April 2, 2024 - Newly added rare technical information on the R-1451, a ground breaking HF submarine receiver. Built by the Army funded Electronic Development Laboratory established and run by Sylvania in Mountain View, CA., possibly the first receiver with an electronic digital frequency readout.

Donated by Mike Kana, these schematics and the block diagram cannot, at the moment, be found anywhere else on the web.

This document is now available for download from the document index page under Sylvania.

Jan 9, 2024 - A nearly impossible to find manual for the rare Regco RG-5545A VHF-UHF receiver. Courtesy of Terry Gains. This is the full manual with all schematics and service info.

This manual is now available for download from the document index page.

Oct 19, 2023 - The best scan I have yet of the manual for the Nems-Clarke 1670 series of general purpose VHF receiver is now available courtesy of Peter McCollum. This series includes the 1671, 1672, 1673, & 1674 VHF receivers. These receivers were often placed in the back rooms of missile and rocket telemetry facilities as demultiplexing, recording and data analysis equipment moved out front. This front panel style was used on most Nems receivers in the early 1960s after Vitro pruchased the company.

This manual is now available for download from the document index page.

July 4, 2023 - A different scan of the Nems-Clarke 1306 surveillance receiver manual is now available courtesy of Peter McCollum. The 1306 was the first receiver Nems-Clarke designed and marketed for surveillance use. They were years late and out of step. Dozens of Nems employees had taken their skills and expertise over to Communication Electronics, Inc which already had receivers 1/3 the size and better performance. An interesting, still capable radio.

This manual is now available for download from the document index page.

May 12, 2023 - A manual for the 1400 series of Nems-Clarke receivers. These receivers were widely used in the missile and early space programs. Many thanks to Peter McCollum for submitting this manual scan.

This manual is now available for download from the document index page.

April 10, 2023- Three small pieces of ACL manuals are now available. The SR-212C and the SR-212A-2 & SR-212A-3VHF/UHF receivers. And the PHU-201 power supply unit and SH-205-6 tuner for 1-2 GHz and the SH-206-6 tuner for 2-4 GHz. These are brief and without schematics. I'd love to post full manuals, but ACL documentation is even rarer than the equipment and this is all I have.

These manual fragments are now available for download from the document index page.

April 5, 2013 - Another wonderful article from Paolo Viappiani. This one a comparison and the story behind the Watkins-Johnson WJ-8711 and Ten-Tec RX-340 and their no front panel cohorts, the WJ-8712 and RX-331. A fascinating piece on two revered and popular radio designs.

This article can be found on the Collector Corner page.

April 5, 2023 - A front panel tester for the Microprocessor Front Panels (MFP) of the popular Watkins-Johnson WJ-8718/MFP and WJ-8716/MFP HF radios. A neatly done device designed and built by Paolo Viappiani for quick and easy testing of the front panels of these top notch radios.

This article can be found on the Collector Corner page.

December 2, 2022 - The service manual for the Racal RA6397A HF antenna filter unit is now available. I don't know how many years I've had it or where it came from because it was misfiled.

This document is available for download from the document index page.

July 18, 2022 - Thirteen manuals for the Microdyne 1100-AR receivers and modules are now on this site. For many years, a Microdyne 1100-AR has been on display at the National Cryptological Museum at Fort Meade, MD as part of the Rissman satellite intercept system. Manuals include 3 different copies for the receiver, 3 different tuners, the spectrum display and a variety of plug-ins.

These documents are now available for download from the document index page.

April 19, 2022 - A rare service manual for the Motorola R-220/URR VHF receiver is now available. Also known as the AN/URR-29, this radio was used, among other places, by the Army Security Agency for SIGINT reception along the borders with the Warsaw Pact countries from the mid 50s into the early 1960s. There was also a Signal Corps version, the R-644/URR but any differences are currently unknown. Many thanks to Carl Cramer, W9BJ, for sharing this very rare document.

This document is available for download from the document index page.

March 28, 2022 - Another Collector's Corner article, this one from Paolo Viappiani delves deeply into the front panel control boards for the WJ-8716 and WJ-8718 series of radios to unravel the mystery of the MCM-2 board, as opposed to the more common MCM board (MCM is the Manual Control Module).

This article can be found on the Collector Corner Page.

March 6, 2022 - Newly added to this site are two Collins engineering reports, both in two forms - original and reformatted by Al Tirevold. The R-389-390 Final Engineering Report is an explanation of the circuit designs and choices. It was a restricted document when first published in 1953. The R-390 Cost Reduction Report covers the design choices made to develop the R-390A from the original R-390. None of these four documents are fully complete as there some figures missing from the two originals and Al Tirevold omitted most of the figures because of the poor quality of the originals. Nonetheless, they are fascinating documents if you are a fan.

These documents are now available for download from the document index page.

January 23, 2022 - In 2016, a chapter I wrote on the life of WJ founder Dick Johnson was published in the National Academy of Engineering's Memorial Tributes book series.

Dick Johnson partnered with Dean Watkins to form Watkins-Johnson in 1957. In 1967 they purchased Communication Electronics, Inc and financed the building of the Gaitherburg facility for their new division. Most of the radios mentioned on the companion Watkins-Johnson website were made by this division.

Links to this chapter can be found on the My Publications page.

November 20, 2021 - Eleven more data sheets from a M/A-Com catalog including the intriguing SPECTRE system (Special Purpose Emitter Collection & Tactical Receiving System) and the GUI (Graphical User Interface for Search Receivers). Also added are six receivers, the SMR-5550, SMR-5550i, SMR-5550i-FE, SMR-5555, SMR-5688e and SMR -5688e-04, two frequency extenders, the FE-3820 and FE-3830 and one tuner, the TU-5550.

These documents are now available for download from the document index page.

November 19, 2021 - Data sheets for three M/A-Com microwave receivers, the SMR-3822, SMR-4820 & TU-3822/IFD-3822 and three microwave tuners, the TU-3840, TU-3950, and TU-6400.

These documents are now available for download from the document index page.

November 17, 2021 - RDF Products manufactures radio direction finding equipment. Now avaiable on this site are the operating manual and data sheet for their DFP-1000B DF Processor. Also available are five application notes on DF operation and equipment. They primarily cover the Watson-Watt method but also contain information on psuedo-doppler techniques. A wonderful collection of uncommon information.

These documents are now available for download from the document index page.

October 15, 2021 - The full operating and service manual for the OAR 3045 direction finding receiver. An unusual 12 VDC powered mobile DF unit.

This manual for this receiver is available for download from the document index page.

October 6, 2021 - The Nems-Clarke 200 and 300 spectrum display units may be the first dedicated spectral monitors for receivers. Introduced shortly after Sputnik orbited the earth the 200 and 300 were widely used in missile and rocketry test programs. The 200 displays 2 MHz of spectrum with a 21.4 MHz input and the 300 displays 3 MHz of spectrum with a 30 MHz input.

This manual is available for download from the document index page.

October 5, 2021 - The TMR-6 receiver was a commonly used for unmanned earth orbiting satellites in the early 1960s. The appearance betrays its close relationship to General Engineering Laboratories equipment which was designed by many of the same engineers. I was lucky to stumble across a partial manual for this receiver with the theory of operation for most of the radio and three main unit schematics.

This manual is available for download from the document index page.

October 2, 2021 - Another rare find - the manual for the Nems-Clarke R-2074A receiver. This radio was installed all over the world as part of the Manned Space Flight Network during the Apollo program. An all-in-one box diversity version of the R-1037A (hence doubling the model number), they much more rare than the R-1037A. It came in single tuner and dual tuner versions.

This manual is available for download from the document index page.

October 1, 2021 - Just added, a copy of the 1969 Racal catalog with many classics from the RA 17 HF receiver and many specialized militray radios.

A fascinating document available for download from the document index page.

October 1, 2021 - The sales brochure for Defense Electronics, Inc's beautifully designed and built TR-711 sold-state receiver. Introduced during the Apollo Manned Space Flight program, this radio was the company's last major design (the small GPR-20 surveillance receiver was their swan song).

A fascinating document available for download from the document index page.

September 29, 2021 - Added scans of the rare manuals for the Micro-Tel PR-700B receiver and the options manual for the Micro-Tel PR-700B.

These documents can be downloaded from the document index page.

September 27, 2021 - A rare sales catalog for the Microdyne 1100 series of receivers. Thirty-two pages of data on the mainframes, tuners, spectrum displays, IF modules, demodulators... Includes tables and photographs of installations and uses of these nicely built microwave receivers.

Includes the mainframes: 1100-AR, 1100-AR(5), 1100-LS, 2200-R(T)
The tuners: 1185-T(D), 1115-VT(SYN), 1116-VT(D), 1111-VT (10)(D) and more.
Second IF modules: 1120-I(B)(3), 1120 -VI (.1-3.5) and more.
The demodulators: 1142-D(A), 1144-D(A), 1145-D(A), 1151-D(B), 1151-D(T), 1152-D(A), 1155-D(A) and more.
And complete Special Purpose Receivers: 1100-LS, 550-AR, 1100-AR(70).

A fascinating document available for download from the document index page.

September 27, 2021 - The Microdyne manuals, one complete from 1973 for the the 1100-AR receiver, one update instruction from 1985 for the 1100-AR receiver, and one for the 1115-VT(W) RF Tuner.

These documents can be downloaded from the document index page.

May 17, 2021 - Fifteen files from the manuals for the Defense Electronics, Inc. TMR-15 telemetry receiver. This manuals are scanned documents originally from the NASA Deep Space Instrumentation Facility that was used during the Manned Space Flight Program at Hartbeesthoek, South Africa. A very similar looking radio appears in other publications as the TR-101 and these documents may be useful for restoring that radio as well. Many thanks to Leon Heinkelein for scanning and sharing these extremely rare documents.

These documents can be downloaded from the document index page.

May 6, 2021 - Two new files for WJ-8716, WJ-8718 and MFP versions of these radios courtesy of Paolo Viappiani. 1) A WJ-8718/MFP troubleshooting guide, featuring corrections to the original WJ manuals and diagrams for easier trouibleshooting. 2) An updated field installation guide for the very desirable Microprocessor Front Panel (MFP) option into WJ-8716 and WJ-8718 radios.

These documents can be found in the Collector Corner link show at the top of the page.

Revamped feature: Collector Corner. A place for articles written by collectors and hobbyists on how to do things with these radios, tips and techniques on repairing and/or improving them, and projects involving these radios. Go to Collector Corner via the link in the masthead.

This feature has existed since the start of the website but has been buried in the back pages.

October, 18, 2020 - A previously classified Bendix telemetry station manual yielded the circuit description, alignment instructions and a schematic for the classic Clarke Instruments 167-E receiver.

This can be downloaded from the document index page.

August 29, 2020 - The Nems-Clarke R-1037A receiver service manual. It appears to be missing some schematics, but it is all I have at the moment. The R-1037A was widely used by NASA for telemetry, including reception of data from Saturn V rocket launches. Some units were made when Nems was a division of Vitro Corp. Others were made after purchase of the division by Defense Electronics, Inc. An extremely well built and reliable receiver.

This can be downloaded from the document index page.

August 19, 2019 - Added very rare manuals for Defense Electronics TMR-74A telemetry receiver (a huge manual split into two parts for download). Manuals for the receiver, the TU-74-LA tuner (1435-1540 MHz), TU -74-SA tuner (2200-2300 MHz), the DNC-301 predetection downconverter, and the UPC-301 predetection upcoverter. Donated courtesy of a listener/reader in Maryland.
These can be downloaded from the document index page.

May 26, 2019 - Added the manual for the Racal RA6337 LF converter.
This can be downloaded from the document index page.

May 20, 2019 - The start of a long process of revamping and expanding this site. Over 200 MB of new files. Manuals for ACL SR-209 receiver, ACL IF-212-300 and IF-212-500 modules, ACL SH-203-P-1 tuner module, Cubic CDR3250 & CDR3280 DSP VLF-HF receivers, Cubic R-2411 VLF-HF receiver, Cubic R-2412 VHF-UHF receiver, Mason A-2 (early version), Mason MPR-5 user manual, Mason MPR-5 service manual, Micro-Tel 1200 receiver, and Micro-Tel MSR-904A receiver. And many new data sheets and catalogs. These can be downloaded from the document index page. This is a big undertaking so if you see any broken links, please let me know.

March 19, 2019 - Added two rare Astro Communication Laboratory manuals; one covering the SDU-102AP and the SDU-103AP plug-in spectrum display units and one for the IP-804-GR spectrum display unit in a 3-1/2" high rack mount. These manuals can be downloaded from the document index page