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 Seeking Three Transistor Regenerative Radio Info
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 Return to top of page · Post #: 1 · Written at 2:13:48 PM on 22 May 2018.
Vandos's Gravatar
 Location: Brisbane, QLD
 Member since 7 May 2018
 Member #: 2245
 Postcount: 5

New member Mike here, from Brisbane. In my youth, I built several projects. For most of these, I have photos and more to remember them by. But one project in particular I have no photos of, and it has defied my best efforts so far to locate the original plans for it. It was a three transistor all-wave regenerative receiver, with 276P battery, plug-in coils to change bands, and a 3" speaker. It was built on an aluminium chassis. I'm pretty sure I used a rectangular vernier dial, but I might be thinking of the next radio project, the EA-160. It looked something like Sue's All Wave 2:

https://vintage-radio.com.au/photos/eaawic2-1-160716.jpg

It used three germanium transistors, I think OC44/45, OC70, and OC72/74. I may have substituted what I had available, which likely came from my Uncle who worked with hearing aids at the time. I think it used a centre-tapped audio transformer, of some 300-400Ω primary impedance, possibly sourced from Kitsets Australia. The plug-in coil formers I used were green, likely sourced from Trackson's Radio division in Elizabeth street, Brisbane. The coils were one my my main blunders; I didn't realise that it was important to keep the RF wiring short, so I used long wires from the coil pins that ran over the rim of the coil formers and down to the windings.

For a long while, I assumed that it must have been an Electronics Australia project, or more likely Radio, Television and Hobbies, given the age of the transistors. I had back issues of RTV&H from the same uncle. But I've recently downloaded the Silicon Chip DVD of RTV&H, and I can't find it. I've also spent some time at the State Library of Queensland, where they have all issues of Electronics Australia. I looked through many of these.

It could have been another magazine, such as Wireless World.

But now I'm thinking that it might have been from some sort of Boys Book of Radio or the like. I've had a quick look through what I can find of those on-line, but none of the covers seem to provoke a memory.

So here is my question: can anyone suggest where I would have found the plans for this, be it magazine or book? I would have built it when I was 8-10 (wild guess), so that's around 1966-1968.

I remember in school, I despised tradition and nostalgia. Now I'm somewhat consumed by nostalgia, at least for things technical.

Thanks in advance for any clues. I'll feel better when I can put this one to rest.

Edit: added "Info" to title.


 
 Return to top of page · Post #: 2 · Written at 11:13:24 PM on 22 May 2018.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 5262

I remember in school, I despised tradition and nostalgia. Now I'm somewhat consumed by nostalgia, at least for things technical.

I hated the subject of history at school -- mostly because the teacher was like death warmed up -- but my ears would prick up if anything technical was raised. Loved science, especially lab work.

I cringe to think of the number of radios and the like that I destroyed as a kid by pulling them apart on a one-way trip to the junk box.

My own restored valve radio collection comprises only instances of those radio models that my immediate and extended family owned back in the day, with two exceptions: a 1930s era console radiogram that my grandparents owned as I have never been able to identify it (plus it would be too big to keep in the house), and a portable stereogram that my mother owned.


 
 Return to top of page · Post #: 3 · Written at 1:38:21 PM on 25 August 2018.
Sue's avatar
 Sue
 Location: Daylesford, VIC
 Member since 13 January 2011
 Member #: 809
 Postcount: 311

Hi Mike. There was the E.A. "FET-3" three transistor set, March 1968, which looked exactly the same as the ""All-Wave Two" from the front, and there may have been a similar set before this using three bipolar transistors. I'll keep an eye out for it.

Did you try building the EA 160? Any success with it? I've got one in the works.

Sue.


 
 Return to top of page · Post #: 4 · Written at 11:57:29 AM on 26 August 2018.
Sue's avatar
 Sue
 Location: Daylesford, VIC
 Member since 13 January 2011
 Member #: 809
 Postcount: 311

OK, I've found a possibility. ED&E Sales P/L used to advertise a large range of kits based on RTV&H/EA projects; your mystery set may be the "All-Wave Transistor 3". This isn't listed in the HRSA index to RTV&H/EA, but I can see from my collection of the magazines that that this index isn't complete. I don't think the radio could have been in Wireless World if it used a plug-in 276P battery, the Brits had the PP9 instead.


 
 Return to top of page · Post #: 5 · Written at 5:41:30 PM on 26 August 2018.
Johnny's avatar
 Location: Hobart, TAS
 Member since 31 July 2016
 Member #: 1959
 Postcount: 319

I remember building a similar regen driving a speaker, in the early 60's.
Three transistors oc44,oc71 and oc72.
However there were no plug in coils, only broadcast band.
And from memory you could use a ferrite toroid, loopstick or air toilet roll.
I built many of these types of receivers and have to admit, built one recently, One transistor regen and driving a speaker.
Very impressive.
JJ


 
 Return to top of page · Post #: 6 · Written at 8:47:01 PM on 26 August 2018.
Sue's avatar
 Sue
 Location: Daylesford, VIC
 Member since 13 January 2011
 Member #: 809
 Postcount: 311

JJ, that could have been the regenerative TRF "Three Transistor Mantel Set", RTV&H March 1959, broadcast band only, using the OC44, OC71, and OC72.

The other set that comes close to Mike's description is the "Simple All-Wave Transistor Set"
of June 1960; this has plug-in coils, is a regenerative TRF, but is two transistor for headphone operation only. However, the article mentions that it may be extended to a three transistor set using the output stage of the March 1959 design. But I don't know if RTV&H or EA actually published this three transistor version as a project.


 
 Return to top of page · Post #: 7 · Written at 8:24:52 PM on 20 October 2018.
Vandos's Gravatar
 Location: Brisbane, QLD
 Member since 7 May 2018
 Member #: 2245
 Postcount: 5

Sorry I've been away from this forum for some time; life does that sometimes.

> Did you try building the EA 160? Any success with it?
Yes, it worked to a point, but its selectivity wasn't great. I was terrible at trouble shooting in my youth.

> I've got one in the works.
I'm envious! I occasionally dream about building another one, but I can't justify the time or the space. Perhaps I can enjoy some vicarious construction if you post lots of photos Smile

> The other set that comes close to Mike's description is the "Simple All-Wave Transistor Set"
of June 1960; this has plug-in coils, is a regenerative TRF, but is two transistor for headphone operation only. However, the article mentions that it may be extended to a three transistor set using the output stage of the March 1959 design.

I've looked at that one before, and somehow it didn't resonate as "the one", mainly because I have a moderately clear picture of the speaker featuring in the construction photos. I have to admit I've been looking at later articles, which would have come out at about the time I was constructing. But I guess there's no reason why it can't have been say an 8 year old article.

Looking at the values in the June 1960 set, a lot of the values do look familiar. It's possible that the circuit I worked from was from two separate articles, and transistor substitution was quite likely. I do recall that I had a problem with "motor boating", and it took a suggestion from my tech savvy uncle (add a 1000 μF bypass capacitor across the battery) to fix it. It strikes me that such a problem is unlikely if I'd copied the prototype of a complete magazine project, and indicates that perhaps it is the result of merging two projects.

So thanks a lot, Sue, for the pointer. I'll scour my CD of the RTVH archive now that I know where to start. I was frustrated that I seemed to be needing the years where there is a break in available scans; the RTVH archive is complete to about 1965 from memory, and other archives start about a decade later. But now it looks like it will be in the RTVH archive after all, if it exists as a complete project.


 
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