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Old 25th Nov 2021, 12:26 am   #1
jagnut66
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Default Medium wave transmitter builders

Hi,
Is there anyone on here who builds medium wave transmitters?
My radio dates to 1939, so I'd like a transmitter (that I could tune the radio to) with a USB port and a CD player intergrated into it.
I would then be able to play things like Neville Chaimberlains declaration of war (in full) and other wartime broadcasts through a set and speaker that they would have been heard on the first time around.
Plus of course I would be able to play music of the era through it as well.
Many thanks in advance in advance for any help with this.
Best wishes,
Mike.
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Old 25th Nov 2021, 12:52 am   #2
Radio Wrangler
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Default Re: Medium wave transmitter builders

Medium wave transmitters as such, no.

Usually 'Transmitter' is used to describe something which covers some degree of range, either for communicating point to point or for broadcasting. Doing so intentionally puts it squarely under the wireless telegraphy act, and it needs a licence from Ofcom. Without this you would be treated as a pirate broadcaster, and the penalties are scaled to be hard-hitting for commercial operations.

At the other end of the scale, it is quite usual for people to have signal generators to test and evaluate radios with. These can be modulated with whatever audio you want. Normally they are connected to the external aerial socket of a radio, but not all radios have these. Plenty of sets have internal aerials, either as a frame wound with wire, or the common ferrite rod type. To test these radios, it is necessary to feed your signal generator into a coupling coil, or antenna wire fairly close to the set.

Some people do this more to listen to the set than to do formal tests. Rather than tie up an expensive bench instrument, they build small single-purpose units. The aim is to not have any detectable amount of signal beyond their own property. The name they go by is odd, and I've never come across the reason. Search for "pantry transmitter" and you'll find them. It might have been better if they'd been called test sources, or something like that, without invoking the T-word.

David
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Old 25th Nov 2021, 2:32 am   #3
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Default Re: Medium wave transmitter builders

Many members of the forum have built a very simple pantry transmitter called the Minimod, and one member went as far as supplying a ready made printed circuit board for the project; https://www.vintage-radio.net/forum/...hlight=minimod. I think there's another DIY Pantry job called Spitfire.

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Old 25th Nov 2021, 6:10 am   #4
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Default Re: Medium wave transmitter builders

This is what the minimod looks and sound like (you will need to build a case). It's powered by a 9v battery and connected to my phone. There is no direct connection between the minimod and the radio

https://youtube.com/shorts/6by5oGwOFxk?feature=share
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Old 25th Nov 2021, 10:01 am   #5
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Default Re: Medium wave transmitter builders

To clarify, we allow the discussion of so-called 'pantry transmitters' here, which aren't powerful enough to be heard significantly outside your property, though they are a legal grey area. We don't allow discussion of actual illegal broadcast transmitters or pirate broadcasting, no matter what the range.

There are many designs of pantry transmitter here and on the wider internet if you search. They have varying levels of complexity and can use valve, transistor and IC technology. Terms to use are 'pantry transmitter', 'microtransmitter' and the American 'phono oscillator'.
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Old 25th Nov 2021, 11:56 am   #6
Ian - G4JQT
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Default Re: Medium wave transmitter builders

Quote:
Originally Posted by Gabe001 View Post
This is what the minimod looks and sound like (you will need to build a case). It's powered by a 9v battery and connected to my phone. There is no direct connection between the minimod and the radio

https://youtube.com/shorts/6by5oGwOFxk?feature=share
Useful video but it sounds like you've got a bit too much audio going into that MiniMod.
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Old 26th Nov 2021, 10:18 am   #7
jagnut66
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Default Re: Medium wave transmitter builders

Quote:
Originally Posted by paulsherwin View Post
To clarify, we allow the discussion of so-called 'pantry transmitters' here, which aren't powerful enough to be heard significantly outside your property, though they are a legal grey area. We don't allow discussion of actual illegal broadcast transmitters or pirate broadcasting, no matter what the range.

There are many designs of pantry transmitter here and on the wider internet if you search. They have varying levels of complexity and can use valve, transistor and IC technology. Terms to use are 'pantry transmitter', 'microtransmitter' and the American 'phono oscillator'.
It sounds like a 'pantry transmitter' is what I'm after then. But one with the added USB / CD facilities that I mentioned in my original post.
Does anyone know of someone who could build this?
Many thanks,
Mike.
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Old 28th Nov 2021, 9:43 am   #8
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Default Re: Medium wave transmitter builders

I think you will be unlucky trying to find someone to build an intergrated unit.
Probably the easiest way to go is to have separate CD player and a pantry tranmitter connected to each other by audio cable.

Peter
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Old 28th Nov 2021, 11:29 am   #9
Chrispy57
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Default Re: Medium wave transmitter builders

Hi Mike,
perhaps you could clarify why you require a USB port - is it just for the ability to provide the DC power for your CD player?

Cheers
Chris
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Old 29th Nov 2021, 6:57 am   #10
Gabe001
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Default Re: Medium wave transmitter builders

For a fancy one with Bluetooth streaming and a smartphone app, have a look at this
https://www.6v6.co.uk/vcomp/pages/hurricane.htm

No affiliation and I don't have experience of one.

Gabriel
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Old 29th Nov 2021, 9:19 am   #11
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Default Re: Medium wave transmitter builders

Plenty of CD/USB players out there, either 19" rack sized ones or smaller units generally designed to be mounted in a PA amplifier or speaker, or a car radio with RCA outputs could also work, combine that with a pantry transmitter and you could have a nice compact setup.
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Old 2nd Dec 2021, 12:01 am   #12
jagnut66
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Default Re: Medium wave transmitter builders

Quote:
Originally Posted by Chrispy57 View Post
Hi Mike,
perhaps you could clarify why you require a USB port - is it just for the ability to provide the DC power for your CD player?

Cheers
Chris
Hi Chris,
So I can play WW2 broadcasts etc. that I have downloaded onto a memory stick.
Best wishes,
Mike.

Quote:
Originally Posted by dglcomp View Post
Plenty of CD/USB players out there, either 19" rack sized ones or smaller units generally designed to be mounted in a PA amplifier or speaker, or a car radio with RCA outputs could also work, combine that with a pantry transmitter and you could have a nice compact setup.
Struggling to find something suitable at present.......
Best wishes,
Mike.
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Old 2nd Dec 2021, 11:16 am   #13
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Default Re: Medium wave transmitter builders

Quote:
Originally Posted by jagnut66 View Post

Hi Chris,
So I can play WW2 broadcasts etc. that I have downloaded onto a memory stick.
Best wishes,
Mike.
One possibility is a car radio / CD unit as these often have a USB port that you can plug a memory stick into and play mp3 files stored on it.
These often also have audio out connections as well as the speaker ones.
You would of course have to use a separate 12V supply but this could also power the Pantry transmitter.

Peter
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Old Yesterday, 12:45 pm   #14
wireman
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Default Re: Medium wave transmitter builders

Perhaps it is my imagination but I seem to recall that when CD players were introduced you could get a player that would transmit to a car radio. They still seem to exist, this was one of the hits I got from a google search...

https://www.amazon.co.uk/Transmitter.../dp/B08G86JNBH
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