DENCO (CLACTON) LIMITED Leaflet.

[Anthony Thomas]

I have just ONE Denco coil amongst my treasures and it is a Green coil (range 5 possibly from memory), I gave up on trying to find Denco coils at a decent price and purchased some formers made by Isoplethics and still have them somewhere together with some octal formers from the same source Isoplethics. I purchased some chokes at the same time but do not think that this company exists any longer.

I have a lot of backnumbers of PW and nearly all construction projects by FG Rayer rely heavily on Denco products, I am fortunate in having inductors from scrapped Tandberg radios that one day might be used to build some of these PW projects. (either that or a silent key type sale or skip one fine day )

The data on Denco is out there, I admire David (Radio Wrangler) for his inventivness on reverse engineering but I was never that smart to work things out

[Aub]

I am lucky to have 3 IFT11, 455 Khz, IF transformers, from when they started making them again, briefly, in 1998. I've been saving them for a receiver project when I eventually get chance!

I also have an old SMA baby milk tin, in which there is an assortment of Denco coils which I don't need/want any more. I've been meaning to offer them to other enthusiasts for some time now. Perhaps I'll take some pictures and post on here soon.

All the best.

Aub

['LIVEWIRE?']

I still have a Multiband Receiver which I built to a PW Design many years ago. This uses Denco coils in the Red, Blue, & Yellow B9A based series, and Denco double and single tuned 1.6Mhz IFTs. Somewhere in my 'archives' I have a Denco data book with suggested circuits and other data

[Jon_G4MDC]

I bought some Denco Coils from Watford Electronics in the 1970s.

Quite an experience. I expected a shop but the address was an ordinary 1930s house in a
residential road. I knocked on the door and it was answered - yes this is the right place.

It seemed the stock was all in the loft which was accessed by a pull down ladder.
Coils appeared , money changed hands, and another F.G Rayer design from PW was built with them. It worked but wasn't much good - that was my fault since I was guessing at layout and just moving up from crystal sets!

[yesnaby]

Yes! Been to Watford Electronics Cardiff Road 'shop' in the late 1970s.

[dave walsh]

Comments on here shows the breadth of different experiences I think.
Nuvistor [p9] thought Denco was getting a bad press but he seemed to be in a minority. I didn't ever use their coils and I suppose that might have been finance based [not sure] but my PW reading impression was that they did seem to be very popular and sell a lot of items. Whether that was the influence of PW or not I can't say though and I'd never even considered that really.

It did appear that a lot of people appreciated having ready made [and conveniently small] plug in coils to build projects or experiment with at the time. Certainly, a few years ago, there was a lot of nostalgia being expressed about Denco as a firm. it's history owners and s products on this Forum. It then extended to links with sites showing how to make up your own versions of the Denco "plug ins". One or two people wanted to build early designs but couldn't find enough coils.

I happened to look at a Denco based design yesterday from PW Feb 1966 [with Blueprint] A Progressive SW Receiver 5 valve Superhet by R F Graham [very nice]. I thought it might be the one that Live Wire mentions [p23] but it's a 465k IF not 1.6k .

Dave W

['LIVEWIRE?']

The radio I built is from a design published in PW in the early 1970s, possibly by David Gibson or F.G. Rayer. I still have the issues concerned in a box with a lot of other PWs & RCs, etc., but not easy to get at. It used 4 x OC170 (AF117) or 5 with the optional Crystal Filter extra I.F. stage, with a BFO/Product Detector built around 3 x OC44/45. This ran from a 5.6v stabilised supply, using a 'top hat' zener diode. The whole receiver was powered from a 9v Battery, although I fitted a DIN socket wired to the Philips convention in order to power it from a PSU designed to power one of the EL series of Cassette recorders. (This was before the days of cheap 'wall warts'!). The original design used a Transformer coupled Audio amp., but I built a transformerless one based on a Mullard Circuit using AC127, 128, etc., and fitted DIN sockets for speaker, PSU, and Tape recorder. Maybe I'll take some pictures of my RX and post it on here. Someone may recognise it!

[dave walsh]

Thanks for that LW. I'll have a look for the issues later. Apart from the different IF it's transistor construction rules it out as well. It would be good to see photos though. Perhaps a "Gallery" of sets that did actually get built from published designs would be an interesting feature on the Forum? PW didn't really do that at any point. It's always impressive to see what people have produced at Rallies and Open Days etc but these achievements don't really get much exposure. I've seen brilliant work that was hardly ever really shown to anyone.

Dave W

[G8HQP Dave]

I have a set of Denco coils which I bought many years ago - B9A valve versions for 1.6MHz IF. The receiver I was going to build with them will now have an Electroniques front end instead. At some point they will emerge from one of the boxes in the back bedroom and then I will make them available either on here or ebay.

[KeithsTV]

I built a converter from the August 64 PW which used the plug in Denco coils. I only had the range 3 coils and used to listen to the local amateurs on Top Band. Later I bought the range 4 & 5 coils and suitable IF transformers to build a short wave receiver. It never quite worked as expected so I stored it away in a box. I recently found it and have got the IF strip working so only the front end to sort out now.

Keith

[Nuvistor]

Originally Posted by dave walsh

Comments on here shows the breadth of different experiences I think.
Nuvistor [p9] thought Denco was getting a bad press but he seemed to be in a minority.

Nothing new, I can accept that.

Frank

[Radio Wrangler]

F G Rayer probably only had one set of Denco coils and they moved from set to set as he made and published them. PW would have paid a page rate that made it quite worthwhile. But just think of the numbers his designs sold.

David

['LIVEWIRE?']

I've found my Receiver,minus it's I.F. strip, Crystal Filter board and Filter in/out switch. Those items are in a cupboard or box somewhere, although I used the switch and spindle coupler for another item ages ago. Before taking any photos, I'll find the missing items.

[Cobaltblue]

I don't think its fair to describe Denco as the bad boys here

Although in a way I suppose that's just what my earlier post suggested.

I think I carry the frustration of being unable to build the the things I wanted to build in the late 60's.

After a while I took the approach of my best friend who never worried about such things and just used what he had to hand. (parts from old valve sets mostly)

As he says the worst that can happen is it wouldn't work!.

How right he was.

The coils of course in many domestic receivers were of decent quality and usually easily adapted.

That said the Denco coils with their colourful plug in formers still appeal to me and I have a pretty decent collection of them.

Cheers

Mike T

[Nuvistor]

Originally Posted by Cobaltblue

After a while I took the approach of my best friend who never worried about such things and just used what he had to hand. (parts from old valve sets mostly)

Probably learned a lot more doing it that way rather than following a script.

Like I said in a previous post, everything was expensive or in short supply, made a generation of make do and mend. Isn't that in a way what we are doing keeping old items working.

Frank

[KeithsTV]

You can also learn a lot by working out why it doesn't work, investigating any faults, putting them right and getting it working.

I very rarely built anything from a magazine exactly how the author had intended. I used to try to adapt the design to suit my requirements. You can learn a lot more that way than just following the published design to the letter.

At a previous company one of the production engineers was always trying to build something from one of the magazines and would often come up to me and say will this transistor do instead of, say, a BC108. 99% of the time it wouldn't matter. Part of the learning process is to be able to assess how critical the use of a particular part is and be able to make a substitution if the specified part isn't available.

Keith

[jim_jobe]

I built some really good stuff in the old days using bags of untested transistors and diodes from both Bi-pak and Bi-Pre-Pak (there was definitely no connection between them). The secret was to test them first. Quite a few of these devices were as good as, and more than a few better than, so called branded jobs. I still have them and occasionally still use them.
As for Denco - their coils were expensive it's true but they were high-spec and worked. I still use F.G Rayer's Double Conversion Amateur Bands radio from PW 1975 and it works as well today as it did then using Denco Coils and some Bi-Pak trannies. When I lived in New Guinea for a few years in the late 70s I converted it to general Coverage and used to listen to Dad's Army regularly on BBC World Service coming from the Singapore Trensmitter.
Jim

[Radio Wrangler]

No, Denco weren't evil.... far from it in my opinion.

It's just that seen from a schoolboy's pocket money perspective ALL new components were expensive. Ditto compared to all the war surplus stuff. AND coils were one of the easiest components to make for yourself.

David

['LIVEWIRE?']

Maybe this is a subject for another thread, but back in 1971, I also built the PW 'Carlton' MW Receiver which used Weyrad coils and a Motorola Audio amp IC. That one used BC108 or similar in the RF/IF stages. Weyrad (Weymouth Radio) products were often advertised in PW and other magazines, and used in not a few construction projects, IIRC.

[G0HZU_JMR]

Up in the loft somewhere, I've got a set of the green Denco coils and a few in other colours.

Back in my youth I built several of the receivers in the "Solid State Short Wave Receivers for Beginners" book by R A Penfold. All of the receivers in that book use Denco coils and I spent a fair bit of dosh on the coils required to cover the SW bands. In the back of the book it listed Electrovalue and G&P Powles (Clacton) as suppliers for Denco coils back in those days.

I also remember visiting the Repanco coil company in Coventry back in the early 1980s. That was a strange experience... I asked the old guy who answered the door if I could have a look around the factory after they sold me the coils I wanted. He seemed very paranoid once I asked this and he said no. I was hastily escorted to the sales desk and once I'd bought my coils he escorted me out. I made the mistake of looking across the building and asking a question about how many coils they make a year and he basically accused me of 'casing the joint' for a future break in. He told me to only look forwards and not to look at the rest of the building. I was just a skinny/spotty student...? Very strange chap... I never went back there again and never bought any of their products again after that experience.