Ham Radio KITS - TOP PAGE - Washington Island BOOKS

July 3, 2014 - SOLD OUT - Prescaler "X" kit

Please email:

if you would be interested in having this kit revived. It would probably be done on a larger circuit board with all through-hole components except for the prescaler chip itself and probably the price will be higher.

[prescalercircuit board picture - 
click for larger version]
The Prescaler "X" kit is a lower cost version of the Prescaler kit which is identical EXCEPT that the board has a defect: the builder must add a missing connection from pin 5 of the prescaler chip to the ground plane. A printed note will be included with the kit showing this required board modification.

Prescaler "X" 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 larger quantity purchases, to combine with other items, for DX purchase price or for any other questions, please send an email to me, Chuck Olson, WB9KZY at:

with your question or the items you want and we'll email you a Paypal invoice.

Ham Radio KITS - TOP PAGE - Washington Island BOOKS

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