What would this receive in 2020? - UK Vintage Radio Repair and Restoration Discussion Forum

daviddeakin · 14th Jul 2020, 3:30 pm

I mostly build valve audio -I'm ashamed to say I've never done anything with radio. So I'm a total newb when it comes to this, but I'm curious, if I built this in 2020, what would it receive? Local taxi firms or something interesting?
(From practical wireless, July 1965)

paulsherwin · 14th Jul 2020, 3:55 pm

It would depend on which coils are fitted. It could be anything from 19 metre band broadcast shortwave to BBC R4 on 198kHz.

That design isn't particularly simple as a first project. There are plenty of alternative designs here: http://www.vintageradio.me.uk/radconnav/valvetrf/

hannahs radios · 14th Jul 2020, 4:09 pm

Agree with Paul depends what coils are fitted basically you'll hear whatever's on the broadcast bands. Doesn't look like it can do SSB so you wouldn't be able to resolve ham transmissions and no taxis either, they use VHF and usually FM. Outside this set's capabilities

paulsherwin · 14th Jul 2020, 4:32 pm

It's regenerative, so you could listen to SSB after a fashion by letting it oscillate. Not very practical though.

If I were you I'd start off with a relatively simple 2 valve design tuning MW and driving a speaker through an output transformer. Any scrap transformer set should have most of the parts you need. You can then move on to more complex SW designs if you want to. Remember that there's a lot less broadcast stuff on SW than there used to be though.

Something like this: http://www.vintageradio.me.uk/radcon...pw/circuit.jpg

snowman_al · 14th Jul 2020, 4:40 pm

Best place to start a 'project' is to search out the coils first.
Google Denco Green range valve coils. They were specifically designed for TRF regenerative / reaction sets and have 5 different ranges. (3 x SW, 1 x MW and 1 x LW.) They plug into an octal or B9A socket, depending on their vintage. There was a site to reproduce them at one time.

You can receive AM broadcasts and amateur SSB and morse. You have to advance the regeneration / reaction control to near oscillation to resolve SSB, but it is possible once you get the 'knack'. The regeneration control on that diagram is VR1. But no FM or taxis...

paulsherwin · 14th Jul 2020, 4:50 pm

Denco coils are quite pricey now. Most simple projects describe how to wind your own coils, which is very easy for MW.

mickm3for · 14th Jul 2020, 5:06 pm

Hi this is a good website lots of information i built the bbc studio E set finished after many years started in 1957 finished in 2020 ? home made coil . Mick

Radio Wrangler · 14th Jul 2020, 5:27 pm

The disadvantage is that if you let it oscillate, then everyone can receive YOU.

The plain amplifier stage on the front end is most likely there not just to amplify the signals, but also to suppress the oscillation reaching the antenna. Particularly important with a super-regen set.

David

russell_w_b · 14th Jul 2020, 6:07 pm

Quote:

Originally Posted by Radio Wrangler

The disadvantage is that if you let it oscillate, then everyone can receive YOU.

I remember my dad telling me that when he was a kid (1930s) there would be announcements in the local newspaper along the lines of 'Would the people living in the vicinity of 29 Senhouse Street PLEASE stop their wireless oscillating'.

Radio Wrangler · 14th Jul 2020, 8:43 pm

I've just had an optical illusion with Russel's avatar

It flipped into being the face of dark grey greyhound or whippet looking out of the frame
RevMC and the centre ohms adjuster forming the eyes, the right ohms adjuster a black shiny nose and the meter scale a jacket round the dog's body.

I swear I only had one beer!

David

daviddeakin · 14th Jul 2020, 9:20 pm

Quote:

Originally Posted by paulsherwin

It would depend on which coils are fitted. It could be anything from 19 metre band broadcast shortwave to BBC R4 on 198kHz.

That design isn't particularly simple as a first project. There are plenty of alternative designs here: http://www.vintageradio.me.uk/radconnav/valvetrf/

Thanks I'll take a look. Actually I'd be pretty satisfied if I picked up BBC R4. Changing the audio output stage isn't a problem -I can do the audio stuff, it's the detection that's new to me. I do have a Cossor Melody Maker* kicking about that I could cannibalise, but I didn't really fancy tackling a superhet for my first radio project.

Before someone suggests it, I don't particularly want to restore that set. It's kinda big and ugly, and I get more satisfaction out of building up circuits from scratch.

EDIT: Dumb question, but is the circuit I posted is an AM or FM receiver?

russell_w_b · 14th Jul 2020, 9:34 pm

Quote:

Originally Posted by Radio Wrangler

RevMC and the centre ohms adjuster forming the eyes, the right ohms adjuster a black shiny nose and the meter scale a jacket round the dog's body.

I swear I only had one beer!

Haaaaaaaaaaaaahahaha!

Once you see it, you can't un-see it!

Jon_G4MDC · 14th Jul 2020, 10:23 pm

Too much grog?
I think it would be a pity to cannibalise a working set for bits to make homebrew, but if it doesn't work...?

That said, it's yours so you can do with it what you please.

I built my first top-band TX from some Cossor radio-gram. Looking back from here I wish I had preserved the VHF tuner or even just kept the valves.
In the end it was only the PSU parts which were used.

Ho-hum.

paulsherwin · 14th Jul 2020, 11:06 pm

Quote:

Originally Posted by daviddeakin

Dumb question, but is the circuit I posted is an AM or FM receiver?

It's an AM receiver. The simplest way to think of it is that AM transmission makes the signal go up and down, while FM makes it go from one side to another.

lesmw0sec · 15th Jul 2020, 9:43 am

In my very first job (Sparkes data sheets), one kit we supplied had an EF89 in a similar arrangement to that shown and an EL84 output stage driving a speaker. No RF stage, but the performance was very good. With around ten feet of aerial wire, you could certainly receive any of the broadcast stations and a good deal of SW stuff too. Amazing what a bit of positive feedback can achieve!

14th Jul 2020, 3:30 pm	#1
daviddeakin Hexode Join Date: Apr 2007 Location: W Yorks, UK. Posts: 407	What would this receive in 2020? I mostly build valve audio -I'm ashamed to say I've never done anything with radio. So I'm a total newb when it comes to this, but I'm curious, if I built this in 2020, what would it receive? Local taxi firms or something interesting? (From practical wireless, July 1965) Attached Thumbnails

14th Jul 2020, 3:55 pm	#2
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,947	Re: What would this receive in 2020? It would depend on which coils are fitted. It could be anything from 19 metre band broadcast shortwave to BBC R4 on 198kHz. That design isn't particularly simple as a first project. There are plenty of alternative designs here: http://www.vintageradio.me.uk/radconnav/valvetrf/

14th Jul 2020, 4:09 pm	#3
hannahs radios Hexode Join Date: Jan 2012 Location: Weymouth, Dorset, UK. Posts: 422	Re: What would this receive in 2020? Agree with Paul depends what coils are fitted basically you'll hear whatever's on the broadcast bands. Doesn't look like it can do SSB so you wouldn't be able to resolve ham transmissions and no taxis either, they use VHF and usually FM. Outside this set's capabilities

14th Jul 2020, 4:32 pm	#4
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,947	Re: What would this receive in 2020? It's regenerative, so you could listen to SSB after a fashion by letting it oscillate. Not very practical though. If I were you I'd start off with a relatively simple 2 valve design tuning MW and driving a speaker through an output transformer. Any scrap transformer set should have most of the parts you need. You can then move on to more complex SW designs if you want to. Remember that there's a lot less broadcast stuff on SW than there used to be though. Something like this: http://www.vintageradio.me.uk/radcon...pw/circuit.jpg

14th Jul 2020, 4:40 pm	#5
snowman_al Octode Join Date: Dec 2018 Location: Llandeilo, West Wales, UK. Posts: 1,092	Re: What would this receive in 2020? Best place to start a 'project' is to search out the coils first. Google Denco Green range valve coils. They were specifically designed for TRF regenerative / reaction sets and have 5 different ranges. (3 x SW, 1 x MW and 1 x LW.) They plug into an octal or B9A socket, depending on their vintage. There was a site to reproduce them at one time. You can receive AM broadcasts and amateur SSB and morse. You have to advance the regeneration / reaction control to near oscillation to resolve SSB, but it is possible once you get the 'knack'. The regeneration control on that diagram is VR1. But no FM or taxis... __________________ Never Leave Well Enough Alone...

14th Jul 2020, 4:50 pm	#6
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,947	Re: What would this receive in 2020? Denco coils are quite pricey now. Most simple projects describe how to wind your own coils, which is very easy for MW.

14th Jul 2020, 5:06 pm	#7
mickm3for Heptode Join Date: May 2015 Location: Chatham, Kent, UK. Posts: 964	Re: What would this receive in 2020? Hi this is a good website lots of information i built the bbc studio E set finished after many years started in 1957 finished in 2020 ? home made coil . Mick

14th Jul 2020, 5:27 pm	#8
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,876	Re: What would this receive in 2020? The disadvantage is that if you let it oscillate, then everyone can receive YOU. The plain amplifier stage on the front end is most likely there not just to amplify the signals, but also to suppress the oscillation reaching the antenna. Particularly important with a super-regen set. David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

14th Jul 2020, 8:43 pm	#10
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,876	Re: What would this receive in 2020? I've just had an optical illusion with Russel's avatar It flipped into being the face of dark grey greyhound or whippet looking out of the frame RevMC and the centre ohms adjuster forming the eyes, the right ohms adjuster a black shiny nose and the meter scale a jacket round the dog's body. I swear I only had one beer! David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

14th Jul 2020, 10:23 pm	#13
Jon_G4MDC Nonode Join Date: Nov 2015 Location: Welwyn Garden City, Hertfordshire, UK. Posts: 2,015	Re: What would this receive in 2020? Too much grog? I think it would be a pity to cannibalise a working set for bits to make homebrew, but if it doesn't work...? That said, it's yours so you can do with it what you please. I built my first top-band TX from some Cossor radio-gram. Looking back from here I wish I had preserved the VHF tuner or even just kept the valves. In the end it was only the PSU parts which were used. Ho-hum.

15th Jul 2020, 9:43 am	#15
lesmw0sec Octode Join Date: Jul 2009 Location: Carmel, Llannerchymedd, Anglesey, UK. Posts: 1,507	Re: What would this receive in 2020? In my very first job (Sparkes data sheets), one kit we supplied had an EF89 in a similar arrangement to that shown and an EL84 output stage driving a speaker. No RF stage, but the performance was very good. With around ten feet of aerial wire, you could certainly receive any of the broadcast stations and a good deal of SW stuff too. Amazing what a bit of positive feedback can achieve!