Thursday, April 20, 2006

Tech: Making your wi-fi network actually usable

My wi-fi (802.11b/g) network sucks. Connections tend to drop out at random times and it often gets completely killed whenever someone uses our 2.4GHz cordless phone. My building and the buildings on either side of me are multi-unit dwellings and there are plenty of other wi-fi networks overlapping. I figured between all the networks and all my neighbors' cordless phones, it was probably impossible to get a perfectly reliable wireless network. And I thought The Powers That Be were absolute fools for designing a wireless standard that was so vulnerable to the thousands of 2.4GHz cordless phones already in use.

I'm planning on buying a wireless digital music server, so I was finally motivated to see if there was anything I could do to improve the wi-fi reliability. A digital music server ain't much good if your music keeps dropping out whenever you or your neighbors get a phone call.

The good news is there is a solution.

The most important tip I discovered was that you should only use channels 1, 6, or 11 for the wireless network. The other channels overlap each other and allow for greater interference. Knowing this, the next step is to determine which of 1, 6, or 11 is least congested in your area. Most wireless routers default to channel 6 so chances are channels 1 or 11 are your best bets.

The easiest way to view the congestion on each channel is to download NetStumbler.
see: NetStumbler downloads

Run this on your wireless laptop/PC and see how many networks are on each channel and how strong they are. "Strength" is determined by both a high signal-to-noise ratio (SNR) and a high Signal level (just note that Signal is displayed as negative decibels, therefore a smaller negative number is a stronger signal: -30dB > -50dB).

In my area there were about seven networks on channel 6 all fighting with each other. Two were on channel 11 and at least one of those had a pretty strong signal. A very weak signal was on channel 1. Easy choice.

I configured my network to channel 1. I got a strong connection to my laptop and did some tests. I reached for the cordless phone and was able to use it without disrupting my network connection! The connection strength throughout the apartment seemed a little stronger as well.

So it turns out that 802.11b/g networks actually are pretty robust and can withstand a fair amount of interference and overlap - just not too much. The Powers That Be aren't complete morons; though they do need to get better information out to the public.

For more on wi-fi network tips and wi-fi security (especially important if your wireless network is not secure):
see: How To: When Wireless LANs Collide!

See the following post for the next wi-fi upgrade: Homemade parabolic reflector antenna boosters!

Tech: DIY Parabolic Reflectors / Wi-Fi Antenna Boosters

First of all, the phrase "parabolic reflector" is just damn cool. "So what'd you do today?" "Eh, just made some homemade parabolic reflectors to boost my wi-fi network signal."

Secondly, parabolic reflectors LOOK damn cool.

Third, they really work.

While researching how to make my wireless network more reliable I came across a link with information on making cheap, effective antenna boosters.
first see: Deep Dish Cylindrical Parabolic Template
then see: Ez-12 Parabolic Reflector Template

The idea behind a parabolic reflector is that it reflects signals back to a specific focal point - the antenna. Any signal that hits the reflector (assuming it's not an extreme angle) will be redirected towards the focal point. This has the effect of collecting a broad signal and concentrating it at the antenna, making it easier for the antenna to receive. This is an inherent property of parabolas, if you remember your Algebra 1 or Algebra 2 days in high school.

It also works in reverse. A signal emanating from the antenna will strike the parabolic reflector and be bounced back out in the direction the reflector is pointing. This has the effect of minimizing the strength of the signal behind the reflector (useful for wi-fi security - why send a signal into your neighbors' house or out onto the sidewalk?). But because it's a reflector (as opposed to an absorber), it also strengthens the signal in the direction of the reflector. All that energy is bounced away from the undesired direction and towards the intended direction.

The end result is that you get a stronger signal where you want it, you enhance security by containing your transmissions, and you enhance the antenna's ability to collect and receive your incoming requests. Quite a miracle all-in-one solution!

I began with Erskine's EZ-12 template linked above (the EZ-12 is an enhancement on his earlier design, but it helps to read about the old design first since he doesn't duplicate the info on the newer EZ-12 page). It's a very easy solution. You basically print out his template onto a piece of cardstock paper and cut out the two sections. You wrap the rectangular section with aluminum foil and then curve it around the funny-shaped parabola guide/spine. Cut out the focal point Xs and feed your antenna through the holes.

It does work and can be confirmed by an increased signal measured by NetStumbler (see the earlier post about wi-fi networks).

The downside is that it's a bit fragile and imprecise. The shape of the parabolic curve and the position of the focus point (i.e. antenna) are crucial. The card stock spine just isn't strong enough or precise enough - it tends to sit crooked on the antenna and the parabola its contour traces out is a bit compromised by the six insertion slot tabs. The top and bottom edges of the reflector also might deviate from the proper curve as there is no guide to shape them.

Therefore I created my own Do-It-Yourself parabolic antenna design, using the EZ-12 template as my starting point.

I traced out two copies of Erskine's parabolic curve separated by about 1/8" onto a section of cardboard. It's also important to remember to draw in the focal point.

I then used an X-acto knife to cut out the curve and the cardboard piece's exterior border. I duplicated this process and ended up with three pieces of cardboard that were all the exact same size and shape.

I measured the width of my wireless router's antenna and made appropriate mounting holes in two of the cardboard guides (the antenna has two parts - a fat bottom and a slender top. I measured such that one cardboard piece would sit at the bottom of the fat end of the antenna while the middle piece would sit at the base of the slender portion of the antenna). You have to be careful to make sure that the focal point sits at the center of the hole you cut for the antenna.

My original plan was to then connect them together using disposable chopsticks as a spine. But then inspiration hit.

I realized I could just cut notches into the cardboard and build a notched spine that would interlock and hold the structure together. This has the benefit of simplicity and makes for a clean, strong connection. The problem with taping chopsticks to the cardboard is that there isn't a good way to achieve a strong perpindicular connection between the two. The rigidity and right-angled nature of cardboard make it perfect for this application.

Once assembled the whole thing looks rather awesome. It was surprisingly rigid - I'd cut the interlocking spine notches just right so that the fit was just tight enough. I didn't even need any tape or glue to hold it together. The angles were mostly perpindicular, though there was some error factor.

At this point I took the EZ-12 design's rectangular reflector piece (though elongated to make it taller) and printed it out on a piece of cardstock. It's important to note that you must match the size of the parabola traced onto the cardboard with the proper width for the rectangular reflector (otherwise it won't fit width-wise). And it's not enough to just measure the width of the curve from endpoint to endpoint - the reflector will end up being too small if you try that.

If you use the EZ-12's curve (take the top edge, ignoring the three mounting tabs, all the way from edge to edge, stopping when it curves back inwards), the resulting parabola will be perfectly fitted to the rectangle piece in the template. However, give yourself some extra wiggle room as nothing is ever quite so precise. And I found the EZ-12's curve to be a bit imprecise. I ended up using the curve provided in his earlier template. Just remember that the rectangular reflector must match the size of the curve you trace - I used Photoshop resizing to match the first template's curve with the width of the rectangular reflector from the second template. Either get the sizes correct or just guess and check the reflector width against your cardboard guides.

Wrap the rectangular reflector piece with alumninum foil. Pre-curve the cardstock before you wrap the foil. Foil doesn't stretch, so it won't take to bending very well if you apply it flat and then try to curve the reflector. You can apply either the front or the backside of the reflector. The back is easier but it looks much cooler if you do the inside.

I opted for the inside. I taped down the left side of the foil to the pre-curved cardstock. Then I laid the foil down inside the curving paper. I didn't have any kind of glue that would dry flat (you don't want to use glue that will create ridges in the foil) so I had to find some way to tape the foil down without wrinkling it and make sure it stayed flat against the inside of the curve.

As you can see in the picture I cut vertical slats in the top and bottom of the foil up to the point where it met the cardstock. I then wrapped each slat around the cardstock. The slats allow the foil to fan out as it's wrapped over the edge of the curving cardstock. Try it without the slats and you'll see what I mean. They also keep each section of the foil tight to the inside of the curve (more or less). From there it's an easy job to tape down the remaining right section of the foil.

That accomplished, it's time to feed the reflector through the cardboard guide array. Spiffy, eh? I love this photo - I inadvertantly captured the light bouncing off the reflector and collecting at the focal point! It's especially obvious in the middle cardboard piece.

I made two of these reflectors and mounted them on my wireless router. The antenna mounting holes were just the right size to make for a snug, secure fit.

After some testing and re-aiming, I realized a definite improvement in my wireless signal. In truth the simple EZ-12 reflectors also did an excellent job, but my design ended up being a lot more precise and a lot easier to make small aim adjustments. My overall signal gain was about 8dB - not quite the 12dB advertised in the EZ-12, but I'm measuring through the floor and at least one wall (my router is upstairs in my bedroom. The wireless digital music server will be downstairs in my living room).

The biggest difference between the EZ-12 and my design was signal stability. Though the signal was improved by the EZ-12, the strength meter bounced around quite a bit. With my design (and lots of careful, precise aiming) the signal has steadied significantly.

The other nice thing about this design is that it's easy to just slide new reflector materials into the array. I'd eventually like to replace the flimsy tin foil with a solid sheet of alumnimum roofing, mesh screens, or other similar material. As long as I can cut the width correctly I should be able to experiment with all sorts of different possibilities.

Anyway, I'm very happy with the results and I'm thrilled with the way these reflectors turned out. I love building things myself and I really didn't anticipate this by-the-seat-of-the-pants design to turn out so well.

Wednesday, April 12, 2006

Audiophilia: Depeche Mode on SACD... in the UK only

see: Depeche Mode Remasters

Depeche Mode's landmark "Violator" album has been remastered and re-released as a special Hybrid SACD + DVD package in the UK. Note that the above link lists the US release date for April 25th... but without the hybrid SACD. The US release will be a standard CD and not a hybrid SACD.

You can order the UK release from various stores in the US as an import, but it costs about $30.

Out of curiosity I cruised over to and found the SACD+DVD set to be shockingly cheap at £7.99.

see: Violator [CD + DVD] [SACD] [Original recording remastered]

Using a British pounds to US dollar converter that comes out to only $14. But that price includes UK VAT (their sales tax) which does not apply to sales outside of the UK. The final tally is actually just £6.80, or $12. Shipping Air Mail to the US adds another $5 for a grand total of $17 delivered.

So am I missing something here or are people just fools for ordering imports through US distributors? And it was all very easy. already has my Amazon USA user information and accepts Visa.

Not only is this obviously cheaper than $30 imports, the UK £7.99 price is a huge bargain, especially considering that the label is also releasing a (presumably cheaper) hybrid SACD without the DVD. The other two remastered releases that launched with Violator are more expensive at £10.99 ($19, but a little cheaper in the US without the included VAT).

I suppose must be cutting prices on the big new Violator release to drum up sales (a "loss-leader" item). Either that or it's a mistake in their catalog listing. Actually there is a mistake - they list the catalog number as "CDXSTUMM64" which is the number for the SACD-only release, not the SACD+DVD package.

Anyway, we'll see what arrives in 10-12 days. Even if it's just the SACD, I'll be happy since the DVD is Region 0 encoded for Europe and is in their PAL format anyway. I'm pretty sure I don't have a DVD player that can deal with Region 0 PAL discs. If I really want the DVD, I can always buy the US CD+DVD release on April 25th and give the CD away to someone.

Update: The DVD is PAL but is supposedly region encoded for ALL regions. That opens up more possibilities for the DVD to be playable in the US; some North American DVD players do support PAL discs.

see: Depeche Mode - Violator

Update 2: Ah, I learn more every day. Region 0 discs are "region free". Europe is Region 2. And my Bravo D1 DVD player is apparently very good at dealing with PAL content.

Tuesday, April 11, 2006

Illinois Basic Skills Test results, in detail

The Illinois Basic Skills Test was never going to be a big problem. Anyone who wants to be certified to teach public schools in the state of Illinois has to pass the test. Even kindergarten teachers have to be able to pass this test. No disrespect to kindergarten teachers (I sure couldn't do that job!), but that tells you something about how difficult this test is; no one demands kindergarten teachers to have mastered multivariable calculus or be able to dissect a Shakespearean sonnet at the drop of a hat.

In its earlier form the test was described to me by a science teacher with thirty years of experience as "insulting to my intelligence". It evolved from there and became "ridiculously easy" (which, if you think about it, is a step up from "insulting"). Then in the last few years the State Board of Education realized that the test was only assessing teachers on an 8th to 9th grade level. So they made it more difficult, requiring the knowledge and ability equivalent to a sophomore college student.

I knew I'd be able to pass it without problems. The only question was how long it would take. While I was in town I wanted to catch a gymnastics meet that was starting later that same morning. Could I rush through the test - though still being careful enough to be sure that I passed it - and make it to the meet on time? This was the drama of my IL Basic Skills Test experience.

Four hours are allotted for the test. I was hoping to be done and gone in ninety minutes. Fast as I was, ninety minutes was out of the question. Still, at a furious pace I got out of there in just about two and a half hours. I wrote the concluding 5-paragraph essay in about twenty minutes. I was the first person out of the room and left with many surprised/resentful faces staring at me as I left.

So how did I do?
Well, I got an email that said I passed and that my score was a 290 out of 300 (a passing score is 240). 290 isn't bad, but I really wanted to know what I'd missed. I absolutely tore through the math section, but I was totally rocking it. I was going to be very mad if I'd missed any of those questions. Reading Comprehension is always a little iffy, but Grammar is pretty straightforward. I'm sure my essay was more than sufficient but not spectacular.

Well a few days later I got my written results and they included the following breakdown:

click for more details

Yeah baby, perfect Math section. If I hadn't been such a nerd in high school and didn't have a tech degree and a tech job, I can see how the Math section could present problems for people. I'm serious - most people don't recall things like the Angle-Angle-Side rule in geometry or understand how the interest rate formula works (I know that one because I've been very carefully saving and investing my money the last year or so). There were two full-on geometry proofs that a lot of people in a geometry class would have struggled with, let alone people who haven't dealt with geometry proofs in years or decades.

Still, I was just flying through those questions. There were two tougher questions that took a little extra time, but the others took no more than ten seconds each. It was pretty damn sweet. I haven't been back in that pedal-to-the-metal, kick ass and don't look back mode in a long time.

Reading Comprehension is respectable. I always seem to be faced with answers that all seem wrong to me and then it's a matter of choosing the least wrong one. Maybe I'm over-analyzing them or maybe I'm just weaker here or maybe the questions just aren't that well written (you can guess where my opinion sits). A 289 must be about two questions wrong in the section. Oh well.

Language Arts (aka Grammar) is a little annoying that I missed one. Those were all pretty easy. I'll chalk that one up to carelessness on my part. Damn my rushing!

I'm trying not to take the weaker Writing score personally. It's funny how much it makes me grumble though. I know it's not a comment on my real writing abilities, but it still hurts my pride to see it come in so far below the others when I'm much more proud of my writing than I am of my Math abilities. Whatever. It was twenty minutes' worth of work. I'm probably lucky it wasn't any worse.

Anyway, that's that.

It wasn't as ridiculously easy as I thought it was going to be (and made me miss the first rotation of the gymnastics meet), but at least now I can be a little bit more proud of my scores. If it were all at an 8th and 9th grade level, I'd hardly see it as much of an accomplishment. At least this way I feel justified in boasting a little bit.

And that perfect Math section really tickles my inner nerd.

Monday, April 10, 2006

Cartoon: Noah vs the fossil record

see: Tom Toles on Yahoo! News

Funny stuff. This is, of course, in response to this recent finding that helps flesh out the fossil record linking fish with land creatures:

see: Fossil Fills Land-Sea Animal Gap

Audiophilia: "Slowhand" - Eric Clapton SACD

Eric Clapton, "Slowhand" - Hybrid SACD.

Audiophile Audition's review

This is an exceptional album both for its content and for its recording quality. This album features a very blues-rock Clapton with well-known hits "Cocaine" and "Wonderful Tonight". The remaining songs are all excellent and are well-worth owning. I previously only owned Clapton's "Unplugged" and 1998's "Pilgrim" and have found "Slowhand" to be an exceptional addition. Not surprisingly many consider it one of his finest albums, if not the best.

The audio quality of this material from 1977 is phenomenal. The drums are particularly tight and present without being too forceful. Right from the first measure of "Cocaine" it's obvious that this is an exceptional presentation. There are almost no sonic defects to give away the fact that this was recorded almost thirty years ago! That's not to say that it rivals today's best direct-to-DSD recordings but at that point you're splitting hairs between "spectacular" and "awe-inspiring". Besides, those direct-to-DSD Mozart violin concertos may sound incredible, but I'd bet that most people will enjoy "Slowhand" a lot more.

There are so few high-resolution offerings of popular music; "Slowhand" belongs in the rarefied air of Pink Floyd's "Dark Side of the Moon" and Dire Straits' "Brothers in Arms". However, though it belongs in their company, absolutely no one sits above "Dark Side of the Moon"...

The SACD's surround mix is generally effective, though I dislike having the backup singers directly behind me in "Wonderful Tonight". For most other tracks it adds a nice sense of depth and immersion. For those philosophically opposed to surround mixes, there is of course a new 2-channel SACD mix included on the disc.

Performance: Must-Have
Recording: Best of the Best SACD, popular music

Audiophilia: Mozart Violin Concertos Nos. 3 & 4, etc / Julia Fischer SACD

MOZART: Violin Concertos Nos. 3 & 4; Adagio K.261; Rondo K.269 - Julia Fischer, violin / Netherlands Chamber Orchestra / Yakov Kreizberg - PentaTone multichannel SACD.

Audiophile Audition's review

Ah, now here's a small ensemble that is excellently recorded. The recording still isn't mic'ed quite as closely as I'd prefer (I want to hear the fibers of the strings on the violin!), but the dynamic range and presence are excellent. It's one of those recordings that sounds decent at modest volumes, but really comes alive when played full-bore. I don't know if my speakers/amp need to cross a certain power threshold to really open up; whatever the case, volume is required here to really get at the good stuff.

I am unfamiliar with these Mozart pieces so once again I must defer my review of her performance until later. From what I've heard so far I'm pleased.

Performance: tbd
Recording: Top-Tier SACD

Audiophilia: Naxos' Brahms Symphony No. 1 / Marin Alsop SACD

BRAHMS: Symphony No. 1 in C Minor; Tragic Overture; Academic Festival Overture - London Philharmonic Orchestra/Marin Alsop - multichannel SACD - Naxos.

see: Audiophile Audition's review

Audiophile Audition loved this SACD both for Marin Alsop's direction of the London Philharmonic and for its audiophile recording quality.

I am a Brahms neophyte and haven't had enough time to really absorb the performance yet, so I can't comment on that aspect of the disc. I will update this review when I've properly considered the performance.

I can however strongly disagree with Audiophile Audition's glowing review of the audio qualities of the recording. The recording may be excellent, but I find the recording technique to be very unsatisfying. The microphones seem to be placed so far from the orchestra that the overall impression is rather broad and almost completely lacking in detail. Certain instruments are clearly to the rear or far sides of the orchestra and as a result come through only in distant, muddled tones.

I don't have many full orchestra recordings to compare this to, but Naxos' approach on this disc is very disappointing. Naxos apparently has a reputation for poor recording quality which this disc was supposed to refute. It's possible that I just prefer more closely-mic'ed recordings or small ensembles, so take this with a grain of salt.

Performance: tbd
Recording: Not Recommended

Audiophilia: More DIY Power Cable Bliss

I built another set of homemade power cables using Chris VenHaus' "Flavor 1" and "Flavor 2" recipies.

see: DIY Power Cables - VHAudio "Flavor 1"
see: DIY Power Cables - VHAudio "Flavor 2"

The new analog Flavor 2 cable will power my second PS Audio UPC-200 line conditioner while one of the digital Flavor 1 cables will power my Proceed PDSD (the second Flavor 1 cable was an economies of scale I'll find a use for it someday that will probably be used for my HD source).

My previous set up had my SACD player, connected with a Flavor 1, sending its 5.1 analog out to the PDSD with its regular power cord. The amp was then fed with a Flavor 2 (as was the UPC-200 line conditioner that everything was plugged into).

I knew that the PDSD could benefit from a Flavor 1 cable; it's my DAC for regular CD playback as well as DVD/HDTV Dolby Digital and DTS decoding. And indeed the PDSD did improve quite noticeably with a Flavor 1. Regular CD playback (of a well-recorded CD)is now almost as enjoyable as an SACD.

But what really thrilled me was that the PDSD's new Flavor 1 improved my SACD playback. The analog SACD signal is going through the PDSD and undergoing volume attenuation in that box. So there is some logic to getting improved sound with cleaner power delivery to the PDSD. Still, with so many tweaks and enhancements already in place, it was surprising to achieve yet another audible improvement in the sound. And now my SACD playback - especially full 5.1 channel playback - is just drop-dead gorgeous.

At this point I think I've almost maximized every bit of performance I can get out of my equipment. It's even more obvious to me now that the components themselves aren't necessarily the most important elements of the equation; by applying the right tweaks (upgraded power cables, biwiring, proper crimp terminations, vibration dampening, Walker SST, a line conditioner) a modest system can sound like an excellent one.

So I no longer think it's a matter of buying the best equipment that you can afford. What you should first do is set aside money for the necessary tweaks. Then buy the best you can afford with what budget remains. The tweaks come first!

Think about it: a modest system without the tweaks will just sound average and an expensive system without the tweaks will be a waste of money because of all the wasted potential in the system. The common denominator are the tweaks. And most of them can be transferred to a better system when the upgrade bug strikes.

I'll have to put together a list of "must-have" tweaks vs "budget" and "high-end" tweaks.

Audiophilia: Woe is SACD...

I ordered the Rolling Stones' Hot Rocks greatest hits collection from CD Universe last week. All of ABKCO's remastered releases from 2002 are Hybrid SACDs, meaning that they play in regular CD players but also contain a hidden high-resolution SACD layer for players that support the format.

However, rather than confuse the market, ABKCO simply released these remasters as if they were regular CDs and made no mention of them being Hybrid SACDs. They also charged no premium whatsoever for these Hybrid SACDs (which cost slightly more to manufacture). This move was applauded by audiophiles; consumers get better sounding remastered CDs and audiophiles get glorious SACDs at the same price.

Unfortunately, as of March 2006, ABKCO has officially decided to dump the Hybrid SACD approach and is now releasing all of their remasters as regular CDs (including another well-received remaster, Sam Cooke: Portrait of a Legend).

see: ABKCO Removes Hybrid SACD Stones Albums From Catalog

And, I suppose in keeping with their earlier approach, they're not telling anyone about the fact that these discs are now regular CDs. The original packaging had no indication that the discs were Hybrid SACDs and now the latest batch of pressings have no indication that they are regular CDs.

At least for the Rolling Stones remasters, it seems that you can tell the difference by the "Digipak" cardboard packaging of the Hybrid SACDs vs the standard plastic jewel case of the new regular CD pressings.

see: AVS Forum - Rolling Stones SACD confusion

What's confusing here is that it seems that this regular CD approach had already started by this time last year! The posts on the above thread discuss this problem back in April '05. Perhaps ABKCO began shipping regular CDs when they fell behind on demand (due to the Hybrid SACD output issues discussed in the first article), but continued producing limited quantities of the Hybrid version. But maybe they finally gave up entirely in March 2006. I don't know. Whatever the case may be, the whole thing is really confusing and frustrating.

CD Universe has partially updated its catalog to reflect the change. The discs are now listed as regular CDs, BUT they still appear in the SACD Bestsellers list and their descriptions still say "This is a HYBRID SACD".

My regular CD copies of both Hot Rocks and Portrait of a Legend will be shipped back to CD Universe today. I've placed a replacement order with which still lists them as Hybrid SACDs (and at least the Hot Rocks disc is still listed as the "Digipak" version). I'm somewhat optimistic also because both discs are listed as "limited quantities remaining".

If those come back as regular CDs, then I'll have to start trolling Best Buy and Circuit City stores for old pre-March inventory.