N4TZ wrote:
>According to Doug Smith's web site, the DSP engine in the Orion should
have 100 dB dynamic range before the analog AGC kicks in. This is based
on the 24 bit A to D conversion. It seems to me that with only two signals
in testing, if the AGC is turned off then the Orion should measure 100 dB
dynamic range even for very closely spaced tones within the wider roofing
filters. For that matter, even the IC7800 should be able to do that.
So, the question is, is the basic analog radio only a 70 or 80 dB dynamic
range radio, which may or may not be able to be field modifiable (improved)
by a knowledgable person, or is the DSP software not working properly? The
DSP software could be upgraded by the factory.
Terry, the problem is with nonlinearities which occur prior to
the DSP stage. These are due to filters, amplifiers, mixers, switches,
etc. No DSP, no matter how perfect or what dynamic range, can solve the
problems that appear ahead of it.
On another topic (the TS-850S), my favorite all time radio is the
TS-930S. Great audio (RX and TX), ergonomics, and one of the few which
had a continuously adjustable CW Pitch well below 300 Hz which I like for
extremely weak signal DX-ing on the low bands. It lacked digital I/O
(which can be added with the Piexx board) and a strong front-end. On a
relatively uncrowded band, the TS-930S worked extremely well. I won the
CQ 160 CW many times for Zone 4 and even placed in the Top 10 several times
which is not easy to do from Colorado. If Mario will just find that $200
500 Hz BW filter at the 930's First IF of ~45 MHz, I'll sell my Orion and
be a very happy camper!
Unfortunately, with the possible exception of the TS-850S, I believe
the 930 was Kenwood's last hurrah and signaled the end of their dominance
of DX/Contest rigs in the 80's. The TS-940S had terrible phase noise and
then Kenwood seemed to go the way of gadget-itis in lieu of performance
(does that sound familiar?) Today I don't know of many serious DX/contest
guys using recent Kenwood radios (maybe a very few the TS-870S).
73, Bill W4ZV
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