Years ago I read somewhere that the tempco of polystyrene caps was well matched to pot core tuned circuits.

Yes, indeed! -- IIRC they 'complement' (Siemens) N28(?) cores quite nicely...

There are certain types of ceramic capacitor specifically for RF tuning circuits - NPO is probably one of them.

Correct! NPO (i.e. EIA COG) ceramic Caps exhibit the lowest dissipation factor (of said dielectric type) -- hence their applicability to RF applications to > 300 MHz

Best regards
HP

 

Wow!! A new word for my condition! My wife and kids call me a "hoarder", I call myself a "packrat", now I can be known as a "syllogomaniac". Makes it sound important.

I was told I had "Disposophobia" because I keep about 1 ton of old components in a shed, from old record player valve amps, old ww11 equipment, stripped pcb's from Plasma and lcd tv's etc and a very large collection of n.o.s transistors, Ic's capacitors, resistors, ( Who remembers Panclimatic resistors?)
Added to that are several Yaesu FT101 h.f trancievers, atu's etc etc. This does not include my little home lab with all my current equipment.

My excuse, (not that I really need one) is this :-
About 45 years ago, I bought from a deceased amateur radio hams family, a very large box of new and boxed very early valves dating back to the early part of the 20th century. Some were incredibly rare, looking more like a bulb but with the vacuum pinch off on the top. I think HL4's were the newest!!!
Anyway, I left them in a friends shed for "safe keeping" but his horrid little brother found them and shot them all with an air rifle. So now they were gone forever and to me it was like burning the Mona Lisa!
Since then, I hate seeing things destroyed just because they are not used anymore, someday, someone will really need one of those "obsolete" parts, so I happily hang on to them. (hoard?... NO!)

 

Anyway, I left them in a friends shed for "safe keeping" but his horrid little brother found them and shot them all with an air rifle.

Aye! Aye! Aye!

With heartfelt condolences
HP