Re: Topband: Receivers, Noise Blankers and Key Clicks

[Bill Tippett <btippett@alum.mit.edu>]

W8JI wrote:
>If close-spaced dynamic tests were published in QST reviews, many of these
problems would be corrected. Manufacturers will only test the parameters
that get headlines in reviews, so the real key is getting the ARRL to
publish close-spaced test data and occupied bandwidth data for transmitters.

>The tests would have to be at 500Hz spacing on CW, not 2kHz. One new radio
about to be released has a ~2kHz roofing filter making it have really
inflated 2kHz test figures, but we really need 500Hz or less spaced
performance data for CW.

        ARRL does test BDR and IMD to 1 khz, but you have to dig for the data
to find it.  It appears in the Swept BDR and IMD graphs which normally can
be found around page 20 of each Expanded Test Report.  Unfortunately, I
learned that ARRL will discontinue the ETR's except for top-of-the-line
transceivers (the IC-7800 may be the last one for awhile).

        The only exception to 1 kHz measurements below is for the original
MP, done in 1996 before KC1SX took over ARRL's testing in 1997.  Since
then, they should be fairly consistent since they done made by the same
person using the same test procedure.

In order of 1 kHz IMDDR3 results (14 MHz, 500 Hz BW, preamp off):

Radio                        IMD               BDR

TT Orion                        84 dB*                  119 dB*
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

*Orion's IMD and BDR were also shown with preamp on and
were 91 dB (surprisingly) and 119 dB respectively.

**FT-1000MP IMD at 2 kHz and BDR at ~500 Hz per KC1SX.

Source: 
<http://www.arrl.org/members-only/prodrev/reports.html>http://www.arrl.org/members-only/prodrev/reports.html

                                                73,  Bill  W4ZV



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