[TenTec] DDS for Corsair II

[David and Dianne on Comcast]

Hi Paul,

Do you want to build it or buy it? You can do 
either. See what follows:

*Build:*You should see and study this web site: 
*http://www.karinya.net/g3txq/corsair_pto/* I did 
this project two years ago and it was both a very 
challenging DIY project for me but the results 
were spectacular IMO. It was costly (*/not /*cost 
effective) and time consuming… but loads of fun 
especially when it was done. I did it in the PTO 
in the CII and the PTO of the 263G external VFO. 
N1EU-Barry has also done this project and his 
metal work was much more refined and polished than 
mine. He likes his as best I can tell. Jerry-W5JH 
was an immense help to me in sourcing parts, 
giving advice and especially moral support when I 
got to some points along the way where I did not 
know how to proceed.. Most parts are Mouser and 
Newark stock available but one connecting part is 
now hard to source and only available from a 
Mouser (?) supply house in the UK in quantities 
above “one of’s”. The most difficult part of the 
process for me was the metal work especially the 
shaft adapter to permit continued use of the stock 
VFO tuning knob and skirt. Hard but doable even 
with the crude had tools that I used.

*Buy:*See these two web sites: 
*http://www.n4yg.com/Corsair.html *and 
*http://wb8yqj.yolasite.com/corsair-ii-dds.php* I 
have two CII’s and will doing the N4YG version to 
my second one later this winter. The external VFO 
263G will no longer be needed for this one as the 
N4YG version introduces dual VFO capability and 
split mode op  in that  DDS.  Don WB8YGI has done 
it and reports that is a fine DDS mod for his 
CII.  N4YG is an excellent man to do business 
with. Cost effective and relatively inexpensive.

*To further answer your specific questions (as to 
my results with the G3TXQ version):*

*--Is it a direct drop in replacement with no 
modifications?*—See all the web sites above. Both 
are “modified” drop in’s.

*--**T**uning rate?*—The G3TXQ has a variable rate 
depending upon the speed of the QSY on the VFO. 
Not sure on the N4YG version but I think so. Some 
might have preferred a slower standard rate in the 
G3TXQ version but I find it great as is. Personal 
taste. Frequency excursions up and down the band 
are as you expect with a DDS VFO in other radios. 
Swift and slick.

*--Do you lose the offset function?*--No

*--More freq. stable than the PTO?—*OMG!! so much 
more stable you will never go back to that PTO 
junk box. Almost seems TXCO controlled though it 
is not of course.

*--Good things/bad things?*—IMO mostly all good. 
Some birdies are introduced as with all DDS units 
but they are virtually not audible with an antenna 
connected. Both versions can easily be reversed to 
a PTO if ever desired but why would you???

*--Availability?*—See above.

Then…you should see Barry-N1EU’s web page on 
modifying the CII IF/AF chain for some really 
spectacular SSB RX audio. I have done all fully as 
he details there and can attest that the results 
will blow you away. 
*http://corsair.wikidot.com/corsair-afrx *They are 
the crowning CII mods.

73 de N1LQ-Dave