[Lowfer] crystal oscillator sources

[JD]

In general, the best solution is to use an oscillator in the MF or HF range 
and divide it down to the frequency of interest.  Crystals for 160-190 kHz 
tend to be expensive.

Probably the most popular solution for experimenters in recent years has 
been the Epson SG-8002 programmable oscillators stocked--and custom 
programmed--by DigiKey.  An article on those is at 
http://lwca.org/library/articles/k0lr/epson/ although the data sheet link is 
outdated (download one through the DigiKey site instead), the cost is a 
smidgen higher now, and the part number recently changed because of the 
elimination of lead from the chip.  The new Epson part number for the most 
commonly used version is SG-8002DC-MPTROHS, and the Digi-Key number will be 
SGR-8002DC-PHB-ND.

Those modules are quick and inexpensive, but are not the most stable with 
temperature.  Some experimenters with greater need for accuracy use PLL or 
DDS oscillators with reference frequencies derived from ovenized 
standard-frequency oscillators, and some use GPS disciplined oscillators.

John