The AM Forum

Here is an very unusual one for you.  1947 vintage John Meck T-60-1.  Pair of 6L6s plate modulated by a pair of 6L6s.  I have this one on the air.  Any others out there?

73,  Jack, W9GT

The KLUGE California Kilowatt ?

(http://www.ominous-valve.com/images/calif-kw.jpg)

The AN/URT-12 (ser. # 40). I know of only three still existing. Two of them are owned by Sam KF4TXQ. Maybe a 4th in a Coast Guard museum ship but unverified. 100W CW/90W carrier, par. 4-65 mod by pp 4-65.

Eldico SSB-100M mobile AM, CW, SSB transmitter.

Palco Bantam 65 mobile AM/CW transmitter.

Moore's book on Transmitters 1930-1980 details many transmitters, many of which could be considered rare and uncommon.

You need to look no further than N3IBX's basement. If it was ever manufactured, he has at least one or two of them! !

Frank said:
Indeed! Also included is 'home-brew'!  ;)

what about that TMC 750 thing that there are only around three of?  W3JN has one  I think.   The one with the AM modulator deck option.

You mean TMC GPT-750?

Subraco MT-15X   I have one of these little jobs...not working yet, but should be easy to get it going.  2E26 plate mod by class B 1635 (similar to 6N7).

http://www.rigpix.com/mischam/subraco_mt15x.htm

http://www.qsl.net/la5ki/org/su/mt15x.htm

73,  Jack, W9GT

I think there were more than three GPT750s around.  I recall hearing quite a few of them in the 70's.  One model has a factory modulator, which uses a pair of 810's.  The other is minus the modulator deck.

I remember a fellow who had one on 75m AM in RI in the mid 70's.  Can't recall his name or callsign now.  It put out a good signal, but the audio was strictly space shuttle quality.  I'm sure that  could have been corrected with a little work on the speech amp. I believe I recall seeing ads for them in the mid to late 50's ARRL handbooks, along with the matching receiver which strongly resembled a Hammarlund, at least appearance wise.

Not sure of the type of modulation, but they had a voice multiplex unit available for the GPT-750 that would provide 4 voice channels.  They were used commercially for telephone circuits in the Caribbean.  A ham friend that I worked with at GTE had a GPT-750, so equipped, that was scrapped in the 80's.  He acquired it while working for the phone co in The Dominican Republic.

73,  Jack, W9GT

When alive, Gary/W7FG had 3 GPT 750s, one had the AM mod deck and another the SSB deck.  The third did not have anything.  I don't know where they went but Gary bought them from the guy who owned Electric Radio when he sold to Ray and moved.

yep that's the one.  a T3 on steroids.   But, ya gotta have the AM modulator to be rare.

Bet one brings a high price when it is for sale.

1936 Lafayette PB-46 at W1UJR
Advertised as a "Professional" rig for the ham.  ;)

See -->> http://www.w1ujr.net/bruces_bench_2009.htm

(http://www.w1ujr.net/Bruce's%20Bench%202009/sc00305993_small.jpg) (http://www.w1ujr.net/Bruce's%20Bench%202009/sc0030a4c4_small.jpg)

(http://www.w1ujr.net/Bruce's%20Bench%202009/DSC_0011_small.jpg) (http://www.w1ujr.net/Bruce's%20Bench%202009/DSC_0019_small.jpg)

my 1939 Stancor 110C driving my first HB rig back when I had it all.

812 final cathode modulated by a pair of 6V6's . absolute mint operating condition, 9.9/10.

Here you go Frank - The Starflite Transmitter

Here is a LIL More Juice

Not really rare or uncommon. Was around for several years and we sold thousands of these rigs.

WRL Globe Trotter.  Designed by Ted McElroy, licensed to Leo Meyerson, who immediately got threatened with a lawsuit by RCA, claiming they owned the "Globe Trotter" tradename.  He convinced them to allow him to use up all of the 1000 front panels he already had made up.   But I don't think he sold anywhere near that many before discontinuing the unit, since so few seem to exist.  Worlds heaviest 40 watt rig!

73, Bob W9RAN

Is that a pack of smokes in the compartment for scale?

Saw one of those at the AWA meet a few years back, would have picked it up, but was pretty ratty and don't need another project, still, looks like a neat little rig.
But didn't Meyerson design it, and McElroy sold it.
I know that Mac was a big CW man, always thought of Leo as the design guy.
Figured it was an add on to the line of other products sold by Mac - keys, bugs, oscillators, etc.
Interesting tidbit on the RCA issue, makes sense.

Where did the Stancor go OM?

Yep, I have one, but the mod deck is HB - pair of 813s driven by a quad of 807s in class A.  BT-500 mod tranny and reactor.  The mod deck was built by N4VMY (SK) and I bought the rig from another SK's widow in Tennesee, not too far from K4KYV's.

Jared W1ATR has one (AKA "The Iron Curtain"  ;D), so does Brown W1NZR.  I met a young guy at the Carroll Cty MD hamfest several years ago that was going thru one that had the SSB deck.  Howard Mills built a mod deck for someone (don't know where it is now); W2XR has one with the SSB deck I believe; he's in the process of restoring it.  W2VW had one or two, and Gary W7FG (SK) had several.  There's a guy in MD who used to work for TMC that had no less than 3 in his basement.

They show up on eBay from time to time.  They seem to float around from person to person seldom making it on the air, which is a pity.  They're basically plug 'n' play, even if you are saddled with the SBE sideband exciter, from 160 thru 10 (160 mod requires cutting a STRAP on the final tank coil).

Here's a pic of mine

(http://i19.photobucket.com/albums/b153/throbbo/gpt750.jpg)

Thanks John--I imagine when one comes up on eBay it is big bucks and PU only of course!  that has to be the ultimate non-homebrew AM Rig for a ham.

The last one I saw, with a very ugly HB mod deck with a black wrinkle face that didn't match the rest of the xmitter, went for about $300 on eBay.  A steal.

Here are a couple more:

Of course any home brew is generally going to be rare and uncommon, as the transmitter on the left in the picture.  This is a pair of 4-125As modulated (presently) by a pair of TZ-40s.  This transmitter was originally built by a W4 around 1948.  It is in the process of being re-built with a pr of 4-250s or 4-400s modulated by a pair.  Using mod iron from a Bauer 707.  Note the GT logo. ;D  (part of the re-build)  The transmitter on the right is the trusty Federal 167B Marine transmitter.  Built in 1943, this rig has a pair of 813s in the final...originally CW and MCW only.  This transmitter is a physically smaller version of the rigs that were used on the Liberty ships during WWII.  The speech amp, modulator(pr 811As), and power supplies are all in the base cabinet/short rack that it is sitting on.  Got this transmitter in 1991 at the Wabash, IN hamfest, took a year to build the modulator, etc...been using it ever since.

73,  Jack, W9GT

I have a RCA MI-8167F that was the precursor to the TechRad TX-350D. I also have a British made MK-214D that last saw duty in an Algerian embassy. Although it has all the hallmarks of the Marconi Co. there is no one particular company that made it.

I sold the stancor to some guy in wisconsin last time i flipped out and went insane in the membrane.  :P

Hi Bruce,

The story of the Globe Trotter is explained in Leo Meyerson's book "In Touch with Leo", where he says "..for whatever reason, he (McElroy) canceled his plans to manufacture them"...and Leo and his employee Fred Davis negotiated a deal to buy enough parts to build 1,500 transmitters from McElroy.  Single 807 final, Heising modulated by a pair of 6V6s  Three sets of plug-in coils could be installed in the cabinet and the desired band selected from the front panel.  He says WRL "made a few changes" (including the front panel)  but mostly just took the McElroy design to market under the Globe Trotter name stating in June 1946.  Then the letter from RCA lawyers showed up ;-)

One of the McElroy MT-35 versions has been offered for decreasing BIN prices on eBay for some time now - and was just relisted:  http://tinyurl.com/2b7a5kh   It looks pretty hacked-up, but restorable.

Thanks for the info Bob!  I always wanted a Globe Trotter for my collection, but never got one.  They are pretty rare, although I have seen a few.  Very interesting story about it originally being designed by McElroy.  I did not know that.  The Globe Trotter was the forerunner of the Globe Scout, of which there were many versions over the years.  I believe the very first ones had plug-in coils.  I have an early band-switching model 40A which is 1953 vintage.  It works great and looks decent, as well.  I purchased it at the Findlay, OH hamfest many years ago.  It had been converted for 6 Meters and was a little hacked-up, but all the original parts were there, except the meter, and I managed to restore it to working condition.  Had to find the original meter, and replaced that to get it looking reasonable.  Globe Scouts are probably one of the most popular and enduring rigs of them all.  Lots of them still around and many still on the air.  Globe Scout 40, 40A, 65, 65A, 65B, 66, Deluxe....any more?

73,  Jack, W9GT

OK so the Lafayette might not be so rare - especially if they sold thousands! Unless all of them went in the dumpster.

Of course the SIGNAL ONE comes to mind and the CX-7 and CX-11, but did you know that they also made separates? The CT-1500 was a transmitter circa 1972. Anybody seen one of these?

Mike WU2D

Pre war Hallicrafters HT-9 (http://home.comcast.net/~chnord/HT-9.JPG)

That's a cool one Carl!  I believe Bob, W8MNQ in Port Huron, MI has an HT-9 as well.  Not sure if he has it on the air.  I saw one or two of them at Dayton 2 yrs ago.

73,  Jack, W9GT

I have both the black prewar and gray postwar HT-9 and know of several others of both. The black one uses an early Signal Shifter and the gray has a HT-18 for the VFO. The HT-1, HT-2, HT-4 and HT-6 are pretty scarce.

Any of the NTX National's.

Various Lettines, called Latrines in their and my home town ;D A true schlock basement operation.

The Meisssner 150B and matching VFO rate as one of the heaviest table top rigs. I have the Army version of the Signal Shifter VFO with a full set of coils and use it regularly on 30M with a FB-XA receiver.

Temco, Subraco and Standard had 100W and up models that are seldom seen.

Many other one-off companies were around and never made it into QST ads. CQ is a good source for info on the 1945 and later companies.

Carl
KM1H

Perhaps the main reason that 1930's, and even 1940's vintage commercial ham transmitters are so rare is that most hams built their own rigs.  Especially during the depression years, hams could barely afford a single tube or a handful of parts to build a rig, let alone buy a nice commercial transmitter.

Later on, in the early days of WWII, hams were encouraged to donate such things as panel meters, and other items that were in short supply to the war effort.  They were off the air during the war years anyway.  After the war...tons of military surplus equipment and parts became available....further encouragement for hams to build their own transmitters from surplus parts, or modify military units for ham use.  By the fifties, companies like Johnson and Heathkit and others really started cranking out the stuff that hams could actually afford.

73,  Jack, W9GT

And many of the earliest Heathkits used WWII surplus parts- or so I have read

Carl
/KPD

Big, gray boxes. Collins KW-1 and 30K-5. The model -5 was the last of the line, made up to 1960 or so, but also in the lowest numbers since it was an older design. Used in places like airports and hydro dams.

Also a shot of the Johnson Viking 'Desk' Kilowatt now at GMS Radio in 3 Land. Can't wait to see (and work) the finished version.

Another Knight - Rare? Uncommon?

Mike WU2D

Rare or uncommon?

Hey John JN,
The few times I visited Howard, W3HM, he had a GPT750 that he was restoring and was building an 810 modulator. There were some quirks about tuning the transmitter. He ended up calling a guru who stepped him through some weird tuning procedure. Don't know what was so troublesome about tuning.

Fred

Back in the early sixties it seemed to be a fad to put a small AM station on the air.
Everyone was doing it.
A slightly older teenager in my neighborhood had a friend of his build him an AM transmitter
that put out around 75 watts into an L antenna. It was great 'playing' disc jockey and making
dedications to all our friends around town. I would drive around to see how far it could be heard.
Then one day coming home from school there was a grey van parked infront of his house
with the FCC lettering on its doors. I was scared and ran home and hid.
Found out later that the agents took the tubes out of the transmitter and told the older teenage who did it, in very stern language, not to try that again. Seems his harmonic was heard hundreds of miles at sea on the old marine band.
Funny, the guy grew up, became a lawyer and went to work for the Justice Department.

Regards
Q

  " Funny, the guy grew up, became a lawyer "

Yes, breaking the law can lead one down the road to perdition.... ..


klc

Very rare. Legend has it there were no prototypes of the Knight T-400 ever built, only an artists rendering. Or, that there was only one prototype built, and it was last seen listed in a FS ad in 1998 for $200.

Wonder if the Kahn operation in Long Island was connected with Albert Kahn of Ten-Tec?

BW 6100.   About 200 where made. Some say 300.   Mine is 198.   The first synth ham transmitter. AM and SSB.  One day I will get mine going with the R390 and BW 370 converter. 

C

I believe that these transmitters are rare.

Long Island? Well here is a bit on Al.  From the “Famous HAMs” website http://users.tellurian.com/gjurrens/famous_hams.html
By N2GJ and W2SG:

K4FW Albert R. "Al" Kahn

"Founder of Electro-Voice, which derived its name in an interesting way:  Legendary Notre Dame football coach and Professor of Chemistry Knute Rockne needed a device to amplify his voice during practice so his players could clearly hear him. In the late 1920's, Mr. Kahn built him a public address system which Knute referred to as his "Electric Voice."  The name stuck. Electro-Voice grew and emerged as a leader in professional audio equipment.   K4FW was also instrumental in the founding of Heathkit, supplying it with WWII surplus parts in the late 1940's; in 1968, he founded Ten-Tec with Jack E. Burchfield, K4JU, now Ten-Tec's President.  See biography.  Official web site. (ex-W8DUS, QSL via W2SG)"

Electro-Voice is in Minnesota these days, was in Michigan, did have something in NY I think.

Think I saw an Electro-Voice factory building off I-84 up around Port Jervis, NY a while back.

I have one of the Eldico SSB 100M mobile transmitters with the original mobile supply and catalog sheet. Several years after acquiring them I was on the air and just by chance had a QSO with the original designer. The very fact that the topic of Eldico & the transmitter came up is amazing. He very kindly sent me a copy of his "manual". I think it was mimeographed, but it is legible and included the schematic. From what I gather only about a dozen were made. Having the transmitter and running into the designer on the air has got to be one of the greatest long shots ever!
Skip

1952 Navy FRT-17, 81 tubes and 1500 pounds

I built one of these little Graymark 515 transmitters when I was a kid. Not so rare but getting there. http://www.smecc.org/graymark_transmiter.htm