Perry,
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.
Jerry W5JH
-----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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