[1000mp] ARRL data - 1 kHz IMD and BDR performance

[Bill Tippett]

SP5CFD wrote:
 >Notice the FT-1000MP receiver has been measured by ARRL with two cascaded
500Hz filters. Mark-V and Mark-V Field have been measured with only one 500
Hz filter. It can make some difference in measurements with close spacing
high level signals.

         Peter, I just did a quick scan and it was not clear to me that
only one 500 Hz was used in the Mark-V / Field tests.  I thought
ARRL always bought all 500 Hz filters available for their test units.
The following is from their test procedure document, and note the
phrase "IF filters":

"The test is conducted with the receiver in the CW mode using the
500 Hz, or closest available, IF filters (or audio filters where IF filters
are not available . For DUTs that have appropriate IF filters, all audio
filtering is disabled.)"

http://www.arrl.org/members-only/prodrev/testproc.pdf (page 38)

         If you are correct, this could indeed account for some of the
differences between the original MP and subsequent Mark V / Field
measurements.  I'm copying KC1SX at ARRL on this note so hopefully
Mike will clarify this issue for us.

                                 73,  Bill  W4ZV