In a message dated 9/5/03 10:22:30 AM Eastern Daylight Time,
jimlux@earthlink.net writes:
>>I'd like to know more about that. Indeed, phase and amplitude matching
(particularly with respect to nonlinearities and differing distortion
products from each amp) is a challenge. It's a challenge today with any
amplifier that uses multiple amplifying components, which is why the usual
commercial design rule is use the biggest single device you can find that
can put out the power you need. I don't know about reradiation being an
issue. You're already reradiating in any multielement array, passive or
active.<<
Big difference between passive and active. Passive there is no problem, we
are dealing with one signal being split and phased. With active array there is
a
problem with induced and
rectified/amplified signals from other elements causing distortions. Next
time you hear station with mushy and wide signal, he is probably running two
antennas with two amplifiers closely coupled (except propagation induced
distortion).
Again, what about receive??? Forget the argument of using piece of something
and preamp. If there is no signal from the antenna, there is no amp in the
world that can amplify it. Then there is requirement for Signal to Noise and
QRM
discrimination (pattern control) that is so crucial on receive. This is why
antenna and its phasing is so important, works on TX and RX.
It is easy to use the argument about the progress, but the reality is that
things catch on if they are better, cheaper, easier and other -er. We are
looking for that active, miniature, super-duper antenna that will fit on the
front
lawn or in the attic and beat stacked beams. There are those miserable laws of
physics that are in our way.
Good luck and more power to you, we are standing by and waiting for that
magic solution and the bottom line.
Yuri, K3BU
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