[TenTec] RX-340 vs. Orion, Dynamic Range

[Jim Reid]

Hi,

Last October, before I placed an Orion on order,  I had
asked Doug Smith about trading in my RX-340.  I have
always been very interested in "clean" signal performance
of rcvr's,  thus my interest and paper conceiving the 
intercept point test method way back in 1965,  for my
employer at that time,  of course, hi.  Anyway, here is
the response from Doug (note, nothing proprietary or
private,  and he does express just his personal opinion
about comparing the two radio rcvrs):

"Well, I am glad to hear from you again
and I'll try to comment as best I can.
The 340 is a fine machine.  

I believe you will find the Orion's front
end to be quite capable.  Its ham-band-only
preselectors mean you potentially would get
less IMD3 problems than with the 340. I
think the 340 has half-octave jobs.  Unless
you are seriously inundated with large 
international broadcast signals (S9+30 or
more), I doubt you would ever notice
a difference anyway.

The Orion's high analog AGC set point
comes from the 100 dB of dynamic range
we are getting from DSP.  If you are doing
much general-coverage stuff, then the 340
would be hard to beat.  It will be impossible
to beat the Orion for close-in dynamic range
on the ham bands.

Lately, I have done a lot of research on
IMD measurement techniques.  It has 
resulted in some articles for QEX (see 
my "Improved Dynamic Range Testing,"
Jul/Aug; and U. Rohde's series in the
upcoming Nov/Dec 2002 and Jan/Feb
2003 issues).  I don't think S-meters are
necessarily a good way to judge actual 
IMD performance.  I'm sure Carl tried
to be careful, but Ulrich has found much
better numbers for the 340 than what
Carl allegedly reported.

[Note the above comment is in reference to
Carl,  N4PY,  measurement of the 340's dynamic
range,  some of which Phil just posted in his note
today.]

 The Orion has a programmable AGC
capability like the 340's.  I would think
the new features of the Orion, both in TX
and RX, would be what would influence
your decision.

Confidentially, were it my decision to 
make, I would let both the 340 and Pegasus
go in favor of the Orion.  But I would do
that only after having all three in the shack
for a month and satisfying myself.  

    73,

    Doug, KF6DX"

I subsequently have sent in the Pegasus in trade for
the coming Orion,  but am keeping the 340!

73,  Jim  KH7M