[Elecraft] Orion versus K2 1 kHz dynamic range numbers

[Eric Swartz WA6HHQ - Elecraft]

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
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