On Jan 2, 5:16 am, M0WYM wrote:
JIMMIE wrote:

SNIP



I had a little one band kit radio that was varactor tuned in my hands
for a while and used the sweep voltage from a scope to to drive the
varactors. I was interesting but the scope didnt have enogh
persistence to show a good display. It really looked cool when you
used a marker generator with it in a dark room.

JImmie

Jimmie,

That sounds like fun - I will have to try that with my BITX20A which
I modding to varactor tuning

Charlie.

--
M0WYMwww.radiowymsey.org

Sign today!http://petitions.pm.gov.uk/SaveShortwave/

Hey OM
You'll have to find that sweet spot for the ramp sweep frequency,
depends on the bandwidth of the scope or the persistence of the crt.
The sweep bandwidth depends on the varactor tuning voltage, not on
the frequency. So you have to adjust the peak voltage of the ramp to
adjust the bandwidth. On the scope where X input is your ramp voltage
and Y input is the detected output of the tuner, with the sweep on the
scope turned off. The resolution will depend on the input bandwidth of
the tuner.

73 OM
n8zu