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Re: [Amps] Duty cycle for processed SSB in contest conditions?

To: sm0aom@telia.com, k8ri@rogerhalstead.com, amps@contesting.com
Subject: Re: [Amps] Duty cycle for processed SSB in contest conditions?
From: peter chadwick <g8on@fsmail.net>
Reply-to: g8on@fsmail.net
Date: Sun, 23 Feb 2014 13:59:33 +0100
List-post: <amps@contesting.com">mailto:amps@contesting.com>
Karl-Arne

>I personally believe that if and when the administrations finally catch up, 
>the results will be lower power limits and type accepted equipment, as in 
>other radio services.<

I am not so sure. Admittedly, requirements for spurious emissions for the 
amateur services got pushed in as a result of the work of TG1/3 'tidying 
matters up for all services', formed after the WARC 93 (and the TG1/3 really 
only came about because emissions from Iridium were interfering with the radio 
astronomers, who have a surprising amount of influence). The 'Unwanted 
emissions in the Spurious Domain' as they now are creeps via a very convoluted 
and non-explicit route into requirements of the Radio Regulations. But the 
Administrations these days are seeing fewer and fewer engineers being employed, 
most of whom have no experience of equipment design or maintenance, and 
administrative bureaucrats who want to spend less money on regulation and 
international standardisation.

Plus the attitude of less regulation encourages industry.......

But, as you say there is no excuse for a bad transmitted signal as a result of 
overdrive or misuse of equipment. With homebrew amplifiers, that means keeping 
harmonics down by at least 43 + 10 log P dB, without needing to be more than 
50dB for transmitters below 30MHz and more than 70dB down for transmitters 
above 30MHz. That includes IM products more than 10kHz away from the 
transmission centre frequency. 

73

Peter G3RZP


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