Interesting Quick Thought

Darryl Smith Darryl at
Sun Jan 20 21:12:44 EST 2002

It is certainly possible for people to have antennas one one or many
frequencies. The problem is making the antenna usable at many
frequencies. A switch between frequencies of the antenna is called a
filter, or diplexer. 
Invariably though the TV antenna needs to be pointed in the wrong
direction. Even if you do have all antennas pointed to an access point
at the source of the TV transmissions, things get worse since all users
are attempting to use the same access point. 
Making a high gain antenna needed for 802.11 netwotking is also not easy
to build into a TV antenna - but it is possible. 
Really though the main killer is the connection from the antenna to the
computer. This is where the major capital cost is. You cannot use normal
coax if the computer is where the WLAN box is. The best way is to put
the WLAN up the antenna, meaning USB or Ethernet. Of these USB is the
cheapest, can it should be possible to stick it up an antenna... 5m
booster cables are available for USB... And you can use 5 of them
Really the solution is not to use an infrastructure... But ad-hoc
networking... I wrote a paper on this a few years back... Without
infrastrcuture you create a mesh and run things that way...
Of course when everyone starts using 802.11 it will become useless. That
is a promise. Just look at FRS radios in the USA running on 900 MHz...
Just try using one within a mile of Disneyland... You cant... The same
will happen to 802.11. I have been into Spread Spectrum networking since
1994, so I generally know what I am talking about....

Darryl Smith, VK2TDS POBox 169 Ingleburn NSW 2565 Australia
Mobile Number 0412 929 634 [+61 4 12 929 634 International]
Darryl at | for domain names 
-----Original Message-----
From: wireless-admin at
[mailto:wireless-admin at] On Behalf Of Ben Smith
Sent: Sunday, 20 January 2002 8:07 PM
To: wireless at
Subject: Interesting Quick Thought

Hi Everyone,
I had a brief thought today. Everyone's main concern with wireless
networking is cost, It's great new technology and is actually reasonably
cheap to setup in comparison to other typical communication networks.
Anyway, my thought was is it possible to use existing TV antenna's on
peoples roofs for wireless networking, would it be possible with some
tweaking to enable the antenna to be used to both TV and WLAN? They run
at 2 completely different frequencies but considering most TV antenna's
pick up both UHF and VHF then I'm assuming it might not be a problem.
The other thing would be WLAN needs literally no interferace between the
antenna and the WLAN card and good line of sight. There are also other
issues to consider such as If the TV and the WLAN is being used at the
same time, would it be possible to creat some dual connector similar to
an RF switch or something? There are several things to think about and
consider, most people would look at it and think it's not possible and
that it's a waste of time, but surely if we could eliminate the cost of
the user installing an all new antenna then the possibilities when it
comes to expanding our wireless networks would be limitless!
I myself will be doing some research into the concept and hopefully come
back with some interesting results. If anyone else has some thoughts on
this subject please tell me about them. Best Regards,

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