beginner question about broadcasting, and associated issues (long range wireless-networking)

[upgrdman]

hi everyone.

i have never posted here before, or in any other radio-related
newsgroup, but i figured now would be a good time to ask some
questions about a field i am curious about for various reasons.

i hope you guys don't mind me posting to the rec.radio.amateur
newsgroup, because it is partly about digital broadcasting...however i
chose not to post to the rec.radio.amateur.digital newsgroup because
my questions are mainly about general amature radio broadcasting.

now to the point.

basically my goal is long-range wireless-networking for a laptop.
currently most if not all wireless networking is limited to about 100
meters from the receiver. i understand this limitation, but i would
really like the ability to use a laptop with wireless-networking more
than 100 meters away from my house.

what i really want is the ability to broadcast to about a mile or two
away, or if im really lucky...10 or 20 miles--but i highly doubt that.
my house is about a mile from some of the places i would routeinly use
a laptop...my high school, the library, and the local coffee shop

i know of some of the ways to boost the typical wireless networking
technologies...some legal, others not. but i would really prefer to
stay within the bounds of the law.

what would i need to accomplish my goals, if it is at all possible. i
have researched a little into this topic, but it doesnt seem to be too
popular, which surprises me. microwave seemed good until i head about
the costs. i cant afford a lot...perhaps 500$ (USA) at most to both
send and recieve the signal. and if i heard right, microwave is
line-of-sight, and i would really prefer omni-directional as most of
the places i would use a laptop aren't located in a line. then i heard
about shortwave, but i havn't heard that much about it. all i really
know about shortwave is that it is used by many countries to broadcast
radio around the planet. i hear that the broadcast works by the
bouncing of the shorthwave signals in the atmosphere, but that without
a high-power signal, reception is poor and spotty if your too far away
from the broadcaster. other than those two technologies, i have little
idea as to what i could possibly use.

if the method you guys suggest requires liscencing from the FCC or
other organizations (i live in the USA -- Southern California) what
are hte requirments/fees? will there be any tests i would need to
pass, and how much is the fee? is it anually, one-time, etc?

if it isnt already obvious, im not very fluent in radio terminology or
technology. my strenth is in computers.

i appriciate your time, and thank you in advance for any replies to
this thread of mine.

thanks,

farrell farahbod

 

[JOE]

You don't have the courtesy to punctuate correctly - a basic courtesy to the
reader - and you're asking for free advice.

**** OFF !!!

 

[Mark]

Since regs don't permit greater power in that band
on those devices. You are left with directional antennas
on both sides. With a yage and direct line of site a mile
should be mo problem.

 

[lbudney]

basically my goal is long-range wireless-networking for a laptop.
currently most if not all wireless networking is limited to about
100 meters from the receiver. i understand this limitation, but i
would really like the ability to use a laptop with
wireless-networking more than 100 meters away from my house.

Note that this question is addressed in the last couple of issues of
QST magazine. Here are the issues to consider:

1) Probably a show-stopper: it is illegal to use your Amateur Radio
license for any commercial purpose whatever. That includes ordering
books from Amazon.com, sending work-related emails, and possibly
even forwarding banner ads to your laptop.

2) Some of the 802.11b frequencies are inside the license privileges
of a ham, and can theoretically be used at higher power levels by
hams.

3) Radiation exposure limits probably confine you to a few watts, if
the antenna is near your body. Since 801.11b uses direct-sequence
spread spectrum, you are confined to a maximum of 100 watts under
all circumstances.

4) Amateur transmissions must be identified. The usual approach
suggested is to make the network ESSID be your call sign. This
limits you from talking to normal APs with different network IDs.

Your first best plan is to look at antennas, but that isn't likely to
give you a mile. The Orinoco Gold card, and some others, have an
external antenna jack, and you can experiment with beam antennas,
AFAIK without any legal implications. That's what I'd do first.

my house is about a mile from some of the places i would routeinly use
a laptop...my high school, the library, and the local coffee shop

School: Get an access point and a DSL router, and set them up
somewhere on your school's LAN. Much easier than beaming a signal to
home.

Libary: Offer to provide wireless as a free service, and put an AP and
router on their LAN, too. (In fact, this gives me an idea.)

Do the same at your parents' and in-laws' houses, but first get them
to go with broadband.

Regards,
Len.

 

[Stacey]

You don't have the courtesy to punctuate correctly - a basic courtesy to
the reader - and you're asking for free advice.

**** OFF !!!

There's not supposed to be a space between "OFF" and "!!!". The nerve of
these people using punctuation incorrectly!

 

[Strontium]

Actually, they forgot one thing...
-
Stacey stood up, at show-n-tell, and said:

To correct you, it should be: "You don't have the courtesy to punctuate
[,] correctly.

Funny, that. One who does not know how to use punctuation, correctly,
using that as a flame. But, I'm not surprised. The well of human
stupidity, is endless.

 

[Master of the universe and supreme ruler of all li]

hi everyone.

what i really want is the ability to broadcast to about a mile or two
away, or if im really lucky...10 or 20 miles ...

... microwave seemed good until i head about the costs ...
... line-of-sight,

Now this will sound a bit strange, but there are several methods of
communicating up to about 1 mile WITHOUT a licence. Radio Amateurs will try
to tell you that you HAVE to get a licence to transmit. This is not so (and
I am a radio ham!). Some methods below are omni-directional, but remember
that most antennas are not omnidirectional. The only omnidirection antenna I
know of is an "Isotropic" antenna, and that is entirely fictional, just like
the square-root of -1, Father Christmas and DXing via a VHF repeater.

1 - Hammer two copper posts in the ground. Attach a wire to each and connect
to them the output of an amplifier. Connect a modem tot he input of the
amplifier. You will need to set the modem to "leased line" operation so it
doesn't look for a dialling tone. The receiver station, 1 mile away, is two
copper posts hammered intot he ground and connected to a small-signal
amplifier input. The output of the amplifier is the input of the second
modem. You should easily get 1-mile if both have the rods about 10 meters
apart.

Disadvantages - It doesn't work too well in the dessert (I have tried it
just outside Jeddah on the old Makkah road). It is not too brilliant in well
built-up areas since you also pick up a load of mains hum. It may not be a
problem for a modem, but it sounds bad on the ears. A filter?

Advantage - it DOES work well underground, if you can fid a place to hammer
the electrodes. When experimenting in "Swildens Hole" in the Mendips there
was a river following the cave (a stream, actually, but it seemed like a
river when 1/2-way up an electronladder and it's pounding down on your
helmet) and the electrodes can just be dropped in the water. Most caves just
have rock.

2 - Modulated Laser transmitter and photocell receiver in torch / headlamp
reflector, but this is quite directional. The laser can be modulated quite
rapidly by bouncing it (reflecting) from one of the side electrodes of a
Quartz crystal. They are plated with copper and allow you to modulate up to
several 10's of MHz. The laser only needs to be a low-power 5mW or so
visible-light laser. I used a 2mW to get over 100 feet this way.

When I tried a 25mW laser I had the police round (Grunty Fen,
Cambridgeshire, 1988 - G8TGL). They said I had "crossed communication
routes", but I was shining the thing on Ely Cathedral clock face (3 miles
away), so I suppose I deserved what I got. Incidentally, I used this method
to make a 4' square oscilloscope - HiFi driving speaker cones with mirrors
mounted on them. Beam projected down garden and reflected by by mirror. HiFi
channels driven from Apple IIe computer.

Disadvantage - not exactly omni-directional, or anywhere near it.

3 - Modulated infra-red LEDs. Can be made about as amni-directional as a
2-ele Yagi and you can modulate with a whole radio spectrum, up to about
10MHz. This means that instead of antennas you can transmit using your own
private radio spectrum. Great for teaching boyscouts and newbies to hamradio
how to operate a transmitter or training morse code. Use ordinary
commercial/homebrew receivers and QRP transmitters. You can even add a part
of the radio spectrum as background noise by connecting an antenna to
wideband amplifier and modulating another IR LED. This method is great since
the only radiation is modulated light for which you do NOT need a licence.

Disadvantage - if you shine each LED on the ceiling you can cover a whole
church-hall using, sensitive receivers (mine was FRDX400) and each LED
transmitter is a bank of LEDs - but it is crap outdoors, since you cannot
see IR so you cannot focus or point the beam.

4 - Magnetic induction - If this were in reality "radio" then Mahlon Loomis
would have been the father of radio in 1868, NOT the spaghetti-basher
Maccaroni in 1904orsomethinglikethat. Basically, if you pass a DC current
through a wire, you get a momentary DC current induced in a parallel wire,
since the two are coils (transformer principle).

In 1970 (RAF Locking, and Tern Hill) I listened to my HiFi whilst in the
bath in an RAF barrack block. The distance from my room to the "ablutions"
(millitary talk for bathroom) was about 150 feet. I took a 20-foot length of
10-pair telephone cable and cross-connected the ends so I had a 20-turn coil
of wire about 6-foot in diameter. I connected the two ends to the two
speaker terminals of my HiFi and the ground to the centre-tap.

The receiver for this was a TV Line-Output transformer ferrite core (they
come in 2 halves) stuck (glued) end-to-end with a rod of ordinary MW aerial
coil between. In effect I had a 18-inch long ferrite rod; the middle bit
thin. I wound about 600 turns of wire on the middle bit and connected that
to a transistor amplifier. Voilla! I heard my stereo (now in Mono). Perhaps
you can connect this system to modems? Dunno about the range, I had a VERY
strong signal, but I never tried to exploit the range above the required 150
feet.

Dissadvantage - In those days ordinary hearing aids used valves and had a
magnetic microphone. The corpral on the floor below me was megga pissed-off
since he did not like Jethro Tull and "Groovin With Mr Bloe", but he never
found out it was me, thank God! Today there are other magnetic thingies
around. You may have other problems, but I am sure that the old corpral from
Turn Hill is now dead. He was an "old codger" over 30-years ago.

Finally,
5 - Broadband - Get yourself a broadband connection from your local ISP and
connect to your home computer. You should know the IP number. You could even
try putting all your info on a single hard disk and taking that around with
you. But these simple solutions are often not the most impressive when
showing-off to visitors.

http://w1.859.telia.com/~u85920178/

Very best regards from Harry -
(Alias - Master of the ... oh, my fingers hurt!)

 

[Master of the universe and supreme ruler of all li]

hi everyone.

Now this will sound a bit strange, but there are several methods of
communicating up to about 1 mile ...

I forgot something -

1 - Delete "Turn Hill" - insert - "Tern Hill"
2 - Correct all the other spellin errrors
3 - Forgot one last method: - telephone!

 

[Terry Judkins]

http://www.oreillynet.com/cs/weblog/view/wlg/448
"Master of the universe and supreme ruler of all living beings (but only