Not to get too far off the milsurp line, Hayseed Hamfest, when they had 
the RAN Technology IC DIP crystals you could by programmed from Mouser, 
had a nice set up using a RAN chip and keying it in a manner parallel 
with the Conar, that you got a good chirp free note.  The DIP packages 
are no longer made, and the last I heard, he was redesigning his boards 
to take the surface mount chips now.  

Since through-hole components are being discontinued at an increasing rate,  we have to think outside the box to find ways to adapt.   I think I've come up with an easy way to use SMT programmable oscillators for those who are comfortable with through-hole components - more information can be found here:

https://tinyurl.com/bdeew29c

"Hayseed Tom" WBØDVM and I put together a little animated video showing the use of one of my 4 channel programmable oscillator boards to de-chirp the "Chirping Conar" as a fun thing to play at the Cedar Rapids hamfest one year:

https://youtu.be/uyZ942H5b2U

It was a bit of a friendly poke at our (now SK) pal Glen Zook K9STH,   who used to claim that his Conar 400 would chirp,  even when unplugged and stored in the attic!

73, Bob W9RAN