We've spent much of the past week in the dark ages. Thanks to crappy support from our ISP, we've been thrown back into the terrifying isolation of pre-Internet days.

Or not quite, thanks to a fabulous little gizmo - the mi-fi.

For those not familiar with the concept, a mi-fi is a small, battery-powered device into which you slot a SIM card for a mobile broadband service. In France, such SIM cards are normally sold by the likes of Orange & SFR as USB dongles. The problem with a dongle, though, is that it gives Internet access to only one device. The mi-fi acts as a wi-fi hotspot and allows up to five devices to connect simultaneously.

I bought an unlocked 3 device from eBay (the Huawei E585 which you can also get from Amazon) and used it with a Vodaphone Pay As You Go (PAYG) SIM while in London - mainly with my iPhone. I'd only just got the phone and Orange hadn't yet enabled roaming. Fortunately, with the mi-fi, I could use Skype.

We also used the mi-fi while on a week's holiday in Brittany. This time I used the SIM from an SFR PAYG mobile broadband dongle. I bought 500Mb worth of bandwidth which lasted most of the week. SFR also offers 48hrs of uncapped access for 9 euros - something we've been greatful for the past few days, as we'll see. The mi-fi allowed us to use both laptops and the iPhone at the same time.

We returned from the holiday on Saturday afternoon to find that our Internet connection at home - a 1Mb/s wimax service provided by WiBox - was down. We couldn't do anything about that until Monday: being a French company, WiBox's customer support keeps office hours (I feel another blog coming on about this).

In spite of repeated calls, here we are, a week later, and still no wimax connection. So we've been reliant on the mi-fi - and that's where the fun & games started.

Searching for the sweet spot

I tried every spot I could think of in the house to get a connection. Most places the mi-fi reported 'no network'. Sometimes it said 'SMS only'. Occasionally it would report a 2G connection though only with a single signal bar. Hopeless.

So we got in the car and toured the local countryside. We tried our nearest town. Not a sniff of a 3G connection. (The iPhone, on the other hand, using Orange, reported good 3G connections everywhere. But Orange's tethering service is horribly expensive.) In the end, we wound up in a bar in Mayenne, 30km away from home, where we got a reliable & fast 3G+ (HSPA) connection. We worked for a couple of hours, typing furiously to catch up with our work. The locals looked bemused. Two people working on laptops in a cafe wouldn't raise eyebrows in London or Paris. But out here in the boonies you could see the looks of puzzlement: some people were wondering how we were getting Internet access; others were confused by our mysterious tapping on magic boxes.

Our next attempt involved going to another local town. In spite of rising high above the surrounding countryside, Domfront turned out to have lousy 3G signals - with SFR, anyway. We spent some time in the local computer shop, which offers Internet connections (via Ethernet) rented by the hour.

Desperate for a connection closer to home, we tried touring again - and found the perfect spot. It was at the junction of two country lanes running through crop fields miles from any town. At the junction is a calvary. These crucifix memorials are a common sight in rural France. I've seen hundreds of them but had no idea that they operate across the cellphone network. Clearly, god needs decent bandwidth.

Parked near the calvary we could get a superb 3G+ signal. It must have presented a strange sight - the two of us, at night, sitting in the car with the hazards flashing and our faces lit by the glow of the laptop screens. Several people passed by (mostly farmers driving tractors) but nobody stopped to ask us what we were doing.

Then, this morning, a miracle happened. Daunted by the prospect of having to get dressed just to drive up to our local hotspot for a bit of browsing, I checked around the house again. And in one corner of the bedroom, in the air above my tallboy, I found the sweetspot - a 3G+ connection. Some parcel tape, a leather thong and a drawing pin soon had the mi-fi set up. And it's been working reliably since.

Ridiculous pricing

Now a word about pricing for mobile broadband. The SFR tariff of 9 euros for unlimited access for 48hrs is starting to look very cheap. On its French website, Orange makes it virtually impossible to find out how much it charges for top-ups for PAYG mobile broadband. But it seems that just 12hrs connection might cost 25 euros. That's around 10 times what SFR charges.

I also have an, as-yet unused, T-Mobile SIM sourced for me by my good friend and mobile guru Steve G. It's a UK SIM but I figured I'd check their data roaming prices anyway in case they were competitive. In fact, in T-Mobile's literature the company is very excited at just what a good deal it offers - at £1.50 per megabyte! (It'll be handy for my next trip to the UK where T-Mobile's offering is very reasonable.)

While researching deals, I've found that all the mobile service providers drastically underestimate how much data you might consume. In one session up at the calvary, we used 80MB of data - no filesharing, video or image transfer involved. Admittedly, that included emailing a 1.2MB PDF, but even so...

This morning, I'm testing whether SFR really does mean 'unlimited' data. While checking emails, sending a few files, writing this blog and surfing the web, I'm also downloading some podcasts into iTunes and the iOS4.2 update for my iPhone. So far we're up to 800MB of data transferred. That would have cost £1,200 with T-Mobile!

No wardriving

Oh, and by the way, for the hackers - yes, we did try wardriving. Seems that everyone is sensible around here about securing their wi-fi hubs. Good for them.