Hi!. I am trying to devise a varactor (varicap) tuned dip meter, that
can also work as wavemeter by turning the oscillator off.
The target is to reach up to 1GHz by exchanging coils (each with its
own complete oscillator), but needing as few as possible of them.
The main problem with the prototype is at the low end of each band:
even with back-to-back diodes, the RF amplitude goes lower giving a
false broad dip illusion. This also causes the freq scale divisions
for the dipper do not match those for the passive wavemeter.
Trying to reduce amplitude with some automatic level control often
gives rise to low f oscillations.
Any idea on low and stable amplitude oscillators?. I've already looked
up in the group and the web.
73s & DXs
Daniel Perez LW1ECP

"lw1ecp" wrote in message
oups.com...
Hi!. I am trying to devise a varactor (varicap) tuned dip meter, that
can also work as wavemeter by turning the oscillator off.
The target is to reach up to 1GHz by exchanging coils (each with its
own complete oscillator), but needing as few as possible of them.
The main problem with the prototype is at the low end of each band:
even with back-to-back diodes, the RF amplitude goes lower giving a
false broad dip illusion. This also causes the freq scale divisions
for the dipper do not match those for the passive wavemeter.
Trying to reduce amplitude with some automatic level control often
gives rise to low f oscillations.
Any idea on low and stable amplitude oscillators?. I've already looked
up in the group and the web.
73s & DXs
Daniel Perez LW1ECP

The German magazine Funk Amateur of April 2006 had a interesting design:
they modulated the oscillator with a 400 Hz FM and measure the oscillator
amplitude. At a 'dip' this is at a maximum. A can send a scan if you want
(in German of course)

Wim

The German magazine Funk Amateur of April 2006 had a interesting design: (...)

The DK1HE "Superdipper" "Dipit"?. Yeah, it's a fantastic idea!. It's
like manually rotating a little forth and back the tuning knob, 400
times a second. A little drawback is its (understandable) complexity.
And it goes up to only 42MHz. The english version is in
www.qrpproject.de/UK/DipItUk.html
If I can't find an already chewed design, I may end up building this
thing, plus some ideas from the DUBUS VHF UHF Technik book by DL7QY,
reaching 1GHz but with the aforementioned amplitude clipping at low
end.
If this is NOT what you have, then I will gladly accept your offer!
Thank you for answering!.
Daniel Perez