[TowerTalk] The bad news

Tom Rauch w8ji at contesting.com
Thu Jul 21 00:24:22 EDT 2005


> However, the evidence is that narrowband digital  (psk31)
will
> copy at signal levels you cannot hear...making CW less
than the
> ultimate weak signal mode...although certainly simpler.

Sorry Jim, that just isn't true. That rumor probably comes
from the fact many people using PSK don't understand radio
systems very well.

People listen to a receiver on 2-3kHz bandwidth and can't
sort the tone from noise. They then go away enamored with
PSK, thinking it is a magical answer to all things weak.

What they forget is the PSK system "listens" through a
narrow filter of less than 100Hz. If they knew CW and
listened to the CW or PSK tone with the same bandwidth and
the same slow sending rate as PSK they would find a good CW
op can copy as well as or better than a PSK signal will
print. The balance really tips in favor of CW when you
consider transmitter energy used and dynamic range of the
system.

PSK has horrid dynamic range, that's why PSK operators are
constantly at each other's throats about antennas and power.
They demand everyone run low power and often suggest people
use an intentionally poor antenna to keep signal levels
down. The reason they make those demands is PSK is
inherently a very poor system for dynamic range. PSK depends
on distortion-free operation of every mixer and gain block
between a D to A converter in the sound card at the
transmitter and an A to D converter in the sound card at the
receiver.

I think what Hams miss is the dumbing down we are going
through, and make no mistake about it Ham radio is dumbing
down, is a social change. Societies eventually peak
technically. They lose basic skills because those basic
skills are replaced by "advanced" technology that springs
from the basic skills. That's where we are at.

Get used to it. Basic skills that are the root of our
technical advancement are going away. People are getting
lazy, and most people don't want to learn technical things
just for the sake of enjoying learning. The fashionable
thing is to make an excuse why basic skills aren't useful.

73 Tom



More information about the TowerTalk mailing list