[Elecraft] K3 VS 7600 Sherwood List

[Geoffrey Mackenzie-Kennedy]

Hi Craig,

The spacing of the two test signals used to determine a receiver's 3rd Order 
Dynamic Range (IMMDR3) should include tests with both test signals inside 
the receiver's *overall* passband, which in the case of receivers designed 
for amateur use would provide us with some measure of receiver performance 
in the presence of strong QRM inside the IF passband (and up on the filter 
skirts) e.g. in a "no-split" pileup.

The results of tests, in which the spacing between the two test signals is 
much greater than the receiver's overall passband, do not provide this 
measure of performance because the IF and stages which follow see only one 
healthy test signal due to the presence of an IF filter, e.g. 2 kHz spacing 
with 400 Hz filter. Thus the post filter stages do not or should not 
generate significant IMD products during this test. In reality these test 
results reflect the IMDDR3 of the front end, sometimes coloured by the input 
crystals of the filter.

The phase noise generated by the test equipment must be suitably low of 
course.

Deliberately I am not making comment on the effects of receiver LO phase 
noise, nor multi-signal IMDDR3 evaluation.

Sorry to be slow to reply and brief, we have visitors staying. I will reply 
to you later about splatter removal.

73,
Geoff
GM4ESD



----- Original Message ----- 
From: "Craig" <vk3he at yahoo.com>
Sent: Monday, September 14, 2009 11:19 AM

> Hi Geoff
>
> What do you mean by  "complete dynamic range tests" ?
>
> Could give us a brief description of what these "analog splatter removal 
> techniques " are and how  they are used?
>
>
> 73
> Craig
> VK3HE.