vhf/wifi antenna

So I bought myself a little UBS wifi adaptor which accepts a coax cable for an external antenna ...works like a charm, even with the tiny 'duck' antenna that came with it.

I figure it would work even better if it had a real antenna mounted externally, maybe on some high point on the boat ... the mast head, maybe? So as I was looking up in that direction, a strange voice said 'why not just use the vhf antenna for wifi'? Not simultanously, of course, but maybe with a switch that feeds either the vhf, or the wifi?

Seriously, has anyone tried that? Is there any real reason it would not work, provided I find a way to plug the vhf antenna into my USB wifi adaptor? Naively, I'm imagining that an antenna is really just a piece of wire, so why wouldn't it work?

Coax Loss

For my 2 cents, I would not try and use the VHF, I think the signal loss due to the long coax and wrong antenna tune would defeat your purpose. If you need an permanent mount, I would propose you mount the actual USB powered WiFi adapter unit on the mast and run USB compatible cable instead, that way you have no signal loss, the long cable run is digital to the computer. Perhaps you could dip the adapter in wax or liquid electrical tape to protect from the weather. I have seen homemade units installed in short 2 inch sealed PVC pipe with a USB connection on the outside only, the WiFi adapter is in the pipe with the little antenna.

Good luck...
Steve

The USB specification limits cable runs to 5 meters. USB 2.0 is 3 meters, maximum. To go longer than that, you need a USB hub every 5 meters of cable run. There are purpose-built extender cables that have, basically, a 1-port USB hub built into the plug at one end. You can daisy-chain these together to get the required cable length.

Your VHF antenna will NOT work well as a WiFi antenna as the band it is optimized for (~145 MHz) is VERY different from the WiFi band (~2.5 GHz). You would be better served to purchase and install a WiFi specific antenna such as the one at the link below.

http://www.radiolabs.com/products/antennas/2.4gig/11dbomni.php

showstopper

Guys, thanks for the guidance, and you're 100% correct ... I ended up calling amphenol and their engineers confirmed that the setup would not work because:

a) the frequency ranges are a total mismatch and I would need to power up the antenna beyond what the USB adapter can do
b) wi-fi uses reverse polarity, so I would need an additional adapter (not sold by amphenol)
c) the FCC would have an issue with this setup, as it's not legal

That probably seals my creative idea ...

Zoran

I just read about a wifi amplified antenna in the latest issue of GOB last night.

The 5milewifi.com thing? Yes, at $399 it sounds like a solid product ...

I already bought another unit for a fraction of the $, it works well but would probably be even better if I could attach a masthead antenna, or find a way to hoist one when needed.

External WiFi

My slip neighbor has just returned from a year plus cruise to Trinidad and back and was very happy with the performance of the unit at www.portnets.com.

Pricey, but it saved them many a trip to an internet cafe. They had great success at anchor in populated areas. Swears by SSB email, though, as the most consistently successful method. Doesn't help you surf the net or use Skype, but it was always there when he needed to get email out, even underway.

Really high on Skype, too.

802.11b Homebrew WiFi Antenna Shootout

How To Build A Tin Can Waveguide WiFi Antenna

Pringles cans work, too.

all done

I ended up building a housing for my adapter+antenna using a 2' PVC pipe (from Home Depot), and running a 15' USB extension cord back to my laptop in the cabin. I simply hank the pipe to my boom topping lift and raise it half way up using the main halyard ... works great!

pix attached

USB WiFi interface

Here is a commercial version.
http://www.5milewifi.com/

I was re-reminded of it in a "product announcement" in the new issue of YachtWorld. (A really great sailing mag from the UK.)

Have not tried it, and will hold off until they certify it for 10.5 (the most current Mac OS version)

FYI...


Loren