[1000mp] Rig Comparisons - ARRL Lab Results

[Tom Rauch]

> privately with Mike Tracey at the ARRL labs and have concluded that
> this table of figures, which has been widely circulated, is an
> inaccurate presentation of the relative performance of these radios. 

Right you are. IMD and blocking figures measured at 20kHz or 
even ten kHz (if you are not careful to have BOTH signals within the 
roofing filter passband) are useless for real-world operation.

The exception would be if you operate on nearly empty bands, with 
no one strong within 5 or 10 kHz of your frequency. 

> For example, close-in BDR for the K2, Omni 6+ and 1000MP from the
> ARRL's own published graphs reveal figures of 116dB, 86dB, and 108dB
> respectively, disagreeing considerably from this table.  As soon as
> the spacing is greater than 10Khz, the 1000MP beats the K2.  At a
> spacing of 20Khz, the 1000MP delivers almost 20dB better BDR than the
> K2 and 15dB better than the Omni 6+.

A performance comparison that is useless in most cases, unless 
you are running two radios on one band at one location.

For example, I found the FT1000D totally useless in contests 
because several modest strength signals inside the roofing filter 
bandwidth (+-5kHz or so of my operating frequency) generated all 
sorts of spurious bloops and bleeps. This wasn't even in a crowded 
contest with many high power stations, it was in the Stew Perry 
160 contest! Operation was so disappointing, I stopped and took 
the radio out to my shop to see what was wrong.

Turns out Yaesu has the noise blanker amplifier transistor run full 
gain when the noise blanker is OFF, and that transistor generates 
all sorts of crap that feeds back from the gate into the 70MHz IF.

MP's do something similar, although turning down the blanker gain 
control in the MP does help reduce the problem.

IMO, even 5kHz is a wide test. BOTH test signals must be within 
the passband of the roofing filter to produce a valid test of real-world 
conditions on crowded bands.

Maybe Yaesu did the same silly thing with the MKV blanker they 
did with the 1000D blanker, if so it would be an easy thing to repair.

73, Tom 


> >Close In IMD Dynamic Range and Blocking Dynamic Range at 5 kHz Signal
> >Spacing (ARRL Lab Results)
> >
> >(Pre-amp off, 20M)
> >
> >     Rig            IMDDR3   BDR
> >Elecraft K2          88     126
> >Ten-Tec Omni 6+      86     119
> >Yaesu FT-1000MP      83     111
> >ICOM IC-756 Pro      80     104
> >Yaesu FT-1000MP MkV  78     106
> >ICOM IC-775DSP       77     104
> >ICOM IC-706 MkII G   74      86
> >Kenwood TS-570D      72      87
> >ICOM IC-756          67      98
> 
> 
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