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Re: [Amps] Maximum RF output in practical application: 4-250A

To: "zdtech" <zdtech@iprimus.com.au>, <amps@contesting.com>
Subject: Re: [Amps] Maximum RF output in practical application: 4-250A
From: "Tom W8JI" <w8ji@w8ji.com>
Date: Mon, 3 Jul 2006 08:32:03 -0400
List-post: <mailto:amps@contesting.com>
I think based on the work by SM5BSZ i think a good standard 
to aim for
in ham transmitters would be the FCC's Part 80 maritime IMD 
mask
standard. It requires  3rd order products to be down 30 db 
as referenced
to 1 of 2 tones. The standard  addresses   the specific 
issue of wide
band splatter in that the standard requires higher order IMD 
products
of the 11th order to be down 75 db. This is even more 
stringent than
what SM5BSZ wishes for. I think from memory it  was 
something like 80 db
down at 20khz that he was calling  a "clean" transmitter, i 
cant recall
what reference  he was using whether it was PEP or below one 
of 2 tones.

Craig
VK3HE>>>>>>

The high-phy audio boys aren't going to like this, because 
to meet that spec we would have to restrict the amplitude 
level of the lowest and highest modulating frequency as well 
as make sure exciters were cleaner.

Otherwise we would have to toss out the -80dB at 20kHz 
concern, and if we do that we might as well let everyone be 
a bandwidth pig whether from class C splatter or Ted Baxter 
syndrome. Doesn't matter how it gets there if it is out 
there.

What we need to do in amateur service is just set a 
bandwidth limit. If you are below such a signal level at 
3kHz on SSB, you can be doing anything you want in that 
3kHz.

The ARRL's BW proposal was a good basic idea.

73 Tom 


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