16592Re: Daughter board on SR 15/17m
- Dec 1, 2007
> no I don't get around 84450KHz the most i got was 79230 UNSTABLE soI guess
> there must be an error somewhere.am done.
> I got this reading with 7 turns when i reached 6 turns the oscillator
> The total amount is 9 turns... As I don't have an impedance meter I
> Can your give me some more suggestions.Hi Jose,
I was playing around with the 15m/17m oscillator board (N2PK) today
and have some data for you.
With the suggested 9 turns I measured .26uH on my AADE L/C meter.
With that coil (L100) in place my oscillator measured:
w 1800 pf cap: 71Mhz
w 1500 pf cap: 71.4Mhz
w 470 pf cap: 72.7Mhz
w 100 pf cap: 76.4Mhz
w 28.06 XTAL: 84.25Mhz
w 28.224 XTAL: 84.73Mhz
The cylinder 28Mhz XTAL Tony gave us to try didn't oscillate with the
stock 9T coil.
Just to compare my 20m/30m: it resonated at about 46Mhz. Using the
tank circuit of .43uH (spec'ed) with the 12pf the calculated
additional Cexternal is about 15pf.
If you add this Cexternal of 15pf to the 6.8pf and .22uH for the
15m/17m circuit it calculates out to a resonant freq of 73Mhz. This
matches quite well to what I measured using the caps instead of the XTAL.
Hope that help some. Summary: mine works fine with the stock 9T
73, Mike Collins KF4BQ
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