Radio hobbyist Jon the Grimm built this beautiful “homebrew” AM transmitter using tube technology, in the style of an original 1930s radio transmitter. Operating under Part 15 regulations, his transmitter has achieved a short range – perfect for feeding modern music to antique radios that might not otherwise have a way to receive programming without interfering with your neighbors reception.
Built using period-correct enclosures and wiring techniques, this 5-tube transmitter uses the aesthetically pleasing “globe” style of vacuum tubes: #36, 37, 38, 38, 80 according to this schematic:
His inspiration came from this photo of an original 1930s-era miniature AM transmitter:
Jon posted some design photos in the thread at the Antique Radio Forums, which I’m sharing here. You can see the design take shape, from the initial circuit prototyping, to the full breadboard, to the final product. I especially like paper towel/toilet paper tubes being used as coil forms.
It’s a functional work of art. If I didn’t see the construction photos, I’d swear it was actually from the 1930s. Some more views, note the attention to detail with the wire lacing.
And with the last touch, correct power and switch knobs:
Jon doesn’t have a web site, but I thought his work deserved some recognition. This is a stunning piece of engineering, using period-correct pieces combined with a modern eye for engineering and circuit design. Not to mention it’s just beautiful. You can contact him via the Antique Radio Forums if you have any questions for him about the build process.
How about a parts list and supplier list along with tube types and resistor, capacitor ect, ID numbers so the rest of us can acquire parts to build this type radio transmitter ?
You should be able to get most of that info from the schematic. The tube numbers (36 37 37 38 80), R and C values, transformer voltages, and inductances in H of the chokes and coils is given.
You’d be on your own for winding the coils and picking out an okay modulation transformer (to the right of the lower ’38 tube) though.
You should be able to get most resistors from Mouser or Digikey; Angela Electronics will sell you sockets, and you’d probably want to check eBay for variable capacitors and panel meters like that.
Hi, great info! I’ve updated my QRP website, I’m sure it’s of interest to fellow shortwave radio enthusiasts.
Here’s the link: http://www.stationqrp.com
You have to give a tube radio at least 20 to 30 minutes just to warm up and then you decide
what frequency you want to be on and load the
plate and tune them up. It was an entertaining radio program that played the music people
wanted to hear combined with his groovy upbeat personality.
Super neat radio, I’ve never seen such AM transmitter replica before. A lot of compliments.