Hi all -
I love buying and playing with radios, but I must admit the Icom 756 Pro II has
stopped me in my tracks. My Omni's, Elecrafts, etc have all been sold becuase
the Pro II just does everything better - at least for me at my operating
station. So this leaves me wondering what new rig I could look into. Only two
really come to mind: The Orion and the 516. The Orion is way out of my price
range so I guess that answers that. And the 516.....well it's really hard to
sort through the various reactions on the 516 reflector...so I just don't know.
But while I'm exploring, two questions come to mind:
1)I've paisted below a description of the DSP in the Japan Radio NRD-545
receiver. It mentions 40 bit floating point processor with 18 bit over
sampling. The Pro II and the Orion are newer yet use 32-bit. In my simple brain
I have to ask why is that? How much of a difference does this make? I don't
pretend to understand DSP - so SIMPLE explanations would really help:-)
2) My Pro II can hear anything my K2/100 and my Omni V did and has better
ability to narrow filters/notch/noise reduction etc. The Pro II does not
require me to buy additional filters (of a design that have been around for
years). That makes the Orion even further out of my reach. Why does the Orion
need those filters? I cannot imagine that 5 years down the road all DSP radios
will still have filters in them. After all, most companies are trying to get
away from such filters because the are getting more costly. So why is Ten Tec
throwing them into the Orion? How much better could it make it than the Pro II?
Can someone shed some light?
3) - I cannot figure out if the 516 is a flash in the pan, or here to stay, and
what the majority of users feel about it at this point? Anybody have a clear
impression there yet?
OK - here's the clip from Universal Radio about the NRD-545 receiver: 73/Tim
NZ7C
"The NRD-545 uses a 40-bit extended floating point Digital Signal Processor
with an 18-bit over-sampling system A/D converter and a 16-bit D/A converter.
The DSP functions on 13 types of circuits after the IF, previously configured
using analog circuits. DSP is used for all-mode detection including AM
synchronous detection (ECSS). Incredible selectivity characteristics are
achieved by the use of an Infinite Impulse, structure concurrent Chebyshev-type
digital filter. In English this means, the NRD-545 gives you a continuously
variable bandwidth from 10 Hz to 10 kHz in 10 Hz steps. You virtually have 990
different bandwidths, each with excellent adjacent channel rejection. DSP is
also used to control Pass Band Shift, another tool to reduce QRM. A 256 step
DSP Noise reduction circuit and 256 step DSP Beat Canceller and DSP Auto-Track
Notch are other new tools in your arsenal to dig out difficult DX signals. The
DSP AGC works in all modes and is continuously variable from .04 to 5 seconds
in SSB/CW/RTTY"
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