA AND VCO TUNING. SAME THING WITH THE DEVELOPMENT OF THE PRC-68 AND URC-68. I HAVE HAD A FEW VARITIES OF THEM TOO. ALSO, REGARDING THE FS-5000. I THINK DHALMER/BENZ AND DEUITCHE AEROSPACE( NOT TELEFUNKEN ?) WAS THE MAKER OF THE SETS I HAVE. THEY PUT OUT A MODEL HRS-7000 ( IN JANES) THAT IS SIMILAR, BUT HAS ALL THE STUFF IN 2 CHASSIS, AND NOT SEPERATE. MIKE ed) My luck! Bet all these examples are now long gone! ****************************************
    MYSTERY RADIO; The PRC-28. by Dennis Starks Back when I first started collecting military radio equipment, and my reference library would not fill my desk draw(now it's one room of my shop building). One of the places I'd strive to learn about equipment I didn't have, was the "Can Communicate With" section of operators manuals. This is the first place that I saw reference to a PRC-28, The "Can Communicate With" section of an PRC-25 manual. It didn't tell ya much, but it did let ya know the thing existed, and operated between 30 and 42mc. 20 years later, I own one, and it's operator's manual, and I don't know much more now than I did then. Below is a description of the set taken from Ref.#1 among others: PRC-28/RT-339; Backpack VHF, FM transceiver, Identical to PRC-9A or 10A, except is not continuously tunable. Ops 30-42mc on any one xtal control channel, with an RF output of 850mw. All other parameters, accessories etc are the same as PRC-9A. Requires 135v, 67.5v/20ma, 1.5v/500ma(rec),135v/55ma, 67.5v/15ma, -6v(trans), supplied by BA-279 or AM-598. Accessories include H-33 handset, CY-744 battery box, BA-279 battery, AT-271 & AB-129(long antenna & rubber spring base), AT-272 short tape antenna, AT-339 homing antenna, M-1945 belt, CW-216 ant & acc bag, ST-120 backpack harness. RT-339 less battery box 9.5 x 3 x 10.5in, 9lbs. Original cost, circa 1953, $810.00. Ref.#3 Only after a close inspection can you tell that a PRC-28 is not a PRC-8A, 9A, or 10A, or vice versa. Externally they are almost identical. Even when looking inside the radio, it's not easy to see the differences. For simplicity, we'll just include the PRC-9 in the following comparisons, but the PRC-8A, 9A, and 10A will also apply. #1. Most obvious, the PRC-28 has a xtal control transmitter, vice the continuous tunability of the PRC-9. What is not obvious, even when referring to the radios manual, is that the receiver is not xtal control, and is tunable over the radios entire range. But the user is denied access to this receiver tunability. There is no dial pointer adjust (but the protective ear is still there). And the normal tuning knob has been replaced with a screwdriver adjustment, protected by a screw on cap, same with the dial lock control. #2. The cost, the PRC-28 cost $810.00 as ordered from RCA circa 1953, and 1954. In comparison, the PRC-8 was $326.37, the PRC-9 $513.96, and the PRC-10 $592.78, all from the same source. What could account for the great difference in cost, when the same basic radio was involved? #3. Internally, the transmit oscillator module has been replaced with a crystal socket. And while the manual states there is no Pulse Sweep Generator module, in reality, there is. The later is normally function of the transmitters AFC system, and would have no place in crystal control radio, except that it also provides for side tone of transmitted signals. The last odd internal feature is the Discriminator module. normally this a hermetically sealed module in all variants of this PRC family. But the two known examples of the PRC-28, both have screw down end caps that can be removed to allow adjustment. Manuals state that the PRC-28 uses the same Discriminator module as the PRC-9A, but this version has never been found installed in them. #4. The PRC-28 was apparently not operable with the AM-598 vehicular power supply/audio amplifier. Though I can see no reason why not, the manual specifically states,"There is no current modification which permits use of the AM-598/U or AM-598A/U with radio set AN/PRC-28". As we have absolutely no historical information on the set, we can only draw on it's physical attributes to form some kind of idea as to it's intended purpose in life: #1, The PRC-28 was obviously an attempt to "dummy proof" a PRC-9, or 10. And as all known examples show Marine Corps use, this would tend to support that assumption.(I can't help but slur those poor dumb bastards every chance I get) #2, The frequency range of 20-55mc was subdivided into three segments at the time. 20-28mc(Armor), 27-39mc(Artillery), 38-55mc(Infantry). As the PRC-28 overlaps those frequencies used by the Artillery, and Infantry. Could it have be meant as a liaison radio between these contingents? Or between them and a their supply/support organization? #3, Remember our last series,"Off the Shelf Prick's"? Note, those radios that were capable of low-band FM operation, covered the same frequency range. Could the PRC-28 have been specifically modified for enhanced compatibility with these types? Intended to fill a similar role, but one requiring a more robust radio? Like the PRC-21 but in a different band? If this were the case, the logistic, and support problems would have been greatly reduced due to the fact the PRC-28 could use all the same ancillary equipment as the PRC-9, even the manuals and running spares. This alone would justify the added expense of the radio, especially as the commercial,"Off the Shelf" PRC's, weren't cheep either, and they required their own peculiar support channels! #4, The PRC-28 is listed in Ref.#3 as "Used By" the U.S. Navy. Again referring back to "Off The Shelf Prick's" we know that the Navy was by far the largest user of these type radios. Would this tend to support point #3 above? Ref.#3 is the only known reference material that list these "Off the Shelf" types, as used by all the branches of our military. It is also the only one to list the PRC-28. It's update, printed in 1964, drops all those types, including the PRC-28. Yet PRC-28 manuals are typically dated late 1961. Hmmm? #5, Ever since the introduction of the BC-1000 in WW-II, most all U.S. backpack FM radios have been designed to allow back to back, unattended repeater operation using two radios connected together. Could the PRC-28 have been specifically adapted to better perform this task? We do know that specially designed equipment was provided expressly to the Marine Corps in later years to serve in this capacity using the PRC-25, or PRC-77. At least three contracts were let for the PRC-28 between 1952, and 1954. All appear to have been with RCA. The one in my collection is of a 1952 contract, has the serial number of 164, a U.S. Navy inventory tag screwed to it, and if the magic marker writing on it's case is correct, was originally on 41.95mc. You should note that the standard channel spacing of the time was 100kc, thus 41.95 would not have been a standard tactical frequency. On the other hand, 50kc spacing was typical of commercial equipment by virtue of it's crystal control. Hmmm? To be honest with you all, I had not noticed the above similarities between the PRC-28 and the "Off the Shelf" types until I started writing this article. Nor would I have, if I hadn't just finished writing the "Off The Shelf" series. But the more we look at the limited evidence, the more it looks as though point #3 above might be the proper conclusion, with #1, and #2 following in second place. What do you think? OK, so what's the next Mystery Radio to be? Dennis Starks; MILITARY RADIO COLLECTOR/HISTORIAN References: #1) MILITARY RADIO DATA, VOLUME I, PRC Designated Radio Equipment, by Dennis Starks (copies available from the author) #3) TM11-487A,1958,MIL-HDBK-161,Military Handbook Electronic Communication Equipment. TM11-5820-292-10, Sept 1961, Operator's Manual, Radio Sets AN/PRC-8, 8A, 9, 9A, 10, 10A, and 28 MILITARY COLLECTOR GROUP POST, OFF THE SHELF PRICK's; FEB. 11/98, FEB.13/98, FEB.16/98, FEB.17/98, FEB.19/98, FEB.21/98, FEB.23/98, MAR.3/98 by Dennis Starks ***********************************************
    PRC-28, AND 2 CENTS; Lenox Carruth, and Dennis Starks Thought I would add my 2 cents worth to the PRC-28 discussion. I read a book a while back about a Special Forces radio operator in the early years of our Vietnam involvement. Seems one of the big problems with the PRC-10 was keeping it on frequency. The biggest problem was being issued out-of-date batteries. They would take several batteries on a patrol just to be sure of having one that might work. Crappy way to fight a war in my opinion. Anyway, back to the original discussion. The crystal control would have been an obvious solution to staying on frequency. Apparently a lot of the problem had to do with poorly trained Vietnamese who went on patrol with the Special Forces guys. I guess it would not take too may dorking fingers to get a PRC-10 off frequency. The other radio they used was the GRC-109. Used it from their base camp to communicate with higher commands. Lenox Dallas, Texas Collector of WW-II Communications Equipment and Memorabilia --------------------------------------------------------------------------------
    Len, the book you refer to is: Tan Phu, Special Forces Team A-23 In Combat, By Leigh Wade. We used extracts from it in the our GRC-109 series. True, the writer did sight some disgust with the PRC-10, but this was for the most part, in regard to the bad batteries they were receiving. Personally, I was impressed with the performance of the PRC-10 in his accounts, particularly if you notice the ranges the radio was being used at, and the topographical conditions. One thing that's not mentioned in the text, was if the radio had a good battery in it, it did communicate. One thing must always be remembered, combat radioman always hate their radios. I was one, and every radio I used was a peica shit.(Whether it was or not). Over all, the book is a good one, and there is only a couple of very minor errors, mostly with radio model numbers. Poorly trained Vietnamese were indeed a problem, especially those irregulars participating in the above mentioned book. But a complete line of radios had been fielded expressly for their use. The OPS series which included the HT-1, TR-5, and TR-20 among others. These radios too are mentioned in the book, and history records them as being generally well received by all those that used them, including Special Forces. The biggest complaint being that they were not compatible with other tactical equipment, being AM vice FM. I forgot to mention in the PRC-28 article, that while it has the same hasp fasteners to secure the radio into it's cabinet as the PRC-9 etc., they have had a hole drilled in the lever so that they can be screwed down. This denying access to the radios entrails by the user. The more we look at this radio, the more it becomes apparent that it was not intended as a front line, combat, tactical radio set. But at this point, we still can't dismiss any possibility. Dennis Starks; MILITARY RADIO COLLECTOR/HISTORIAN *********************************************** MYSTERY RADIO; The Navy RBZ O Joy, the Mystery Begins, One of the first military radios I ever acquired, after my RT-70, & from the same source, the late Bob Boller N0RB, was an RBZ. Bob was a retired Collins engineer from Dallas, and long time MARS member. First licensed as an Advanced Ham, and commercial CW operator at the age of 15 in 1938. He was never one to throw anything away, or allow anyone else to. Forty years of digging through the electronics grave yards at Collins, & numerous military bases(along side Tucker, of Tucker Electronics fame), had yielded him the finest assortment of neat junk I've ever seen in one spot in my life. Even though we were competitors in the electronics repair business, we often collaborated on medium to large size jobs. He was my mentor, and more like a father than my own ever was. Because of his years of scrounging, Bob had many, MANY tons of the most oddball connectors in the world. I would often take off a day to go digging through them to find what I was in need of for some project, a full day was needed! On one of these Search & Sort missions, I walked into Bob's shop to find him playing with this tiny receiver. I couldn't believe how small it was, nor that Bob even had it without my knowledge. I normally knew more about his stuff than he did, do to my intense snooping. He had taken a bunch of used camera film, the old defunct Polaroid stuff that had built in batteries for the flash(like I said, he never threw anything away), taped them all together, stuffed them in the case, thus had it operational. It took a good full day of whining, but he finally gave it to me. It had the scull cap, & original antenna lead, but no canvas bag. Too Many Questions, It Just Don't Make Sense! Immediately, questions filled my head. What was it used for? Who used it? For what? Did it have a matching transmitter?(this was a long time ago). After I'd had it for awhile, I found a manual, this just added to the questions. The manual was for an RBZ(Special), as most are. It contains an error in that it states that the radio operates from 12vdc, when a minimum of 67.5 volts B+ is needed. Also the "Special" tuned from 5-13mc vice 2-6. The tactical frequency range of the day was approx 3-6mc for radios of this type. Then why an obviously tactical radio with a none tactical frequency range? The supplement contained in the RBZ(Special) manual was obviously printed by the Signal Corps, not the Navy, or Emerson. Then what was the Signal Corps doing with it? Why didn't they correct the 12vdc error? We all know how sticky the military is about error corrections in their manuals, hell the first couple pages in each is devoted to the subject, then there's at least one form in the back for this purpose, yet no corrections were EVER made! What's An RBZ, You Ask? Built by Emerson, the RBZ is an ultra small five tube superhet receiver, smaller than a carton of non-filter cigarettes, it's size would still put Sony to shame 30 years later. All permeability tuned with sliding slugs like an old AM car radio, It tunes 2-5.8mc(for the RBZ), or 5-13mc(for the RBZ"Special"). The receiver itself is housed in a plastic(phenolic) water tight case, while the batteries and audio interconnections are housed in an identical, and interchangeable case. Together, the two are carried in a canvas bag, worn on the chest by the user. Antenna connection is made via a miniature banana jack on the front panel. The antenna itself consist of a piece of wire about 2ft long with thumb screws on it's extreme end for attachment to the soldiers tin pot helmet. Believe it or not, it works! The headset used is the common combination CUP type elements contained in a nylon scull cap, same as that used on the MAB, and DAV among others. Controls are the minimum volume/power/on/off, and the frequency tuning. The later is a marvel of mechanical design, it must be pushed in & turned at the same time to engage the internal skunk works, thus tune the thing, also preventing accidental de-tuning. The dial is the good old Radium illuminated drum type, and is very useful in testing & calibrating your PDR-27 radiacs. It's impressive that even with this radio's extremely small size, this dial actually gives you some degree of resolution. There is absolutely no difference between the RBZ, and the RBZ"Special", either physically, or electronically. The later is a simple field modification that involved pasting a paper frequency scale over the existing dial face for the new tuning range, and a re-alinement of the radio. No circuit changes at all are made. Tube line up includes 2ea 1T4's for the RF and IF amps, 1R5 for the mixer, a 1S5 detector, and a 1L4 audio amp. Power was derived from a standard commercially available 67.5 volt battery (BA-51)for the B+, and 2ea "D" cells(BA-30) for the heaters. The Printed Matter Didn't Help! Several years of searching didn't turn up any info on the little radio at all. It's manual didn't help, printed by Emerson, it had no dates at all , & very little other info, the Signal Corps supplement dated 27 March 1945, simply added to the mystery. It was not contained in Ships 275, nor any of the TM11-487 series up to 1958. No magazine/conversion articles were ever written, nothin! Then finally, something, not much, & it didn't help, but it was somethin, the June 1944 issue of QST had a report on the "Raider" receiver. It was just one paragraph, and a picture. Obviously just Emerson promotional hype it stated "Marine Corps raiders and paratroopers now receive their orders over (Raider) receivers", along with the credit for the photo as "Official Marine Corps Photograph". The Photo was straight out of the RBZ manual! The only value of this tidbit of info was that it proved the radio existed in early 1944. The RBZ does not appear in any Para-Marine, or Raider documents found to date. The only eye witness account, and not from a very reliable source, places it in use by the shore patrol, Pacific theater, late 1945. The next time the RBZ would appear in print was 14 years later, in the 1958 edition of TM11-487, remember that one? It's 2300 pages long. This issue also marks the first appearance, and descriptions of the PRC-1, & PRC-5 as they were then declassified, both being classic suite case radios. Coincidence? Here the RBZ is listed in the PRR "Type" section of the handbook, having a unit cast with spares of $70.00. It All Comes Together. Everything I had learned, or couldn't learned about the RBZ told me one thing, we weren't suppose to know! I had my suspicions, enhanced by the fact that a tactical receiver was supplied covering a frequency range that wouldn't allow it's use in a tactical/combat role. But I didn't have the proof. Then one day while reading a borrowed book, totally unrelated to radio. I found the following lines, [The most important time of the day was when they listened to the BBC broadcast from London that announced their next supply drop. The signals came on three successive days. Their first warning would be a cryptic message: "Suzette has hung her washing out to dry". (The operation will take place Saturday at the designated dropping point.) The following day BBC would announce "There are red flowers in the forest". (the drop will be made tomorrow night as planned.) On the third day, as they crowded around the tiny RBZ set on their mess table, they would here the final message: "Snow will fall in early December this year".] The name of the book was Cloak and Dagger, The Secret Story of OSS, by LT.COL. Corey Ford, and MAJ. Alastair MacBain. The events here described are those of a Maquis (French resistance unit) receiving instructions for their next supply drop. The radio they are using is the RBZ"Special", it's frequency range covering that of the BBC broadcast. One Mystery Solved, Another Begins While the above pretty much solves the mystery of the RBZ"Special", it doesn't do much for the standard RBZ. Most of the questions for it still remain. We at least now know why the set was kept hush hush for so many years. What did the Navy use it for? One of the sets in my collection has a PMS(Preventive Maintenance Schedule) tag on it dating up to 1964. What could they have been using it for at that late date? Recently one of our group has sent me info on his 110vac RBZ power supply, the only one known to exist, and until now completely unknown. Housed in exactly the same case as the receiver, and battery box, it will operate from either 110 or 220 volts AC or DC. Designated RBZ POWER PACK MODEL 2, serial number 12, it also has a headphone jack rather than the standard in line connector. So we continue our search for answers. Conclusion, The RBZ is not at all a rare or particulary valueable radio, they are just slighty harder to find than a BC-611, and well worth having. The RBZ"Special" on the other hand is pretty scarce. For some reason they seem to be more common on the American east coast, and several have recently turned up in Europe. Most likely those in Europe have been there ever sence their clandestine days of WW-II. We need more information, and historical documentation on them both. By the way, the missing canvas bag for my first RBZ surfaced a couple months later. While Bob and I were on an antenna job together, I noticed the canvas bag over his shoulder, he had been carrying his staple gun around in it for over twenty years. Strangely, it took three times the whimpering, and whining to get the canvas bag than was required to get the radio. The next two radios to be featured as Mystery sets will be the Navy AMA, and Marine Corps PRR-15, so if you have any info, please send it in. Dennis Starks; MILITARY RADIO COLLECTOR/HISTORIAN ************************************
    MYSTERY RADIO; Navy AMA, by Dennis Starks While it is relatively common to find Army Signal Corps type radios in the hands of the Navy/Marine Corp. Two things, both somewhat rare, serve to confuse us. The first, and most common, is the existence of Signal Corps equipment that is painted simi-gloss haze gray rather than the regular Olive Drab. These examples are in every respect a Signal Corp set, right down to the data plate. We can only speculate as to the different color, and why, or that these radio sets were indeed even meant for Navy use. To date the only equipment to be encountered in this condition are the BC-1000, BC-620, and BC-659, and they are far more rare than their Olive Drab counterparts. One rumor has it, that these Haze gray Signal Corps radios were supplied to resistance groups prior to the "D" Day invasion, that their color was altered to prevent their users from being accused of stealing them. But this story is completely unfounded besides being very shaky. Actually it sounds more like a sales pitch than history. Another possibility would place these radios in use by rear echelon personnel such as Shore Patrol or other security forces. While this is certainly a more plausible answer, it too will not hold water especially when the AMA inters the picture. Then we have the second variant, here a Signal Corps set is not only painted Haze Gray, but also has a Navy data plate, and designation. Inter the AMA! The AMA is in every respect identical to the Signal Corps BC-721 except for it's color of Haze Gray, and Navy data plate. Whatsa BC-721 you ask? The BC-721 is a modification of a BC-611F that allows it's use in a special rack while aboard a glider. Rather than the standard audio jacks in it's bottom cover, the 721 is provided with an eight pin Jones connector, it also has a sliding door that allows connection to an external antenna that is not found on the standard BC-611. The game plan of the BC-721/AMA was for it to supply communications between the pilot of a glider, and the towing aircraft. Once the controlled crash was completed, the BC-721 could be removed from the wreckage, and used on the ground as a standard BC-611(if anyone survived ). It is very doubtful that the AMA ever saw any wartime service, or at least in the above capacity, particularly in light of the very short lived history of Para-Marines, and their area of operations which would have ruled out the use of gliders from the start. If indeed the AMA had the same role in life as the BC-721 to begin with. Is it possible the Navy had a different intended use for the set? Note it's AMA designation that would tend to indicated aircraft use. Could it have been intended to fill a similar role as the RCA AVT/AVR series? Here we have a very small aircraft radio set that we know had two main uses. The first as a cheap, small, easily installed, operated, and removed radio set, it was installed in newly manufactured aircrafts of all types right off the assembly line. This to provide it's pilot with a temporary means of communications while the aircraft was flown/delivered to it's destination. The pilot mainly just needed to communicate a very short distance, with the destination control tower, to get landing instructions. Because of this application, the AVT/AVR series were commonly referred to as "Delivery Radios". The second, and more glorious role the AVT/AVR series was as a liaison radio in very small spotter aircraft. Here the aircraft was so small it had no electrical system of it's own. The radio equipment was either powered by a small wind generator mounted under the fuselage(as with the AVT/AVR), or dry batteries contained in normally backpack ground radios as we have already seen with the BC-620/1000, RT-70, PRC-10,25 etc. If this possibility is compared with the excellent account given in the reference below of the evolution of controlled Naval, and Artillery gunfire, maybe we have the AMA's true intended purpose. It certainly would have presented some advantages in either of the above applications. But we don't know, and I'm just guessing. What do you think? Shit! Have I just written an article about Aircraft Crap? Heaven forbid! We are left with the questions; with the production fascilities at home bogged down to the max already, why bother stopping the line just to change colors on an extremely common radio? Or with the supply, and logistics problems already almost insurmountable, why further complecate the system with a completely new number for a radio that already existed, or one that's simply a deferent color? Today, of the Signal Corps type radios encountered, their Haze Gray counterparts are far more rare than the Olive Drab. While Navy field type equipment in general is harder to find than Signal Corps types, the AMA remains one of the rarist with only one known to have survived. Currently known Haze Gray Signal Corps radios in the hands of collectors include 2ea BC-1000(one in my collection), 1ea BC-620, and 1ea BC-659. While this count can by no means be complete. The point is to show in comparison the hundreds of OD sets I know of in the hands of friends, this is all the Gray variants. The next radio to be featured as a Mystery Radio is the Marine Corps PRR-15, after that no candidates have as yet been nominated. If you have any input at all, either with this article, or future ones, please let me know. Dennis Starks; MILITARY RADIO COLLECTOR/HISTORIAN Referance; Military Collector Group Post, Dec.20/97 Evolution of Marine Corps Amphibious Doctrine; an Essay, by Brian Scace **************************************
    MORE ON GRAY SIGNAL CORPS RADIOS; Hi Dennis, FYI, I've seen two other gray radios: I recently traded away a gray BC-603. It had a professionally-built (but unmarked) AC supply in place of the dyno - it had a matching connector just like the dyno, so no wiring mods were made. It also had an AC power light in place of the spare fuse holder. The wiring for this light looked "official" also: old-style wire, and a dab of red paint on the solder joints. I have a gray RT-68 (the knobs and the dzus knobs are still green). The panel markings were re-stenciled in black. Pete ---------------------------------------------------------------------------
    Dennis: With regard to your post of 12/24- BC-721. Two of my BC-721's are as follows. Antenna cap is extrused AL. Receiver and Transmitter Chassis "CGG-43014" Data plate on case reads TYPE CGG-43014" "AIRCRAFT RADIO TRANSMITTER - RECEIVER" "INPUT: INTERNAL BATTERIES""6.00 POUNDS" "SERIAL 243" "A UNIT OF MODEL AMA AIRCRAFT RADIO EQUIPMENT" "MANUFACTURED FOR" "NAVY DEPARTMENT-BUREAU OF SHIPS" "BY CONTRACTOR" "GALVIN MANUFACTURING CORP" "CHICAGO ILLINOIS" "CONTRACT NUMBER" "CONTRACT DATE" "NXS - 5717" "JUNE 30, 1942" ALL of the above is on a BLACK PLASTIC PLATE. Plastic ear and speaker caps. ******************************************************
    MYSTERY RADIO; the PRR-15, by Dennis Starks, & Bill Howard Dennis, As you can tell by the information below, I don't know a hell of a lot about this radio but have made some pretty good guesses, I think. Bill Howard -------------------------------------------------------------------
    The PRR 15 Radio I was talked into buying this by Kevin Kuzel. It seemed cheap at about $125.00 and would fit in somewhere. It finally arrived and was in two containers. Container one housed the radio and had space at the bottom for a power supply and a Dictaphone cassette recorder. Case number two had four compartments, one housed the extra power supply, one held extra tape cassettes. two more compartments held an assortment of wires, cables and a Dictaphone michrophone. There was no Technical manual so I do not know what all should be with this radio. There was a lot more space in the second chest so I concluded there must be somethings that were missing. Supposedly this set was devloped for the U.S. Marine corps during the Vietnam era. Efforts to track down information from the Marine Corps proved futile as did the efforts to get information from the U.S. Army Signal Corps. The set is a receiver which is connected to a dictaphone cassette recorder and allows the program listened to, to be tape recorded. It is powered by either a 120 VAC power supply or from batteries that fit in the second power supply. When it arrived and after I figured out what all was there and how to connect things, i powered it up and with the 2 foot (Approximate) steel ribbon antenna such as was used on the PRC 6, 10s, etc the set began to pick up some message traffic. I listened only long enough to be certain the set was working. It was my conclusion that this set was designed to be used by a sort of long range patrol, set up on a hillside and would monitor enemy communications. There was a microphone connected to the set which allowed you to make comments on the tape at the same time it was recording. The basic plan must have been for a patrol to set up on a hillside and monitor and record enemy radio traffic and every so many hours take the tapes to a pickup point and get a new supply of tapes. The recorded tapes would then be taken to the rear where they would be transcribed or decoded. If there is a better explanation, I would accept it. I have never seen any document or book which outlined this set or even mentioned it. THE WILLIAM L. HOWARD ORDNANCE TECHNICAL INTELLIGENCE MUSEUM e-mail Telephone AC 813 585-7756 ----------------------------------------------------------------------
    MYSTERY RADIO; the PRR-15, Part II, by Dennis Starks FORWARD, Did the PRR-15's Dictaphone support a variety of tape speeds? If so, could it have been used to record GRA-71 msgs, then play them back at copy-able speed? Just a thought, Pete ------------------------------------------------------------------------------
    Pete, The recorder included with the PRR-15 was not really a dictaphone. It simply allowed for the operator's narration of the recorded signals. The same is included on current equipment of the same ilk. Our search for the equipment used in the GRA-71 application, I don't think will be found in any particular set. Rather it will most likely be simply the recording apparatus. The radio equipment listed as in use by the Special Forces "B", & "C" detachments (which would have needed to receive, then slow down to copy the GRA-71's signals), was of the most ordinary type, GRC-26's (including the R-388), GRC-19's, & later the GRC-106's. Besides the PNH-5 tape recorder listed as part of the PRR-15, the manual list provisions for use with an external TNH-4 or PNH-4, perhaps when we find out what these are we will know more. GENERAL, The PRR-15, and it's major component, the R-1484, were obviously designed for intelligence gathering purposes, much like the R-901/GR, R-395/PRD-1, R-744/PRR, TRQ-30(R-1218, R-1518) etc. If compared to some of those other receivers listed above, the PRR-15 had several very obvious advantages as listed below. #1) it was a 100% solid state design. #2) operation was from a multitude of various power sources, including 12vdc, & 110vac. #3) as a set, it was much smaller than any of it's contemporaries. #4) it had a much wider frequency range than any of the other radios in this family. Even if compared to the current TRQ-30 which requires two receivers to cover a similar frequency range. #5) and expanded modes of reception include AM/FM/CW/ & SSB. While the example in Bill's collection includes more of the accessories than that in mine, I do have the advantage of a manual copy. TM-05599A-15, Dated May, 1969. Saddly though, the manual does not list the sets intended purpose. As of 1969, other radios of this type were still in their experimental stages, these include the R-1410(XE-2)/GR circa 1967 which lead to the R-1518, R-1218(XE-3)/UR circa 1968. The standard issue set for other branches of the service then, and later, was the PRD-1. If you have ever seen one of these 1950 vintage monsters the need for it's replacement becomes immediately evident. So it would seem that the Marine Corps with it's PRR-15 beat the rest of the U.S. military services in the race to devise a viable replacement for the extremely antiquated PRD-1(which by the way remained a standard issue item with the Army & Air force until 1980). THE RECEIVER, Built by Zenith Radio Corporation, Chicago, Illinois, the R-1484/PRR-15 boast some very impressive features not found on any other receiver of it's time, and very few today. Most notable is it's continuous frequency coverage of .54-205mc in ten bands, even the current TRQ-30 with it's two receivers would only cover .53-150mc. The receiver has IF frequencies of 455kc(.54-9mc), .455 & 2.9mc(8-30mc), and 10.7mc(30-205mc). Narrow and Wide bandwidths can be selected that switch between 6/10kc(.54-30mc), 40/120kc(30-205mc) respective. While these might seem rather wide for todays discerning SW listener or Ham operator, there is a reason for it in radios of this type. If the receivers passband were any narrower, the operator might pass over a suspect signal while scanning from one end of the band to the other, remember, this is not a communications receiver. Modes of operation include Diversity operation with two receivers, AM, FM, CW, and SSB. Built in crystal calibrators for 100kc, & 1mc. Dual, switch selected antenna input connectors, SO-239 for whips, and a BNC for external, a binding post for long wire antennas is also provided. Front panel connections include a BNC IF output, dual 1/4 inch covered headphone jacks, mic input, and recorder output, aux power input ( these last three connections are similar to those used with the GRA-71, GRC-109's, & PRC-64's). A panel meter provides relative indications of received signal strength, and battery condition. Front panel controls include a dual speed tuning knob, Narrow/Wide bandwidth switch, 10 position band selector switch, Push to Cal button, combination meter/calibrator frequency selector, a toggle switch selects external or whip antennas, RF, and AF Gain controls, variable BFO pitch control with OFF position, and separate miniature toggle switches for AGC/OFF, LIGHT/OFF, AFC/OFF, and AM/FM. The receiver is housed in a fiberglass water tight cabinet which is externally identical to the accessory case, both are 11.5h x 13.5w x 10.75d inches. In the center of each lid(receiver & acc case), there is a threaded mount to allow the use of these lids as a whip antenna base. The power supply, and tape recorders slide into a recessed area at the bottom of the receiver. THE POWER SOURCE, Several power supply arrangements and sources can be used with the set. The receiver proper, operates from 10-15vdc. Alternately a choice of two different power supplies can be mounted in a recessed area below the receiver, but in the same cabinet. The first is the battery power supply(PP-4833). It can accommodate either 8ea batteries BA-30("D" cells), or 9ea BA-42("C" cells). The second is the PP-4834/PRR-15 regulated power supply. It allows the radio to be operated either from 110vac of 50-400cps, or an external 24vdc source. Both power supplies are identical in size, and mount in the radio in the same way with no manual connection to the radio required(a connector in the back mounting area mates with the power supply). THE ANTENNAS, Two different antennas are supplied with the set. The first is a 3ft steel tape type(SG8788) having a PL-259 connector at it's end. Primarily meant to be used directly from the front panel connector of the radio, a right angle adapter is also provided to vertically postilion it. The second is a 9ft sectional whip, though it has it's own designation of SG8787 it is identical to the AT-271 whip antenna used with many other portable types. It can be mounted to the front panel in the same manor as the tape antenna using a supplied adapter, but the manual recommends that it be screwed into the receptacle provided on the equipment case lids. It can be seen that an antenna of this length could present an excessive load to a front panel SO-239 connector. Though the manual does mention the use of direction-finding antennas, and detector, as one of the radios modes of operation, there are none supplied with the set. And for operation with these types of antennas, the reader was referred to the "appropriate technical manual". THE TAPE RECORDER, Referred to as "Sound Recorder, Reproducer AN/PNH-5", this item has never been encountered with any other piece of equipment. It uses a non-standard tape cassette referred to as a "magazine" (this set predates the advent of the now familiar cassette tapes we all use). A double sided cassette, each side provides 30 minutes of recording time. It can be powered either by it's internal batteries ("C" cells, now we know why the receivers battery box has a dual battery type capability), or from the radios power source via a rather strange adapter cable that physically emulates the C'cells. Controls are included for REWIND/PLAYBACK/RECORD, ON/OFF, record & playback volumes, and a tape counter is included. It has only one connector for attaching it's external accessories, described as a 5-pin twist locking, and is similar to those found on the receiver. Connections for the headphones, mic, foot-switch(for pause control) are all made via this same connector using various adapter cables. The mic supplied with the set resembles an old commercial Sure communications mic, complete with PTT. The headphones were the common H-113, not my choice for comfort, or extended wear, and a foot switch is included for remote pause control. THE ACCESSORIES; Other than those items already listed, support equipment supplied with the set also included: (note, all of these items when contained either in the accessory case, or with the receiver, were all strapped to a standard Quarter Masters Pack board for field transport). CY-6237/PRR-15, accessories case. SG9349, Wire Antenna, 15ft, used alone or as a connecting cable for the remotely mounted 9ft whip. 52G3064, Wire Antenna, 50ft. SG8793, Power Cable, 24vdc, 15ft. SG8794, Power Cable, 110vac, 10ft. SG8790, Cable, Receiver, Recorder, coiled cord that provides interconnection between audio, and control circuits of the PNH-5 and R-1484. SG8791, power adapter cable used between the PNH-5 and R-1484. SG8817, Foot Pedal, Transcriber, used for remote pause control of the PNH-5. SG8792, Cable Interconnect, AN/PNH-4, allows the use of the PNH-4 recorder with the R-1484. SG7903, Cable, Dual Receiver, used when two receivers are combined for diversity reception. SG8818, Tape Magazines, for the PNH-5 recorder. SG9348, Cable Extension, Earphone. SG8796, Microphone. 17G3154, Battery Holder, for PNH-5. UG-146A, Adapter UG-924, Adapter UG-306, BNC, right angle adapter M359A, UHF right angle adapter DAGE 4752-1 adapter NS-7, Service Manual, Dictet Recorder (Keep in mind, and on the lookout for all these items, as I do not have them in my collection) SO WHAT'S THE MYSTERY? You might ask the above with all the info that has been presented. But we don't know anything about the life of this set. The questions are many. Who used it? Where? When? Was it used at all? Why, as the set seems such a viable one, was it not more prevalent, & used by the other services? Was it simply adopted as a "Stop Gap" until other designs then under development could be fielded? The serial number on my receiver itself is #77, while the one on the data plate of the receiver's cabinet is #19, this would let us think that not many were made, but I don't have other numbers to compare it to, and low numbers to quantities built are common with this type of equipment. Regretfully, as my main computer is down, I do not have access to a multi CD changer, thus I can't consult FEDLOG for more info, or to see if it is listed there. If you do, the FSN number for the set as shown on the front of the manual is 5820-082-5186. Any additional information about this set would be greatly appreciated. The next set to be featured as a "Mystery Radio" will be the GRR-5, then possibly the SCR-511/BC-745 (Pogo Stick), if you have any information about the use, development, or fate of these radios, please let us know. Dennis Starks; MILITARY RADIO COLLECTOR/HISTORIAN ***********************************
    MYSTERY RADIO; GRR-5 by Dennis Starks FOREWORD, The GRR-5 is not at all an uncommon radio, in fact, it is probably the most common, and affordable military receiver out there. I think you probably have all at least seen one in your travels, if you don't indeed own one. If you don't own one, contrary to what you might read here, I highly recommend that you should. What you may not be aware of is what this fine, but simple, receiver was actually meant to be used for, or how it was eventually used in the field. Not all that glamorous, but it did a fine job none the less. The GRR-5 is one of three radio's I'm most often asked about by Vietnam Vet's when I'm on tour, "do you have a PRC-25/77, Angry 9, Angry 5?". Often these vet's not being technically inclined, just remember the set being used. Most that asked, wanted to find one for old time sake. On each occasion I'd ask "what did you use it for?". In the case of the GRR-5 the answers were unanimous, "we used it to listen to AFRTS". But that's not what it was originally intended for, nor was it provided to the troops so that they could be entertained! GENERAL, Starting in approximately 1951, they were built by the thousands, just a few of the manufactures involved were Motorola, Zenith, Emerson, Arvin, and so on, with an original cost of $835.78. Not cheep, even by today's standards, but if compared to it's contemporaries, was quite a bargain, R-388 ($1307.00), R-390 ($2,210.00). (Ref.#1) The quantities built, and the unit cost, further do not support the idea they were meant for troop entertainment purposes, as these types are generally pretty rare, and cheep in comparison. Also they were not built to the front line/tactical heavy duty specs as the GRR-5 was. The R-174, The major component of the GRR-5 is of course it's receiver, the R-174. The circuits it uses are classic designs who's lineage can be very easily seen in the BC-1306, and GRC-9 which are both nearly identical right down to the tube line up, and chassis construction. It tunes from 1.5-18mc in four bands, has controls for RF, & AF gains, BFO. A mode switch selects between Phone, CW, NET, and CAL. (built in 200kc xtal calibrator), and an antenna trimmer. The set has a dual speed tuning control with provisions for nine preset frequencies (a very precarious procedure). Dual antenna options are included that allow the use of a cabinet mounted whip antenna composed of standard AB or MS mast sections, or any wire type antenna via binding post. The performance of the receiver is excellent in some areas, lacking in others. AM reception is very good, aided by a very stable master oscillator. The stability in fact is quite good, even for SSB, & TTY. However in the latter modes, the set is afflicted by anemic BFO injection thus the operator must constantly ride the RF gain control. In the case of strong CW or SSB signals, you can't copy them at all. This same affliction can be seen also in it's cousins, the BC-1306, & GRC-9. Fear not, this is very easily fixed. Dial resolution is fair, as are tracking, and backlash. The biggest problem is setting the dial. Though the set has a built in 200kc xtal calibrator, there is no way to set the dial without removing the receiver from it's cabinet, and adjusting the master oscillator, another precarious operation, and fruitless as will be seen! The calibrator can best be used for either setting the channel presets(which do not really work that well) or aligning the complete receiver. Problems is, once done, and all is excellent, when the receiver placed back in it's cabinet, everything changes drastically. Even though the shielding is very good. Many hours have been spent trying to cure this ailment but to no avail. The inadequate BFO injection is very easily fixed. I spent a great deal of time trying to figure out how to up the output of the BFO. I changed coupling capacitors, did all kindsa stuff, but couldn't fix it. Then it hit me, just inject the BFO signal where there is less signal to beat with. As is, the BFO signal is injected at pin 6 of the second IF amplifier, I simply moved it to pin 6 of the first IF amp. All is perfect now. There are many other mods for this receiver, but unless you got one that's trashed already, I don't recommend them. The PP-308, Probably the biggest mystery now is the GRR-5's power supply. It's horribly over-complicated and heavy! The PP-308 provides the receiver's primary operating voltages of 1.5vdc(heaters), & 90-105vdc(B+), from a multitude of external sources including 6/12/24vdc, 110vac, or switches out for use with multi cell dry batteries. It also housing the set's loud speaker. The mystery is, why so heavy? Why did the sets vibrators still need be running even when operating from 110vac? Why the change over relay, the likes of which no one has ever seen? This designer had to be way ahead of his time, being all doped up hallucinogens long before it was popular! Clearly 2/3rds of this radio set's $800.00 cost is in this power supply, and it's highly specialized components. The QUESTIONS, Fledgling owners of a GRR-5 all have similar questions. What transmitter was used with it? What was it mounted in? How was it used? In order: There was no matting transmitter, though it is obvious with a casual inspection of the radio, it's entrails, and manual, the GRR-5 could be used with a transmitter. It has front end overload protection, though primitive, a "NET" facility on the front panel, and provisions for remote muting of the receiver. None the less, it was never intended as a full blown communications receiver. Possibly these features were included so the set could be used as a backup. But who knows? The manual does state that "Radio Receiving Set AN/GRR-5 may be used alone as a conventional radio receiving set, or with an appropriate A-M transmitter in a particular communications system", but this was never done however attractive it may have been. (ref.#3) What was it mounted in? Just about everything! The short/true version, every place that there was an existing HF radio set(usually referred to aw the "The Good Radio"). The long/in theory version, alone or with a GRC-19 as part of Air Warning Nets, or Air Request Nets, in Armored Personnel Carriers, M-38A1's(later M-151's), M-37's(later M-715's), 6x6 trucks. Or in the same vehicles, alone or combined with a GRC-9 in Armored Division Aviation Company's. With a VRQ-1 in jeeps of Military Police Company's. Combined with the GRC-3, GRC-19, & ARC-27's in Tac-Air director units. Just about any type vehicle, with just about any other type radio set, dependant on the mission of the unit in question. (ref.#2) How was it used? Officially, the GRR-5 was intended to replace the SCR-593/BC-728 of WW-II fame in air early warning nets. This is the reason for it's channelized nature(the presets). It's ironic that this monster was meant to replace a quite small shoulder carried set, seems like reverse evolution. None the less, that's what it was meant for, what it was used for is a completely different story. Those installations listed above were for the most part, in theory, or at least in the early days, and reflect this Air Early Warning Net capacity. The Vet's are unanimous in their testimony of their use of the GRR-5, "to listen to AFRTS', but the radio was clearly not intended for troop entertainment. This is what it was used for, but they were not installed for this reason. Remember, the GRR-5 was installed in every location that there was a pre-existing HF radio set, regardless of that existing set's size, purpose, or deployment, but not with VHF/FM sets. This was for one reason alone, "so the grunt's would keep their hands off (the GOOD SET)!" I/E the GRR-5's primary mission was as a pacifier, it's use as a backup receiver was only a bonus to it's being there. The squelch controls present on the GRC-19, & GRC-106 made them perfectly suited for long term monitoring of emergency net's, the GRR-5 had no such provision. This from Ref.#4, "it was found that the individual solders's inability to keep his hands off a station's primary receiver rendered many control nets inoperable", this is also confirmed by several eye witness account's which also state that the GRR-5 was installed to cure this problem. The next radio to be featured as a Mystery Radio, will be the BC-745/SCR-511 (Pogo Stick). The Mystery? What happened to them? So get busy sending in your tidbits of info. Runners up for Mystery Radio's are the TRC-7,10, GRC-13,14, BC-728/SCR-593. Dennis Starks; MILITARY RADIO COLLECTOR/HISTORIAN Referances, #1, TM11-487, 1958 #2, FM17-70, 1957, Signal Communications in the Armored Division. #3, TM11-295, Aug.1952, Radio Receiving Set AN/GRR-5 #4, Military Communications,A Test For Technology,The U.S.Army in Vietnam,HB,by John D.Bergen,CMH Pub 91-12,1986. ***********************************************
   (The preceding was a product of the"Military Collector Group Post", an international email magazine dedicated to the preservation of history and the equipment that made it. Unlimited circulation of this material is authorized so long as the proper credits to the original authors, and publisher are included. For more information conserning this group contact Dennis Starks at,

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