Many options are available on the market for spectrum analyzer hardware. Some of them comes with a cheaper price-tag, while others are more costly. All having different pros and cons. During the past years I have used different options, to sum these down I wanted to make a comparision of the difference in information they are bringing the user, when used. Devices used in this review comes in a price range more towards the cheaper range. All tests are made using Metageek’s Chanalyzer to gather data. The hardware used is Metageek’s Wi-Spy 2.4x, Metageek’s Wi-Spy DBx3, Ekahau Spectrum Analyzer Version 3 and AIR-CAP3502I-A-K9 – Aironet 3502I IEEE 802.11n.
Metageek Wi-Spy DBx3
Ekahau Spectrum Analyzer version 3
Chanalyzer identified the hardware of Ekahau Spectrum Analyzer version 3 as Metageek Wi-Spy DBx3.
Metageek Wi-Spy 2.4x w/ included antenna
A slightly higher noise-floor could be seen from Wi-Spy 2.4x.
Metageek Wi-Spy 2.4x w/ DBx3 antenna/mount
As a test if the noise-floor was impacted by the antenna included with Wi-Spy 2.4x, the antenna belonging to Wi-Spy DBx3 was connected to the unit, and fit in the same position as the previous tests with DBx3 and Ekahau analyzers.
Cisco CleanAir AP AIR-CAP3502I-A-K9
Tendencies for a higher resolution of the spectrum and faster sweep times could be seen with AIR-CAP3502I-A-K9.
Summary
The output from Wi-Spy DBx3 and Ekahau Spectrum Analyzer ver 3 could be seen similar compared to each other, with a slightly lower noise floor using Ekahau stick on 2.4GHz. The difference could be a coincidence and would need more testing to rule out. As the Chanalyzer software detected Ekahau unit as a DBx3 it is probably rebranded hardware. New DBx from Metageek is $500 USD, while I found a used version years ago on ebay for $250 USD. DBx with software Chanalyzer the total price-tag is $1000 USD (or ~$250 can be saved finding a 2nd hand stick.)
Wi-Spy 2.4x demonstrated a slightly higher noise-floor than the other devices included in the test. As the Wi-Spy 2.4x was released many years ago, the hardware has probably been adjusted and improved in the later versions (DBx-series). Wi-Spy 2.4x can nowadays only be found as used (2nd hand market) as Metageek no longer sells this version. The version used in this test was found 2nd hand on ebay with a price-tag of $120 USD. These may be found cheaper today, but a modest price-tag with Chanalyzer would be $600 USD.
The Cisco AP 3502 showed unexpected promising results from the test, with what seems like higher resolution and more granular data, seeing more interferers in 2.4GHz band (the three higher pitches, wireless audio?). Compared to the others, small tendencies for faster sweep times, more granular data and lower noise-floor could be observed. Each separate signal stands out a bit more (look how easy it is to spot each separate transmitter even at low strength compared to the others). One of the cons of this solution is that it non-portable, compared to the USB-sticks. It needs a PoE switch/injector or separate power supply, which makes it somewhat troublesome to use for walking spectrum analyzing test and instead makes it more useable for a static position in a specific area. An older used Cisco AP with CleanAir can be found very cheap today. AP used in this test was bought 2nd hand on ebay (5 years ago) for $28 USD. PoE injector (AIR-PWRINJ4) was bought 2nd hand at $15 USD. A special license is needed “Cisco CleanAir Accessory for Chanalyzer” for the use of Cisco AP as spectrum analyzers in Chanalyzer. The license has a cost of $150, therefore a complete solution including hardware, software and licenses would approximately cost $700 USD.
All tests were setup in order to monitor maximum range of channels that was allowed by each device, in order to create similar conditions. This means sweep time could been improved by monitoring only a selected number of channels, allowing a more narrow range.
Wi-Spy, Chanalyzer and licenses can be found at https://www.metageek.com/store/catalog/
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