John
Can't help you with numbers, just the experience of friends in that
situation, ie they can operate with special receivers having special mixers,
often home brew, whereas it is impossible without.
David
G3UNA
David Cutter wrote:
Some folk suffer extremely strong QRM from broadcasters on 40m
(particularly on the east coast of Scotland) and to them there is a real
desire for the best possible gear to hear weak stations amongst huge bc
signals from Europe. That's where receivers like the Perseus and others
come in to their own.
Hi David,
Yes I can see your point, and I am certainly not questioning the benefit
of High Dynamic range receivers in those situations. I guess what I am
having a hard time understanding how it would be possible for any
receiver, regardless of the dynamic range of the receiver, to receive a
weak signal 2 Khz away from, say a 80db over 9 broadcast or other signal.
Would not the IMD, sidebands, and splatter from the broadcast station
itself be so severe as to prevent this? Or am I overstating the effects of
transmitted phase noise and IMD? As I mentioned in my previous post, there
is no way I could see operating 2 Khz away from the very strong signal of
my ham neighbor. His transmitted IMD would be way too severe. But I can
easily operate 20 Khz or more away with the K3. To me, any minor
difference in close in dynamic range between say the Perseus and the K3 is
of little or no importance in this situation. I could not receive a weak
signal so close to such a strong signal anyhow because of his transmitted
IMD. But the wider spaced number's matter a great deal, and that is what
concerns me when I see a 117-123db BDR as compared to 140db at wider
spacings.
73,
John, KD8K
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