Topband: Receivers

[Bill Tippett]

W9GE wrote:
 >First choice for me would be a Kenwood TS830S with remote VFO, and
second but about equal choice is the Kenwood TS930S.

         Bob, the TS-930S is probably my all-time favorite rig...I
still have my original bought in 1984 for my a backup.  However, for
160 I do not recommend it for strong-signal handling over the TS-830S
which I had prior to my 930.

         The TS-930S was Kenwood's first rig to include general
coverage and was the first to offer FM.  As a result, it used
up-conversion, 1st IF at VHF and a wide roofing filter.  It
suffers similar IMD problems most JA rigs of this design have.
I think both the TS-830S and Corsair II were ham-band only rigs
with 1st IF's in the 9 MHz area and narrower roofing filters,
which gave them an automatic design advantage.  Here is IMD
data by Sherwood for the Corsair (not II), 830 and 930:

Rig             IMDDR3 @ 2 kHz
830             81
Corsair         79
930             73

http://www.sherweng.com/table.html

         With the sole exception of the IC-7800, I believe the top
rigs on Sherwood's list are ham band only, 1st IF's at HF (not
VHF) and narrow roofing filters.  The saving grace of the 7800
is that Icom added a 6 kHz roofing filter at its 65 MHz 1st IF,
or it would have fallen farther down the list.  The Yaesu FT DX
9000 will use a 3 kHz roofing filter at its 40 MHz 1st IF, so it
should also have decent performance (but probably not significantly
better than the IC-7800).

         You can "almost" rate strong signal handling performance
of receivers simply by the width of their roofing filters, all
other things being the same.  Of course not all other things ARE
the same with phase noise becoming a very important issue for
close signal spacings (a problem shared by both the K2 and 7800).

                                                 73,  Bill  W4ZV