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Wireless Spectrum Analyzer on the Cheap
PennyManDeux writes "There's an article over at TheTechLounge looking at the Wi-Spy wireless spectrum analyzer. Here's a quote: 'Although most wireless boxes are able to push through the lower amounts of interference, some people, such as those living in apartments or otherwise deluged with many wireless signals may have problems. It is with this dilemma in mind that the people at MetaGeek created the Wi-Spy spectrum analyzer.' Cool thing is, it's only $100..."
Why could these guys not had this a few years back when I owned a WISP?!? Just goes to show you, timing is everything. With the improvements in Wireless, and the accompanying hardware/tools, it seems that more people will be using it for commercial implementations.
----- I have bad karma for a reason! -----
Yes, it's under $100. That's news. But many other comparisons to the higher-priced analyzers aren't there.
1. Does it do channel characterizations? Apparently not.
2. Does it have channel reticules? Apparently not.
3. Does it do 802.11a? Apparently not.
4. Does it have enough resolution to find Bluetooth and other spread-spectrum devices? Apparenly not.
5. Can it identify specific kinds of interfering devices, like 2.4Ghz phones, microwaves, door openers, etc? Apparently not.
I say apparently not because none of this functionality, commonly found in other spectrum analyzers of this type, is even mentioned. It's nice to have a cool A-to-D converter in the 2.4Ghz region, but comparing this to Cognio or Air Magnet is like comparing a bicycle to a Porche. I can buy a bicycle for under $100. I can barely touch the ugliest old 914 Porche for $3K.
Don't be fooled by price, or comparisions that hardly scratch the surface of what diagnostic tools are all about. For under $100, it's pretty damn cute. But it's just the basics.... and minimalist basics at best.
---- Teach Peace. It's Cheaper Than War.
Wires: the new wireless!
You can analyze spectrums all day long, meanwhile me and my Cat 6 are enjoying gigabit speeds! Thats some fast, fast porn baby!
I don't need no instructions to know how to rock!!!!
It doesn't really solve the problem of interference. Let's say you have a 900 Mhz (old tech, I know) phone, which has constant interference. You buy one of these spectrum analyzers and find, not surprisingly, there is some interference at the 900 Mhz range. So what is someone going to do? Buy another phone, either at 2.4 Ghz or 5.6 Ghz, which would have less interference, but you didn't need a spectrum analyzer to get you to buy the higher frequency phones. You would have done that anyway.
This is surely not a replacement for a spectrum analyzer, but it will give you a general idea of interference in your house.
I have conducted many site surveys for businesses wanting wireless networks. The purpose of a spectrum analyzer is to pin-point sources of RF interference that may limit wireless connectivity, so that measures may be put in place to reduce RF emissions. You'd be surprised at amount of RF interference generated by industrial equipment, which poses a problem for RF engineers.
This product merely shows you that you have interference, and lacks the ability to pin-point the source. This product would be better if you could have an external parabolic antenna, but it looks like someone will need to figure out how to jimmy rig a Pringles can antenna to this unit. What can you expect for $100?
/whisper/ Thanks for the candy!
A link to the actual product page?
http://www.metageek.net/
You feel sleepy. Close your eyes. The opinions stated above are yours. You cannot imagine why you ever felt otherwise.
You know... it would have been nice to have when I moved into my apartment. Although I never figured why for the past three months my wireless wasn't working on Channel 6, I changed it to Channel 10 and all of a sudden my Wireless network works fine now... unless I use my microwave, that's another story.
jagossel
Netstumbler will do most of what you need done and it's free. Here's a link to a tutorial.3 589131
http://www.wi-fiplanet.com/tutorials/article.php/
I'm not trying to justify the price of more expensive SAs. Instead, the article misses a lot of points and comparisons with the higher priced stuff, then baits the article with price so as to justify it. A good RF engineer could do his/her own fairly easily. The software that does the rest takes a helluva lot more. Basic FFTs are cute and a freaking high schooler ought to be able to do them.
This 'review', however, tries to make the comparison with higher priced equipment, then doesn't cite the features that makes that higher costing equipment compare to the under $100 variety-- only cost is used. Nice bait.... not very sharp hook.
---- Teach Peace. It's Cheaper Than War.
I say apparently not because none of this functionality, commonly found in other spectrum analyzers of this type, is even mentioned.
How many high end frequency analyzers count as "of this type?" It's a $100 USB accessory. You wouldn't expect the same performance you'd get from a professional grade unit, would you? You mention some exceptionally useful functions, but you wouldn't expect them in a $100 box. Hell, the companion software for some of the nicer analyzers costs way more than $100. As for "others" in the type, what others are there?
Your Porsche to Bicycle compareson's not entirely bad, actually. But they're useful in different contexts. A Porsche may be awesome for canyon crawling or long distance driving, but I'd take a bike over one any day for short haul urban commuting.
Here, it doesn't take a $5000 professional grade spectrum analyzer to determine whether your microwave oven or portable phone is interfering with your $50 AP.
Different needs. Different tools.
Now Idon't know exactly what they put in that little USB pod, but it's unlikely it has the expensive dual-conversion superheterodyne signal chain, the interdigital varactor tunable filters, the low-noise Gallium-arsenide preamps, and the other expensive features of a real spectrum analyzer.
These cheap ones *may* be *mildly* useful, under *some* conditions, at *some* temperatures, and in *some* environmnts*. But usually the times we really need one of these eexpensive beasties is when all the conditions are unsuitable for the cheapo ones.
For example, just leaving out the tricky filters means the cheapo device will be very sensitive to other, out of band signals, that are of no consequence. False positives, very bad thing to see when you're trying to impress the client. Even worse when they pay big bucks to relocate the interfering devices, and the network still doesnt work.
www.wifigear.co.uk
.NET 2.0 to run
And from the review if you can't load it:
Conclusion
The 2.4 GHz spectrum is unlicensed. This means anyone can throw any type of signal they want into it. Anything from wireless AP's, to home automation products, to everyday appliances will throw out signals in this radio frequency. What all this means to the average person is this... interference. Either interference from other AP's, or a microwave, or a cordless phone. Either way, multiple devices vying for the same spectrum can never be good; it will affect your signal and degrade your throughput. The way to deal with this type of interference is to either ignore it, or try to go around it. Ignoring it might be acceptable for some, but finding ways around it is really a hit or miss proposition. It is hard to work around something you can't see. Sure, changing the channel on the router or physically moving the device might work, but in the end, you are just guessing. Now you no longer have to guess. With the introduction of the Wi-Spy, you can "see" the interference you are trying so hard to avoid. Before, you might have gotten the channel or the position right and enjoyed a cleaner signal, but I doubt that happened quickly. With the Wi-Spy, you should be able to figure out quickly and definitively just what your monkeying around might have eventually revealed. If anything, being able to rule out what won't work, you have won half the battle. With all the time you save, you can finally get out and do more important things like mow the lawn or clean the kitchen. (Ed: Oh goody!)
You just can't beat being able to "see" the spectrum you are using. Not having to take out a personal loan to buy the equipment is another plus. The software may have its quirks here and there, but no matter what, it still provides a good view of the spectrum you will be attempting to navigate. Software can be upgraded and fixed, and I believe that as time goes by, it will only get better. Considering its competition, the Wi-Spy is a steal at $100. If you do any type of wireless network setups, or you get drafted to set up everyone else's, the Wi-Spy should most definitely be in your laptop bag.
If you'd like to purchase the MetaGeek Wi-Spy, you can get it for about $100 directly through MetaGeek.net or you can buy it at ThinkGeek.com.
Pros
A spectrum Analyzer on the cheap
Portable
Easy to use
Did I mention it wasn't $3000+
Cons
Software could use some tweaking
Requires
Only works on 802.11b and g, not 802.11a
What I've wanted for a long time is an "EM camera" where I could "see" sources of electromagnetic radiation in real-time, something like a modern digital camera with an LCD view screen. We've got cameras for EM in the light range, but why not for other frequencies (higher or lower)? For example, I want to point this camera at an EM source like a microwave dish and see it sending out a beam like the headlamp on a car. I'm not saying it's practical. I just want one. If you could do this at low enough frequencies, you might be able to detect radio transmissions at a distance (say finding someone hiding in foliage across the street and using a FRS/CB/amatuer radio).
Ouch! The truth hurts!
I feel I have to chime in here...
You act as if the tools are not necesary for the job.
Next time you have to do something that requires the least amount of precision (due to fines, complaints and general hazards of being wrong) try using the bare minimum equipment or none at all.
The guy was dead on in his assessment and insulting him does nothing to further your point.
So yeah, it's crap, if you want this same functionality... you can go out and buy a wireless repeater and flash it with the "spectrum analyzer" firmware for monitoring. Don't care to look up the name, but I'm sure more then one company offers those options.
"You should always go to other people's funerals; otherwise, they won't come to yours." -- Yogi Berra
Faster? Nah. More reliable? Hell yah.
I never whine about getting fragged in an online deathmatch because someone reheated a cup of coffee in the microwave, or the phone rang, or the channel 5 news van ran a remote feed too close to my house.
I whine because the guy was CAMPING AND THATS LIKE TOTALLY GHEY MAN STFU N00B kekekekekeke
I don't need no instructions to know how to rock!!!!
I bought one of these...neat toy. The hardware is nothing special, it appears to be a Cypress WUSB reference design manufactured by Unigen. The firmware may have been modded a bit...if for no other reason than to change the USB strings (or not, I can't remember how it enumerates.) At any rate, I'm going to bet that they just look at RSSI across the band and report it back in a meaningful way. Clever use of the technology.
As many other readers point out, a spectrum analyzer it's not. I really don't think that's the intended purpose. It gives you an indication of band occupancy over time, and that's about it. For many uses that's just fine. If I'm trying to get some ISM-band device to form a link and it won't, the WiSpy gives a good first-order indication of band conditions. If WiSpy comes back clean, I move on to other diagnostic steps, generally involving test gear that costs (easily) 100 times what the WiSpy did. If it saves you some time, great. In my opinion, it's cheap insurance.
It's not a spectrum analyzer, but it is a nice panaramic receiver.
The difference between the two is resolution. A panaramic receiver is just
a band scanner. It will tell you what channels are occupied and the relative
signal strength. A spectrum analyzer will do the same and more, such as
giving you a good idea of the kind of signal you are looking at, and it's
purity. Many years ago Hams used panaramic receivers (scope display) to
see where the dx and band openings were without having to tune from one
end of the band to the other. If you are looking for a clear (or occupied)
channel the panaramic receiver is good enough. If you want to know why the
FCC cited you for a dirty signal, then you want a spectrum analyzer.
-- that's exactly the point. at $100 it has potential use to a non-professional. At 20k, its effecively out of reach as a part of the toolkit you can think of using to try to improve your connection.
The problem with quotes on the internet, is that nobody bothers to check their veracity. -- Abraham Lincoln
$5000 will get you a working HP 8566B on Ebay.
100 Hz to 22 GHz, 10Hz resolution, and if you can lift 100 lbs :-)
you can even call it portable
...I prefer to roll my own... Granted, it's only 250KHz of resolution (although you can change the filter, not sure how narrow you can get), but it's enough to get you started. I'm also seeing references to SA front-ends made from old TV IF strips. With lots of people upgrading their TVs, I expect to see a lot of these IF strips available.
Just junk food for thought...
I'm a small office / home office IT consultant, and I bought one of these a few weeks ago after stumbling across it on ThinkGeek. It's fabulous for my needs, which are simple: figure out if interference is the reason someone's wireless network is flaky.
Wi-Spy does a great job of doing this. I fired it up at a downtown client and saw there was a strip of intense interference down in channel 1. Moved them up to 11- problem solved. I've also done some tests at home... it's very easy to tell the difference between a microwave, spread spectrum phone system, video sender, and other wifi networks... they have rather distinctive appearences in the graphs Wi-Spy produces. Now that I know what they look like, I can take an educated guess, where before, I was grasping at straws.
For those of you getting your panties in a wad about it not matching a $5000 spectrum analyzer: Duh? Of course it doesn't. But that doesn't mean it's useless... there are a lot of folks (like me) for whom the cost of a "real" spectrum analyzer is completely unjustifiable. But I can spend $100 easily, and *for what I do*, which is occasionally troubleshoot SOHO wireless networks, it provides most of the functionality I need.
The really interesting fact is that this thing defines an entirely new product category: inexpensive spectrum analyzers. I would really like to see what could be done for $500... that's still an order of magnitude cheaper than the existing solutions, but I bet you could add a bunch of features.
-R
I wote a review for labratmagazine.com last month, and I did review the OS X third party software...which is MUCH nicer than the stock stuff. Reg required, but its a decent review. As for picking up Bluetooth....it picked up my headset just fine.
Always value the individual over the system. --Bruce Lee "I don't need a Sig - I have a custom 191" - me
Netstumbler only shows you other *wireless networks*. Wi-Spy shows you *all* RF interference in the 2.4 GHz spectrum, such as that caused by cordless phones, microwave ovens, etc...
-R
A better review is available from Tom's Networking, including comparison to one of the $4000 Cognio devices:
i spy/
i spy/page2.html
http://www.tomsnetworking.com/2006/02/12/review_w
Comparison table on page 2:
http://www.tomsnetworking.com/2006/02/12/review_w
There is already a separate Linux app that has most of the functionality of the Windows app. I suggest using that versio (available from http://www.kismetwireless.net/wispy.shtml) instead of trying to get the Windows app running under Mono. The reason for this is that the USB library used by the Windows app, probably will not work under Mono.
Like the other poster pointed out, $5000 gets you some pretty decent SA hardware nowadays. Not state-of-the-art, but then, the actual RF hardware hasn't changed much since the 1980s. Most of the R&D progress has gone into making them cheaper and faster (e.g., replacing crystal filters with FFTs), rather than "better." And obviously, instrument firmware is way more capable now.
Host-based utility programs can go a long way toward covering the "firmware gap" between older and newer instruments, though. I have an open-source surveillance package that works well with most of the late-80s and newer-vintage Tektronix and HP analyzers (see website in comment header), and there are others. A $2000-$3000 (US) Tektronix portable took this screenshot with my freeware Win32 app.
But yeah, for simple WiFi diagnostics, this USB dongle sounds like a much better fit. High-resolution, high-precision spectrum analyzers don't add much value when dealing with wideband modes like WiFi. Cheap ones are fine. I don't know that I would advocate that the average Slashdotter drop $5K on an HP 8566B.
Dahlmann tightly grips the knife, which he may have no idea how to use, and steps out into the plain.
Ok, I know you were making fun of those people, but that's a bit of a pet peeve of mine: people who call others "noob" for using the most effective weapon in the game, or choosing their battles carefully. People, realize that if a less experienced player than you is killing you more than you're killing them, they are using superior tactics. Adapt. (ok it's possible they're outright cheating, but that's outside the scope of this rant.)
Rising to their challenge is exactly what makes the game fun, not racking up an enormous number of kills using some byzantine code of warfare that only the "elite" are privy to. Now granted, due to imperfect game design, there are some superior tactical positions and weapons that make the game rather boring (i.e. camping & the BFG du jour), but those are problems that can be solved with insightful level design, patches, and administrator options disallowing certain weapons/behaviors. If it is allowed, it is fair game.
I used to love campers and BFGers. The former are easy targets once you understand the level, and the latter are so confident in their superior weapon that they rarely catch you sneaking up behind them with the knife. Easy money. Until they learn not to do that, that is, but then becomes more challenging and fun. There is a lot more to a fun combat game than everyone running into an open field, jumping around like drug-crazed hyenas, and spraying bullets around haphazardly in a winner-takes-all twitch fest of epilepsy.
Can you be Even More Awesome?!
...fiddling with my HP8590 spectrum analyzer bought via the internet....
/Me *hugs* his REAL spectrum analyzer ;)
You can keep your 100 Dollar wifi-thingy
My baby can do so much stuff the owners of a 100 Dollar wifi-spy can dream about
It can scan everything realtime (I do mean REAL-TIME) oh...and did I mention it can scan
the WHOLE darn spectrum...not just the Wi-Fi spectrum? And yes...it's still realtime
and it's from the 80's and didn't cost an arm and a leg.
I'd say it's better with a 1000 Dollars worth of real results rather than 100 dollars of promises!
What this world is coming to - is for you and me to decide.
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