K3 VS 7600 Sherwood List

[Craig-89]

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.




Without doubt there are many SSB transmitters heard on the ham bands which
do generate splatter, but the operator of a "clean" and properly driven SSB
transmitter risks being accused of generating splatter by somebody whose
receiver is generating the splatter. You have mentioned poor front ends, to
which I would add poor filters (in terms of Group Delay Variations out to
the stopband regions), and small dynamic range IF systems as found in many
if not most commercial amateur receivers.

If the ARRL would run complete dynamic range tests, then 'weak' IF systems
would be exposed in the reviews.

Transmitter generated splatter can be dealt with by a receiver, but the
receiver's IF system MUST have a large in-passband 3rd order dynamic range
if analog splatter removal techniques are used.

73,
Geoff
GM4ESD


     
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[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" <[hidden email]>
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.

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[N5GE]

On Mon, 14 Sep 2009 03:19:40 -0700 (PDT), Craig <[hidden email]>
wrote:

>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.
>

Here we go again.

I thought a request to close this thread was made several days ago.

Why not continue the discussion off line by communicating directly?

Thanks,

Tom, N5GE

[hidden email]
K3 #806, K3 #1055, PR6,
XV144, XV432, KRC2,
W1 and other small kits.
http://www.n5ge.com
http://www.swotrc.net

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[n7ws]

Maybe some of the rest of us K3 users are interested.

--- On Mon, 9/14/09, Radio Amateur N5GE <[hidden email]> wrote:

From: Radio Amateur N5GE <[hidden email]>
Subject: Re: [Elecraft] K3 VS 7600 Sherwood List
To: [hidden email]
Date: Monday, September 14, 2009, 9:44 AM

On Mon, 14 Sep 2009 03:19:40 -0700 (PDT), Craig <[hidden email]>
wrote:

>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.
>

Here we go again.

I thought a request to close this thread was made several days ago.

Why not continue the discussion off line by communicating directly?

Thanks,

Tom, N5GE




     
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