On 09/20/2014 03:28 AM, Heinz Diehl wrote:
On 20.09.2014, Doug wrote:
> First: Higher power does NOT increase noise in the signal. It just increases the
amount of
> radio frequency energy in the general area, which may be "noise" to some
_other_ piece of equipment.
Yes, you are right. I was imprecise. What I meant is that barely
increasing Tx power is not verly likely to help. Increasing it over
the limit does more harm than good, leading to unstable connections
and data loss.
The Tomato firmware wikibook says:
"Transmit Power: Sets the transmit power in milliwatts. High settings
may cause nonlinearity in the transmitter causing loss of data,
interference to other users and channels, and a high “noise floor”. It
may also overheat and shorten the life of the transmitter."
I have experienced that myself while experimenting with it. A subtle
increase did no harm, but was no improvement either. Increasing the Tx
power further lead to a big amount of retransmissions and decreased
speed.
As you mention, increasing transmitter power without modifying the transmitter to
handle more power
would make it non-linear and the distortion would increase the error rate. Nowhere did I
advocate
raising transmitter power. I mentioned several ways of increasing the _signal strength_ by
either
moving the antenna to a better location--i.e., higher up and in the clear, or by finding
an
antenna with higher gain. It is obviously not within the purview of the average computer
user to
increase transmitter power. An antenna has "gain"--when it puts more of the
signal into a
specific area than one which spreads the signal in a large volume of space. Normally one
thinks of an antenna putting out power in almost all directions, like the light from a
bulb.
Notice, however, that if you put a reflector behind a bulb, more light goes in one
direction.
It is also possible to get more _effective power_ in a circular--not globular--space by
scrunching
the radiation pattern down vertically into a horizontal pattern that resembles a
phonograph record.
So the power which is not going up towards the ceiling lights is now going out to other
workstations.
--doug