----- 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.
>
> In 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
>
>
>
> Paul wrote:
>
> > RE: K2 Rig comparison chart.....
> >
> > Several K2 owners have Tentec rigs and several Tentec owners have
Elecraft
> > gear and belong to both boards.
> >
> > It is the Expanded Test Report rating list that is what caught my
attention
> > and where the our beloved K2 is ranked so far down the list ......
> >
> > The red numbers for the competition posted on the website can be
corrected quickly
> > but will having a newer K2 with all modes submitted for ARRL
re-evaluation
> change
> >the results of where the K2 stands in this most recent ranking of
radios? The
> > competition will use this report as the ready reference for
all...........
> >
> > Listed in order of 1 kHz IMDDR3 results:
> >
> > Radio IMDDR3 BDR (interfering signals at 1 kHz)
> >
> > TT Orion 84 dB 119dB
> > FT-1000MP 78 108
> > IC-756PRO 75 104
> > IC-775DSP 73 103
> > TT Omni VI+ 71 85
> > IC-746PRO 70 92
> > IC-746 70 88
> > IC-756PRO2 69 92
> > FT-1000MkV 69 100
> > Elecraft K2 66 115
> > TS-870 63 87
> > FT-1000Field 60 88
> > JRC NRD-535 50 86
> > IC-756 50 85
> >
> >
> > This quote is then added
> >
> > " Also, it is interesting that the K2 goes from stellar performance
> > at 5 kHz to one of the worst at 1 kHz. This may have to do with the
> > quality of the K2 CW filter which was available at the time of the
> > test (unit was S/N 495) which has subsequently been improved for
> > S/N >3000 (a mod is available as an update for older units). I
> > understand ARRL is doing another test of the K2/100 which will
> > probably be more meaningful, so I would take these results with a
> > grain of salt for the current K2."
> >
> > Wayne - How is the newer K2 going to rank in the retest?
> > And what do you think of this Expanded Test Report and how it places
> > the K2?
> >
> > Paul K8QT
> > _______________________________________________
> > Elecraft mailing list: Elecraft@mailman.qth.net
>
>
>
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