How can I improve my iMac wifi reception?

Question

Hi there… looking for help to figure out how I can improve the wifi reception on my early 2008 iMac. I get very intermittent wifi signal – coverage varies from zero to full bars, but is very unreliable. I get much better wifi coverage from other devices in exactly the same location – XP laptop, iPod touch & iPad.
The iMac is located in the garage in our back garden which is about 30m from the wifi router in the house. I don’t have direct line of sight between the iMac & the router (although there are windows in the facing walls). I don’t have an option of running an Ethernet cable to the garage.
Here’s what I’ve tried so far:
1. Added an Airport Extreme. While this upgraded my UPC router / network from G to N, it gave no noticeable improvement to the iMac reception.
2. Added an Airport Express. I set this up to “Expand existing network”. I initially positioned this in the house (at the socket that is physically closest to the garage) but again, no noticeable improvement.
3. I then moved the AExp in the garage itself. For 30 seconds I had a green light on the AExp & full coverage… but then the coverage dropped & I got the flashing amber light in the AExp.
So now, I’m now wondering if it is possible to connect some kind of USB wifi aerial into the iMac that would enable me to boost the reception and / or run an external antenna away from the iMac & closer to the router (possibly in line of sight). I have checked in local stores & online, but couldn't find anything that fits the bill.
Any ideas?... I should add that network coverage in the house itself is great. I brought the iMac into the house & immediate got full bars & excellent reception. I have a lot of networked devices in the house & they all operate with no issue whatsoever.

Answer 1

hi Ralph,
what is the behavior of these devices with respect to surge protection?
to be honest i don't know. we have very stable power supply in Germany.
Can they be placed on the safe side of a surge protector?
don't see why not. i'm using a pair to get internet from the main router to my TC. the TC is operating in +bridge mode+ and creates a separate network for me.
the adapter next to the main router is plugged directly into a wall outlet, the one for my TC is plugged into my iMacs UPS. no problems there.
If you live in a high thunderstorm area like Tampa, FL in the US, you would not even consider using electronic equipment without very high quality surge protection.
irregardless where you live, operating my precious Macs without an UPS for each is unthinkable for me. surge protectors, IMHO, don't cut it ! it ought to be a UPS. heck, even my TC has one although just a simple one. my desktop Macs each have a UPS with a USB port so the UPS can send a shutdown command to the Mac in case of an emergency. my MBP has a built-in UPS, obviously.
so, everyone reading this: do yourself a favor and get a decent [_*Uninterruptible power supply (UPS)*|http://en.wikipedia.org/wiki/Uninterruptible_powersupply] such as [this|http://www.google.com/products/catalog?client=safari&q=apc+ups&oe=UTF-8&cid=118 8217317658000104&os=tech-specs].
Also, will these function on a circuit with ground-fault interruptors installed?
if power to the units is interrupted, they won't work. once power is restored, the will work again. again, if you connect everything to UPS systems, you will @ least have your local network running, even if the connection to the internet is interrupted.
JGG