At 11:49 AM 7/9/2012, Jerry Haigwood wrote:
> Steve hunt- G3TXQ, who is the original designer of the DDS VFO that Dave
>refers to, has made spectral purity measurements. His design uses a five
>element low pass filter in the DDS output which helps with harmonics, etc.
>All DDS have spurs at different frequencies. Most of these are way below
>the desired output. However, the filters in the Corsair II take care of any
>spurs that might cause a problem. Steve has documented his design at
><http://www.karinya.net/g3txq/corsair_pto/>.
> BTW, I am running the same DDS on my Corsair II. I also have the 263G
>remote VFO which still has the original PTO and I can use it as a reference.
Thanks, Jerry: I was thinking of phase noise when I asked about purity.
I realize that some birdies may show
up. (even with PTOs)
I'll check Steve's web site.
73,
Perry
>-----Original Message-----
>From: tentec-bounces@contesting.com [mailto:tentec-bounces@contesting.com]
>On Behalf Of w8au@sssnet.com
>Sent: Monday, July 09, 2012 2:03 AM
>To: Discussion of Ten-Tec Equipment
>Subject: Re: [TenTec] FS--N4YG DDS VFO Conversion Kit for Corsair II and
>Others--Brand New & Unused
>
>At 07:43 PM 7/8/2012, you wrote:
> >This past April I finished converting the PTO in my Corsair II to a DDS
> >VFO from the design of Steve-G3TXQ with great success. (I discussed my
> >project in a May 24th posting on this reflector.)
>
>Have you made TX spectral purity measurements before and after?
>
>Perry
>
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