Hi Bob,
This is from the FAQ. Hope it answers your question.
73
Greg
With a first IF of around 8 MHz, how can the receiver be
general coverage? Will there not at least be hole in the
coverage around the IF frequency?
General does not mean continuous in this case. There is a
small gap at 8.215 MHz. You may be able to tune to this
frequency, or not, depending on the firmware. There is a
trap circuit to suppress response at this frequency, so
the receiver won't work very well within several kHz of
8.215 MHz if it does allow you to tune there.
On Mon, 14 May 2007 14:03:30 -0700
Bob Nielsen <[EMAIL PROTECTED]> wrote:
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
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