The AM Forum

Way back when I was a High Schooler in the early 1970's, my shop teacher and mentor was introduced to an outfit called Fair Radio by yours truly. Fair happened to have a big shipment of new in the box RU-18 sets in with all the trimmings and they dumped them for a fairly decent price. Anyway he bought the whole kit and built a beautiful box around it (being a shop teacher and a EE to boot, nothing was spared) to hold the set and the goodies. I always wanted to get hold of that setup every time he brought it and teased me with it when I would visit him over the years. Anyway suddenly last moth he said that he wanted to see it go to a good home and we came up with a price!

Now it is in the WU2D Shak! The RU-18 is a shortwave TRF set that uses unitized plug-in coil sets with a tracking BFO. This is the complete set new in the box with all spares. He dropped it at my door on the 24th as he and his XYL were visiting the daughter in Boston.

Now that is what I call a Christmas present for a military radio nut.

Mike

Mike,

That was a great Christmas gift!  It looks beautiful.

Rodger

The top of the box has the mounts for the Receiver, Dynamotor and Control Head and all of the cables for DC or AC operation are configured. I have it running tonight for the Old Military Radio Net (CW Edition) on 3570 kHz. This is a pre-war design but it was built on a War contract. These went into Army planes.

The BC-AR-430 was very strapping on the Old Military Radio CW Net tonight Mike!  The wind is howling, the snow is flying, a great night for radio!

Congrats Mike, a very cool set up, even more meaningful with the story behind it!
I KNOW it went to a good home.
Many more Christmas to you!

- Bruce

Mike that's a Christmas Story alright !

40 years later you're still in touch with him, and look how your interest was shaped by HIS interest way back then.

AND that he kept you in mind when he thought about "good home."

AND that he's probably of the same mind as George and Phil Sellati in saving all this old gear from the scrap metal yard.

It's all a win.

Correction: the RU receiver is Navy not Army. Black Crack = Navy I guess.

My heavens that was a storm but the radio weather was perfect! That BC-AR430 (which is the same pedigree and is a "matching" transmitter but is Army and no paint) chirps. Last night it was really chirpin away. It uses VT52's and VT25A's The Audio guys like those tubes.

I got SWL'd and put on YouTube with it.

http://www.youtube.com/watch?v=hTWjh0Karqc

A good article is in ER mag, March '10.

Informative w/pix.

73DG

Another article about this radio in the October 1930 QST.

This set has been around a long time...

73DG

One of the tubes missing the glass envelope?   ???

It would be hard to imagine a better gift for a radiohead, especially with your affinity for Command and ARC-5 sets, Mike. The RU set is a precursor of sorts to the ARC-5 types as I recall, actually coming from the BC- Army equivalent. Mike Hanz can probably rattle off the details and dates without missing a beat, hopefully he'll spy this thread.

The -18 was a stand alone receiver with no matching transmitter, 24-28 volts IIRC. The -16 and earlier were 12 volts for the most part, and the matching transmitter was the GF-11, also black wrinkle. You could pick up a GF-11 pretty easily if you wanted to match it up better, but I bet you're quite happy with it as-is for the personal history alone. 

One of the neat things about the RU type receivers is the ability to remove the top tube cover and then attach one of the ARR-1/ZB-3 beacon set to the top. There's a pic of one atop a nice RU-19 near the bottom of this link:

http://home.versatel.nl/gmwzijlstra-prummel/SCR74.html

About 10 years ago I had a friend in Colorado gift to me a nearly complete NOS RU-16/GF-11 set up with all the coils, control boxes, mounts and dynamotor. Was missing one connector, the spline cables, spares kit and manual, all but the splines and one spline switch have been located. I hope to have it mounted on some sort of transportable surface and bring it to NEAR-Fest one year.

Maybe you'll bring this one to operate sometime? Nothing is quite as cool as a set run by a dynamotor!  ;D

The BC-AR430 was missing the VT-52's and I stuck something in to drop the voltage in the 28V string. That is why there may be missing tubes in the pics of the TX on the YouTube. That TX was a mess as the wiring harness had completely degraded and would not tolerate high voltage. I ended up rewiring it. I figure it saw water and was not stored correctly or simply had insulation that went bad. It used SCC with the plastic black stuff inside with tinned copper strands. The black stuff was brittle and powdery made a better resistor than an insulator. Big SNAPS all over the harness.

Mike

Here is what the primitive BC-AR430 transmitter looks like. The GF-11 is similar in technology. CW MCW and AM at about 15W out on CW and 6 Watts phone 2 - 6 MHz with plug in coil units which contain the VFO and OUTPUT tank... Perfect for aircraft formation coms and CW for long distance back to the Carrier. It is essentially a triode Armstrong VFO driving a neutralized triode final (both VT-25A's which are essentially Type 10 tubes on steroids) modulated by a pair of VT-52A's in parallel off a carbon mic. Very primitive early 1930's technology but very light and compact for fighter aircraft. A tickler feedback VFO is quite unusual except in receivers HFO's of the time. Curtis P40's would have used this gear.

I found an old dynamotor mount at a hamfest with holes in it and made a small AC supply for it.

Mike WU2D