racal: Racal TR-28 backpack/manpack shortwave military radio

I worked at "CONRAD Construtora Radio Electrica, Lda" in Lorenzo Marques (currently Maputo) in Mozambique as a telecommunications engineer servicing RACAL and STORNO communication equipments. I maintained these RACAL TR-28 radios, among several other models, starting at 1974, but the Portuguese military forces used them well before that.

 

As far as I knoww, RACAL UK had no direct action on the developing the RACAL Electronics South Africa TR-28, as RACAL UK left South Africa well before the RACAL Electronics S.A.engineers have designed this TR-28 backpack/manpack transmitter/receiver oriented to militaty forces in the southern Africa region.

There are plenty of information in the Internet in portuguese language if you look for "RACAL TR-28 Portugal", or try "RACAL TR-28 Ken Clayton" for mostly in English pages.

The famous Ken Clayton was one member of the RACAL Electronics S.A. design team back in the 60's.

Several model iterations were designed, including custom versions for specific military forces on several countries.

 

The RACAL TR-28 ​(Transmitter-Receiver 28) was used by several southern Africa countries, among the South African and Portuguese military forces, starting in mid 60's.

There were several TR-28 iterations (at least 5 of them, even custom versions for different military forces), but the base design was the same, where the original TR-28 was designed and put into production in 1966, by South African designers working for RACAL Electronics S.A..

RACAL (on AM/SSB SW bands) and STORNO (on VHF and UHF professional bands) were also used by civil organizations in remote zones at the farms where there were no telephone land lines and at a time when commercial mobile phones were not yet invented.

During the Portuguese administration (up to 1975) of Mozambique, RACAL Electronics S.A. was marketed in Portugal by "CONRAD - Construtora Radio Electrica, Lda" based in Mozambique, and even assembled in a few Portuguese manufacturing plants, distributed between Portuguese colonies and Portugal Europe, under license of RACAL Electronics S.A..

The TR-28 was designed in South Africa, as the RACAL UK had left S.A., and the design engineer was Ken Clayton (among others in the team). The TR-28 is seen as a evolution of the older RT-14B equipment made by RACAL SMD (look for it in Internet).

The TR-28 was also assembled in Portugal (Europe) at "Standard Electrica" manufacturing plant  where the components were imported from South Africa by Mozambique CONRAD company. CONRAD also assembled these radios for some time as well in their manufacturing plant, along with National consumer radios assembled under Panasonic license. 

The original TR-28 model initial production batch was delivered to Rhodesia military forces in 1967, followed by South African and Portuguese military forces.

 

The TR-28 series operates on HF AM/SSB for voice and morse, from 2 to 8 MHz (selectable channels  frequencies by installing sets of crystals) at a maximum transmitter power of around 25 Watt (SSB). The removable 12VDC NiCd battery pack (10 x 1.2V "D" size cells) was part of the radio enclosure, attached to the main unit by clamps. The battery pack could be recharging while the radio was being used by connecting it to the car electrical system. Various antenna types were designed including a whip  to use the radio while walking.

The later TR-28 versions featuring up to 36 channels were developed with the Portuguese cooperation (Standard Electrica and military forces) to RACAL South Africa. The later portuguese version had the label "Exercito Portugues" stamped on the front.

A popular civil version used by farmers in Mozambique and Angola under Portuguese administration and other southern countries was the RACAL TR-38(D). It was a TR-28 but using a less robust enclosure, powered from the car batteries and a fixed car whip antenna if installed in a car, or it could be used as a tabletop radio at home.

More powerful 100 Watt car mobile versions were designed, like the RACAL TR-422 series, where the transmitter output stage used two 6146 tretode valves (if my memory serves me well). An sophisticated office tabletop version was also designed, the RACAL TR-15, with 100 Watt but using only transistors, where one model variant, the RACAL TR-15S, used a synthesizer for much more flexibility operation.

 

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Racal Electronics South Africa, Limited advertizing The TR-28, TR-38, RT-422, and TR-15.

 

 

A publicly available article covering the history of Racal TR-28 series radios designed and manufactured in South Africa by Racal Electronics S.A.:

 

 

 

 

 

 

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