|Here is a 718U-2A (AN/VRC-81) in an M151 jeep. The 718U-2A is a 400W HF radio, built using URG-2 slices. This -2A version uses a 671U-4A receiver/exciter, which is inside the larger of the two watertight cases. The control head is shown mounted on the transmission hump, and the driver's seat has been removed so it would be visible from this camera angle. There is also a 718U-2B version of this radio and as far as I can tell the only difference between the -2A and the -2B is the type of frequency selector - either knobs or levers. The M151 jeep itself is apparently owned by Collins and probably makes the rounds to all the trade shows carrying various radios.|
|And here is a 718U-2 (AN/VRC-80) in a different M151 jeep. The 718U-2 is also a 400W HF radio, again built using URG-2 slices. The -2 version uses a separate 671U-1 receiver/exciter, which is shown next to the radio case and in front of the jeep's rear seat. Note that, with the separate 671U-1 receiver/exciter rather than an internal 671U-4A receiver/exciter, the 718U-2 main radio case is narrower than case on the 718U-2A pictured above. All the 718U-2 variants use the same power amplifier module & power supply module & antenna coupler case.|
Another photo of the 718U-2 with a better view of the 671U-1 receiver/exciter. This jeep appears to be painted in CARC.
The 671U-1 receiver/exciter is also part of the 718U-1, where it is paired with the 100W 548S-1 PA/coupler. The 718U-1 was sold to the U.S. military as the TRC-169. The TRC-169 came with a rucksack frame for use as a manpack, where it was powered by a BB-451 silver-zinc battery. The TRC-169 also had facilities to mount in and be powered by a vehicle.
The mounting plate is a simple affair and attaches both the radio case and also the antenna coupler case to the jeep.
It looks as if the antenna coupler case was specifically designed with a corner missing so that it the radio install would not require removal of the rear seat.
It's a bad idea to have the antenna coupler sticking out further than the jeep's bumper, especially considering that the radio costs about 10X what the jeep costs...
USMC 329413 is the hood number on this jeep, possibly it was loaned to Collins as "GFE" - Government Furnished Equipment.
All the 718U-2 variants use a 548T-1 RF power amplifier and a 636X-2 power supply - the supply operates from +28VDC generated by the jeep's alternator. In a 718U-2, the PA & PS are inside a 718F-7 case, and in a 718U-2A the PS & PA are in a 718F-8 case along with the 671U-4A receiver/exciter.
The antenna coupler used in these 718U-2 radios is a 490B-4. What's inside the waterproof case is just a 490T-2, which is nothing more than a 490T-1 with a fan.
The whip antenna is an AT-1011/U - a 32' fibreglas whip - looks like only the bottom 16' was in use for these photos.
Here are three unique manpacks - a 719D-2, a 719D-15, and a PRC-105 in a vehicular mount. The 719D-2 is sometimes called a PRC-515 or an RU-20 - it is a 20W HF transceiver which is powered by a NiCd battery pack. The 719D-15 is the big brother of the 719D-2 and is about the only instance where the suffix of the Collins model number means anything in the real world - the 719D-2 is a 20W radio and the 719D-15 is a 150W radio. Both use the same receiver/exciter & control head, but the -15 version has a much larger PA/coupler unit and is powered by a BB-451 silver-zinc battery.
The PRC-105 is a strange beast - it uses a Collins-built power amplifier & antenna coupler unit, but has a Hughes-built RT-1209/URC receiver/exciter. Must have really frosted Art to have to build the PA/coupler and not sell his own receiver/exciter with it. The PRC-105 was intended as a 100W manpack - it too is powered by a silver-zinc battery. The PRC-105 shows up in PRC-104 marketing literature from Hughes but Hughes doesn't mention the origin of the PA/coupler unit.
These two test sets are intended for front-line troubleshooting of the ARC-58 radio set. The test sets can be carried aboard the plane and connected to the radio while the radio is still mounted in & powered by the plane - they provide a go-nogo test and are not used for module-level troubleshooting. The test sets are used one at a time - they are connected between the unit under test and the plane's radio wiring, so that the test set gets it's power from the plane.
The TS-1063/ARC-58 can test the basic functionality of the ARC-58 control head, the ARC-58 receiver/exciter, and the ARC-58 power amplifier. A backlit tape roll prompts the operator what tests to run next and how to run the tests. The TS-1063 has an internal signal generator and also an internal 1KW dummyload (!).
The TS-1064/ARC-58 tests the ARC-58 antenna coupler controller. The controller is the brains of the ARC-58 - it uses a motor-driven rotary switch 'sequencer' to orchestrate the tune-up and operation of the ARC-58. The TS-1064 fully exercises the sequencer in the antenna coupler controller, and also can be used as a final alignment tool for the antenna coupler's loading & phasing servo amplifiers.
|Not to be outdone by the U.S. Air Force, the U.S. Marine Corps had their own test sets made for their own TRC-75s. Pretty much the same boxes but for the new nomenclature and the new O.D. color, the USMC's versions are the TS-1324/TRC-75 antenna coupler controller tester and the TS-1325/TRC-75 radio test set.|
|Now this has got to be a very limited production item. The ASC-12 was used to add comms capability to an aircraft when the mission required more radio than was built into the aircraft originally. It looks as if the unit pictured in this brochure is the same one that is in the photo shown three pages down.|
|The text mentions a AN/TGC-15(XN-4) teleprinter. The photo shows a variant of MITE ASR teleprinter. The MITE ASR in the photo is different from the usual MITE ASR in that there is a hinged panel just above and to the right of the slide-out keyboard. This hinged panel is missing in the common MITE ASR and the TGC-29 MITE tactical ASR units. My guess is that this MITE was designed for crypto use, I have no idea what is behind this hinged panel.|
|The word 'matrix' shows up at several places in the block diagram. It describes the interconnect scheme used between the audio section (operator & interphone & modems) and the HF radio. First guess is that the audio matrix is implemented in the 452S-6 and a 452S-5 units.|
|What's behind door #1? A stack of URG-1 gear. Top row, the left two boxes appear to be a 452S-6 and a 452S-5 - if I read the number correctly then both are described as a 'relay unit' but beyond that they are a mystery to me - could be they have to do with the implementation of the modem switching matrix. Then a TE-204A-4 modem, and three more modems, a 700B-4 and two 700B-2 units. Next row down is the HF receiver section - a 789R-1 IF translator, a 618Z-4 RF translator, and a 635V-1 preselector. The bottom row in the rack is the HF transmitter section - left box is unknown, next is a 789T-1 IF translator, a 618Z-4 RF translator, and the 548L-4A 1 KW RF power amp. On the bottom deck is a hefty ventilation fan, an ARC-51 and an ARC-54.|
|This second ASC-12 is a bit different - no MITE ASR, just a garden-variety non-tactical MITE KSR. Note the tail number on the engraved panel - 58-6970. This tail number belongs to a USAF VC-137B (Boeing 707-153B) which saw service as Air Force 1. US Presidents Eisenhower, Kennedy, Johnson, and Nixon all flew on this plane. For more info on the tail number, click here. Nice elapsed-time clock by Breitling-Wakmann.|
|This is the bench test set for the ARC-58. Many of the URC-32 bench test pieces show up here, plus a dummy antenna which 'simulates the characteristics of a B-52 tail-cap antenna'. There is a mount for the T-605/ARC-58 1kW power amplifier which has clear plastic hinged sides - the sides give visibility into the PA tuning mechanisms without disturbing the forced air cooling of rhe PA unit. An 'octopus box' provides interconnects for all ARC-58 units plus provisions for aircraft interphone connectivity.|
|A Bird 1kW dummyload is part of the GRM-10, as is a small adapter which is used to attach the ARC-58 antenna coupler discriminator to the front of the Bird dummyload. RF power is fed through the discriminator to the Bird dummyload, and then the discriminator can be adjusted for zero output given a 50 Ohm resistive load.|
|The GRM-21 is the bench test set for the TRC-75 and has a dummy antenna that mimics the characteristics of a 16' whip (one half of an AT-1011/U). Also included is a mount for the TRC-75 microphone amp & speaker amp, and other bits and pieces specific to the TRC-75|
|Although it doesn't say so in the book, the J-1125/GRC-21 octopus box is easily modified to allow the use of the PP-2352 inverter to power the TRC-75 on the bench, rather than a standard three-phase power supply.|
|This looks like a photo collage that probably hung in the Rockwell/Collins marketing department. I recognize some of the radios, if you know what they are drop me a line and I will add your ID to this text. At the center of the photo is an 718U-5 (ARC-174), a 100W HF transceiver consisting of a 671U-4A receiver/exciter, a 548S-3 power amplifier & antenna coupler, and a 514A-4 control head. Directly below the 718U-5 is what appears to be a rack of HF-80 gear, but all I recognize is the HF-8023 1KW RF PA and it's power supply (two units at the bottom of the rack). To the left of the rack is a 719D-2 20W HF manpack and a 719D-15 150W hf manpack. Right above the 150W manpack is an ARC-190 (I think...). Far lower right is an HF-380A, the military version of an HF-380 with a keypad as standard equipment. The two white radios in the upper right are unknown to me, but I think that the one on the left is maybe an HF-121A or HF-121B or HF-121C.|
|Here's a photo of the MRC-83 production floor at Alpha near Dallas, Texas. In the foreground is an M38A1 with a TRC-75 1kW HF radio installed, the radio is under a protective wrap. Behind the first jeep is another, the radio is visible but has it's front watertight cover installed. Third jeep ditto, fourth jeep ditto. Lower left is a jeep that looks to be in the middle of an alternator install. Middle left on the floor appears to be accessories for the MRC-83 in a cardboard box banded together with an AT-1011/U in it's canvas case.|
|This is the same photo as above, just brightened up a little. Now visible at the top of the photo are four TSC-15 "Communications Central" radio shelters, shown with their vent covers open.|
|Still at the Alpha facility, here's a teamster type driving the finished product up onto a car transporter. Note that the TRC-75 install really flattens out the rear springs in the M38A1.|
|I am not sure quite what to make of this photo. Looks to me like a government source inspector checking out the MRC-83 vehicle before he signs it off as being "OK TO SHIP". The worried techie is on the left looking on, and the guy in the bowtie is a Collins exec showing off how much he knows about the radio set. Both seats have been pulled out of the M38A1, the TRC-75 has it's fan covers & air filters removed and the PP-2352 inverter has been pulled out of the power supply box. On top of the TRC-75 is the dummy antenna, you can see it wired into the radio's antenna cap. An exhaust pipe vents the M38A1's exhaust up to the roof, but it appears that the radio is running from shore power - note that the radio's power cord is plugged into a shiny metal box just above the rear of the inverter. There appears to be some sort of test equipment behind the PP-2352 inverter, you can see a perforated box with a leather handle between the inverter and the right-hand door sill of the M38A1.|
|Another publicity photo - bowtie guy is blessing the traveler tag with the "OK TO SHIP" stamp.|
|Publicity photo of a complete MRC-83 radio set, a TRC-75 installed in an M38A1 jeep. Visible underneath the radio is the power supply box carrying the PP-2352 inverter - the inverter runs off 28VDC and makes 115 VAC 400~ 3 phase power for the radio. On the front of the power supply box are controls for the inverter and also a rudimentary selftest setup for the inverter with lamps to give a go-nogo indication as to the health of each chopper transistor in the inverter. The MRC-83 first saw the light of day around 1960 - in those days it was quite a feat to put a 1kW automatically-tuned HF radio in a vehicle. I saw over 2000 TRC-75 radio sets come up for disposal at DRMO Barstow in the early 1990s, and I guess that most of those radios were installed in M38A1 jeeps just like this one - the 1960s was an excellent time to own stock in the Collins Radio Corporation.|
|This appears to be some sort of MRC-108 prototype built in an M38A1 rather than an M151. Visible is the 618T-3 box & control head, with a PRC-41 with rucksack frame on top for UHF AM coverage. To the right of the 618T box is a PRC-47 with cover attached, and on top of that is the rear of a PRC-25. There is plenty of room on the M38A1 floor, underneath the 618T box and the PRC-47 and it looks like there are other radios under there, probably another UHF aircraft AM radio and also another VHF vehicular FM radio. The PRC-25 & PRC-41 & PRC-47 are probably meant to be dropped off and operated 'on the ground'.|
|Another photo of the same M38A1 with MRC-108 electronics, this one with the canvas top attached and the vehicular UHF AM antenna erected.|
|This looks to be an early MRC-108 in an M151, there is a 400W HF SSB radio using a 618T-3 with an 850 CPS teletype modem and 115 VAC 400~ inverter in the box on the right sponson. Usually a Kleinschmidt TT-4 sits atop the 618T-3 case - it is not present here. A 180R-6 antenna coupler is in the case on the left sponson. Since there is a UHF antenna on the jeep, I assume there there is more radio gear in the jeep even though it is not visible in this photo.|
|Here is a plainjane MRC-95 in an M151 - just the 400W HF radioteletype setup with no VHF and no UHF radios. The TT-4 Kleinschmidt teleprinter runs from rectified 400~ 115 VAC power from the inverter inside the 618T-3 case. The radio control head is attached to the M151 dashboard, the 76F-1 amplified speaker sits on the transmission hump.|
|Another view of the MRC-95 radio, this time it is ready for business - set up for RTTY use with the radio control head attached to the radio box, the TT-4 teleprinter cover removed, and the passenger seat facing rearwards.|
|Here's the marketing brochure for the TRC-75, main component of the MRC-83. I do not have actual numbers, but I suspect that the TRC-75 radio & power supply & antenna & 100 Ampere alternator had an acquisition cost of about ten times the acquisition cost of the M38A1 that all that stuff rode around in. The R-761/ARC-58 receiver/exciter is used in the TRC-75 - in the early 1980s, acquisition cost of the R-761/ARC-58 alone was over $29,000.|
|The "REAR, PANEL REMOVED" view of the TRC-75 shows the CV-786/TRC-75 850 CPS teletype modem on the upper left. Under the modem is the T-730/TRC-75 1kW RF power amplifier. Next is the RE-111/TRC-75 loading coil assembly, the CU-749/TRC-75 antenna coupler, and the C-2848/TRC-75 antenna coupler controller (note that the two coils in the RE-111 and the unseen variable inductor inside the CU-749 are all mutually perpendicular). The RE-111/TRC-75 automatically switches in one or both of the loading coils when using the whip antenna at lower frequencies, and switches the loading coils out entirely if using a wire antenna. On the far right is the R-761/ARC-58 receiver/exciter. Right above the central compartment and under the cover visible on the top of the TRC-75 case is a compartment containing all the messy little bits necessary to make the radio work, such as multiple terminal blocks, several coax relays, the speaker amplifier, the microphone amplifier, the forward/reverse RF power sensor, and other miscellany & minutiae.|
The TSB-101 seems to be a prototype TSC-15, probably built by Collins on their own nickel as a demonstration of what can be done in the way of packaging portable HF radio sets. The text mentions that the TSB-101 was built for the Signal Corps. I think that the first TSC-15s went to the Marine Corps, and no doubt the Corps had a lot to say about how the TSB-101 design was modified into the TSC-15 that actually saw volume production. The TSB-101's 'two or four land lines' became five telephone lines, and any or all could be either two-wire or four wire, and any or all could connect to a field 'phone or to a central office trunk line. There is no mention of any teletype capability in the TSB-101, but production TSC-15s carried a MITE KSR teleprinter in a tactical case plus a TGA-1 modem with both 850 CPS shift capability and also four-channel teletype multiplex capability. Additionally, there the TSC-15 could talk with up to five external teleprinters.
The TSB-101 wanted 60~ single-phase power, a much more convenient source of power if the unit is intended to be used as a demonstrator rather than to see actual field deployment.
This shelter is tiny, 4'8" wide and only 5' tall - probably the same size as a GRC-46. A shelter this small could fit under the canvas top of an M37 3/4 ton truck. Too bad we do not have more detailed photos of the rest of the radio gear, the panel above the switchboard appears to be the remote-control head for a 50E-7B receiver. No transmitter controls are shown in the photos but there is unseen equipment on the road-side wall of the shelter. I will guess that the antenna coupler & antenna coupler controller are in the cabinet on the road-side wall of the shelter, just visible inside the shelter door and under the antenna mast in the previous photo.
Note the typo - "ETERNAL POWER REQUIRED".
This brochure covers the TSC-15 as it was actually manufactured. Shown as the "Typical Installation" is the TSC-15 shelter itself, a PU-454 genset, a shelter-mounted AT-1011/U whip antenna, and a ground-mounted AT-1011/U whip antenna for full-duplex ops.
For transit, the PU-454 single-cylinder diesel genset is stowed inside the TSC-15 - it is bolted to the shelter floor. A trolley & come-along arrangement is used to lift the genset up and roll the genset out the door and lower the genset to the ground.
The text mentions four radio channels - this is done using the CV-976 Voice Multiplexer. The ARC-58 equipment used in the TSC-15 is an ISB radio and has a sideband bandwidth of 300 - 3000 CPS. The CV-976 limits the audio bandwidth of a voice conversation to 300 - 1500 CPS and stacks up two voice conversations in a single 300 - 3000 CPS sideband. The result sounds somewhat muddy but is quite usable. With the CV-976 switched out of the system, a voice conversation occupies a full sideband, from 300 - 3000 CPS.
The normal operational mode of the TSC-15 is full-duplex, with the transmitter being VOX keyed. This VOX scheme is extended to both the 850 CPS teletype modem and also the teletype multiplex modem, in that the modem generates MARK or SPACE tones only when there is activity on it's current loop (that is, whenever the teleprinter operator is typing). If the operator stops typing then the modem will quit generating tones after a few seconds and the transmitter will unkey.
The text mentions a 'bandpass filter' that is used for full-duplex ops. The filter is an F-508, which is a strange mix of URG-0 and URG-1 technology. It uses an Autopositioner for tuning, the only Autopositioner in the TSC-15. The rest of the F-508 is strictly URG-0 technology - the F-508 is no more than a repackaged 635R-1 preselector with preset tuning via Autopositioner added as a bag on the side.
A unique property of the TSC-15 is it's "Automatic Telephone Ringing" feature - once a call circuit is set up between two TSC-15s, no operator intervention is required in order to initiate or terminate voice telephone calls. If a local field 'phone user cranks the ringing generator on his field 'phone, a ringing detector on that phone's line in the local TSC-15 will see the ringing voltage and cause the local TSC-15 radio to transmit a particular two-tone signal on one of it's radio voice channels. The distant TSC-15 will receive & detect that two-tone signal, and send out telephone ringing voltage to the appropriate local field 'phone.
This is a VC-120 installed in an M151 jeep. The antenna is an AT-1011/U and the base looks like something created by the engineering department just for this photo shoot. The VC-120 is also known as a GRC-220, this one apparently has an early power conditioner, since the more common power conditioner units have the speaker on the left side of the front panel.
The antenna post on the radio will accept a 15' whip antenna (like that used on the PRC-47), and the radio can be powered by a BB-451/U silver-zinc battery (like that used with the PRC-47) - the manpack version of this VC-120 radio is called the MP-150 or the 719D-15. Looks like the antenna post is jumpered to ground but the ANT SEL switch is still in the WHIP position, doubtless a radio silence precaution taken by the Collins Marketing 'droids.
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