Tinfoil hat (for EVDO)

July 28th, 2010

The things you’ll do when you’re sitting around the house…

The other day I built a parabolic reflector out of cardboard and some foil tape I had lying about. I was researching various homemade antenna designs I want to tinker with and stumbled on one that I actually had all the parts for on hand. As we are so close to the edge of EVDO reception here that moving down the hill a few feet would kill the signal, it seemed like it would be worth a shot. After all, it cost maybe fifty cents for the foil tape I used and the cardboard was free.

Parabolic EVDO Antenna.

Now, this is hardly a good mobile solution as it’s fairly directional, but after spending twenty minutes or so on the roof pointing the reflector and testing bandwidth, I got pretty good results. The SNR increase doesn’t even register on the cradlepoint’s web interface, which is fairly lackluster, so I had to result to ping flooding our upstream router to detect a better signal. No, I didn’t DoS it, I kept the packet count to 100 at a time while aligning and 1000 packets for bandwidth testing.

I didn’t record all the numbers, but to give you an idea of the improvement: without the reflector, we were seeing 10-30% packet loss and average roundtrip times that ranged from 5 seconds to 9.5 seconds. Even at that, the connection was usable. Once the reflector was aligned, packet loss dropped to 0-1% and average roundtrip times stayed about 2.5 seconds. This equates to a 100-300% increase in bandwidth plus the bandwidth recovered from dropped packets.

The connection is hardly blazing fast, but it’s quite a bit more usable than previously. For our normal usage patterns, it’s actually quite acceptable. Bear in mind that our average roundtrip times are similar to 380ms. The previously stated times are for icmp packets being sent out as fast as possible and saturating the connection.

With that sort of improvement, I’m much more determined to build a waveguide antenna for times when we’re having trouble hitting a tower. Bonus points if I can fit both the wifi and 3g spectrums into the same antenna and use it for a wifi repeater as well.

Dear Brent,

November 7th, 2008

On 2008/10/25 at 12:11 PM, Brent wrote:

Hey guys,

Currently working my way through your all your postings. My wife and I are in the “can we really do this” stage of making the same change that you two have. Very much enjoying reading through your process.

Much like you two, we both work in technology and are somewhat dependent on the Internet. Add to that, the need for research / blogging / and potentially some work while traveling and connectivity gets to be one of our important decisions. So I’m curious, how are you feeling about the cell network decision versus satellite? Working out as you had planned?


Well, Brent, I’d have to say I don’t like any of the choices available. I’m pretty happy with the performance of EVDO, but I’m extremely upset with Sprint changing the contract midstream so that it no longer remotely resembles the class of service that we originally purchased. I have already ranted about this particular event once, so I’ll try and stay on subject…

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May 31st, 2008

For about six months now, we’ve been very happy with our EVDO service from Sprint. We invested in extras such as an external antenna and a Wilson trucker amplifier. We have had some sketchy service as we traveled around, but we have very rarely been in a complete dead zone in our, admittedly, limited travels.

Verizon has a slightly better coverage footprint than Sprint, at least the way most people seem to figure it, but Sprint had one major benefit: unlimited connectivity and downloads. Verizon claims to have ‘unlimited connectivity’, but after 5GB in a month, they start charging you $0.49 per MEG!

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Finding a Place to Sleep

January 13th, 2008

It’s been quite a few years and I was usually busy reading while Dad drove us to the next destination in the family RV, but the best I can remember, we’d often drive until late in the evening and then find a parking lot relatively close to where we were going, park overnight and then ask the manager if it were OK to park there the following day. Sadly, this is not as effective in this day and age – at least not on the East Coast. So many counties and towns have passed laws against overnight parking that it takes some research ahead of time if you don’t want to sleep in the Lowes parking lot, with your slide in, under the bright sodium arc lamps, half dressed just in case the cops show up to roust you.

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Can you hear me now?

July 30th, 2007

It’s funny how the bleeding edge folks often miss the train. For instance, Jenn and I have spent a lot of time working on VOIP networks. Jenn single-handedly ran the NOC for a small VOIP provider and I wrote a software package to do large-scale wiretapping of VOIP networks for a CLEC. In spite of all this, we had never used Skype until last night!

In researching our communications options we decided that we wanted internet and voice communication that would work pretty much anywhere and of course we want it as cheaply as possible.

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