[Amps] rich Richard - tiny antenna

[Jim Brown]

On Mon,4/10/2017 7:45 AM, Jim Thomson wrote:
>    Get your buddy K6XX  to fix the lousy TX imd on the K3.   Its on
> a sweep tube level.  -23dbc for IMD-3.  The 10 watt version of that K3
> is no better either.  It needs a serious re-design of the entire pa section.

IMD in the K3 and K3S are a function of output power and DC supply 
voltage. ARRL tests at rated power, where IMD is highest. IMD is 
considerably lower at 50W, which is what is needed to drive most amps to 
legal limit. And 4X6GP has noted more recent ARRL lab test data. K6XX 
showed data in this talk to NCCC in  2013.

http://k9yc.com/K6XXAmpTalk.pdf

More to the point -- when I have done careful measurements of occupied 
bandwidth of a small sample of rigs and amplifiers, and also compared 
ARRL data for CW bandwidth, the K3, K3S, and now the Flex radios with 
their latest firmware are the cleanest rigs on CW, by far. Next below 
them is the TS590. And on SSB, using pink noise (an excellent audio test 
signal that simulates speech content) or actual speech, there is 
virtually no difference between a K3 driving a Titan 425 or KPA500 and a 
FT1000 Mark V Field at full power or at half power. And the bandwidth of 
the K3 driving the Titan or the KPA500 is virtually the same as with the 
K3 barefoot at the level it's driving the amp.

My measurements are here. :http://k9yc.com/P3_Spectrum_Measurements.pdf

Comparisons of ARRL data is here. http://k9yc.com/TXNoise.pdf This 
summary was done in 2014.

73, Jim K9YC