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[TenTec] DDS for Corsair II

To: Ten Tec Reflector <tentec@contesting.com>
Subject: [TenTec] DDS for Corsair II
From: David and Dianne on Comcast <dhhdeh@comcast.net>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Thu, 29 Jan 2015 06:20:12 -0500
List-post: <tentec@contesting.com">mailto:tentec@contesting.com>
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
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