Yes, "thermal inversion layer" or whatever- I wasn't involved in the call to SAF, but I believe this is why they wanted us to lower the tall side to avoid "reflecting" off the thermal differences. The signal swing is a bit rhythmic
[cid:[email protected]] From: Af [mailto:[email protected]] On Behalf Of Keefe John Sent: Friday, October 23, 2015 10:31 To: [email protected] Subject: Re: [AFMUG] 20+db swing signal can change from thermal ducting On 10/23/2015 11:40 AM, Dennis Burgess wrote: Signal don't change unless you have rain, etc. The last two things are wind (antenna alignment) and tx power. That's it.. Dennis Burgess, CTO, Link Technologies, Inc. [email protected]<mailto:[email protected]> - 314-735-0270 x103 - www.linktechs.net<http://www.linktechs.net/> From: Af [mailto:[email protected]] On Behalf Of Scott Vander Dussen Sent: Friday, October 23, 2015 11:31 AM To: [email protected]<mailto:[email protected]> Subject: [AFMUG] 20+db swing 17 mile link, 11GHz, 3' dishes- it's worked fine for years and over the past few months there has been an increasing fluctuation with signal quality. SAF support suggested we were too high on one side and actually lowering it would help, it didn't change. We've verified LOS, even switched out to a DragonWave 11ghz pair of radios and it exhibited the same behavior as the SAF. We then moved one side of the link to a different tower about 6 miles away (still makes overall link 17 miles) and we're getting the exact same behavior. In years' past the signal was consistent, now we're seeing this: [cid:[email protected]] Am I missing something? Same behavior with two different radios, frequencies, and towers. There are no environmental conditions like moisture, etc. that are obvious culprits.
