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Old 29th Nov 2017, 9:41 am   #1
Argus25's Avatar
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Location: Maroochydore, Queensland, Australia.
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Default Fetron Radio.

The third radio in the trilogy of radios I made.

Again a MW & SW radio, images attached. This radio is the most unusual one of the three. I posted a link to it in the past. It uses the same steel grey painted chassis system as the EF98/OC16 radio and again the engine turning thick stainless panel.

This one uses a modified Eddystone dial, the cutouts for the meters were not there originally but made to resemble some Eddystone radio dials. The dial also had a string of miniature incandescent lamps added.

The thing that makes this radio unusual is that it contains no transistors and no valves either.

The active devices are Fetrons, which are a three terminal device constructed from two high voltage Jfets in a modified cascode configuration.

These were once predicted to "take over the world" as plug in valve substitute, but they came and went in the 1970's quicker than an LED digital watch. They have the higher gain and lower noise than the 6AK5 pentode, but ho heater, little noise and zero microphony. They are called "TS6AK5"

To get reasonable audio output I paralleled 4 of them in Class A.

This radio has a very high gain and low noise and good selectivity, it also utilizes an extra IF stage.

The wiring is again teflon, ceramic "valve" sockets and stainless steel hardware to conform to my construction practices.

The radio runs from a 90V battery (or power supply) the power light on this radio is a 70V striking voltage neon lamp. Again it uses an industrial power switch for MW/SW band change, in this case pulsing latching Teledyne RF relays. The S meter (and volt meter) added to the dial are high quality ex avionics helicopter parts, I repainted/labelled the faces and added internal incandescent lighting.

The Fetron story is quite something, the formal article on this radio is here that also contains the original historical documents on Fetrons:

The S meter circuit uses two high voltage Teledyne Jfets.

I made the radio really as a tribute to the Teledyne company, Their products over a lifetime have always impressed and inspired me with the magic combination of innovation & quality.
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Last edited by Argus25; 29th Nov 2017 at 10:00 am. Reason: typo
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Old 29th Nov 2017, 11:52 am   #2
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Location: Huddersfield, West Yorkshire, UK.
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Default Re: Fetron Radio.

Very well done...... I wont use the adjective "nice" its not appropriate...its BRILLIANT !!!
I guess Fetrons are more plentiful in Aus...
Should get out more.

Wendy G8BZY
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Old 29th Nov 2017, 11:52 am   #3
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Join Date: Dec 2014
Location: Lincoln, Lincolnshire, UK.
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Default Re: Fetron Radio.

Lovely looking radio.

At a quick look I see it is possible to get Fetrons, at a price, from USA (usual sales site).
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Old 29th Nov 2017, 1:27 pm   #4
Radio Wrangler
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Location: Fife, Scotland, UK.
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Default Re: Fetron Radio.

Now that qualifies as jewellery!

Gorgeous construction and it must have been enjoyable doing it.

I'm not sure I'd have used something as off-the-beaten-track as fetrons in something I was planning spending so much effort into. I suppose that if I wanted to do a tour-de-force job of a classic receiver, I'd go for the G3PDM or maybe the G2DAF ones.

I can still remember what teledyne TO-5 relays cost back in the day. Then one Teledyne plant got flattened by a hurricane and the West coast one had a big fire.. The US military sequestered all stocks and HP had to find alternatives pronto

Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done
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Old 29th Nov 2017, 4:12 pm   #5
astral highway
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Default Re: Fetron Radio.

Another beautiful piece of electronic architecture!

I love the use of the Fetronsm, too. The name is very sci-fi!

Thanks for sharing, Hugo.
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Old 29th Nov 2017, 4:29 pm   #6
Join Date: Mar 2010
Location: Dukinfield, Cheshire, UK.
Posts: 1,414
Default Re: Fetron Radio.

Oh will you look at that? I'm full of admiration for your clean and fastidious construction, Argus. I can be very neat when I put my mind to it, but not anything like that!
Andy G1HBE.
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Old 29th Nov 2017, 4:35 pm   #7
Join Date: Apr 2016
Location: Cheltenham, Gloucestershire, UK.
Posts: 519
Default Re: Fetron Radio.

Bonzer..... as they say in Oz !!!
Red to red, black to black. Throw the switch and stand well back!
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Old 29th Nov 2017, 6:32 pm   #8
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Location: Oxfordshire, UK.
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Default Re: Fetron Radio.

I think that pretty much anyone looking a those pictures would say that must be commercial equipment made by a company with high standards.

I recall some of the British-made commercial equipment made in the 1960's for ham radio; much of it was built to rather low standards .

We know there are known unknowns. But there are unknown unknowns ones we don't know we don't know.
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Old 29th Nov 2017, 8:07 pm   #9
Join Date: Apr 2015
Location: Manchester, UK.
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Default Re: Fetron Radio.

That's fantastic !
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Old 30th Nov 2017, 12:13 am   #10
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Location: Maroochydore, Queensland, Australia.
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Default Re: Fetron Radio.

Originally Posted by astral highway View Post
I love the use of the Fetronsm, too. The name is very sci-fi!

They had a real knack of great sounding names for companies and components in the electronic industry in the 1970's. Fetron, Teledyne, Signetics etc and a lot of other companies had a great ring to their names and components.

I think this was also the era when the term "Fembot" was coined and ended up on TV shows like "The Six Million Dollar Man" the idea later to be borrowed by Mike Myers for an Austin Powers movie where the love of his life turned out to be a Fembot all along.

Also the naming concept borrowed again for Sci Fi, for example in the Terminator movie, the Terminator was built by "Cyberdyne Systems".
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