RU stealing stuff from across the web again?
No, Robert was the first the post that link. The people across the web used it without crediting him.
The link has been updated with the schematic toward the bottom of the page. Hope this is helpful.
http://www.tompolk.com/radios/frequencysynthesizer/freqsynth.html
Macrohenry
for sharing this design, schematic, and board pattern. This device will be useful to Part15 experimenters.
Just a note on the 4046 PLL chip which I have used in quantity. The center VCO frequency can vary quite a bit from device to device and this could possibly affect the range of operating frequency of this circuit. If the full frequency range is not achieved then a small change in either the 10k or 1k resistor values will likely fix the problem. The 33 pF cap could also be changed. This should not be a problem if the builder is aware of this since this fix is easy.
Neil
Macrohenry,
That old MC14046 lit my lights because I know these things are rapidly becoming obsolete. The 16-pin DIP version of the old C4046 is no longer available from major distributors. The Mouser part number is obsolete. My searches didn't reveal a current vendor. On Semiconductor has stopped making it. They might still be available from small hobby suppliers that still have a stock. You can still get the original C4046 in a surface mount version.
Your other two ICs are still in production and are still available under your Mouser part numbers.
A sampling of other Mouser part numbers you list indicate they are old numbers and some are still valid and others aren't.
Just thought I would give you a heads up.
After I wrote the above, I still had time left for this post. I looked back at your plans and I noticed a serious discrepancy. Your photo of the assembled board shows the 4046 as an ST Semiconductor part number HCF4046BE. 74HC-series ICs are rated for maximum Vcc of only 5.5 V and yet your schematic shows 12 V connected to the 4046!
The last paragraph in my above post is incorrect. The ST HCF4046BE IC is indeed an original vintage CMOS IC, not to be confused with the 74HC.. series of 5V CMOS ICs. It is rated for max Vcc of 22 V. It still will be difficult to find.
At the very bottom of the Synthesizer Link the date is 6-5-08, so it's an old project making it's weary way back around like an old worn-out comet.
The HC/HCT series of the 4046 are available but as noted by Phil these are nominally 5 volt parts. I use a similar circuit with the same parts (HCT type) in my outdoor transmitter and it was a simple matter of dropping the 10 volt system voltage down to 5 volts with a resistor and a Zener diode for the PLL circuit. It draws little current so this works and the 5 volt square wave output is adequate to drive the final.
Neil
i got the parts to do this. does anyone know the dipswitch settings used to set it on the correct freq?
I DID IT! got this pig running on 1640 on a 5 volt supply using newer cheap chips! hellll yeahhhh, time to build some amp stages!