Further to my tests ages ago with PTO... http://m1kta-qrp.blogspot.com/2010/01/pto-vfo.html
Here I am again with the same test rig but with a different construction technique. Again I post the information here incase others are interested in trying out a PTO.
I have fused a number of M5 nylon nuts together, super glued them and wound red electrical tape about them. Into this I can turn a M5 brass bolt. It is much more stable than the previous constructions. Anyway onto this I close wound about 45 turns (I didn't count them at this stage) of 28SWG enamelled wire.
Final construction of the coil and screw will involve moving this to the PCB and not being panel mounted. A second nylon bolt will hold the far end of the assembly 'true' with the brass bolt.
Then using the same setup as before I retested.
I can now get the PTO to operate between 4.673MHz and 4.3MHz which is perfect for an 8MHZ IF and 80m rig.
Anyway as this is a buffered PTO, needed a little lift in LO signal for the DBM but it added a couple more components to the count so will see how my rig turns out.
I'm not going to use any component that is not generally available and every one must be possible to obtain from the 'usual' suppliers.
Hope mine is going over to Dayton with a UK attendee.
My TX uses just 13 components, crystal controlled and there is about 4-5khz ability to shift frequency using two extra components. That was the easy bit.
My RX... I am still tweaking it a bit so the count is not up to date but overall I am inside 72.
The rig should have a keyer (so an AVR or PIC is my one IC!) but if I don't get the code finished, it won't.
Some images of various bits follow, it is my intention to build this manhatten/ugly style so no fancy PCB required.
In this image the transmission appears to be down 20db (it isn't!)