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Minimalist radio construction project...Ideas?

 
sideband
(@sideband)
Famed V-Ratter Moderator
Posts: 3971

The newer members that have joined in the last 12 - 18 months will probably not be aware of a project that we ran called the 'Minimalist Superhet'. This was developed to try and encourage less experienced members who had never had the pleasure of being able to build their own radio. Back in 'the day' it was very easy to obtain parts from numerous high street suppliers and there were many magazines available for the budding hobbyist. When I first started getting interested in radio (1964) I had a choice of several radio magazines (in my case either Practical Wireless or Radio Constructor) and a plethora of component suppliers within relatively short bus-rides away. There were also the huge suppliers in London although my pocket money at the time didn't cover the fairs into London. However there were also plenty of old radios available at Jumble Sales so spare parts were never really a problem. This meant that for the budding enthusiast, something could be built for little or no outlay even if it meant 'digressing' from the original design slightly! In the early days, I never bought a shortwave radio for listening to the 'hams' on 80, 40 or 20 metres, they were all home-built from published circuits....and very successful they were as well.

The original Minimalist design some two years used valves in an effort to keep all things vintage. This might have put a lot of people off since (a), valves (generally) need high voltages and (b) it was a superhet (admittedly stripped to the bare bones). Despite this I know of several that were built successfully using variations of the final design.

This time around I thought perhaps we should consider a simpler transistor circuit. The advantage of this being low voltage (6-9 volts) and very low cost. Rather than use a superhet (remembering that components like IF transformers are much harder to buy these days) we could consider a TRF radio that needs virtually no alignment and could even use a home-made aerial coil. A two transistor reflex radio can give very reasonable results and with a third transistor could drive a small loudspeaker. We are talking of medium wave only at this stage. FM regenerative sets are also possible but are somewhat more tricky to set up properly

With this in mind, who would be interested in building a small MW radio? We'd need to know abilities (have you tackled home build before)?  Obviously you would need to be prepared to buy or use parts salvaged from other sets. If we can get an idea of beginners abilities, we will know what level to aim for. 

Incidentally, winding an aerial coil is not difficult....I was doing it at 12 years old when I built my first crystal set.

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Topic starter Posted : 23/04/2018 10:41 pm
crustytv
(@crustytv)
Vrat Founder Admin
Posts: 10844

This is a great idea Rich  ? 

I've posted a news item on the blog here

As mentioned above, we've run these projects before and if you're interested, they can be found here :-

 

The all valve minimalist project was a huge success over on our old Vrat 1 forum, from a viewer point of view but only about three or four actually went on to build something. It also produced some very interesting discussions on design and choice of valves, those examples that made it to fruition worked well very well if I recall correctly. 

Bob's TRF was/is a delight to behold, sadly nobody was inspired enough to have a go.

The idea to now start a Vrat 2 "Simple Transistor" project is a logical progression and will I hope, encourage members to have a go.

Anyone who's looking in as a guest and a bit unsure about joining the forum, you can still post as a guest so nothing to stop you all playing along. Rich as project mentor means you're all in very capable hands and its an opportunity to learn loads.

I look forward to following as you all scope out what type of circuit you will decide upon and the list of components. 

 

 

 

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Posted : 24/04/2018 8:33 am
crustytv
(@crustytv)
Vrat Founder Admin
Posts: 10844

Great site for you to consider, many simple TRF transistor circuits and descriptions.

http://www.vintageradio.me.uk/radconnav/transtrf/

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Posted : 27/04/2018 4:19 pm