[Antennas] BCB Loop Antennas

2002年9月28日 12:29:48 -0400

There are devices specifically for cell/pcs devices that act without being
connected to your phone. They are called Bi-Directional Amplifiers (BDA).
An outside antenna is connected to an interior mounted BDA device and then
to an inside antenna -- effectively re-radiating a range of frequencies both
ways.
I've seen these in quite a few buildings... even the Hong Kong subway
system has them to allow riders to use their phones while in the tunnel
between Kowloon and HK Island.
These BDAs are active devices (cost about 700ドル+), as the BDA device actually
has an rf amp. A passive device might work.. operative word is 'Might'.
There were quite a few advertised for use in autos that were dubious at
best... Sota like the foil stick-on that's advertised so heavily and does
little but lighten your wallet.
Virtually all of the hand held cell phones do have an external antenna
connection - sometimes through the plug on the bottom of the phone. For
those that don't, I have seen antenna couplers (fits over the antenna) to
connect to an outside antenna. There are some signal losses in the
coupling, so results may not match manufacturer's claims (haha, what's new).
Nextel, in their early days, was notorious for poor coverage. In-buildiong
coverage was usually provided by Nextel with their own BDA - at a price of
2,500ドル per site. Since then, a number of 3rd party devices have popped up.
They are used by even Police departmetns to bring radio coverage inside
their building for HTs. Same concept used tio bring GPS signals inside a
car,
See:
http://cellantenna.com/
http://www.cellsocket.com/
 ._._.
----- Original Message -----
From: "Tom Bates" <[email protected]>
To: <[email protected]>
Sent: Friday, September 27, 2002 6:27 PM
Subject: Re: [Antennas] BCB Loop Antennas
> >>When I was a kid, we had a large bakelite circle wound internally with
> >>literally hundreds of feet of enameled wire. Dark brown and about 3
feet in
> >>diameter, with gold foil labels. The bottom had four legs on its
outside
> >>and a flat shelf within the very bottom of the loop for the radio itself
to
> >>sit on. The entire contraption occupied a medium sized table in the
living
> >>room. The bottom shelf contained a pair of tuner controls (cap &
inductor)
>> Is this an example of a "passive" antenna ? I am looking to build
something
> like this to improve cell phone performance since my newer generation cell
phone
> doesn't allow connection to an external antenna like my older one did.
>> Any ideas ?? Thanks, es 73, Tom AA1NZ
>> - - -
>> Your moderator for this list is:
> Larry Wilson KE1HZ [email protected]
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