Another attempt to make a superren from 1966 work

[DrStrangelove]

Probably futile but hey! let's look on the bright side.

Practical Electronics October/November 1966: radio remote control by D. Bollen: 

a kalitron transmitter (which I built another example of about 6 years ago & it works).

And a superregen receiver which I built and still couldn't get it to work, instead I built a superhet which did work.

No reason for any of this other than I built "something" back in the late 60s using available bits of scrap & the like & that didn't work either.

So I thought I'd revisit it, being rather better equipped these days than a Hartley 13A scope & an AVO 8.

[Mike Watterson]

I found an old transistor regen FM radio yesterday that I made out of scrap maybe in 1990. It was tuned by a straw in the coil that had a cut off piece of brass screw at one end and a piece of ferrite at the other end to give super wide band. The BBC stations marked on straw. Used 1x AAA cell and 32 Ohm headphones. More audio stages than usual so as to use very low current on all but o/p, which reduces gain. For example 2 x 100uA = 200 uA might be 1/2 gain of one stage at 1 or 2 mA. I forget the details. Probably the parts came from a pocket MW only radio. The RFC in the super-regen RF transistor's emitter looks like the "cup" type ferrite taken from a Japan/Chinese 455 kHz IFT. That point feeds the audio amp. Made on stripboard. I had maybe only an Antex soldering iron and a cheap meter then. Was job hunting and it passed the time. It wasn't built from a design.

[DrStrangelove]

An Antex?

I had a 25W Solon. 

It's in a box upstairs "somewhere" along with a lot of other junk.

I wish I could find the original versions of this stuff from back then.

I'd enjoy being appalled at the quality of the workmanship, not that it's a lot better now of course.

I built the transmitter in a stripped out Cyldon VHF tuner, goodness knows why.

I think I still have some of the reclaimed transistors I used.

They came off some sort of computery pcb I bought in Swansea market from the electronics stall of yore.

I'll have to test them to see how bad they are.

[Mike Watterson]

I remember buying boxes of small PCBs with TO18 transistors and diodes for the parts in the 1960s, I supposed at the time that each plug-in board (metal prongs) was 1 to 4 simple Nor or Nand gates. Down in the market in a run down shop also full of cloth. I think I bought one of those dreadful small Russian radios there that used Ge transistors and button cells. Sort of square front aspect.

I think I had a solon in mid to late 1960s.

[DrStrangelove]

Turns out the PNP transistors are Ge, whilst the NPN transistors are Si.

All TO5.

I must have been keen to desolder all those back in the day.

Dunno what the ft is likely to be though.

I remember a pack from BiPak that had an ft not far off a GHz.

Which explained some of the funnies when connected to my transistor tester which had remarkably long leads.

I wonder where that went.

[Mike Watterson]

See data for ET13X300A, Etoms UHF ASK/OOK superhet.

I bought a bunch of these maybe nearly 15 years ago. SMD, so I used cheap ready made PCBs to Adapt to DIL for stripboard.

RX is set by a 4.3 MHz to 7 MHz crystal. For USA 315 MHz "licence free" it's 4.754695 MHz and for Europe 433.92 MHz "licence free" it's 6.6181 MHz, assuming a cheap 10.7 MHz ceramic filter. Can be used for AM and to measure signal level.

I found a drawer with them and one IC soldered to adaptor PCB tonight while looking for a TTL to serial over USB IC. Which I didn't find. It's not as simple as the Philips designed 70 kHz IF VHF-FM Superhet that uses a PLL so that 250 kHz deviation can be received (RDS and stereo decoders work). That IC now made by Chinese makers too and runs off a couple of AAA for weeks or months. Rotary tuner or up/down buttons. It's easy to make up. Edit TD7088 and compatibles. No crystal, IFTs or ceramic filters. Just one critical 78 nH coil (wind 6t on 3mm drill bit and adjust spacing).

[Murphyv310]

Hi.
I still have my Solon Chassis "bolt" soldering Iron I bought with my 4th wage when I was an apprentice in 1970 still works and still occasionally used. Sorry for being OT.