Hey Bill:
Most interesting information! I'd like to see where the Ten-Tec
Argonaut V ranks on this comparison. Can you shed any light on the subject?
73 pal,
Rod
K5BGB
Bill Tippett <btippett@alum.mit.edu> wrote:
Orion's swept BDR and IMD graphs are very impressive!
While I was waiting for this report to be published, I went through
most of the ETR's for popular radios on ARRL's summary page here:
http://www.arrl.org/members-only/prodrev/reports.html
What I did was to record the lowest data point for IMD and
BDR for all radios. I believe this minimum point represents the worst
case ARRL measurement for 1 kHz interfering signal spacings, but
it could be 5 kHz for some older tests (like the FT-1000MP in 1996).
Maybe Michael can confirm this when he returns from a well-deserved
break! It's difficult to read some of the graphs, but I assumed all are at
1 kHz. Why is 1 kHz important? 1 kHz spaced QRM is not at all
uncommon in popular CW contests (CQ WW, ARRL DX, 160,
Sweepstakes etc).
I may have made some mistakes but I believe this data is
accurate from my interpolation of ARRL's swept BDR and IMD
graphs, which appear only in their Expanded Test Reports. If
anyone finds major errors, let me know and I will update the list.
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
Several of these results seem inconsistent IMHO.
For example, I have never understood the vast differences
in ARRL measurements for the FT-1000MP versus Mark V
versus Field, since they all have basically the same
block diagram. 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.
73, Bill W4ZV
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