Love your videos. You've inspired me a lot and personally I've found out that I could build a simple common base coplitts oscillator with a BC549, give it just enough current to oscillate and connect it directly to my computer running an SDR software. I've had a lot of fun with it. And with a lot of trial and error I've been able to make it stable enough to decode RTTY, WEFAX and lots of other stuff on the 40m band.
I would love to see more of these older rig kits become available. Seems that there is a prevailing attitude that it's a sin to build your own rig. Tubes/Transistors etc it doesn't matter. If it works as its designed and put together correctly more power to us.
Thanks Peter! Yes but playing radio in my shack in high school at the cost of proper work, like pumping gas at the Chevron in town one summer, caused me to become unrealistically bent that someone would pay me for my passion for radio. Lucky it worked out!
First off, I would like to say that I really enjoyed your video. I too, am a real fan of the "solid-state design for the amateur radio" book written DeMaw and Hayward. Also, I was very surprised and impressed to see that you actually built a transceiver from that book. And, that is what I was wondering, is if you could make a video whereby you go through your transceiver and it's various stages along with some good close-ups and maybe even some operational signal tracing with an oscilloscope? Finally, maybe an on-air demonstration? Thanks again and 73...
Hi Mike. I think I will make this my next project. Can you explain how to tune this transmitter? Do the variable caps act like a plate and load control found on other tube transmitters? Can you give more detail on the coil? Thanks for taking the time to make this great video. -Joe KB3KJS
Joe, yes exactly; the tune and loading controls essentially work like the tune and loading controls on a PI network, that is, you dip the plate and can gradually bring up the loading. The output link of 4 turns is placed towards the cold side of the tank, and is moved up for "a bit too much" loading, then you back off on the loading cap. But between you and me, at these low powers, you simply tune for maximum output.
Nothing to be embarrased of, Michael (about you building that QRP in the 80's). Well done video sir. Congratulations! I am working on building a couple of one tube QRP transmitters. One with 6AG7 and the other will be either 6V6, 6L6 or even a 6F6 but now I'm in doubt if this one tube rigs will be good to crystals like yours is. I guess yours uses less current on the crystals thank this bigger tubes ones. I have a couple of FT-243 but no more choices. 73 de Rob YS1RS
@tovarisci - There is no reason why the circuit that you describe would not work. In fact you could likely do it with one tube like a 6BE6 and a carbon microphone. This type of electron coupled oscillator works very well as a multiplier but the power would go down some. I suspect that if you get 2 Watts out on the fundamental frequency, you would lose 1/3 power tripling and more than half x5. But with a tube like a 5763, I suspect you could still muster 2 Watts at 28 MHz with higher voltage.
Hello. Nice project :) It is first time when i work with vacum tube. Please tell me, what is the voltage for capacitor: 220, 39? The secont question, for example the capacitors 0.01; 0.05 is a ceramic capacitors? Because i didnt see electrolitic capacitors with that value (in the schemes you use the electrolitic sign). Next question, the variable capacitors is just for tuning the anntena? If i whant to tune the frequency i have to put in series a variable capacitor with the xtal, you are agree with me? Thanks a lot, 73 from Yo3IQK
if you want a QRO unit then what about a Line Output vacuum tube, what about a KORG NU-TUBE 6P9 should work also but it is a bit micro-phonic but the heaters use 1.5-3V at 0.5ma and a plate voltage of between 9-36V.
hello. can you please suggest or upload videos/links/info/diagrams etc for the beginners? absolute beginners who do not have any knowledge on electronics.. thx.
Gary J Allied Electronics has tube transformers, the 6K49VG will produce about 270VDC. Hammond and Elcor also sell power transformers. I like to use the Triad N-68X isolation transformer myself. If you connect it "backwards" and connect the two "primary" windings in series, you'll get about 260VDC with a FW Bridge. For heater power on small projects I use 6V or 12V regulated wall warts, but you can also find 6.3V and 12.6V transformers just about everywhere (the Allied and other purpose-built tube transformers have heater windings, but isolation transformers don't).
