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Wireless Broadband Router & Gps Receiver Overload


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Does anyone use a GPS receiver at home or at work in the same room where they have a wireless broadband router? I've got a high power router sitting on a desk in the basement. Some articles online point out that any high power transmitter in the 500-2500MHz range can overload a GPS receiver and cause it to become desensitized. So I've been cautious about turning my receiver when the router is on and transmitting.

 

While the GPS receiver is only receiving signals in the 1500MHz range it can still pick up harmonics from other frequencies. This may in fact render your GPSr "deaf".

 

From Motorola

 

"Strong transmitters (500-2500MHz) in the beam of the GPS antenna may cause overload in the GPS receiver causing reduced dynamic range (receiver desensitization) in the GPS frequencies. This also inhibits the GPS receiver's reception to the weaker satellites (satellites at low angles to the horizon)."

Edited by Blue Contrails
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I find that it does not matter what I have running in the basement I can never get a sat showing on the gps anyway when I am in the basement.

 

I do have a wireless router upstairs by the window though and I have never found it to have an effect on the gps when I am using it in the yard.

 

When I have walked around where I live with my laptop and have found 5 or 6 open computers. My gps works fine near all these opn systems so I guess it has no effect.

 

 

:anicute:

Edited by gm100guy
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Well atleast I've got evidence to support my argument. You seem to have your own opinion. You're not in some wittle bar in TX drinking it up with your buddies, BSing about stuff. You know?

What evidence? All you've done is quote from a KB article that used the very relative term known as "strong". You've never stated that you've fried a GPS receiver by putting it next to your wireless router, nor cited where anyone else had.

 

Without a specific wattage range, "strong" and "high-power" are definitely relative terms. There's "high-power" for 802.11b, but there's also "high-power" for transmitters in general on those same frequencies... two different things. A wireless router (something in the milliwatt range, anything much higher would be illegal without an FCC license) is not likely to qualify as "strong" in the potentially damaging sense, but stick your GPS receiver in a microwave oven and you might have problems :unsure:

 

If you've having interference down there, think about the location. How clear a view of the sky are you going to expect to get when you're in a basement? :unsure:

Edited by Maeglin
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I'm afraid some of you are missing the point. When a receiver is overloaded to a point where it causes damage, that damage is permanent. We're not talking about occasional interference.

Actually I think you're the one missing the point. I have the same experience as ddersch and gm100 that I get perfectly good reception indoors even with my eMap in close proximity to our wireless router. We're not even seeing enough interference to cause temporary reception problems and creating damage to the electronics would require many orders of magnitude stronger signals than are needed to interfere with reception.

 

I'm not going to put my GPS receiver in my microwave oven, but I'm not the least bit worried about exposing it to signals from such relatively low power microwave sources like routers.

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Ok Well I think I can speak from a position of some authority on this subject. 30+ years as an electronic technician 20+ years as a RF technician, 20 or so years as a GPS owner.....etc. etc.

Your 802.11x gear if FCC compliant is limited to 100miliwatt effective radiated power. About what the walkie-talkies your dad bought you for Christmas put out. High power just means that instead of being set at 40 miliwatt they have upped the power to be nearer the 100miliwatt level. Pretty insignificant on the RF scale (the satellite dish I am sitting about 40 feet from at this moment is putting out a signal of about 2,000 watts of effective radiated power (my GPSr antenna behind the dish performs very nicely thank you).

The desensing the manual talks about is when the receiver detects a strong signal it will lower the gain of the front end amplifier transistors. Unless the signal gets high enough to present a breakdown potential to the FET the components are not going to be damaged.

You have a much higher risk of damaging the front end (and the rest of the components in the receiver) from the static electricity produced when pulling the receiver out of a nylon jacket pocket or when caching in a thunder storm (very bad idea in any case).

I have used my GPSr in vehicles that have had 40 watt 800MHz transmitter antennas within inches of the external GPS antenna. I generally am not looking at the readout while talking on the radio but have noticed no problems with the unit afterward.

I think the statement in the owners manual is a CYA that takes them off the hook in case someone starts complaining about sensitivity in certain locations. I suppose that if you are relying on a consumer grade GPSr and are running a ground based radar in the Gulf your results may not be so good.

 

Hmm a very long winded way of saying “Don’t worry about it”.

 

Mac

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