Any way to use your car's antenna as a WiFi antenna?

NoNonsense · 06-29-2004, 01:17 PM

I think it would be a nice integration since those of us who ditched the headunits have a useless antenna. I want to put it to use!

Hexerei · 06-29-2004, 01:32 PM

You read my mind

The Grinch · 06-29-2004, 11:02 PM

Antenna's are made to specific lengths to match the radio frequencies that you are trying to receive or transmit on. FM radio is in the lower half of the MHz band, while WiFi is well into the GHz band. Then there's other stuff to consider like antenna resistance and impedance. If you tried to simply rig up a WiFi device to your car antenna, you would risk toasting it's transmitter. Even if you figured out how to safely hook it up, the antenna would give you very poor reception for the application.

The only alternative you have is to replace your car antenna with one that is made for WiFi. You can buy them (they are quite short by the way), and you would have to fabricate a way of mounting it as the connectors are totally different.

Sway · 06-29-2004, 11:05 PM

even if it does not work it was a great idea, because i never use the radio.

cheerio · 06-30-2004, 02:39 AM

you could always drill a hole and look like a police car ;x

NoNonsense · 06-30-2004, 10:24 AM

Quote: Originally Posted by cheerio

you could always drill a hole and look like a police car ;x

That's a negative, Sir! hehe
I just thought that attaching the WiFi antenna to any other long piece of metal (even a metal hanger) would increase the reception, so why not attach it to the car's antenna....it doesn't need to be amplified, so how would it toast the transmitter?

Sorry, i don't understand all this WiFi stuff yet...

NoNonsense · 06-30-2004, 10:25 AM

Quote: Originally Posted by The Grinch

and you would have to fabricate a way of mounting it as the connectors are totally different.

It's all about the adapters!

MikeH · 06-30-2004, 10:37 AM

Quote:

it doesn't need to be amplified, so how would it toast the transmitter?

The output transmitter section of a WiFi client is "tuned" to match a certain impedence (like a frequency-dependent resistor). It looks like a perfect "match" (ie a 50ohm resistor) only at the proper frequency (around 2GHz). Your car antenna is "matched" (looks like 300 omhs) at 88-108MHz and can't really be tuned to look like 50ohms at 2GHz for your WiFi transmitter. Some WiFi transmitters (output power amplifiers) will fry themselves if they try to power an antenna that's not well "matched". Your car antenna COULD look like zero ohms at 2Ghz....That would toast you WiFi PA....

The Grinch · 06-30-2004, 11:47 AM

Quote: Originally Posted by NoNonsense

That's a negative, Sir! hehe
I just thought that attaching the WiFi antenna to any other long piece of metal (even a metal hanger) would increase the reception, so why not attach it to the car's antenna....it doesn't need to be amplified, so how would it toast the transmitter?

Sorry, i don't understand all this WiFi stuff yet...

The ol' coat hanger antenna scenario works (sort of) because a car stereo only receives radio waves. But if use it for transmitting/broadcasting, it's a whole new ball of wax. WiFi fits right into that catagory (send/receives). When you transmit, you are actually sending power to the antenna. If the antenna is not properly matched to the transmitter, it will cook itself.

NoNonsense · 07-01-2004, 07:03 AM

Quote: Originally Posted by The Grinch

The ol' coat hanger antenna scenario works (sort of) because a car stereo only receives radio waves. But if use it for transmitting/broadcasting, it's a whole new ball of wax. WiFi fits right into that catagory (send/receives). When you transmit, you are actually sending power to the antenna. If the antenna is not properly matched to the transmitter, it will cook itself.

I understand now....
so, had anyone developed a WiFi antenna that can be lowered and raised with a button? I'd like to try to utilize that antenna of mine or replace it with something else that would work.

xtra · 07-01-2004, 08:59 AM

heres my idea.

what about using my cordless phone's antenna? it's longer than the one on my wifi card and same frequency 2.4ghz.

NorthGaVigor · 07-01-2004, 09:34 AM

Used a pringles can as an external antenna on my dlink in my laptop and used a coffee can @ my friends house and was able to get a link from his router.
1 mile away! I have the directions if anyones wants them!

NoNonsense · 07-01-2004, 01:18 PM

Quote: Originally Posted by NorthGaVigor

Used a pringles can as an external antenna on my dlink in my laptop and used a coffee can @ my friends house and was able to get a link from his router.
1 mile away!

That's freakin' amazing...here in NYC, that would essentially ensure a constant signal using netstumbler! however, there is no way in hell that i am going to mount a coffee can to my roof or trunk!! hahaha

Quattro · 07-01-2004, 01:25 PM

I've seen that done before on the show the screen savers. They used a coffee can to increase thier wifi signal, it worked really good.
The cordless phone antenna would be much better looking in a car, if it works.

MikeH · 07-01-2004, 01:30 PM

Actually, some of the multi-band cellphone antennas have a ~2Ghz band. they also come in car-mountable versions. This might make a much better looking design.