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Friday 23 June 2006

AmLAN III : The Games [Spiny]

Feel free to edit this table & add in games or voulanteer for getting patches & mods together :)
Game Patch Level Mods Owner
GRAW 1.16 Spiny
Quake 4 1.4 RA4 Spiny
GT Legends None Spiny
Half Life 2 Steam Update ?
Rome Total War / Alexander 1.6 Barbarian Invasion? Muz
SWAT4 + Stetchkov
Total Annihilation N/A Various, including TAUCP and UTASP Muz/Lurks

Tuesday 13 June 2006

Airforce 1, Mother Nature 0 [Brit]

It's a perverted myth that we don't do summer in Britain - whether you subscribe to the tree hugging ozone theory or not, the simple fact is that between June and September the British Isles has a go at some hot weather.
What we don't do however is prepare for summer. Instead we comment incredulously on the heat, our then inability to get a good nights sleep, and we look less suspiciously at retailers pushing huge fans and other cooling equipment... before heading down the pub.
Things are slightly different at Chez Brit this year; indeed, if you were to have walked by last night, you could have been forgiven for thinking we'd driven a refrigeration truck in and left it running. Indeed, this year, we have prepared for the arrival of summer.
We've tried fans, believe me. From the huge chrome slow-rotate ones, to things that have a higher RPM than your average helicopter - and the effect is always the same; warm air gets pushed around a bit, and of course, gets gradually warmer until you might as well be trying to sleep under a hair dryer.
Yesterday, things changed - leaving work early so as to discharge my household duties in a respectable manner, we stormed B&Q's aircon section. Which was just as well, because as we drove up, no less than six other folk were busy cramming ACUs into their own cars.
So enter the Air Force 12000BTU mobile air conditioning unit; a behemoth of a machine at nearly 50kg - a monolithic silver beast that (I kid you not) had most of Brit Towers down to 16 degrees centigrade in about 30 minutes. £250 might strike some as rather expensive for something that seems to run so at odds with the myth of a British Summer, but when you think about it, this stupid weather will continue for at least three months meaning I can now definitely say that a good night's sleep costs roughly £2.70
So, summer is here and we love it - but not at night, when we much prefer our own mini arctic and the Air Force is happy to oblige!

Monday 12 June 2006

Lurks2Houmouse WAN link Phase 2 [Lurks]

As discussed before, the goal is to come up with a very high-performance wireless point to point network with direct line of sight access from the rooftops of two houses between 50 and 100 meters distant. Phase 2 is research of technology to spec some equipment. Since one of the houses is undergoing extensive building work on the roof for the next two months plus, there's no speed impetus on delivering a solution just yet.
The two design criteria are principally near or exceeding LAN speed throughput and link reliability. We'll take security as a given since it's pretty easy to configure.
There are, broadly speaking, just a couple of technologies on the market place which can deliver this sort of performance. Below is a summary of those on the market including the type, base bitrate and what commercial products they can be found in today.
  • Airgo Gen 3 - Boosted 802.11g. 240mbps. Netgear RangeMax 240, Linksys SRX400
  • Marvel Topdog - Draft 802.11n. 300mbps. Netgear RangeMax Next.
  • Broadcom nFinity - Draft 802.11n. 300mbps. Linksys Wireless-N.

The latter two are basically implementations of the draft 802.11n standard which recently failed to be ratified. It should be noted that we don't care about interoperability because we're doing point to point with, presumably, the same equipment/brand.
The only real comparitive analysis of these technologies has been done by Tom's Networking where they basically conclude, somewhat surprisingly, that the Airgo Gen 3 stuff is far better at throughput-versus-range than the new draft-n gear. In fact so is plain old 802.11g which is a bit tragic. However this shouldn't discount those technologies from consideration for this application because we will not be experiencing line losses which will impact upon performance. This application should be able to achieve full speed with each and so the latter two have the advantage of a slightly higher bitrate.
The difficulty, so far, is in finding any equipment at all based on any of this wireless technology which features a so-called bridge mode. In other words. The product ranges are very heavily skewed to the average consumer needs and there isn't even a regular access point available. This is problematic because simply placing two routers at each end will not suffice, the routers will not establish an encrypted network between themselves. For that you need bridge functionality. Eg the product needs a place in the firmware interface to place the SSID of the network you wish to connect to and the WPA keys.
The only other way around this would be to place a computer at one end with a regular wireless client such as a PCI card and have it connect to an access point at the other. Unnecessarily complex but if that's what has to be done, then that's what has to be done.
The second stage of research here involves the construction of directional point to point antennas. Normally this is pretty simple and may remain simple but all of this technology is generally based upon multiple antennas. It's unclear if this is necessary for a direct point to point or if a multiple input antenna array is required. Normally MIMO technologies solve the issue of reflections so it is expected that a MIMO antenna wont actually be necessary since reflections can be ignored. This will probably be an issue of experimentation.
It's also worth noting that these multiple antenna products generally don't have detachable antennas. I anticipate that the products will need to be removed from their packaging and coax wired directly to the mainboards to external antenna(s).

Sunday 11 June 2006

Lurks2Houmous WAN link phase 1 [Lurks]

We moved house into our dream home, at last. It's a bungalow just a row off from the sea on the very south coast of England. Of course a move brings all the usual difficulties with broadband. I was hit up with a triple whammy of having no Vodafone signal for my 3G/GPRS card, no ADSL and my order being cancelled due to the presence of the former owners ADSL on the line, and even my fallback plan of Wi-Fi to Houmous across the road was foiled by the presence of not one but three garages in the direct line of sight (LOS).
The only issue I could realistically do anything about was wireless, so fresh from having dealt with the move of all our stuff from the previous house, I spent probably an hour on a constantly disconnecting crappy GPRS link ordering some wi-fi boosting stuff from Dabs. I decided to choose two solutions for redundancy. We hadn't even gotten up the new name of the house yet but this was the new billing address for credit cards etc so the missus bunged up an impromptu bit of paper proclaiming 'Stormwind'.
The access point I'm connecting to is one of those Belkin Pre-N Wireless Routers. Houmous kindly rejigged his cables to give enough play to set it up on the window sill with all three antennas placed the other side of a metallic set of venetians. Quite frankly given the previous location well inside the room, I'm amazed I picked up the SSID at all earlier on my laptop adaptors. Testament to how much better wireless gear works when there's not 20 nearby screaming access points and other sources of noise like we had in London.
So anyway, what we have here is what I'll call Solution A and Solution B.

It'd never have occured to buy something like the Hawking dish thing but there was an actual banner for it when I was shopping on Dabs and some direct-click is most welcome when every page took 3 minutes to load. It's pretty well rated on the net too. It's a pretty cheap and toy looking plastic widget with a USB mini jack on it and an adjustable dish on the front. 8dB of gain is pretty substantial on something this compact and inexpensive. It also has the advantage that you could use a long USB lead and position it where you like. I was desperate enough to run a huge USB lead out the window and up to the roof and put the damn thign in a plastic bag and gaffa tape it to the guttering if needs be.
Getting it up and running was straight forward and it weirdly scans around the channels but doesn't give an update on found SSIDs until you hit refresh. It reported 40% signal from the access point which you'd think would be quite healthy. However this was at the minimum 1mb bitrate. The ping rate was kinda all over the show but worse still, it just kept sort of pseudo disconnecting. This would happen every 10-30 seconds or so and they'd no more IP connectivity even though it says it's still connected. I'd go into the control software and hit connect again and it'd come instantly good. Why it can't do this itself transparently is entirely beyond me.
The bottom line is that Solution A, despite a good 8dB gain, was ultimately failing to provide any kind of link at all. Strangely moving the dish around didn't improve matters very much. I gave up on the crappy control software for trying to detect signal levels and installed Net Stumbler which has a handy S/N graph. Moved the dish around and not much difference within 20-30 degrees or so. In essence without a direct line of sight, we're relying on microwave reflections for our link. I could have moved the dish outside via a long USB lead but some experimentation with just holding it in the open window at various positions and angles didn't boost S/N appreciably.
Having failed with Solution A, I thought at this point that there may well simply not be enough signal for any solution to work effectively. Solution B consists of a cheap PCI Wi-Fi card, a Dabs value unit but actually quite a respected brand, Edimax, coupled with an SMC directional antenna. The idea was I could actually sit this outside on the window cill if required however there proved to be not quite that much lead unless I moved the entire PC right next to the window.
Here's the thing, I switched Net Stumbler from looking at the Hawking Dish to the Solution B and whammy, S/N is immediately higher. Hang on, the SMC is pointed in the wrong direction! I place it up onto my speaker, angle it towards the access point and the signal pulls up nicely. Blimey! Sat right next to the Hawking, pointing in the same direction, I could toggle A/B between the adaptors and no question, Solution B was at least 10dB higher and it was much more stable too with the Hawking dropping out from time to time.
Was it enough for a link? Kill Stumbler, disable the Hawking (sometimes close adaptors interfere with eachother), fire up Windows wireless networking and connect. Signal strength is measured as low but I'm getting a bitrate which bumps up and down between 18 and 24 megabits. Time for the ping test. Constantly 1ms, the occasional spike up to 20 odd milliseconds. I leave it running, I tilt the SMC around a it and it doesn't really change. Turns out, it's absolutely rock solid and stays up for horus without a single disconnection. Web browsing etc is like I've got a local ADSL connection. Success!
The distance and the lack of LOS here are certainly challenges for Wi-Fi. The fact I've got a decent link is certainly assisted by the multipath technology in the Belkin router. I'm going to surmise that the lack of LOS is why the Hawking dish failed so completely compared to the SMC. I think the SMC has a much wider gain 'lobe' if you like, and is picking up wider path of reflections and it's transmission likewise results in more reflections getting to the access point. Rather like firing at a squirrel behind a rock. If you fire a rifle your chances of a richochet hitting the squirrel are much less than if you fired a shotgun. Of course I have no data to back up this view.
I do suspect the Hawking would do quite well in line of sight test but I remain highly unimpressed with it's performance given it reports 40% signal strength and 60% link quality and dropped out constantly yeilding a completely unusuable connection. I'd be loath to recommend this expensive little toy for any real networking.
Praise here, I think, I can't exactly lavish on the PCI card since I'm sure there's a million like it with similar performance. However if I'm buying one again, I don't thin you can fault one of these for 12 quid. Where I can definately lavish praise is the SMC external antenna. This also came with a couple of adaptors to the tiny 'pigtail' type connections (which you should be able to find on laptop Wi-Fi cards!) and the large N-type connections. Those leads are bound to come in handy at some point and ultimately it's a smart-looking, Wi-Fi antenna with a decent gain. Bargain for 16 quid, highly recommended.
This isn't the end of the experiment in Wi-Fi between our houses. This was a quick and dirty emergency effort to get us through our broadband drought. Next up though will be the implementation of a fixed high performance LOS link from rooftop to rooftop. Signal strength will not be a problem here but we'll be requiring the highest performance Wi-Fi available to give us as close to LAN speed networking as possible. The new draft 802.11n equipment appearing on the market is interesting but so far I note that no one has really applied external antennas to multipath (MIMO) Wi-Fi that I have seen. I'm considering using some of this equipment and hacking on three external el-cheapo home-made antennas in various configurations.
Why the need for a high-performance wireless link? A street-wide WAN for sharing of movies, music and the goal of an eventual distributed LAN party with a live video link-up. Exciting stuff.