How can I make a good, cheap LW radio?

[minidanas]

I posted this in an another section:

I have a question, or more precisely, a problem that needs a solution:

There are places where vast land is inhabited by sparse population. Nomads are on constantly the move, and the nearest radio station is sometimes hundreds of miles away. So the frequency that reliably works is LW - 100-300 KHz (up to 2000 meter waves). By now practically all the good, cheap radios that received LW have been discontinued, and people are struggling to find one. There is no hope that someone will start making them again, because the market is too small for mass production, and the demand is too weak.

I hear that durable radios with good antenna like GE Superadio don't receive LW, while modern, mostly pocketable LW radios by SONY, Kaito/Degen are too flimsy, and have poor reception. Is there an easy, cheap way for a DIYer to combine the two? May be convert Superadios so they can receive LW (preferable). Or maybe, use the Superadio's antenna to improve pocketables' reception. Or better yet, does Radioshack or Parts Express sell some part that could do the trick?

 

[Tom Wells]

You are looking for an outboard converter.
In the simplest explanation it would be a tuned loop antenna, much as a Superadio has inside, but tuned to LW.
It would also contain a mixing oscillator that "tracks" along with your tuning, and is offset in frequency by a certain amount that stays the same no matter where you're tuned. Then, you "receive" that mixed result on a regular AM radio tuned to the difference frequency.
It's an outboard superhet. You tune some unused frequency like 520 AM on your radio.
Now you tune the LW tuner to ..let's say 320 khz. If you then make your osc frequency 800 khz, presto!
You hear your 320 signal on 520.


If you can UNCOUPLE the existing antenna from the AM, and replace it with the signal from your outboard mixer,
you can then tune up and down the LW band on your AM band radio, as the "whole" band will mix, but
you'd lose the advantage of the tuned RF amplifier at the LW frequency. Unless you left the osc fixed and tuned the RF section
manually. But that's exactly how many people got their first shortwave reception when they had a radio but couldn't
afford a "new" shortwave in the middle of the depression.

People used to roll such devices at home, not sure where you buy one. I'm sure they are out there.

 

[minidanas]

Thank you for your response.

Pardon my ignorance: so this sounds like a setup consisting of several elements and not a portable single unit, am I right? I am looking for something that you could carry around, just like Superadios.

 

[kilokat7]

There are places where vast land is inhabited by sparse population. Nomads are on constantly the move, and the nearest radio station is sometimes hundreds of miles away. So the frequency that reliably works is LW - 100-300 KHz (up to 2000 meter waves).

If I may ask, what kind of signals are these "Nomads" trying to hear in this band - what part of the world are the transmitters located? Transmitter power? Are you referring to the European/Asian LW broadcast band? Knowing more details about the desired signals might prove helpful.

 

[kenglish]

You might want to look for radios that are marketed in the UK, Germany, etc.

 

[minidanas]

If I may ask, what kind of signals are these "Nomads" trying to hear in this band - what part of the world are the transmitters located? Transmitter power? Are you referring to the European/Asian LW broadcast band? Knowing more details about the desired signals might prove helpful.

I shouldve provided more information.

I'm referring to sparsely populated Central Asia: Mongolia, former soviet republics such as Kazakhstan, Xinjiang (in northwestern China) etc. I imagine the transmitters are not very powerful. This link http://www.mediumwaveradio.com/longwave.php shows that many stations that are hard to hear are 50-75 KW. Some 200-500 KW stations aren’t received well, either.

Now, I forgot to mention that if money were no object, there would be no problem. There’s plenty of good LW radios, costing $300 and up. What’s desired is to make it affordable, perhaps under $100.