One Tube 10 Meter AM Transmitter

Have you noticed the rise in 10 Meter Activity? Here is an old time Ham Radio Project that will get you thinking about taking advantage of an old mode that never died, on a band where it really works well for DX.

[MirlitronOne]

As a cash-strapped kid in the 1970s UK, I remember those Brown & Kneitel books occasionally appearing in our local public library and I would swoop on them whenever they appeared. For many circuits, the authors would say "...can be readily constructed using items from your junk box..." and I would think "I've GOT to get one of those junk boxes!" After 50 years of intense effort I now have such a junk box (I call it "home") and may even be able to tackle this project! 😂

[radioguy]

Back when these books came out, it was expected that the builder had an awareness of high voltage circuits after all we got our parts from old TV sets and tube type radios and the term "easy" was relative to that time. Many builders had a radio and TV shop in town where we could buy parts and beg for to look through their trash and sometimes get advice from the owner of those shops. I like that you give warnings about high voltages and that you come up with these projects. Thanks for the great video!

[jdschauss]

I always love your project videos, Mike. Thanks so much for the inspiration and good advice. I don't know if I'll try this one or not, but it sure looks interesting and fun. Great video, as always!
-K5SFC

[videolabguy]

16:09 - Stancor PS-8416. I looked over and I have one sitting on my desk! I use that and the Hammond 261C6 for many of my projects.


I see you covered the Hammond as well. :)

[SpinStar]

We demand white-hot glowing plates and sagging glass-envelopes! 🤣😂🤣

[Pixelwaster]

A NEW HIGH VOLTAGE TRANSFORMER??!??! Who knew. Well there goes my retirement stash. At least I will be able to use my Heathkit GDO to set the tanks. You have a 10/6 regen video??

Fun side note, I built a 6 meter filter 30 years ago with that gdo and was unable to use it because I moved house. "Found" it last year and stuck it on my VNA and it was almost spot on for all of six. The last TOKO transformer was't quite right. Knew at the time but it resonated like the rest.

[glasslinger]

Not one word about a spectrum analyzer. Harmonic regulations are much stricter now days than they were back in the 1970's. That "transmitter" is going to be far from meeting FCC requirements on harmonic output. I guess the most common attitude is, "who gives a shit!"

[stephenwilliams]

Great companion for my 50c5 xmitter TKS ok De kv4li

[Steve-GMHUU]

As always, Mike very interesting and much appreciated. 10m DX Machine 😂.

[acestudioscouk-Ace-GACE]

Really interesting and I shall follow the series but am not brave or experienced enough to try this one.

[Capecodham]

Suppressor grids were outlawed in 1978 violating the rights of electrons to be free.

[WanderingNC]

You lost me at "I'm not going to judge".

[JuhaK]

Thanks a lot for a interesting channel!

A lot of useful information and ideas for a homebrewer!

73 de OH8UBJ/Juha

[Isochest]

I remember an American book in the library with articles such as "A one tube novice transmitter for 40 and 80 meters". This rig was my first. Later I built a two valve multiplier and 807 PA rig I used on 10 15 20metres as well as freebanding on 27MHz

[vincei]

Regarding the voltage doubler circuit: If you assume first that the 700V transformer doubler output is floating with respect to ground and the 42K resistor followed by the 4.7K resistor are a voltage divider - of sorts. so ... tying one end (0) of the floating transformer output to the 4.7K resistor and knowing that the current flowing into and leaving that node tied to ground is zero then "poof" magically you get a negative voltage across the 4.7K resistor. I often find that the way things are drawn can make it harder to understand what's going on.

[pharanchemie]

Hello Microwave1. Always happy to see you and your friendly and very interesting videos. Thank you .

[SilntObsvr]

I'd like to suggest a challenge. I've been looking for a while for a single-tube *transceiver* -- just *one* pentode (tetrode, even triode, but I doubt I'll find that) that switches back and forth between receiving (as a regen, I expect) and transmitting (either CW or suppressor modulation AM like this transmitter). I've got some miniature pentodes around, but I've also got spare 6146 tubes I bought for my (still not fixed) Heathkit SB-102 -- one of those, running around 300 V on the plate, might get me close to 10W output (though power supply transformers I can find/afford might limit that). I'd like to avoid being rock-bound, but I'll use a crystal if that's what it takes to tame chirp and drift.

Seen anything like that?

[zachreyhelmberger]

What fun!! 😁 Thank you for the heads up on this circuit! I wish I could clone myself and build one up right now to try it out.

[jimgiordano]

Max plate voltage on the 6BH6 plate is 300, not 700. You could cook steaks on it.

[uwepolifka]

The GU50 is a pentode wich can handle up to 1 kV. Could it work in this case?