Vintage Radio Vacuum Tube Electronics: 1963 Mobile Teletypewriter Military Communications AN/GRC-46

Vintage Radio Technology and Vacuum Tube Electronics: A 1963 U.S. Army Training film covers in excellent detail the mobile Radio Teletypewriter and Radio Equipment of the AN/GRC-46. Great vintage radio equipment explained and demonstrated.
The AN/GRC-46 equipment was originally mounted on an Army M-37 series 3/4 ton truck as shown in the film. The GRC-46 was a military designed radio teletypewriter communications facility, capable of mobile or fixed place operations, containing a variety of communications equipment, including AM voice and CW radiotelegraphy. Primarily used by US Army in tactical units in the 1960’s.
It operated in the HF (High Frequency) band
Its many components included:
Radio Teletypewriter Set
AM Radio High Frequency Voice Transmitter
CW Radio teletype (Continuous Wave)
Hand Key code transmitter
Reperforator for punched paper tape
Antennas, and more
Original Film Source: National Archives film from Public Resource.org
Here are several great web sites with GRC-46 info and a very impressive GRC-46 Restoration!
Post WWII US Army Radios & Radio Teletype Shelters
rattrig.com/def...
AN/GRC-46 info at Radio Nerds.com
radionerds.com...

[@frankowalker4662]

Brilliant. The worlds first mobile phone that's able to send texts. LOL.

[@TheAndyseitz]

Note, it can do it without any infrastructure, directly to similar phone over 1600 km.

[@allenmiddendorff2068]

Thank you. I have a new model An/GRC-146C.

[@joebundens2197]

Somehow I find myself getting smarter when listening to these videos then the modern junk we have today. I appreciate they take the time to explain each component in very concise and simple terms.

[@ronwright2389]

I trained on this unit at Ft Sill, OK. We had exercise with like 6 trucks in a circle each with GRC46. We learned how to setup and tune the gear and passed RTTY traffic between us. We got finished with the exercise early, but were not allowed leave, that was the Army. So as a Ham I tuned up the transmitter and receiver on the 20m Ham band and heard a NY station calling CQ. I hit the tune lever of the T145, picked up the mic and called the NY station from out OK GRC46. We had about 10 minute QSO. The other solder working with me could not believe what I had done. Never saw a GRC46 after the Army school.

[@ComputerHistoryArchivesProject]

Hi Ron, great story! Thank you for sharing that. Can you tell me more about what QSO means? ~ Victor, at CHAP

[@3366larryandrews]

What unit did you work with after your Ft. Sill schooling?

[@russbellew6378]

@@ComputerHistoryArchivesProject QSO = a conversation via radio

[@woodwaker1]

Very interesting. I was in Crypto Repair USAF in 1969, the main teletype unit was the size of a refrigerator and had about 50 vacuum tubes. The "modern" replacement had transistors and was the size of a microwave. A lot of thought and invention went into these units to keep communications secure. Which was undone by the Walkers

[@ComputerHistoryArchivesProject]

Hi David, I was reading your comment with interest, but I do not understand the reference to the "Walkers." Could you clarify perhaps? ~ Victor

[@darylmorning]

He meant John Walker's Spy Ring, mostly family, who gave most of the crypto gear the US Navy used to the Soviet Union, from late 1967 until caught in the mid 1980s.

[@SeekingTheLoveThatGodMeans7648]

@@darylmorning This is why modern cryptography does not rely upon security by obscurity of technology. It operates on the assumption that the enemy knows everything but the key.

[@scratchdog2216]

Love vintage military comms. This is a fun radio. Great A3A. A good solid-state dyno replacement highly recommended. Less noise and amperage draw.

[@RedArrow73]

All that's missing are the dogs.

[@abergethirty]

Not so vintage. They were still using these into the 90's. All they upgraded was the trucks. 1980's Chevy pickups instead of old Dodges.

[@sanremo2649]

😀 i was the comandant of that one in my military time in Austria

[@Dinkleberg96]

In 1963 you would buy a "phone" and the car comes attached to it as a bonus

[@3366larryandrews]

My shop in Vietnam built a brand new AN/GRC-46, complete with new 3/4 ton truck, after the armistice was signed in early 1973. The unit was for a group of United Nation Canadian monitors for a relay station between Saigon and Hanoi. The components came from the Depot in Okinawa.

[@ComputerHistoryArchivesProject]

Hi Larry, that sounds like a great project! It takes quite a bit of skill to pull that off. : )

[@3366larryandrews]

@@ComputerHistoryArchivesProject It didn't take us long to assemble. I was amazed that the Depot in Okinawa had a brand new 3/4 ton pickup for us to use. The sad thing was that after we built this unit and it was sent out, it came under fire before it made it to its relay point. A decision was made for the rig to return to Saigon and another method of communications used from Hanoi to the communications center in Saigon. I never saw the rig again, as we shut down our shop and turned it over to the South Vietnamese.

[@ComputerHistoryArchivesProject]

Hi Larry, sounds like a fascinating and memorable experience! Thank you very much for sharing that memory. ~ Victor

[@abergethirty]

I went radio school Fort Sill in the 80's. When did they start calling the set the Angry 46?

[@3366larryandrews]

@@abergethirty I believe any item that used the AN/GRC designation was shortened to "angry":)

[@plusmilitary]

very good , this is OTH radar

[@samuelfellows6923]

I was intrigued with that transmitter - it needed a filter and had 2 pipes connected to the front and bent into the wall - in one of the external shots we see a plate with 2 holes in it near the back of the shelter = I assume that part of the transmitter is soo hot it needed external cooling - air takin in through the lower pipe and passed hot components and in to a centrifugal fan and out the upper pipe to the outside

[@Elfnetdesigns]

local swap meet here has one of these similar trucks for sale complete with all the radio equipment and a generator

[@ComputerHistoryArchivesProject]

Interesting. I wonder what it was selling for.

[@abergethirty]

When I was in the Army we still had these on Chevy/GM pickup trucks. This was the 80's and even then they were obsolete in the other services. We were using discarded Air force teletype hardware because they had moved on to Digital and Satalites. These are slow too. Under 300 baud. Hell, even a on BBS a phone line was faster.

[@ComputerHistoryArchivesProject]

Hi Allen, interesting. I bet the older hardware had a long endurance life span, but the tech stuff, as you say, was very very slow. ~ Thank you for sharing the recall. ~ Hunter

[@phoneticau]

50 baud 5 bit teletype code around 100 word per min.

[@3366larryandrews]

If I remember correctly, these units could run in two configurations that controlled the speed of the teletypes. The slowest was 60 words a minute and the fastest was 120 words a minute. We ran at 60 words a minute. It's been so long since I used these products, I can't remember if they used Baudot or ASCII. I used them in the 1970's with commercial teletype senders. I used the AP to test the rig. It makes sense that ear;y units might have been Baudot, but I don't think so. The teletypes were probably updated or supported ASCII. If I remember right, the paper tape readers and punches used 8-bits.

[@ricke.2205]

At 23:38, he mentions "online." If he only knew what that word would come to mean. LOL

[@3366larryandrews]

No mystery here. Where do you think they got the idea of an internet?:) The AN/GRC-106 combined a modulator and demodulator into a unit they called a modem. In the case of the AN/GRC-46 it was a converter and modulator unit.

[@ZXRulezzz]

I find it really interesting that back in those days "tuning presets" could've meant that device actually, physically adjusts whatever tuning it has to, itself. I mean, it's no magic, just actuators and servos, but "it's aliiiiiiive" :D Mr. Carlson, I think, featured a radio with "presets" like that in one of his Lab episodes. In USSR, there was produced a radio receiver called "Festival". Again, it's probably not unique to only that receiver, but it has a wired remote control that allows for remote manual tuning, where you turn the potentiometer dial on the remote, and it electrically controls the servo that rotates the tuning capacitor inside the set.

[@ComputerHistoryArchivesProject]

Hi ZXRulezzz, great observation and good info! Thanks ~ Victor

[@3366larryandrews]

Other teletype rigs with this level of power had to be manually tuned and had no presets. Units like the AN/GRC-26D had to be manually tuned. I have never experienced a T-195 that was used remotely. The AN/GRC-106 was much more advanced and released a few years after the AN/GRC-46. The AN/GRC-46 had a separate converter and modulator. The AN/GRC-106 combined these functions into a "modem" unit.

[@w7wv73]

I spent about 60% of my time in this unit during my first assignment in the Army. Hotter than hell with no AC in the AZ deserts.

[@ComputerHistoryArchivesProject]

Hi @w7wv73, that must have been quite an experience! And everything around you also gives off heat, radio tubes, vehicle engines, sand... thanks very much for sharing!

[@w7wv73]

I was hoping to get an asssignment in the 26D, a bigger van mounted on a 2.5 ton. And it had AC! @@ComputerHistoryArchivesProject

[@w7wv73]

Andkeep in mind that the small shelter seated two GIs inside too!@@ComputerHistoryArchivesProject

[@hugh007]

As I recall, that transmitter alone required at least 40 amps at 28 volts for no more than 100 W out on CW. The receiver used all low voltage on the plates, (28 V) but needed heater power. Remaining devices probably doubled that. Overall power efficiency was maybe 10%. Who designed that power supply/distribution system - Rube Goldberg? Thanks for the film.

[@ComputerHistoryArchivesProject]

Hi Hugh, glad you enjoyed it. Thanks for the feedback! ~ Victor, at CHAP

[@3366larryandrews]

We operated the AN/GRC-46 with an output power of 1000W. I have never experienced a unit that was used in CW. From what I remember the output power tube plate voltage on the T-195 ran at 1000V. When keyed it generated about 10K Volts of RF power. I can't remember if there were dual output power tubes or a single output power tube. A converter was used to translate 28V vehicle power or generator.

[@benridley9881]

US Military using the metric system!

[@ronwright2389]

Yes, in 1970 all was in meters for distance. Maps with grids in meters.

[@Rocketman88002]

I remember those old Angry series radios. The RT/524 was about the most modern field radio for a long time. They are all clunkers now and worthless. The M-48 Duster twin 40 mm gun had tube radios! Rugged and reliable at the time.

[@paladin0654]

Ah, the old RAT Rig...came with their own 5KW generators. They always had hot coffee!

[@3366larryandrews]

Funny. We used two 10KW generators mounted on a trailer that we towed. We also had heat and air conditioning:)

[@paladin0654]

@@3366larryandrews I probably served before you did.

[@3366larryandrews]

@@paladin0654 Perhaps. I used the AN/GRC-46 in Vietnam, 72-73.

[@paladin0654]

@@3366larryandrews I used this series of radios during my entire career. When they worked, they were great.

[@3366larryandrews]

@@paladin0654 Interesting. The AN/GRC-46 was being phased out for the AN/GRC-106. Still used the same or similar teletypes, but were much more modular and were mainly transistorized.

[@pcuser80]

Where are those units now?

[@thomaskitz1185]

I have a complete set.

[@ronwright2389]

There are collectors especially for the T145 transmitter and R392 receiver. Some still use them on the Ham bands.

[@berfunkle4588]

9:05 "Wavy line?!" Why didn't they just call it a sine wave? It's high school level math for crying out loud.

[@SeekingTheLoveThatGodMeans7648]

For that matter, they've confounded frequency with its inverse, i.e., period. It basically serves as reminder to those who already intimately understand what's going on.

[@videolabguy]

Kilometers? WTH? Isn't the measurement units of America's enemies?

[@TheAndyseitz]

Yes, Im shoked also. Althogh, he talks "cycles per second" instead "Herz" just because Herz was German.

[@SeekingTheLoveThatGodMeans7648]

Also overseas allies. At some point one has to stop being stupid.

[@ronwright2389]

@@TheAndyseitz Hertz became the term in late 60s, I was there.

[@ronwright2389]

In Vietnam in late 60s meters was used for distance, maps were in grids with meters. Never used miles or feet. I am sure one reason was so US could work with other countries military s. I think the military vehicle's odometers did read in miles.

[@n8ibz1]

We used teletype in 1983 because the emp destroys the computer. Now we have nothing that will work