From Backblocks To High Seas

I came across this great piece of history via the Google+ page of Cristian YO8TNB and had to share it here for others to enjoy. I have a soft spot for New Zealand, being so close to my country of birth, and I particularly noticed the carefully cultured accent of the announcer. On a more serious note, this video is an invaluable record of the wired and wireless technology used in 1939 and the procedures for transmitting a message from land to sea.

Latest restoration project - Espey R-366/TRR-5 Radio Receiver

The Espey R-366/TRR-5 is a general purpose receiving set designed for use as an entertainment unit or auxiliary communications receiver. The receiver is a manually tuned, 16 tube superheterodyne. It has a tuning range of 540 to 30,000 kc in five tuning bands and receives either CW or voice signals.

It is similar to the Scott receiver AN/SRR-3 of the same period and produced under Contract NObsr-43229 dated 15 March 1949.

A user manual is available here : ANTRR5_INSTRUCTION_BOOK

The front panel as it originally looked.

The front panel once it had been cleaned.

First page in NAVSHIPS describing AN/TRR-5 and performance specifications.

Detailed shipping information for AN/TRR-5 receiver.

From the Antique Radio Forums :

Most of them were purged via DRMO in 1968-1973 and I only saw small numbers of them trickling through the system so I am guessing they were made in only a small quantity. None of the ones I have run across have had cabinets and all were in pretty atrocious condition. I vaguely recall the processing papers showing the equipment had come back from Vietnam, Guam, S. Korea and Japan.

Geoff Fors - WB6NVH

If you have any information regarding these receivers please leave a comment. If you have a R-366 of your own please let me know the serial number in the comments!

R-366/TRR-5 serial number registry:

1. #623 : KF5CZO - Owen Morgan
2. #050 : AE5VB - Hugh Coleman
3. #132 : W5AMI - Brian Sherrod
4. #591 : KC9KUH - Brian Love : (Compliance plate missing)
5. #290 : KC5IIE - Chris Krug (Update 01/11/2012 : Sold to W5XTL - Jeramy Ross)
6. #653 (Sold on Ebay, spotted by Brian KC9KUH)
7. #251 (Sold on Ebay, spotted by Brian KC9KUH)
8. #340 (Sold on Ebay, spotted by Brian KC9KUH)
9. #468 Jeff Wewers
10. #140 Gilbert Mendez
11. #097 James Starling

Using the formula N=m(1 + k ^{− 1}) − 1  from the german tank problem where m is the largest serial number observed and k is the count of serial numbers we see that the current estimated number of R-366/TRR-5 receivers produced is N=653(1+11 ^{− 1}) − 1 or approximately 711.

After bringing this receiver up on a variac to reform the filter capacitors I monitored the power usage and found it to be in line with the users manual @ approx 125W.

Audio is great due to the push-pull output stage and either a 6 ohm or a 600 ohm speaker can be used, both impedances are available on the rear connectors.

Readout seems accurate and the VFO is stable after just a few minutes warmup. Tuning the HAM bands is fairly touchy but this is really an AM rig by design.

Serial number 623 of how many? This seems to be a rare radio but I have heard of at least 4 other people with the R-366.

The bandchange is accomplished by rotating the circular turret. Each of the five bands has a complete set of discrete components in its sector of the drums.

Military amphenol right angled connectors. The three pin connector is 110V power in and the four pin is the 6/600 ohm speaker connector.

I was fortunate enough to be given period style military connectors for these sockets. Both neutral and active lines are fused on the power input circuit however I made sure to wire the active line to the power switch side for safety.

The receiver chassis slides out on roller slides for servicing and inspection. The full circuit diagram is also on the band change turret cover ... a thoughtful addition!

The only modification I can find is the antenna connector. Its been replaced with a SO-239 bulkhead connector for convenience. Personally not something I would have done myself but it makes life easier so I'm not complaining.

An unmodified antenna connection from another Espey R-366