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RE: Computer controlled radio seen at AMSAT Annual Meeting 03



Emily:

Some of your critique is right on the mark and Gerald is likely
to tell you that the people he considers his friends and advisors
are telling him exact what you have been saying.  I can tell you
however, that not one of the receivers in the list you have mentioned
can come close to the performance of the SDR-1000.  In my labs
at work, and in the lab of W3IP (who is VP of SAIC) we have measured
blocking dynamic ranges and spur free dynamic ranges that EQUAL to
the FT-1000D.  You are very right that we had to use top of
the line audio cards to get these numbers.  It might surprise you
however to note that top of the line is under $100 for the purposes
you mention.  (M-Audio Revolution 7.1 is $70-ish at most stores).
If you want an extra 3 dB in most of the linearity numbers and
spur free numbers,  you need to spend 10 dB more money for a Lynx
L22 but I do not recommend that for a number of reasons including
that I believe it will be of no use in a year when a new version
of this kind of radio comes out (at least I hope it does!).

So as it now stands, I can get just about the best receiver money
can buy for $600.  It does have drawbacks.  These have been realized
by Gerald and are being addressed in a clever way.  The SDR-1000
will be a 50-100w transceiver with the receive problems addressed
by a simple add on board.  Gerald did the design for all of this
"in his basement" and he made a boo-boo or two.  I might also
say that Gerald has expressed some amazement at the performance
levels being measured now.  The primary uh-oh is he put the
noise and receiver merit determining amplifier BEHIND the mixer
and of course this amplifies the DDS spurs, mixer noise, phase
noise from the oscillator/limiter/mixers as well as the signal
of interest.  This is being addressed in the add on board which
will move large pieces of that gain in front of the quadrature
sampling detector.  Most of the problems with this receiver's
potential disappear once this has been done.  You still have to
contend with the sound card and the interfacing.

Gerald and his friends and owners have all decided that the "next
radio" whenever that comes out, can not depend on the sound card.
As such, it is to have a high speed digital interface such as USB
2.0 for both audio and control.  I am sure Gerald would tell you
that he is not interested in having an opinion of the radio given
by someone who owns an original SB-16 card!

AB2KT and I are testing the Linux version of the radio software
now.  It will be available on my home website soon

( http://rwmcgwier.homelinux.net )

under an open source license.  There will be a php based bulletin
board to discuss this work and other work on that web site. The
site is very rudimentary now as I have just gotten the pieces
assembled and have been concentrating on the linux code with Frank.

Two people are writing Visual.NET versions of the code.  Both have
pieces in Visual C++ and C#.  The primary reasons for going to
.NET development is that it is supported under XP and it has a
real threading model that allows you to write real code (even if
you do have to hide it behind the MicroSH%^ .NET stuff).

I almost puked when I got the code with the radio and saw that it was
VB 6.0.  Gerald can tell you that I was less than gracious about it.
On the other hand, I am one of the better contributors to its
upgrades(in terms of volume and added features, not quality of code).
Now we have folks from everywhere adding features.  VB 6.0 was,
in my opinion, having shut my mouth and thought about it, likely
the very best vehicle for Gerald to have introduced this SDR
to the world.  Many have contributed and VB 6 has made this easy
to do.  Gerald very best business decision was to decide to
do open source for the code and to make it doable in an easily
accessible language with decent signal processing library support
from Intel.

It has absolutely NO PLACE in the future.  VB 6 will be replaced,
and soon, on multiple platforms.  I am building a Qt interface
that can be used on Windoze and Linux with code works for
both platforms (with enough ifdef's to allow you to compile on
either).

Stay tuned and do not despair.  SDR is a revolution and it has
just begun.


Bob
N4HY

-----Original Message-----
From: owner-AMSAT-BB@AMSAT.Org [mailto:owner-AMSAT-BB@AMSAT.Org]On
Behalf Of Emily Clarke
Sent: Monday, December 15, 2003 1:53 AM
To: APBIDDLE@MAILAPS.ORG
Cc: amSAT
Subject: RE: [amsat-bb] Computer controlled radio seen at AMSAT Annual
Meeting 03



I'm note quite as enthused as Alan after looking at the specs.  I own a
PCR-1000 and in the short amount of time I have owned it it has taught me
many things about radios and software, most of which has been less than an
ideal "user experience."  Here are some of the problems I foresee with
SDR's at this time:

1) Connections are old technology and require far too many connections
(Parallel port, serial port, sound card) rather than a modern, progressive
connection (USB 2.0 or firewire).

2) Required use of sound cards require drivers, not always available for
the latest operating systems, and not always reliable.  (For example, my 3
year old Sony notebook is no longer supported by WinXP because Sony doesn't
have a driver for it.)

3) The software is unproven and written in Visual Basic (and not even the
latest version.)  Although I don't own the SDR-1000 and it's software, if
the software for the PCR-1000 is any indication there will be many
problems.  The PCR-1000 came with the Icom software which crashed all the
time and conflicted in namespace and file types with the more common Roxio
CDRW software.  It also came with the Bonito software  which was already
outdated as shipped and cost $$$ to upgrade to the latest version.  I also
don't think it is up to commercial standards of quality.  In the end I paid
even more money for a third party package (Talk PCR) that works OK though
it does have some good features for use with AO-40.  Unfortunately this
takes over interrupt priorities and the sound card, so it can't be used
while you are running MixW, or any of the DSP software packages.

4) I disagree that it's relatively cheap.  If you buy the bundled
transceiver and case you end up with an ICOM 703+ but lacking power (1W vs
10W for the 703+), an antenna tuner and a front panel.  You can build a
computer interface for the 703+ for about $20 (or buy Icom's CT-17 for
about $130).  I'd also consider the Icom 706 MKIIG or the Yaseu 897.

5) It appears to me you are stuck with using PC microphones.  Some would
argue they sound terrible - I wouldn't disagree. While I'm sure there are
some very nice commercially available headseats and microphones I'm not
thrilled with the idea of using a keyboard space key as my push to talk
switch.  I'll keep my Heil mic and the very nice speech processor built
into my 910H  thank-you-very-much.

6) No Mac or Linux support.  A shame really...

7) To put together a full featured transceiver you have to deal with many
vendors. So you add the DEMI 2M Transverter for $400, and then about $150
for an HF power amp (Oh darn! Doesn't cover the 6m side), a VHF power amp
and you still only have a 706 MKIIG or 897 minus the UHF coverage, at a
price that is considerable higher.

So as much as software defined radios seem to be cool at first glance, I am
not convinced I would like to be rebooting my radio in the middle of a qso,
or having to give up my radio because the software no longer runs on
Windows 2005. Maybe in 10 years when the software gets mature and up to
commercial quality, but until that time I don't think I'd go down that road
except as a novel experiment.  It would help if the software was open
source and could be re-developed in C++ on a common IDE, but that doesn't
appear to be the case here.  In one to two years when Microsoft releases an
OS that doesnt' support Visual Basic 6.0's runtime any longer it will be a
rude awaking for anyone relying it.

73,

Emily


At 12:22 AM 12/15/2003 +0000, you wrote:
>An impressive radio.  Not a factor for a TLM-only station, but I was a
>little disappointed that it is inherently non-duplex.  On the other hand,
it
>is, as such things go, relatively cheap, so you could buy two of them, and
a
>second parallel port of course.  I discussed it a bit, and was told that
>modifying the software would not be that big a deal.
>
>
>Alan
>WA4SCA
>
---------------------------------
W0EEC - CM87tm
AMSAT Area Coordinator - San Francisco Bay Area
http://www.projectoscar.net    http://www.emilyshouse.com/W0EEC
http://www.experthams.net/ao7

Help Launch Echo - http://www.amsat.org/amsat/sats/echo/index.html
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