Rangemaster Crystal's & Lower Frequencies

[tybee]

Someone told me (I think it had been Dave) what to look for when seeking crystal's for the older model Rangemasters but now I can't find it again and for some reason not on Rangemaster site either. so I'm not sure what's right..

Anyway I've had thoughts about trying some lower frequencies as an experiment .There at least once existing part15 AM that's been on 1400 for years in Montana, so I'd like to try it for the sake of old radios.

I've seen some AM Crystal's that require a FT-243 socket and also have come across some HC-6/U Crystal's with these frequencies.. what's with the peculiar AM frequencies?

1000
1311.4
1306
1363.6
1400
1572

But my main question is what kind of crystal's is right for the original Rangemasters?

[tybee]

Just bought a Rangemaster 1690 crystal combined with a Ragemagster audio interface for $18 in Ebay

I grabbed it just to have on hand, but like I said I'm really looking for something below 1600..

PS. Surprisingly those little audio interfaces  for the Rabgemaster are $99 at Progressive Concepts.. What makes them so expensive? that really surprised me.