On 15 Nov 2004 20:26:05 -0800, StevenS wrote:
(Chris Howard) wrote in message ...
On 13 Nov 2004 19:50:20 -0800, StevenS wrote:
Hello,

I've been out of the hobby for years now, but want to purchase an HF
rig, possibly with the 6m and 2m and even 70cm options. My main
concern is that the radio have the best and most flexible receiver
possible. I'd like to do some DSP work and if the receiver is a
software receiver and is programmable, that would be very desirable.

Are you looking at the software defined radio angle?
There are a couple of those now being manufactured that
might be better platforms for doing DSP work.

Yes, the software defined radio is exactly what I want. Seems to me
that I want to get very good RF front ends and good A/D, then do the
rest in my PC. I have a signal processing background and want to
experiment on the signal processsing side. I don't want to get bogged
down with the RF amps, or building the transmitter side. Is there
some transceiver that gives me the a/d output and has great RF amps?

I believe it is called the SDR-1000. www.flex-radio.com

I don't know if it is exactly what you want, but probably the
closest thing. Send them an email and they can answer your
questions. I went to a talk by the guy who developed it. He's
a real nice guy.

Looking at sensitivity without examining the other receiver characteristics
won't tell you much.
You should take into account all of these:
Sensitivity
Dynamic range
Selectivity -- Filter Characteristics such as Shape factor (skirt
selectivity) and ripple
Intermodulation Distortion
Phase Noise - Noise floor
Minimum Discernable Signal
DSP performance
More

See Selecting a rig at URL:
http://www.arrl.org/tis/info/pdf/29379.pdf

Then read the reviews

The ARRL transceiver reviews is a good place to compare these specs and what
they mean.
http://www.arrl.org/members-only/prodrev/

A rig can have super sensitivity specs with lousy dynamic range -- it is
difficult to get both -- lots of tradeoffs in receiver design.
Dynamic range is a very important receiver spec as is selectivity as well as
sensitivity.

Look for high receiver intercept points, excellent dynamic range, sharp
selectivity and a low phase-noise synthesizer

Be careful when comparing a $1000 radio to a $3300 radio -- there are
usually good reasons for the higher price.

The Anon Keyboard
I doubt, therefore I might be



"StevenS" wrote in message
om...
Hello,

I've been out of the hobby for years now, but want to purchase an HF
rig, possibly with the 6m and 2m and even 70cm options. My main
concern is that the radio have the best and most flexible receiver
possible. I'd like to do some DSP work and if the receiver is a
software receiver and is programmable, that would be very desirable.

I was looking at the TenTec site and they advertise a transceiver with
0.35 uV sensitivity at 10db S+N/N in a 3KHz SSB mode. On the other
hand, the Kenwood 480 guys are claiming a 0.10 uV sensitivity, but
didn't say what mode.

It looks to me like TenTec is the most technologically advanced, but
then why the lower sensitivity? I wonder if Kenwood is not completely
truthful.

Well anyway, what's going on? Are these the right brands to be
looking at anyway?

Thank you,

StevenS