12 volt valve regen receiver.

[ms660]

Anyone built a 12 volt valve regen? If so what was the performance like?
Did it use 12 volt car radio valves or the usual types?

I'd be interested to know.

I'm aware of the ECH81/ECH83 etc similarities.

Lawrence.

[Skywave]

My copy of the Practical Wireless Encyclopaedia (12th. ed., 1951; pages 70 to 72), gives circuits and assembly instructions for a one-valve set using a 6J7 and a 9v. battery for 'H.T.' and a two-valve set (detector & A.F.), using a pair of 1C5GT/G and a 13½ → 15 v. battery, again for 'H.T.'

I have never built these two ccts., so cannot comment on performance, but they are quite rudimentary, so building either for an assessment of performance should be a relatively quick & simple job.

Al.

[ms660]

Thanks Al.

I've seen a few videos/articles on the subject, it all seems feasible, I would, when I get together, like to build one to operate at a remote location off a 12 volt battery...For SWL of course, mainly for SSB, the usual refinements will have to be part of the build for that.

Hope all's well in Somerset.

Lawrence.

[Skywave]

Hi Lawrence,

If it's of any help, I can scan the ccts. that I referred to and either post them here or send them to you as an attachment to an e-mail.

As for living in Somerset, most things are just fine: south Somerset really is a nice part of England in which to live. We moved here almost one year ago to the day. There are still changes that need to be made to this house: waiting for warmer weather!

Al.

[ms660]

Al, apologies for the delay, bad day down at the woods

Just the schematics would be good, post them here on the forum if that's ok, accessing my email is a PITA at the moment.

Cheers.

Lawrence.

[Skywave]

O.K. Lawrence: two ccts. The 2-valve cct. has a very obvious error.: the grid-leak resistors should obviously be 1 MΩ and 0.5 MΩ respectively.

Al.

Omega (the ohm symbol) was used for meg ohms in the early 20th century.

[ms660]

Originally Posted by Skywave

O.K. Lawrence: two ccts. The 2-valve cct. has a very obvious error.: the grid-leak resistors should obviously be 1 MΩ and 0.5 MΩ respectively.

Thanks for that Al, I see the first one uses a differential capacitor, this afternoon I've been trawling through various valve regen articles for low voltage jobs, there's quite a few, some are based on "space charge" for normal valves where G1 is made +ve, the detection taking place on G2, goes against my way of thinking but you never know.

The link below is a good read for a 1930's regen, The Autodyne Rationalized by George Grammer (QST):

http://www.rfcafe.com/references/qst...y-1933-qst.htm

Not sure yet as to whether the project (if it happens) will be the normal regen or a regenerodyne, at the moment I'm thinking Top Band, 80, 40 & 20 meters, with maybe a couple of wider coverage ranges for SW broadcast stations, plug in coils would give more flexibility although changing them over might be a pain for me, I'll figure out wot's wot in that department.

First things first though, I need to figure out a suitable circuit/design with nice easy tuning ie: no safe crackers fingers required for the operator.

I will no doubt throw a few ideas into this thread and a rough drawn schematic or two at some point.

Lawrence.

[ms660]

Originally Posted by merlinmaxwell

Omega (the ohm symbol) was used for meg ohms in the early 20th century.

I have a Veritable Alter grid leak marked up on it's body like that, it reads 3 (omega)

Lawrence.

[Skywave]

Originally Posted by merlinmaxwell

Omega (the ohm symbol) was used for meg ohms in the early 20th century.

Just for the record . . .
In the aforesaid P.W. book, the cct. which shows two very low grid-leak resistors also gives a parts list. That list states 1 MΩ and 0.5 MΩ. I deliberately did not include that list since Lawrence requested the cct. diags. only.

Al.

[David G4EBT]

In the 1930s there were two sets which used 12 - 18V HT that were very popular in Australia, known as the 'Hiker's One' and the 'Hikers' Two'. They featured in a magazine called 'The Lamphouse'. Interest in these sets continues and many have been built in recent times. They featured on a splendid Oz website which I think may have been called 'oldradios.com', which is sadly now defunct. I think the favoured valve was the '49' but other have successfully used the1Q5GT, which are cheaply available. I got all the bits together to build one, intending to make a mahogany box in which to house it, rather like a crystal set, but it's still on my 'to do' list!

I've attached a couple of circuits - no doubt more could be found on a google search for anyone interested.

Also a pic of an excellent set made by I think an American called John Bauman, along the lines of what I thought I'd have a go at. (He built it in a 're-purposed' test gear box).

(John's set powers a loudspeaker by the way).

Hope that's on interest.

[ms660]

Thanks for the pics David.

Out of interest I've tried to find a schematic for the Hiker's 2 that uses +ve bias on G1 but no luck yet.

The Hiker's 1 used the +ve bias method as per this article:

http://makearadio.com/tube/hikers1.php

Current thinking at the moment for 12 volt operation is EF97 RF Amp. ECH83 (or ECH81) Mixer/Osc. EF97 Regen Det, for a regenorodyne set up or two EF97's for a normal regen assuming there's enough out of the detector to power a set of headphones, the valve line up could change though.

I haven't ruled out a direct conversion receiver either, that would need a bit more audio gain.

Which ever one I'll incorporate a simple note filter for CW, antenna input probably loose coupled, it'll have an RF Amp stage for sure, some folks reckon it's not needed but I prefer to have one, particularly for regens as it can reduce detector overload if it incorporates a gain control, it also helps to reduce interlock/pulling of the detector when tuning the RF circuit. Probably use the low L/C ratio trick, for oscillating circuits and high L/C ratio for the RF tuning, all that to a certain extent will be decided by the frequency coverage needed per range.

As said earlier, it's all at the thinking cap/back of a fag packet stage at the moment.

Lawrence.

[broadgage]

A slightly higher HT voltage would of course give a lot more flexibility and potentially more audio output power.
Have you considered a 12 or 15 volt dry battery in series with the car or similar battery. With 100% of the heater demand coming from a car battery, and about 50% of the HT, then the load on the disposable battery will be minimal and the costs low.
8,9, or10 AA cells would only cost a couple of pounds. For long hour operation D cells cost about twice as much but give about 8 times more service.
In a remote location, another option would be a stack of cheap rechargeable cells and a small PV module.

[ms660]

Yes, two small 12 volt lead acid could be a possibility, I have one already for the water pump down at the cabin, just been looking at the ECH81...83 comparison article on the radiomuseum website, apparently results were obtained with 3 volts "HT"

I recently clear felled a load of trees around the cabin so PV might be a possibility for the batteries, there's also an overflow from the wildlife pond I constructed, the overflow has around 9 to 10 ft drop down to the discharge point so a micro turbine possibly? Pity I couldn't screw a Rutland Windcharger to the top of one of the trees....

There's just enough space down there for a Beverage antenna, Top Band DX maybe? The rest of the trees on the site might affect reception though, There's enough room in the clearing for a decent SWL antenna which will be the main priority antenna wise if I get round to the regen build.

Lawrence.

[G6Tanuki]

There were a number of designs around in the 1920 which boasted of "not needing a B+ battery" - these were usually based around space-charge tetrodes sold under names like "Nutron" and "Solodyne".

See http://www.americanradiohistory.com/...-1924-08-R.pdf

and wander down to page 154 for explanation/associated circuitry including an article by John Scott-Taggart no less!

[ms660]

I had a read of the article, interesting.

I think I will have to experiment with some metal valves, the last time I recall was with a 6K7 as a regen det. I got down to around 25 volts I think it was on the anode and around 18 volts on the screen.

In all this regarding the design I end up doing the main thing will be stability as SSB/CW will be the main use of the receiver, the regenerodyne I prototyped a couple or so years ago was spot on in that respect and I would like to achieve the same for 12 volt operation or maybe 24 volt for two LA batteries in series.

Lawrence.

[ms660]

I've found a supplier for a DDS VFO for reasonable money, board plus display plus out board shaft encoder, basically connect and go...Ideal.

So to keep things simple I'm now veering towards a Direct Conversion receiver, the stability of a DDS VFO should allow AM broadcast reception as well as SSB/CW, I still want to go the low voltage valve route for the rest of the receiver, current contenders are EF97 RF amp, EB91 balanced mixer plus another EF97 or EF98 or two for the audio for 'phones, probably have a fiddle around with a double balanced mixer (SBL1 etc) while I'm at it.

I heard from a chap other side of the pond today, he reckons that metal IO valves can be run at 12 volts HT with careful design, got to admit I do like those valves, might be able to do 1.6 to 30 mhz with just four sets of RF range coils.

Lawrence.

[Colinaps]

Radio Constructor, Feb '64 - the Six-Point-Three. Only a one-lung set, mind. It's not on the AmericanRadioHistory site yet but I can scan it if you like. Uses el91, 6v6 etc.

Cheers,

Colin.

[ms660]

Yes, that would be good, anything that runs off 12 volts I'm interested in for ideas etc.

Lawrence.

I've found a supplier for a DDS VFO for reasonable money, board plus display plus out board shaft encoder, basically connect and go...Ideal.

Where? I don't think it out of forum rules to to say where you got it. Maybe useful to other members.