[Elecraft] Sherwood ranking

[Geoffrey Mackenzie-Kennedy]

Gary,

One answer to your first question is that the results of IMDDR3 tests at 2 
kHz spacing, performed with a 500 Hz IF filter inline, do not themselves 
tell you how a receiver will cope with two or more close spaced and strong 
signals inside its 500 Hz passband.  In the case of a superhet, these tests 
at 2 kHz spacing only provide a measure of the IMDDR3 of the front end and 
usually the input part of the 500 Hz IF filter.  They do not expose any "IMD 
weakness" which might exist in the complete IF filter, the IF or the backend 
of a receiver.

73,

Geoff
LX2AO


On August 11, 2012 at 12:06 AM, Gary Gregory wrote:


> *Barry,
>
> Perhaps more to the point..How does the measurement from Sherwood relate 
> to
> real time performance and usability for the operator?
>
> In what way does an operator detect a difference so small between say the
> top 3 on the list?
>
> Is the price differential worth buying say position one in the rankings
> over a transceiver ranked at 2 or 3?
>
> Whilst the ranking may be valid in the single measurement as shown, in the
> real world the vast majority are unlikely to ever detect such a small
> difference if all the top 3 ranked units were sitting in the shack side by
> side etc.
>
> I guess it comes down to which one looks the prettiest....:-)
>
> Oh yeah, beauty IS in the eye of the beholder right? (I say this everyday
> when looking in the mirror in the hope I don't scare myself too much)
>
> Gary