Dear all,
the only parts I have bought so far for MF (still beeing engaged in
other developments) are two crystals: 6,5536 MHz and 7,0200 MHz, to be
mixed with each other. The mixer is another bipolar transistor, and its
emitter current is being keyed. A final source follower after the
low-pass filter will deliver the output to 50 ohms.
The same solution I have also used on LF.
73 Ha-Jo, DJ1ZB
"Rik Strobbe" <[email protected]> schrieb:
> Stefan,
>
> what about a huff&puff oscillator (http://www.hanssummers.com/huffpuff.html) ?
>
> 73, Rik ON7YD - OR7T
>
> ________________________________________
> Van: [email protected] [[email protected]]
> namens Stefan Schäfer [[email protected]]
> Verzonden: donderdag 5 juli 2012 19:09
> Aan: [email protected]
> Onderwerp: Re: LF: RE: Analog oscillators
>
> Hi Victor,
>
> Am 05.07.2012 19:00, schrieb [email protected]:
> > Hello Stefan,
> >
> > for narrowband vfo i get best results with a clap or a seiler,both with big
> > parallel c over the FET.But of course everything depends on the mechanical
> > stability and the quality of the parts: ceramic coilformer,silvered mica
> > capacitors and tempcompensation with N750 ceramic capacitors.With trial and
> > error you may get very good results.
> OK, tnx. Years ago i built a 137 kHz oscillator (by DJ2EY) which used
> diffent capacitors for temperature compensation. I will see what i get...
>
> > Use big parts,temprise will be less,so
> > stability will be better..
> >
>
> That sounds convincing, tnx. Meanwhile the output stage is built, once
> again using a ICL7667. I would like to use a JFET. And i found a nice
> link in the web, of course from W1VD: http://www.w1vd.com/16080VFO.pdf
>
> That is nice and i have all the parts here. I will build it and hope to
> try it in the evening :-)
>
> BTW are you QRV on 500 CW as well?
>
> 73, Stefan
>
>
>
>
> > GL
> > 73
> > Victor
> >
> > -----Oorspronkelijk bericht-----
> > Van: [email protected]
> > [mailto:[email protected]]Namens Stefan Schäfer
> > Verzonden: donderdag 5 juli 2012 18:32
> > Aan: [email protected]
> > Onderwerp: LF: Analog oscillators
> >
> >
> > LF/MF,
> >
> > I want to build an analog oscillator running on 1888....1916 kHz. It
> > will be used as the input VFO for my PA which divides the frequency by 4
> > internally. A metallic box with 12V input voltage cables and a RG174
> > cable for the output is already available. Also a 78L05 with its 100nF
> > Cs is mounted. Later i can label the scale directly with 472...479 kHz,
> > so the need to divde by 4 in my head will not be necessary any more.
> >
> > The output voltage should be arround 12V. The curve form is not
> > critical, it does not need to be a clear sine wave. However the
> > frequency should be as stable as possible.
> >
> > So, what is the best oscillator circuit? Are there strong differences
> > regarding stability or is it always a question of the temperature? Ah,
> > it must be a LC oscillator. The adjusting part is a variable C of 33pF
> > with a 6mm axis.
> >
> > There are a lot of circuits in the web but maybe one principe is to be
> > preferred..
> >
> > 73, Stefan/DK7FC
> >
> >
> >
> >
> >
>
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