[R-390] IF Deck Problems Revisited

[Flowertime01 at wmconnect.com]

Barry,

So I am like reading in my 1977 ARRL handbook in the VHF section.
And I come across this subject of lead length and caps forming resonant 
circuits.
The book subject was how much cap and how much lead makes a resonant circuit 
at like 144 MHZ.

The point that comes to mine is that an inch of wire and a by pass cap gets 
resonant at 455 (OK so 410 in your deck). 

Where do we get a wire and cap to resonate in an R390 or its new replacement?

One each bad solder joint or 50 year old poor mechanical connection on a 
ground point.

So a poor connection on a ground point leaves a cap and its wire hanging like 
an antenna to some point. Then to really mess with us it behaves like a 
resonant circuit and injects the most unwanted signal back into the Deck some where.

I think you are on it with getting the IF can covers back on. If you do not 
have holes
in the can tops, drill only one can and move it around as needed. Keep the 
other ones covered. The nuts do not need to be installed but drop the covers on.

When you are done leave the can with hole on the AGC transformer.

Running with the covers off may be a self inflicted curse.

Roger AI4NI