Intercept and General Coverage Receivers
I had one of these R107s in the 1960s, (in fact two, one to restore, and one that had been shot through with a machine gun and served as parts for the other one) The R107 was a self contained Rx with a built-in 12V DC and 110/230 V AC Power Supply. A panel on the front allowed a quick test of many different supply rail voltages and test points without needing to open the set. Reception Set R107 Mk 1 was a general purpose HF receiver. With a Frequency coverage from 1.2 MHz to 17.5 MHz. AM R/T and CW and with the BFO and narrow bandwidth filters also good for SSB signals.
Intercept Reception Set R206 Mk.2 (above) was a very high grade HF receiver. a “Van door handle” on the bottom right was turned to select the revolver-drum “Turret” coil pack for the wanted band (six bands) and allowed for a frequency coverage from 550 kHz to 30 MHz. As a high-performance superheterodyne Intercept or communications receiver it was capable of a “high resetting” accuracy.
Frequency coverage on the main receiver (above) is in 6 bands, is as follows,
30.0 to 20.0 MHz,
20.0 to 10.0 MHz,
10.1 to 4.8 MHz,
4.8 to 2.2 MHz,
2.2 to 1.1 MHz
and 1.1 to 0.55 MHz (or 550 kHz)
As well as AM R/T (Amplitude Modulated Voice) and normal CW (Morse) mode, a BFO enables not only better discrimination and resolution of CW in a crowded band, but also due to the selectable Bandwidths (from 0.7 kHz, 2.5 kHz and 8 kHz) allows a good reception of SSB (Single Side-Band) voice signals. It was designed for use with 12 V DC vehicle power. If it was needed an adaptor could be attached that allowed it to run off AC mains.The adaptor also contained an audio amplifier and loudspeaker. (Module on left side in the picture below)
Another adaptor the “Frequency Range No. 1” extends the LF (lower frequency) coverage with additional three ranges covering a total LF range for 600-50kHz.
0.6 MHz (600 kHz) to 260 kHz,
260 kHz to 115 kHz
and 115 kHz to 50 kHz
The HF/VHF Reception Set R208 was a VHF receiver and primarily used with a Wireless Sender No. 36. Frequency coverage was from 10.0 MHz in the HF bands through to 60MHz in the VHF band. Note no FM, no NBFM, just wide AM R/T (Voice) and CW (Morse) reception. Powered from AC mains or 12 or 6V DC
Reception Set R106 was a HF general purpose/intercept receiver which used plug-in coil packs and a complex look-up table to find the desired or discovered frequency on the linear veneer dial. The frequency coverage was a segment of the range 50 kHz (0.05 MHz) to 30 MHz depending upon the actual fitted coil pack from 9 fitted. AM R/T (Voice) and CW (Morse). AKA “Receiver National HRO”
Coil packs for the following frequency bands were available...
A 14.0 to 30.0 MHz
B 7.0 to 14.4 MHz
C 3.5 to 7.3 MHz
D 1.7 to 4.0 MHz
E 900 to 2050 KHz
F 500 to 1000 KHz
(note gap around the normal IF frequency)
G 175 to 400 KHz
H 100 to 200 KHz
J 50 to 100 KHz
A later version had better mechanics for the plug in coils, an ejector come lock down handle made easier removal as well as a good anti-vibration fit for any mobile use. Also the coil pack activated a gear train to move the new display to show the actual frequency like on any other radio of the time.
The east Germans, Chinese and Russians made thousands of their own HROs during the cold war period.
The AR-88 was a (for the time) very high grade HF communication receiver, manufactured in Canada (by Marconi Canada as the CR 91 and predecessor to the CR100) and with identical appearance, made under licence in the USA by RCA. Frequency coverage was from 525kHz (or 0.525 MHz) to 32MHz. as the AR-88D model or 73kHz-30.5MHz 73 kHz (or 0.073 MHz) to 30.5 MHz. as
the AR88LF (Low Frequency) version. AM R/T and CW only. Made for (Jumper selectable) 100, 115, 220 or 240 V AC mains or for 6V DC (common Wartime truck or Jeep) voltage or by common 6 V car batteries.
Marconi Reception Set CR100/2 was a high grade HF receiver primarily used for fixed location services a big magnifying glass made reading the fine tune scale easy. Frequency coverage was from 60 kHz (or 0.06 MHz) to 30MHz. AM R/T (voice) and CW (Morse). Made for (Jumper selectable) 110, 220 or 240 V AC mains or for 6V DC (common Wartime truck or Jeep) voltage or by 6 V car batteries).
More Modern Intercept Rxs
The above R-390 is the follow-up to the R-388 below, (I put the older ones below so they can be seen against the RA17)
See this link for details of the RX collinsmuseum.com/51j4.html (Link opens in new window) The US follow-up to the R388 was the similar R390 which was declared TOP SECRET and so when first withdrawn from service were sent to the crushing presses at the DRMO ( US Army Surplus Sales sites)! Here is a link of stacks of them awaiting certified destruction.... http://www.r390a.com/Archived%20Pages/radio_rape.html (Link opens in new window)
the R-388 is the US made predecessor to the RACAL RA17 (*I have the above black “CIA” version of this Rx, it has a few very subtle modifications, but technically is the same as the normal military version). The RA-17 has the same technical foot-print and “cheese wedge” side shape as the Collins R-388, so that if needed one could replace the other in any emergency needing a loan of UK to USA or USA to UK. Outside the USA some R-388s and R-390s were fitted with explosives to destroy the radio if anyone tried to open it, or also if detonated during a front-line or similar location emergency evacuation.
The Collins parentage (even if technically completely different) is hard to overlook.
The RA17 is UK made, the RA117 made by the US subsidiary of RACAL.
This Eddystone 770U VHF/UHF Rx is from my own collection
Intercept receivers still in use today
Newer versions of the Microtel now cover 3 kHz to 18 GHz...
Norlin SR209s was a surveillance receiver covering the VHF/UHF spectrum from 30 - 2000 MHz. The receivers were built by Astro Communication Labs, (ACL) Each Rx can take two modules, either two different tuning heads, or one head and one SDU Display. The heads were available in 30 to l00, 90 to 300, 250 to 500, 490 to 1000, 990 to 2000 MHz.
Based on the Collins 51S-1, the next two are repackaged and heavily modified Collins receivers, made by LTV for air force (Flying spy) use such as in EC-47 Tactical Electronics Warfare Squadron aircraft, AND of which the 51S-1 in turn was based on the 51J-4 series (further above). LTV made these and a few other variants, as a special receiver for the flying EW Intercept post in old DC-3, DC-8 aircraft.
Brightly coloured and shaped knobs should allow the operator to work them when blinded by Atom Flash, etc., but just why he should want to operate the set, while the pilots are also blind and probably heading towards a mountain, is not explained. These sets also had a very effective backlit legends and dial faces making operation in an aircraft (and on the ground) a real pleasure. The lower set has a clock-face (multi-turn) dial for the BFO control/offset. It also has a slightly different coverage range, but nothing significant.
These were used in the “Top Secret" EC-47 of the American Tactical Electronics Warfare Squadron, (TEWS) aircraft, details of which including some views of this equipment (on which in part these drawings are based), in actual use can be found... CLICK HERE
