[TenTec] DDS PTO replacement for old Ten Tec rigs

Mike Bryce prosolar at sssnet.com
Fri Oct 27 13:13:04 EDT 2017

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
J e e p

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 at 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 at cox.net lstoskopf at cox.net <
> lstoskopf at 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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