----- Original Message -----
From: "Eric Swartz WA6HHQ - Elecraft" <eric@elecraft.com>
To: "Paul" <pfb@adelphia.net>
Cc: <btippett@alum.mit.edu>; "Elecraft List" <elecraft@mailman.qth.net>;
"Wayne Burdick" <wayne@elecraft.com>
Sent: Friday, December 12, 2003 1:36 PM
Subject: Orion versus K2 1 kHz dynamic range numbers
Both the Orion and the K2 are excellent performers. In no way am I
disparaging the Orion, which is an excellent top of the line high end radio. We
are
probably splitting hairs by trying to discern less than 5 kHz spacing data
from low resolution graphs, but here goes :-)
The 1 kHz numbers posted by Bill to the Ten-Tec reflector for the K2 from
the 2000 ARRL expanded test report are not correctly read from the ARRL
graphs. Also, at the time the ARRL made those graphs for the K2 (March of 2000)
and many of the other rigs, I believe they were not focused on accurately
taking data points at less than 5 kHz. For his K2 pre-amp on 1 kHz IMDDR3 number
of 66 dB Bill made the mistake of using a data point on the graph that
appears to be -inside- the 500 Hz crystal filter, not 1 kHz away. (To be honest
there
are very few data points in that area to use.) Also the graph he was reading
uses 50 kHz per division, making it almost impossible to accurately read a 1
kHz number, even when you squint real hard. Our 5 kHz pre-on IMDDR3 is closer
to 88-91 dB, and if you calibrate the graph to that point you get between 75
and 82 dB for our 1 kHz number, which matches our lab data, putting us in the
top performing group of rigs. (But my eyes hurt!)
Even though Bill ranks us #2 in BDR at 1 kHz (115 dB versus 119 dB for the
Orion - well above the JA rigs) he also makes the same mistake, using the
central data point on the graph that is inside the filter, on a 50 kHz per
division scale. A more accurate 1 kHz number looks like around 120 - 125
dB. Don't forget that different test set ups and rigs can vary several dB.
Results within 2-3 dB are essentially the same.
The red numbers on our web site's comparison table are for ARRL results
that are 10 dB or more worse than the K2, a sizable difference. I believe it is
correct, but please email me with any corrections and I'll update it ASAP.
Also, the table is not organized as a top to bottom ranking since many
test parameter results are presented. I
n any case, the latest ARRL expanded test reports have a more accurate
scale for the swept dynamic range tests at close spacings. I can't comment on
the possibility of new ARRL data for the K2, but if they ever post updated K2
data in the future I'm sure everyone will have their questions answered :-)
I'll update our table for the K2 and other rigs as new ARRL data appears.
Its pretty cool that two American manufacturers hold the top receiver
ratings. I hope we can maintain this in the future!
73, Eric WA6HHQ
http://www.elecraft.com
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