So...

I have recently acquired some rock controlled radios... However i'm having some issues finding proper rocks for them... Here is the deal, both radios require that the RX frequency crystals be 455 Khz higher than the TX crystals. Finding TX rocks isn't too bad since they aren't shifted, i.e. 7.030 however finding a corresponding RX crystal i.e. (7.030+.455 =7.485) is proving to be difficult.  I would like a few rocks for 40m, one set for 60m and maybe one set for 80m (no permanent antenna for 60m or 80m at this point)

Second, since these are green rock boxes, I would prefer these in the following configs, FT243, CR-78/u and CR-89/u formats, however, I might be able to hockmere something with other formats.

Any thoughts? Help?

Yes Internal crystal. in OK they custom ground crystals. Its were I buy mine and not a lot of money

www.af4k.com
All shapes, sizes, and frequencies, even the old FT-243 for the boatanchors of the '50s, '60s, & early '70s.

Most of the FT-243 types do have modern crystals stuffed inside them and may not work with some transmitters, especially the ones that use a high level oscillator like a 6V6, 6AG7, or 6CL6.
*****
http://www.expandedspectrumsystems.com/prod4.html
I haven't dealt with these folks, but they do have a stock of popular frequencies.

Never heard of them, got a link? Or do you mean ICM (International Crystal Manufactring), if its ICM, they are going out of business as we speak, I've got an email in with them but have not heard back...

Yeah I emailed Af4k, they might have the right TX crystals since those are common, but no one seems to have anything like the RX crystals I need...

That and I just fired up the TRC-77 after not using it for 6 months, and while RX works, TX seems not to work, so YAY, old radios.
I've got a PRC-64 on the way as well, which uses even weirder crystsals and is the main reason I'm asking.

It can be done but 455 kHz will require removing the existing silver lining and grinding the crystal to reduce it's thickness.
It's a very delicate procedure. The crystal can be ground with a fine sandpaper on a perfectly flat piece of glass. You will need two thin perfectly flat and polished stainless steel plates. The ground and cleaned crystal goes in between the plates. Obviously the crystal should be ground in small increments and resonant frequency must be checked.
You can bring it very close but the final check must be done where the crystal is placed in the circuit it was intended for and allowed to stay on for several hours to get to operating temperature.

There are other ways to change a resonant frequency but usually it only bring F up or down by several kHz. The procedures involve removing some silver coating with a pensil eraser to increase frequency or carefully rubbing it with a stick of 40/60 solder wire to decrease the resonant frequency.
Some silver plating can also be removed (to raise F) by electro-chemical process. A crystal is placed in a glass of water and connected to a positive lead of a 12V battery by an alligator clip. A siver coated wire, connected to a negative lead is placed in water too. Several seconds is all it requires to raise resonant frequency by several kHz.
Other methods involve iodine tincture and a used up fixator liquid from a B&W protography. This will only change F by around 1-30 Khz for a ~5 Mhz crystal. I can describe it if anyone is interested.
This is what we had to do with homebrew radios when I got into this hobby 30 years ago.

If you're an ARRL member, go to their archive search and search for "crystal grinding". You'll get about 3 pages of articles telling how to do it.

I thik rolling my own crystals might be a bit more hardcore than i'm into. I had no idea it could even be done actually.

Thought I remembered a YouTube video about this...

Jan crystals is still manufacturing. Bomar is out too…for those that didn't know already.

I have nothing productive to add, but grinding or etching rocks for radio parts is definitely some next level shit.

I don't know if this would serve you, but I was recently reading N2HTTs interesting blog, and he had been experimenting with a "VXO" (variable crystal oscillator). Mounting several of the modern HC49 crystals in parallel, he uses an inductor and a trimmer cap to "pull" the frequency in the desired direction. There's not a lot of movement available, but there might be something there to assist you.

Here's a post referring to a VXO: https://n2htt.net/2016/11/26/wiggle-room/

Also this one: https://n2htt.net/2017/01/09/another-radio-another-vxo/

Very interesting blog, by the way! Cheers...   Jim

 Yea...started drinking early And that sux there out of business

Well I've got a possibility with Bomar crystals for custom crystals depending on the cost. And I hunted around on ebay and few guys have some receive freqs I can use that are "sorta" close to TX for the TRC-77 which does have a BFO, so hopefully I can use that...

They told me (and about 20 other folks I know) nearly 3 years ago that they had ceased crystal oscillator production for radios.

In case you've never seen this..


Glad to hear Jan is still in business. Ordered many rocks from them as well as Bomar back in the "beeper" days.

Jan is in business, but not doing crystals, I have no idea what their business is these days.

Got me, so far I got 1 email back asking for details, it may turn out that my order is too small though or something like that. However, someone is making crystals for the guys selling them on ebay.

Crystal Clear goes into depth about making crystals for WWII, including the Nazis trying to sabotage the operation.

ROFL.....very first thing that came to mind. That said, a VERY interesting thread.