[R-390] VFO End points

[Drew P.]

Roger wrote:

"Nitrogen being most of the air we breath is no problem.
You may want to bleed the 15 PSI off slowly."

I haven't yet found one with any pressure remaining. But to be sure, depress the Schrader valve core, just like deflating a tire.

Wrote: "I have never done a cosmos VFO myself so I do not
know if you really have to open the sealed chamber
to get to the trim coil."

To access the endpoint adjustment, remove a threaded cap as with non-Cosmos PTO's. 

Wrote: "How do they keep a seal on the VFO shaft into the
pressure chamber?"

A simple O-ring in a groove rides on the shaft.

Wrote: "Ok Fellows, how best to trim up a Cosmos VFO?"

Endpoint is set in the same way as with non-Cosmos PTO's, complete with removing one turn from the endpoint adjustment coil if necessary. Do not confuse the linearity compensation coil with the endpoint adjustment coil which has a threaded stud for adjustment.  There is good information in the "Pearls of Wisdom" on adjusting for linearity of the Cosmos PTO.

Drew



Roger AI4NI