Dale,
Now, that is useful information. I hadn't thought about ducting, but the
problems with the 5GHz links didn't start til two weeks ago, about the time
we would expect to see some ducting in this area. Hmm. I also need to check
the FCC database; hadn't thought about that one, either. I'll do that today.
Thanks for the good leads --
Tom, KT9OM
At 08:15 AM 5/13/03 , you wrote:
>
>Tom,
>
>This information does change the picture a bit. Assuming that you have
>already performed some sort of functional testing to rule out an equipment
>problem in your own system, there are three suggestions that come to mind:
>
>1. Check the FCC data base to see if there are licensed systems operating
>in or near your area in adjacent portions of the spectrum. You could have
>some other system that has developed spurious outputs and is causing a
>problem.
>
>2. Consider either renting a spectrum analyzer, with appropriate antennas,
>and taking readings during periods of system malfunction, or hiring an EMI
>test house to send someone out with equipment to do the work. The
>combination of portable horn (or dish) antennas and a spectrum analyzer
>should allow you to DF the interfering source.
>
>3. Have these problems just begun, or have they existed for awhile? The
>reason I ask is because we are now into the time of year in which tropo
>ducting becomes common. Being an avid VHF/UHF op, I can tell you that some
>real surprises can happen. Your antennas are up high, and that is why I
>raise the question. Years ago, I worked microwave for the "original" Ma
>Bell. I recall being at some field sites in mid-summer and just watching
>signals go up and down, disappear, re-appear, and cause all sorts of
>trasnmission problems when the ducts and/or thermals over the corn fields
>set in. This action occured at both 6 GHz and 10 GHz.
>
>Best luck.
>
>73, Dale
>WA9ENA
>
>
>
>
> Tom Cox
> <tomcox@iquest.ne To: David Jordan
<wa3gin@erols.com>
> t> cc:
rfi@contesting.com
> Sent by: Subject: Re: [RFI] 2.4 GHz
and 5 GHz RFI (maybe)
> rfi-bounces@conte
> sting.com
>
>
> 05/12/2003 02:39
> PM
>
>
>
>
>
>
>As I should have mentioned, this is a point-to-point system of wireless
>bridges, not a point-to-multipoint system as is commonly thought of in
>digital wireless applications. These links are on rooftop or tower mounts,
>from several feet above a building roof to over a hundred feet up a tower,
>connected with high-gain, narrow-beam antennas. The 2.4 GHz links connect
>smaller buildings to one, central "hubsite" in the area, which uplinks the
>smaller buildings to a backbone at 5 GHz. What I need is a way to discover
>and locate RFI at 2.4 and 5 GHz that is (or might be) interfering with the
>system. I hope this makes my situation a little clearer. Sorry about the
>incomplete description.
>
>Tom, KT9OM
>
>At 02:10 PM 5/12/03 , you wrote:
>>Could be a leaky microwave oven in the kitchen or cordless phones, etc.
>>Might try a booster or relocating the WAP.
>>
>>73s,
>>dave
>>wa3gin
>>
>>Tom Cox wrote:
>>
>>>What is out there for searching the 2.4 GHz and 5 GHz. wireless data
>>>spectra for an interfering signal? We have erratic link drops that are
>>>suggestive of RFI, but no equipment for detecting it. Our school
>>>corporation's wireless WAN is really suffering.
>>>
>>>Thanks,
>>>Tom Cox, KT9OM
>>>Anderson (IN) Community Schools
>>>tomcox@iquest.net
>>>_______________________________________________
>>>RFI mailing list
>>>RFI@contesting.com
>>>http://lists.contesting.com/mailman/listinfo/rfi
>>>
>>
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