Re: day light again `inquiry
|
A couple additional comments on the PTO. The brass tubing is 1/4 inch OD. I cut the slit by doubling up a Dremel cut off wheel. My Shakey hand is evident with the cut. The head of the 10-32 screw was cut down to fit inside the brass tubing. I soldered a brad in the screw head slot for the pin. The end of the tubing where the knob is attached, is filled with JB Weld, kwick cure epoxy. This keeps the knob screws from crushing the tubing. A 1/4 inch collar keeps the tube from coming out. A dab of red grease lubes the screw and sleeve. The 10-32 nut was heated with my soldering iron and pushed into the end of the printed coil form.
On Fri, Sep 23, 2022, 4:10 PM barry halterman via <kthreebo= [email protected]> wrote: Allison, here is a pix of my PTO. The limited coverage is FB for my needs. This is going to be a CW rig and not SSB. Stability of this PTO from a cold start is about 60hz. I used a combination of polystyrene, NP0 and N750 caps. Tuning range covers close to 160khz with the 10-32 screw and the amount of L end C I am using. I will look at my filter and spectrum of the PTO when I get some time this weekend. Thank you for your suggestions! 73 Barry
On Fri, Sep 23, 2022, 2:13 PM ajparent1/kb1gmx < kb1gmx@...> wrote: Since it tunes in parallel, my SWAG is VFO (has spurious oscilation) or
Crystal filter (has secondary peak).? Least those would be the first places.
To get wider band coverage more L (inductor) less C (capacitance).
I didn't invent that trick but it was pretty click and easy to make without
a machine shop.
A photo of your work (board and the mechanism) is aluways a good thing
while its still open.
Allison
------------------
Please use the forum, offline and private will go to bit bucket.
|
