The ARRL has not published lab tests on the SDR-1000 to my knowledge,
but I do have one here in the lab.
Its an interesting approach for a 100% computer based rig and in general
its RX performance is not too bad, but is is well below the K2 for IMD
dynamic range and Blocking dynamic range.
It relies on the sound card in the PC to do all of its filtering, which
makes it's performance quite variable depending on what quality sound
card is in use and how it is set up by the user. In any case though, the
current PC sound cards do not have enough A/D input range to get the
same dynamic range performance as rigs (like the K2, Orion. etc) that
use narrow crystal filtering at their first IF.
It also uses a direct DDS based local oscillator (without a following
PLL to clean it up) for its VFO, which will have numerous significant
off freq spurious responses in the -80 to -90 dB range that will mix off
frequency signals onto your listening frequency. These spurious receive
components absolutely can not be canceled out by the DSP once they
occur. They look identical to legitimate on-frequency RX signals to the
DSP. As a comparison, the K2 and other top performing rigs have local
oscillator noise (with no spurs) at -125 to -130 dBc range five to ten
kHz from the carrier. A big difference.
Even more important, the direct DDS approach creates the same DDS off
freq. spurs on transmit. Not a great idea then running 1KW etc.
In results obtained by me with Leif Asbrink on 14 Mhz,
the IP3 is over 10dBm <IF> you set the thing as it should be.
The Elecraft K2 is 20+ dBm with preamp off at 5 Khz.
SDR-1000 BDR is 105 dB, the Elecraft K2 is 135 dB
It IMDDR3 is 99 dB, the Elecraft K2 is better.
The DDS does produce spurs BUT the DDS is not directly driving
the mixer. This is often misunderstood. The DDS output
does not even touch the mixer. The DDS output is hard limited
and that hard limited signal is using to drive a switched
capacitor network. What spurs there are, are CONSIDERABLY
better than driving it directly. In this regard Eric is slightly off in
his implications in that if driven directly by the DDS, the
mixer would be a mess. The worst spurs are "buffered" away
On the other hand, some spurs get through as phase modulation
on the bus switches driving the switched capacitor front end.
I know this well. I spent months perfecting this ingenious
method for escaping the AM spurs and the PM SPURS are what is
These spurs are annoying and I hope that Gerald in his "next radio"
or next generation boards (whatever) finds a way to clean this
up. That said, what spurs there are, are way down and on
transmit, even with the 100w amplifier these transmit spurs
are so far below legal limit as to be not a thing to worry
about. On receive, they are annoying because Gerald has
built too much sensitivity into the receiver. With everything
flaming, he has < -140 dBm as the MDS. This is about 15 dB too
sensitive for HF work and of course you can raise the IP3 and BDR
WITH A GREAT SOUND CARD by attenuating the front end. With a
great sound card, I raised the BDR by 15 dB while keeping the
MDS the same even though I put another 6 dB of attenuation
inline! I was able to increase the IMDDR by changing the roofing
filter (switched capacitor filter values) and increased the
IP3 to TOP OF CLASS, BETTER THAN EVERYONE EXCEPT THE IC7800 with
a change of front end device! By the way, my sound card
cost $1000. SO, you can take your knife and soldering iron
and make it a great receiver. NOT FOR EVERYONE!
The League recently purchased one for review. Their results
will be interesting to see but the K2 will remain the king.
I would take away from this discussion that the Elecraft K2 is
and will be at the top of the heap in these raw numbers. The
SDR-1000 in my view is about 4-th or 5-th on the "Elecraft
receiver comparision chart" as it comes from the shop. I can
make it almost best on the chart with surgery. So the SDR-1000
is for those who do not mind a never ending beta project. It
really is interesting and I have spent hundreds of hours
programming the DSP for it along with AB2KT. It is in the spirit
of the tinkering amateur radio operator who doesn't mind
modifying their existing radio to make it better. SOUND FAMILIAR?
On Field Day, I supplied to W2GD, Elecraft K2's for our QRP
FD (2A Battery) and we came in sixth overall. I own three
transceivers. Elecraft K2, SDR-1000, and FT1000MP. The FT1000MP
has not been here for months because it is at my contest
multi-multi site (N3NGE's house) as the two meter radio (with
transverter). The K2 and the SDR-1000 are fantastic radios
but it pays to investigate what is right for you. If you are
interested in an open source project that is really interesting
and will continue to be interesting for a while, SDR-1000 is a
really good radio. It is NOT the "best radio" in what would
be most people's estimation. Gerald has been in business for
two years and has probably learned a lot from this experience.
He has sold over 500 of the radios and has had 5 returned.
Three of those folks didn't know they needed a computer! Two
of them could not download new software. I don't think he
has had a truly disatisfied customer. The SDR-1000 is a real
darling of many bleeding edge types in the EME community. It
does things others cannot do (some of these ideas stolen from
Linrad, etc.) That said, it is a radio in training and
Gerald's next offering whatever that is and whenever it will
be is likely to be a really nice one. In my mind, the Elecraft
K2 is at the top of the heap for best receiver. It never ceases
to amaze me that Wayne and Eric put together a kit that
continues to put the big boy's to shame.
My Elecraft K2 and SDR-1000 sit side by side and they fight daily
for my attention!