Excellent summary Duane! If anyone missed it,
Duane's post explains very clearly and concisely the
advantages of Orion's Main RX design.
http://dayton.akorn.net/pipermail/tentec/2003-December/040588.html
Regarding the IC-7800, I doubt it will hold a candle to
Orion at 1 kHz BDR and IMD spacings. Regarding the
K2, one of its advantages is its programmable BW crystal
filter, but that becomes a bit of a disadvantage because
it also has a fairly wide shape factor (3:1), and that filter is
the only IF filtering that exists in the K2. Shape factor is
less critical in Orion's roofing filters (6000, 2400 and 1000
Hz are all 4-pole), because their main role is to reject strong
adjacent signals that can create IM products farther down
the IF chain. Beyond about 20 dB down on the roofing filter
skirt, shape factor becomes less important since Orion's
3rd IF DSP can adequately handle what remains.
73 & Merry Christmas!
Bill W4ZV
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