My idea is to use a DDS VFO as a VFO for an old Heathkit SB-104
take the output of the DDS through a filter to produce a sine wave for the
mixers and so on.
and use that beautiful gas discharge display.
All I really need is a DDS that uses an optical encoder that produces 5.0 to
5.550 mhz output.
Mike, WB8VGE
SunLight Energy Systems
The Heathkit Shop
http://www.theheathkitshop.com/
J e e p
o|||||||o
A man with one clock knows what time it is. A man with two clocks is never sure.
> On Oct 27, 2017, at 12:52 PM, Barry N1EU <barry.n1eu@gmail.com> wrote:
>
> Yes, that's what I was alluding to in my previous post. The LO spectral
> purity will go from very clean/excellent to not-so-clean/fair with the
> DDS. If you get the chance, have a look at one of the DDS converted rigs
> tx spectrum on an SDR rx panadapter/spectrum analyzer. And the spurs you
> see will affect rx as well as tx.
>
> Many folks will probably not be so concerned and will be motivated by the
> improved convenience factor.
>
> 73, Barry N1EU
>
> On Fri, Oct 27, 2017 at 12:10 PM, lstoskopf@cox.net lstoskopf@cox.net <
> lstoskopf@cox.net> wrote:
>
>> Just remember that TT went to great lengths to have pure LOs. The Orion
>> was a beast in making sure that the LO was as good as the time allowed.
>> Wonder what engineers designed that. Never have heard the story. Don't
>> expect some cheap DDS to do as well. It would be fun to compare a well
>> built analog VFO to cheaper DDS as far as clean signals are important. Of
>> course, your application may not require extreme close in performance and
>> you will be perfectly happy. That's what this hobby is all about. N0UU
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