The referenced page from Sherwood Engineering has
comparisons of several vintage receivers including the R390
but unfortunately not the 75A4. Since the R390 was a
military receiver and the 75A4 was strictly amateur, it
would not surprise me that the R390 might be the better of
the two but I've seen no test data to support that. The
most important measurement in the Sherwood table is the next
to last column (Dynamic Range Narrow Spaced) with the last
column being the actual spacing of 2 kHz. Let's compare
this to recent ARRL measurements at 5 kHz (which might be a
little dangerous since test conditions were probably not
identical):
Rig IMDDR3 (@ 5 kHz) BDR
Ten-Tec Orion 101 (claimed) ?
Elecraft K2 88 126
Ten-Tec Omni 6+ 86 119
Yaesu FT-1000MP 83 111
ICOM IC-756 Pro 80 104
Collins R-390A 79 (@ 2 kHz) ?
Yaesu FT-1000MP Mark V 78 106
ICOM IC-775DSP 77 104
ICOM IC-706 MkII G 74 86
Yaesu FT-1000MP Field 73 107
Kenwood TS-570D 72 87
ICOM IC-756 67 98
ARRL Test Data: http://www.elecraft.com/K2_perf.htm and
http://www.arrl.org/members-only/prodrev/pdf/pr0208.pdf which
adds the FT-1000MP Field to the summary on the Elecraft page.
Sherwood Test Data: http://www.sherweng.com/table.html
73, Bill W4ZV
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