On May 14, 2007, at 1:53 PM, Bill W5WVO wrote:
Anthony,
I spent a long time lurking on the OMNI-VII Yahoo group and was
primed to buy one -- until the K3 was announced. In addition to
everything Greg says below, I think the most significant single
difference between the two receivers is that the OMNI-VII uses a
typical up-conversion scheme for the first IF, with its narrow
filters in the 2nd IF. The K3 uses a down-conversion scheme at the
first IF. This allows use of very narrow roofing filters in the
first IF, while the OMNI-VII must depend only upon optimizing IF
stage gain distribution to minimize close-in IMD through the first
IF. They obviously did a good job of that, as the 80 dB 2 kHz DR3
shows, but it is expected the K3 will test significantly higher
than that, most likely in the vicinity of the ORION-II. Of course
that's speculation at this point, since the actual numbers aren't
out yet, but it is well-informed, highly credible speculation. :-)
And you don't give away general-coverage receive capabilities, as
you do with many ham-optimized down-conversion receivers. It is
simply a brilliant design, IMO. I have one on order.
Bill / W5WVO
That lead to a question I hadn't considered before. How is general
coverage in the vicinity of the first i.f. achieved?
Bob, N7XY
_______________________________________________
Elecraft mailing list
Post to: [email protected]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com
