[hpsdr] IMD in Ham transmitters

Keith Gooley vk5oq at activ8.net.au
Sat Jan 19 14:38:14 PST 2013

Hi All,

If the commercial suppliers are claiming an extra 6 dB for PEP then that 
doesn't seem right in my view. The IMD level increases at a rate greater 
than the increase  in power, 3rd order IMD which is mostly what we are 
talking about, increases at 3 times the rate of increase of the 2 signals 
generating the IMD product. So if the output power is doubled (3 dB 
increase) the IMD increases by 9 dB. Hence the IMD level relative to the 
main signal is 6 dB worse.

73 de

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