Re: RF power chain mods and improvements..


Howard Fidel
 

This is the regulation for amateur  transmitters below 30 MHz:
 For transmitters installed after January 1, 2003, the mean power of any spurious emission from a station transmitter or external RF power amplifier transmitting on a frequency below 30 MHz must be at least 43 dB below the mean power of the fundamental emission. For transmitters installed on or before January 1, 2003, the mean power of any spurious emission from a station transmitter or external RF power amplifier transmitting on a frequency below 30 MHz must not exceed 50 mW and must be at least 40 dB below the mean power of the fundamental emission. For a transmitter of mean power less than 5 W installed on or before January 1, 2003, the attenuation must be at least 30 dB. A transmitter built before April 15, 1977, or first marketed before January 1, 1978, is exempt from this requirement.

So, -43 dB is our threshold, which we meet.

Howard

P.S.  it is - 60dB above 30 MHz.

On 6/4/2018 8:56 PM, ajparent1/KB1GMX wrote:
Howard,

10 W from IRF510s at 10M is doable I've seen it already.  For  that fact they will
easily produce 10W on 6M (at 13V much more at 24V).

The spur if its 46db down is not compliant as its out of band and it has to be far better.
The accepted number is not less than -60DbC  You may get away with less but 
I'm not comfortable doing that.  Bandpassing it does help. In band you can be
-43db and be compliant so harmonics and spurs must be only that within
the ham bands.

I can run any voltage as the audio amp has a seperate 8V regulator.

Allison


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