What Brian is talking about is what carriers do to model tune (sometimes). It is labor intensive and expensive and must be done with care. I would highly doubt most wisps have the time or resources to do something like this. I wonder what the value is as an insurance policy vs submitting with a "rougher" approach and then proving once you are challenged?
On Thu, Feb 4, 2016 at 12:50 PM, Chuck McCown <ch...@wbmfg.com> wrote: > Pretty sure the FCC would accept this if you did enough samples to prove > the RF model. > > -----Original Message----- From: Brian Webster > Sent: Thursday, February 04, 2016 11:47 AM > To: af@afmug.com > Subject: Re: [AFMUG] Drive Testing > > > The most practical way to accomplish this would be to just validate your > RF model assumptions and then apply them to the fixed wireless propagation. > As you mentioned there is no practical way to test 22 foot CPE install > heights let alone the additional gain that a fixed CPE antenna provides as > compared to some sort of radio you could practically have on a mobile > platform. While you could go out and spot check with a push up mast that > can be time consuming when it comes to gathering a significant number of > sample points. > > The easier method would be to run an RF propagation with CPE parameters of > a device you can install on a mobile unit and drive around with. You could > then drive the areas that you predicted this coverage for and gather that > data in a text file. Ideally you would do the same drive multiple times and > under various climate conditions and seasonal changes. This would give you > sample points that you can compare the measured to the predicted. I would > do this in a GIS platform and create a delta table and map showing > variations between predicted versus measured. I would also have the data > for each clutter/tree class. This would allow me to investigate to see if > there are consistent delta differences and if they only appear to be > variations with certain clutter or if they predictions are off consistently > for the whole predicted area. This would then point me in the proper > direction to make changes in my RF tool, system wide would mean change the > percentage numbers in the mode of variability (fade margin), major > differences in the delta for various clutter classifications would tell me > I need to adjust my clutter/land cover file settings. Once the model is > tuned to your satisfaction you can then run your fixed CPE propagations > with a lot better confidence factor. > > One thing to look out for though is the land cover data being used. I have > both the latest and the next oldest clutter data for North America. There > was some sort of formula change to the data in the latest release that > created some decent sized changes in various parts of the country, this > means your predicted coverage may be assuming trees or lack of in areas > that the reality is different than the land cover data. You can get a > Google Earth file that shows the current vintage land cover > map/classification but I am not sure you can do the same for older > versions. I am fortunate enough to have all of the data on a hard drive and > can easily switch between the two and compare differences. > > Sometimes the old version is better, sometimes it’s the newer version, it > depends on your location. Sometimes there are clutter classifications for > an area such as Urban that you would not expect and thus your model is > applying losses for a clutter class you are not seeing in real life. I have > attached a Google Earth file with three separate areas in the US that have > a new and old clutter map version for the same spot, you can turn them on > and off at will while looking at the aerial imaging to see what the > differences may be. > > Thank You, > Brian Webster > www.wirelessmapping.com > www.Broadband-Mapping.com > > > -----Original Message----- > From: Af [mailto:af-boun...@afmug.com] On Behalf Of Adam Moffett > Sent: Thursday, February 04, 2016 12:11 PM > To: af@afmug.com > Subject: [AFMUG] Drive Testing > > I was thinking about this during my drive to work today, and the > towercoverage.com thread just reminded me. > > Is there a realistic way to do drive testing for fixed wireless? > > I've plotted coverage using a 22' subscriber height, and I can't drive > around with a 22' high mast (vehicles and loads have a 13'6" height limit > in NY State). So rather than collecting data as I drive --which would be > relatively painless-- I'd have to stop, deploy a mast, record coord and > reading, un-deploy mast, move to next test point, repeat. > > I think I could set a drone to a 22' flight ceiling. I'd still have to > drive the drone to different places because it will only work within range > of the controller. > > Or maybe forget about drive testing.....is there a realistic way to > validate your coverage map other than attempting installations and seeing > which ones work? > > If you're wondering why, I've been asked by some officials "how do you > validate this coverage projection?" All I've really got is that we attempt > installs and they usually work where they're supposed to. >
