2 valve transmitter

Hi Harry and Ivan,

Appreciate the help! I'll let you know how it performs; then the next addition to the shack will be https://www.frostburg.edu/personal/latta/ee/6x2rcvr/6x2rcvr.html. It does make me wish I paid more attention during my apprenticeship when the 'old boys' wanted me to work on valve gear, o'well I'm the old boy now so I guess it's came full circle... 

Thanks,

Ed - ZL1TET

Hi Ivan and kiwi_ed,
That project has been on the homepages for well over a decade and you are probably the first to notice it.
The capacitor across the emitter resistor is also a 2.3uf capacitor, but anything from 10nf upwards will work.
The screen resistor is 47K.

I added the choke across the antenna for preventing static electricity, exactly as Ivan stated. I also thought that I would use a choke, instead of a high value resistor, in case the 1nf from the anode of the tube develops a leak - otherwise there cold be 250V DC at the ANT socket (or the antenna/washing line outside in the garden). Another reason is that I was given a big bag of 2.2mH chokes and I used them everywhere 

Very best regards from Harry - SM0VPO


PS - I am thinking about assembling your Drill Press Depth Guide Holder. I need something like that when I do partial drilling of my 3D objects.

Cheers Ivan, makes sense! I've been out of the scene for 20+ years so a nice lock-down/winter project fits nicely. I could probably work out some rough values for those two parts but designer knows best!

Thanks,
Ed - ZL1TET

Hi,
a choke across the TX output is a good practice to bleed out static electricity collected on the antenna. I will better let Harry to specify the resistor and capacitor.

BR from Ivan OK1SIP

Hi,

I'm just about to build the 2 valve transmitter and noticed there are two values left of the circuit. The values of the cathode capacitor on the 6AK5 and it's screen grid resistor.

BTW, what's the purpose of the 2.2mh choke on the antenna output?

Many thanks,

Ed.