Making A Radio? - UK Vintage Radio Repair and Restoration Discussion Forum

MajorWest · 27th Oct 2014, 6:08 pm

I had a brainwave today. Stored on my boat I have an action man walkie-talkie toy. It transmits and receives at short distances. In a fairly impulsive frame of mind, I removed one entire PCB from the case plus the speaker. With a battery wired in, it crackles quite happily. So, I'm thinking of changing the circuit a wee bit to make it into a radio. For that, I'll need a variable condenser and a better ferrite aerial. Then it would be interesting to see with some meddling if I can get it to pick up stations.
Just a thought for a rainy day.

27th Oct 2014, 6:44 pm

A quick google leads me to think these are 49MHz items, a) not quite proper to use here in the UK and b) bloomin' hard to modify into a 'radio'. You might (a big might) get it to work a bit on VHF/FM. I may be wrong.

Restoration73 · 27th Oct 2014, 7:07 pm

The receiver may be a super-regen type for 49MHz AM reception. The only thing worth
saving is the speaker.
You may be able to build this which stands a chance of working :
http://www.rapidonline.com/design-te...-mk194-70-4037

Herald1360 · 27th Oct 2014, 11:28 pm

If it's got two transistors, I'd suggest simply using those plus a few other bits to make a reflex regen MW receiver. On strong signals you should get enough output to drive a small speaker.

Maybe something like this?

http://www.electroschematics.com/601...adio-receiver/

G8HQP Dave · 28th Oct 2014, 12:20 pm

Starting from scratch with the right components may be less frustrating than pressing into service the wrong components.

MajorWest · 28th Oct 2014, 5:09 pm

Quote:

Originally Posted by Herald1360

Maybe something like this?
http://www.electroschematics.com/601...adio-receiver/

Looks a bit like some of my vintage TRF schematics. Of course, there are radio kits as well. I remember a very good one was done by Science Fair. I built that one as a kid and it was fine although it did need a couple of new transistors as I overheated them. At that time there was a shop called Tandy and they fixed the radio in the shop with a couple of transistors. That was very good of them as there was no charge but it also sort of took the fun out of it that I'd not quite done it myself. That set even had a small waveband button to get longwave.

27th Oct 2014, 6:08 pm	#1
MajorWest Retired Dormant Member Join Date: Jul 2014 Location: Stoke On Trent, Staffordshire, UK. Posts: 247	Making A Radio? I had a brainwave today. Stored on my boat I have an action man walkie-talkie toy. It transmits and receives at short distances. In a fairly impulsive frame of mind, I removed one entire PCB from the case plus the speaker. With a battery wired in, it crackles quite happily. So, I'm thinking of changing the circuit a wee bit to make it into a radio. For that, I'll need a variable condenser and a better ferrite aerial. Then it would be interesting to see with some meddling if I can get it to pick up stations. Just a thought for a rainy day.

27th Oct 2014, 6:44 pm	#2
Guest Guest Posts: n/a	Re: Making A Radio? A quick google leads me to think these are 49MHz items, a) not quite proper to use here in the UK and b) bloomin' hard to modify into a 'radio'. You might (a big might) get it to work a bit on VHF/FM. I may be wrong.

27th Oct 2014, 7:07 pm	#3
Restoration73 Nonode Join Date: Jun 2013 Location: Surbiton, SW London, UK. Posts: 2,801	Re: Making A Radio? The receiver may be a super-regen type for 49MHz AM reception. The only thing worth saving is the speaker. You may be able to build this which stands a chance of working : http://www.rapidonline.com/design-te...-mk194-70-4037

27th Oct 2014, 11:28 pm	#4
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,535	Re: Making A Radio? If it's got two transistors, I'd suggest simply using those plus a few other bits to make a reflex regen MW receiver. On strong signals you should get enough output to drive a small speaker. Maybe something like this? http://www.electroschematics.com/601...adio-receiver/ __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

28th Oct 2014, 12:20 pm	#5
G8HQP Dave Rest in Peace Join Date: Sep 2008 Location: Solihull, West Midlands, UK. Posts: 4,872	Re: Making A Radio? Starting from scratch with the right components may be less frustrating than pressing into service the wrong components.