To: qrp-l@lehigh.edu
From: Glen Leinweber
Subject: Xtal calibrator/marker generator
Date: 20 Jul 1995 11:57:41 -0400
Hi everyone,
Here's a simple Xtal controlled marker generator for our little
rigs with "questionable" dials. It takes very little power (CMOS) and
very little space.
I've a bad habit of re-inventing wheels, so my apologies to
anyone whose circuit is similar...this is a fairly obvious one and I'd
be surprised if it hasn't been published before.
Ouput is selectable at 40 khz, 20 khz, 10 khz or 5 khz intervals.
Markers are good up thru 30 Mhz at least.
The chip generic # is a CMOS 4060:
Motorola: MC14060
Harris/RCA/National: CD4060 (DIGI_KEY CD4060BCN-ND $.91)
There's also a HCMOS version too, although I haven't tried it:
(DIGI-KEY CD74HCT4060E-ND $.94)
+5v to +15v
___________________________________ |
27p C1 | | |
____| |___________|10(osc) 16|____|
| | | | | | | |
| X1 R1 | | _|_
| X1 R1 | MC14060BCP | ___ .1uf
| 5-50p X1 R1 | | |
|___| |___|____|__|11(osc) 8|____|
| | |C2 | | |
| trimmer | | |
|_________________|12(reset) 6 14 13 15 | gnd
| |___________________________________|
| | | | |
| | | | |
gnd Out Out Out Out
for 5.12 Mhz: 40k 20k 10k 5k
for 10.24 Mhz: 40k 20k 10k
C1...27pf, NP0 disk preferred
C2...small trimmer cap...used to trim oscillator frequency
nominal capacitance about 25 pf
R1...220k to 1MEG resistor
X1...5.12000 Mhz microprocessor xtal
A 2" wire attached to one of the outputs should provide enough
signal for your receiver.
If you have a frequency counter, adjust the trimmer for exactly
5.12 Mhz on pin 9. Otherwise, tune in WWV, WWVH and adjust the trim
capacitor to zero-beat one of the 40Khz markers.
If you do try the HCOMS (CD74HCT4060E) you'll have to limit the supply
voltage to no more than 6v DC, 5v nominal. This one might work OK
with a 10.240 Mhz crystal (DIGI-KEY SE3421-ND) $1.29, but you'll
lose the 5Khz output.
No association with DIGI-KEY here... blah blah blah.
Enjoy,
Glen Leinweber VE3DNL leinwebe@mcmail.mcmaster.ca