Wireless Outputs Limits

[Biker]

Question, I have been using the inSSIDer software to monitor wireless devices I have and notice some strange signals on the 2.5GHz band. The device is a netgear with a lot of output power; measure 0dBm on the chart, which randomly pulses; very small bandwidth, across the whole channel spectrum during the day. I do live very close to a tower that belongs to the Gov/Military. Is this normal that some users, Gov/Military, are allowed more power output which could possibly interfere with normal wireless operation.

 

[Mark Uhde]

Question, I have been using the inSSIDer software to monitor wireless devices I have and notice some strange signals on the 2.5GHz band. The device is a netgear with a lot of output power; measure 0dBm on the chart, which randomly pulses; very small bandwidth, across the whole channel spectrum during the day. I do live very close to a tower that belongs to the Gov/Military. Is this normal that some users, Gov/Military, are allowed more power output which could possibly interfere with normal wireless operation.

inSSIDer is relying on beacon frames your wireless card can read, and isn't telling you anything about the realities of the RF environment around you. Grab a spectrum analyzer and then you'll have the best idea of the reality.

If you can find one, the best value around there is the (now discontinued) Ubiquiti Airview2. It's not terribly sensitive (I think around -90dBm) and it's very slow (about three frames per second). It's good enough though to show you the radio realities around you, because I'm guaranteeing you're seeing a glitch. 0dBm just isn't possible, that would mean at your wireless card's input the signal level is one milliwatt. There's just no way.

 

[Biker]

Mark, understand what you are stating about using a spectrum analyzer for best results, tho the inSSIDer does have a nice tracking of receiver rf dB over time, and yes, the dB level I have notice is very high and pulsing over time/scanned. I have not seen anything else around me; and I am remotely away from others with a level that comes across so high. One note, I used a homemade parabolic antenna with a CISCO Linksys AE1000 attached and have found the signal appears to be coming from the direction of this Gov Tower. Just wondering if they are allowed a much higher dB level output.

 

[Biker]

the site name is; Raven Rock Mountain Complex

 

[Mark Uhde]

Mark, understand what you are stating about using a spectrum analyzer for best results, tho the inSSIDer does have a nice tracking of receiver rf dB over time, and yes, the dB level I have notice is very high and pulsing over time/scanned. I have not seen anything else around me; and I am remotely away from others with a level that comes across so high. One note, I used a homemade parabolic antenna with a CISCO Linksys AE1000 attached and have found the signal appears to be coming from the direction of this Gov Tower. Just wondering if they are allowed a much higher dB level output.

They're the government they can do anything they want, LOL. No, seriously, as far as I know - no, potentially amateur radio operators are but there's a lot of restrictions there. Amateur radio operators are required to not encrypt, or to publish their encryption keys, the purpose of the communication is limited, etc.

The government has no real use for higher power anyways. Higher power is not, unlike people like EnGenius and Amped would push, the answer to everything. I like the EnGenius product, it's good small office equipment. The higher power, however, can be as much harm as benefit - and should often be turned down to 20dBm (the strongest any typical wireless card is) - depending on proximity to neighboring AP's on the same channel. The stronger transmitted signal isn't balanced by stronger stations. It does improve downlink SNR and speed somewhat, in theory. If you read Tim Higgins' reviews of high power products, you'll see that rarely plays out in the real world. For example, read this article - http://www.smallnetbuilder.com/wireless/wireless-reviews/31733-engenius-eap-300-retest

Even there, you're not seeing a HAM at 0dBm. You're seeing a glitch. Your card wouldn't even know what to do with a signal that strong it would just overload the receiver. I guarantee it Possibly a non-standard narrower channel your wireless card doesn't report properly or something. You really need to see what's going on on the RF level. I'd love to see spectrum analysis of that, know what would cause your wireless card to report that.

 

[Biker]

Mark, I am not using a wireless card, I run mainly hardline for the main computer, tho I am using the CISCO adapters as a test base for reviewing EnGenius ESR600H and the older ESR9850.

 

[Biker]

BTW, when I see it again, I will do a capture of the signal and post it

 

[Mark Uhde]

Mark, I am not using a wireless card, I run mainly hardline for the main computer, tho I am using the CISCO adapters as a test base for reviewing EnGenius ESR600H and the older ESR9850.

Umm, the Cisco-Linksys wireless card you're running inSSIDer with is the wireless card I'm referring to.

 

[Biker]

I'm not sure why you are calling this a "Card" its an adaptor that plugs into a USB 3.0 port on my workstation

 

[Mark Uhde]

I'm not sure why you are calling this a "Card" its an adaptor that plugs into a USB 3.0 port on my workstation

Because I'm using the term "wireless card" as an easy and widely-understood generic way to say "IEEE 802.11 station client adapter connected to an I/O bus on a host computer and being driven directly by driver software the host computer" (as opposed, to say, a bridge that's doing all the work and then spitting out standard Ethernet)

 

[stevech]

Question, I have been using the inSSIDer software to monitor wireless devices I have and notice some strange signals on the 2.5GHz band. The device is a netgear with a lot of output power; measure 0dBm on the chart, which randomly pulses; very small bandwidth, across the whole channel spectrum during the day. I do live very close to a tower that belongs to the Gov/Military. Is this normal that some users, Gov/Military, are allowed more power output which could possibly interfere with normal wireless operation.

I'd first suspect your measurement device. 0 dBm is most likely a software flaw in what's reported by the WiFi adapter via the software API that inSSIDer relies upon.

The unlicensed ISM band is not 2.5GHz.

Gov't users of the 2.4GHz unlicensed ISM band are under the same FCC regulations as the rest of us.