[ale] OT: How fast is your connection, and how much do you pay?

[Glenn C. Lasher Jr.]

On Tue, 26 Mar 2002, Charles Marcus wrote:

> I believe that the wattage is very small - a friend of mine has one,
> and I seem to remember reading something somewhere about his, and
> thinking that it was really small.  I guess it is the high freq that
> makes it usable.

Quite the contrary.  Higher frequency tends to work against you in
propagation matters.  The reason why you can use very low power levels on
satellite are twofold.  First, you are using a very high-gain antenna, in
the form of a parabolic reflector (i.e. the dish).  Second, you have an
almost-completely unobstructed line-of-site.  Given such an unobstructed
line-of-site, you can have satellites operating on 144-148MHz (ham radio
frequencies) just as easily as on 30GHz, if not more so.

The only physical requirement with respect to frequency and reaching a
satellite, is that the frequency be high enough that it is not reflected
back by the upper layers of the atmosphere.  Such reflection is called
"skip" and is responsible for shortwave radio being able to have the
tremendous reach that it does (worldwide communication without satellites
or cable is possible on shortwave).

The exact frequency varies, but is usually below 30MHz.  Sometimes it
ventures as high as 80MHz, sometimes as low as 7 or 8MHz.  If you want to
look it up, it is referred to as the "Maximum Usable Frequency" or MUF.
Of course, usability here refers to usability for skip, which
counterindicates usability for satellite.


--
glasher at nycap.rr.com
You've been programmed by the Illuminati not to see the word "".


---
This message has been sent through the ALE general discussion list.
See http://www.ale.org/mailing-lists.shtml for more info. Problems should be 
sent to listmaster at ale dot org.