Ham Radio KITS - TOP PAGE - Washington Island BOOKS

Prescaler kit

11/8/2012 - sold out - consider the Prescaler "X" kit as an alternate.

[prescalercircuit board picture - 
click for larger version]
The prescaler kit is a simple divide by 10 ECL circuit which can be used to extend the range of most PIC based frequency counters from 50 MHz up to 500 MHz. The kit uses surface mount components except for the 78L05 regulator.

The kit includes the 5 volt regulator, two .1 uf bypass capacitors, two 1000 pf coupling capacitors, a 51 ohm input resistor and an 820 ohm output loading resistor along with an MC12080 prescaler and the circuit board. The passive components are 1206 sized while the prescaler is in an 8 pin SO package - these are both relatively easy to solder but the kit is not for surface mount kit beginners. The circuit board is about 1.3 by 0.7 inches and has one mounting hole sized for 4-40 hardware (1/8 inch).

Printed manuals available for an additional charge or save money by downloading (Right click/save target as) and printing the prescaler kit manual , schematic diagram and hookup diagram all in Adobe Acrobat (.pdf) format.

User Questions:

Is it normal for the prescaler to output a frequency when the input is unconnected ?
Yes, my prescaler does this at roughly 20 MHz.
If this bothers you, Earl, N8ERO, suggests this fix, add a 100 k ohm resistor across capacitor C1. This results in slightly lower sensitivity.

What is the sensitivity of the prescaler ?
Here is some customer measured sensitivity data.

For any questions, please send an email to me, Chuck Olson, WB9KZY at:

Ham Radio KITS - TOP PAGE - Washington Island BOOKS

Page accesses: