Why
so hostile? I am not trying to upset you. I made it
perfectly clear that I was referring to the transverter port
at 0dBm and that I only operate at 50MHz and above. I also
said that the K3S PA was a disaster on 6m, it is and that is
why I use the TS-890S. I also said that I cannot achieve
these numbers on 50MHz but accept it because of the higher
noise floor on 6m. My aim is to be a good radio neighbour
and to try and get others to do the same. You are obviously
one who cares about such things, so I think that we are on
the same side here. You did not bother to read my post
because you have your own preconceptions. You just want
agreement that PS on the ANAN-7000 is the cleanest possible
signal available. I agree FWIW.
My
measurements were on HF, 28MHz to be precise and appropriate
for some potential users.
You
made a statement that Class A amplifiers cannot be better
than -40dBc 3rd orders, that is not correct.
Analogue TV amplifiers are better than -50dBc and have been
for years. They used to operate at 1kW or more. I just
grabbed the first thing that I could find that was not
heavily mathematical to show that class A amplifiers were
not limited to the constraints you mentioned. A mini
circuits datasheet seemed reasonable. It is harder to get
good IMD at 950MHz.
I
am not the only one who is going to use the Hermes with
transverters, the thread was originally about Hermes. Simon
said that it is better to start clean rather than use pure
signal as a crutch. I agree. The Hermes is a clean source.
Regards
Conrad
PA5Y
On Fri, Feb 25, 2022 at 08:16 AM, Conrad,
PA5Y wrote:
Look here at figure 3a, this is a Class A
RF amplifier with no pre-distortion running at 2W per tone.
The IM3 is -51.48dBc, this is at 950 MHz.
Conrad,
Good grief! This entire topic of your claims of wildly
spectacular IMD3 numbers for your K3S and 890S has nothing to
do with tiny amounts of power at 950 MHZ! The radios we're
discussing (and the 7300 and the ANANs) operate at HF, not
gigahertz!
And we've always been talking clearly in terms of final PA
stage IMD3 levels, not some measurements taken at a
transverter jack.
Show me the measured IMD3 from your K3S or 890S at the output of the PA finals
at any power level over 5 watts, at any frequency the
finals are designed to
operate at, and show me it's anywhere near -50dB. Go ahead,
I'll wait...
Mark
