Re: BitX17 IF Frequency

Greg Derda
 

Thanks to all who have replied so far!

Arv,

Thank you, this is what just I needed to help visualize the whole
process! Now i can stare at the schematics and figure out what is
going on. I actually have a "spare" stabilizer from my build of a WN5Y
ELR kit (long story - I ended up with two stabilizers). Picture is
here...

http://jezebel.ucns.uga.edu/~derda/elr/P6200001.JPG

I thought about using it (once I figured out "how") with my BitX20a,
but I am very happy with the stability of that radio. Of course, I am
telling myself that I might build my third Bitx (I ordered the version
3 boards from Sunil) for PSK31, so I might want to use it there ;-).

Anyway, thanks again, I think I have enough information to keep my
noodle turning for a while.....

Greg
ki4mmm

On Feb 15, 2008, at 2:16 PM, Arv Evans wrote:

Greg

My latest BITX20A H&P stabilizer taps the VFO output at the junction
of
R-27 and Q-6 collector (top of R-27 on the kit circuit board). I fed
the common point between H&P integrator caps to a 150K resistor that
connects to the junction of R-38 and D-9.

At present I am using the G8SEQ idea

<http://downloads.hanssummers.com/sprat122b.pdf>

of an intact watch unit providing 32 Hz reference with half a 74HC74
as
the latch. The other half of the 74HC74 is used as a buffer to square
up
the VFO output.

The Ron Brink PA2RF circuit is probably a more elegant solution, but
this simpler method seems to work well enough for my needs.

Arv
_._

Greg Derda wrote:
>
> Martien,
>
> Thank you for the reply and info. I have considered a stabilizer,
and
> I have tried to learn more about them, but what is not clear to me
is
> where to tap the VFO for the output to, and input from, the
stabilizer.
> For example, if a person wanted to add one to the Farhan-circuit
VFO,
> where would you tap it?
>
> Greg
> ki4mmm
>
> On Feb 15, 2008, at 10:25 AM, Martien wrote:
>
> > --- In BITX20@... <mailto:BITX20%40yahoogroups.com>,
> Greg Derda <gderda@...> wrote:
> > Hello Greg,
> >
> > You could use the 10MHz standard with an 8Mhz VFO. This VFO can be
> > easily stabilised using a "Huff and Puff" circuit. There are many
> > examples on the web. I used this simple one (fig.1 schematic)):
> > http://home.hetnet.nl/~brink120/huf2.htm
> <http://home.hetnet.nl/%7Ebrink120/huf2.htm>
> > VFO is rock solid, PSK 31 is no problem.
> >
> > Text is in Dutch but the schematics are quite clear.
> >
> > Martien PE1BWI
> >
> >
> >
>
>
>
>

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