Collins R-390/URR versus Racal RA17L

December 2018:

I have a confession to make. If you had asked me a year ago if I had any interest in the Collins R-390 or its successor, the R-390A, I would very likely have said said no. Not that I had anything against them... I just figured that if I were to ‘dip into’ the Collins ‘universe’ there was a danger that I would get hooked. I just preferred to stay safe and restrict my collection to Racal equipment. However, as of October 2018 I confess that I am definitely a '390-convert'.


I have been refurbishing RA17s since 2009 (to date, 40 receivers) but until earlier this year (2018) my only experience with the Collins classic was limited to viewing various photographs. I will even admit that there were several aspects of the R-390 (or 390A) that I found unappealing. Firstly the front panel layout just didn't look right; the Veeder-Root counter was clearly a ground-breaking innovation in 1951, but its inclusion meant that this was no band-cruiser; and then there is that unbelievably complex gear-train! But when I was asked if I was up to the challenge of getting an R-390A up and running, I actually gave it some thought. The first thing that came to mind was that famous gear-train, but I said yes. My friend already owned one of my refurbished RA17Ls but had recently purchased a pair of Collins classics; a supposedly working R-390A and an R-390 which had seen better days and was missing several parts. Now, several months later, both receivers are up and running beautifully, and although this piece does include various 'work-in-progress' photographs of both receivers, this is more about comparing the Collins classic with the Racal classic.


When Racal was formed as a company in 1950, Collins was already an established manufacturer. When Racal won a contract to supply the Royal Navy with a variant of the Collins 51-J receiver, Collins refused to supply the licence leaving the fledgling Racal with a contract to supply a receiver that it couldn't provide.  I read somewhere that firstly Collins had stipulated that components used in the 51-J variant had to be sourced in the United States; something which Racal objected to since that would increase the cost. And secondly, Collins allegedly objected to their receiver being manufactured in what was clearly a bomb-damaged building with holes in the roof. I can see their concern! So without the Collins licence, Racal set about designing their own receiver. Enter the enigmatic genius Trevor Lloyd Wadley, a South African of British descent. In his biography (written by his sister, Mary Wadley von Hirschberg) the RA17 is described as being Wadley's receiver. However I had a chance encounter with a Racal engineer several years ago who confirmed that the design was very definitely Racal's, but it would never have come about had it not been for Wadley's ingenious drift-cancelling Local-Oscillator arrangement.


In fact, what is termed 'The Wadley Loop', actually dates back to the early 1940s when the young Wadley was an officer in the South African Signals Service (SSS) and stationed in Egypt.  Dr. Brian Austin writes in Radio Bygones that during this time Wadley converted a conventional Hallicrafters receiver into a panoramic display with selectable 1MHz-wide segments without the need for mechanical band switching. This technique was ultimately referred to as the Wadley Triple Loop System. It was this system that Racal employed under licence from CSIR (Council for Scientific and Industrial Research) with Wadley's close guidance. As far as I can ascertain, at no point was Wadley actually employed by Racal. The RA17 would go down in history as the product which would launch Racal into the defence Electronics business and at its peak see it become the third largest Electronics Company in the UK. Who knows how different things would have turned out had Collins granted Racal a licence to produce their 51-J variant?