[HBR] Where Is Everyone and expensive crystals?

[Walter A. Hutchens]

Don said:
> One suggestion for experimentally adventurous and for eliminating
> expensive crystals is to use microprocessor crystals in a ladder design.
> It allows the use of same frequency crystals at a fraction of the cost and
> size. Performance can be outstanding.

This is indeed an excellent approach.   I've never seen a really good 
description of the ladder design process but you can do darn well by just 
starting with four or six crystals of the chosen frequency in any ladder 
circuit and changing the caps and load resistors until you get the width and 
shape you want.   

> BTW, Mouser sells 5.00, 5.068, 5.185, 5.9904  MHz crystals around
> 40 to 60 cents each. Using 5.185 one can get both 80/40M. The LO
> would run from 1.18 to 2.11MHz. But a 10 cent diode switch could be
> used to shift the LO frequency for one range and allow a much more
> limited LO tuning. Just an idea.

Another good way to go.   I wanted band imaging without switching the 
oscillator.   With the high power level at which I'm running the oscillator 
(driving the mixer in the cathode) I'm not sure about diode switching but 
there's probably a way to do it.   Reducing $75 of expense to a couple 
dollars is certainly an incentive!

In the planned general coverage design, the addition of another mixer gives 
another degree of freedom for the IF and I'm going to use microprocessor 
clock crystals at 7.3728 Mcs.   Already purchased, 20 for $8.20.   A quick 
check indicates that most of them are within a 50 cps range. 

Think I'll go work on a radio!  

Walt 
KJ4KV