Dave's Homemade Single Tube Breadboard Radio
I haven't built any tube sets since last year. This one has been planned for several months. I build crystal sets during the winter and tube sets in the summer. The band conditions aren't so good in the summer so that is the time to build radios with amplification.
As you know, a true breadboard radio that is original can cost thousands of dollars. I don't have that kind of money to spend on old radios. I would rather build radios than collect them. This radio came about because of some lucky bidding on eBay. Lucky for the seller anyway. I really like those old dual rotor Remler variable capacitors. I use them when I can. The variometer is an old time radio receiving tuner.
The tube socket is one my dad had when he was a kid and now it has been passed on to me. I used it when I was a teenager in the mid sixties to make a little code practice oscillator. Even then, I wasn't the first one to solder to it. The tube in the picture above is just for display as I intended on using a #30 tube in this project.
The circuit is the same as an old homemade radio I restored nearly two years ago. This radio isn't my best performing radio that uses a #30 tube. My first tube set works better. I built this circuit due to how this variometer was built. The other radio has a variocoupler.
This radio could use an rf choke in the line to the headphones A bypass capacitor across the headphones wouldn't hurt either. This set does oscillate to beat the band. I lowered the filament voltage battery to 1.5 volts and the filament rheostat is turned nearly off. This radio seems to receive the lower frequencies rather than the higher. The tuning is highly dependant on the antenna system.
I built this radio because I knew right off that it would look nice! This set will proudly sit on my living room shelf or perhaps I will show it off where I work.
73, Dave - N2DS