Use your house as a giant antenna

[Tony81]

This is sort of a newbie question. Has anyone used your house's wiring system as a giant antenna? I was wondering if this product is any good http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3068764478&category=15064

[JustinH]

I can't remember the last time I heard of anyone using an antenna for a television set.

JH

[sysKin]

A good antenna isn't big. Good antenna has exactly half of the wavelength long (but can be 1/4 with 1/sqrt(2) efficiency), is perpendicular to the direction to source antenna and has the same polarization as the source antenna.
There can be more than one antenna in a set and if so, the 'basic' antennas are sparated by one wavelength (no wait, any integer number of wavelegths) in the direction of the source.

House wireing is designed not be be an antenna (and isn't, it's too long) so that it doesn't pick up or create any interference.

Radek

[auenf]

Originally posted by JustinH
I can't remember the last time I heard of anyone using an antenna for a television set.

JH

well, i cant get cable here, so an antenna is compulsary, unless you want a dish, which is basically a directional antenna anyway :P

Enf...

[Happygolucky]

Originally posted by Tony81
This is sort of a newbie question. Has anyone used your house's wiring system as a giant antenna? I was wondering if this product is any good http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3068764478&category=15064

The "house antenna" devices have been around for a long time, and they've never worked. As mentioned in another post, there are technical reasons why they don't work, which aren't apparent to most non-electrical engineer persons.

Go to http://www.antennaweb.org. There is a lot of good info there, and links to most manufacturers. You can enter your zip (or full address) and get a detailed listing with compass directions of all the stations you should be able to receive, with antenna recommendations. Great FAQs.

[Sirber]

for USA only :(

[Neo Neko]

Originally posted by sysKin
A good antenna isn't big. Good antenna has exactly half of the wavelength long (but can be 1/4 with 1/sqrt(2) efficiency), is perpendicular to the direction to source antenna and has the same polarization as the source antenna.
There can be more than one antenna in a set and if so, the 'basic' antennas are sparated by one wavelength (no wait, any integer number of wavelegths) in the direction of the source.

House wireing is designed not be be an antenna (and isn't, it's too long) so that it doesn't pick up or create any interference.

Radek

On a technical note an antena can be any length. The only requirement is that it be a harmonic length. Which would include any length that corresponds to any multiple of whole or half wavelengths. Resonance and harmonics are quite interesting and have inumerous aplications etc. It can have weird and unusual effects. At a local restraunt one of the cylinders they used to contain the syrup used to mix Cocacola was the exact right size to resonate strong enough with a local radio station it was audiable if you were standing next to it.:D

[sysKin]

Originally posted by Neo Neko
On a technical note an antena can be any length. The only requirement is that it be a harmonic length. Which would include any length that corresponds to any multiple of whole or half wavelengths. Resonance and harmonics are quite interesting and have inumerous aplications etc. It can have weird and unusual effects. At a local restraunt one of the cylinders they used to contain the syrup used to mix Cocacola was the exact right size to resonate strong enough with a local radio station it was audiable if you were standing next to it.:D LOL :D

Yes you're right of course. Half-wavelength is good because antenna acts like a resonating 'cyliner' with two 'ends closed'.
Where antenna ends, it's always cut flat (not round, not spike, but often with a small metal cyliner to make the 'flat' even more flat) and this end reflects the elecromagnetic wave.
The other end also reflects the wave but also transmits it to the cable.

In the end, the electromagnetc wave resonates like vibrations resonate in a guitar's string.
The condition is that the length equals any integer number of half-wavelengths (like you said) - and the extra wavelengts don't help resonance, so antennas don't have them :)

Quarter-wavelength antenna acts like a trampoline with a jumper on it - one end is 'closed' cut flat, the other is 'open' by means of extra inductor which resonates with it - just like one end of a trampoline is fixed to the wall and the other is free.

A disclaimer: My knowladge of antennas comes mostly because I know about waves, electromagnetsm and some extra physics. I'm not an expert by any means ;)

Radek

[Neo Neko]

Ditto. Though I have had a decent ammount of electronics training. Just enough to get me in trouble.