Phase Locked Microwave Signal Sources

Frequency-West Nomenclature

W3RJW, Ron J. Whitsel

Wandering around flea markets one often sees stacks of Phase Locked sources which can be used as the local oscillator for a microwave transverter. A lot of the units are not too useful if they don't have the necessary features. Below is something you might want to put in your wallet so that you can decode the model number that is on every Frequency -West brand of signal sources.
M S - A B C X 2 3 4 - 5

Two Digit

Three Digit

Low Power 5-10 mw

High Power 20-50 mw

Phase Lock
Stability Options

O - Internal Oven

E - External Reference

A,B,C - .005% to .0005% w/crystal
No Oven


L - Lock Limit Alarm

M - Standard Modulation Input

Factory Specials

Typically, using 10 GHz as an example, what we need for most applications is the following:

MS-72XOL 10200-10700 MHz, 10 mw, 100 to 105 MHz Crystal, Internal Oven, Lock Limit Indicator


MS-740XOL 10630-11230, 20 mw, 98.4 to 104 MHz Crystal, Internal Oven, Lock Limit Indicator

The key is the letter "O" after the "X" which indicates an internal oven. The lock limit indicator is desirable, but not necessary. Most units can be tuned far outside the indicated frequency range by retuning the output filter.

Below is a portion of the model number table for Frequency West sources. The catalog number for an International Crystal (ICM) crystal is #00585132.