we use a trupulse for agl, but even with agl being accurate at that slice in time, is the ground level accurate?
On Mon, Dec 28, 2020 at 12:35 PM Mathew Howard <[email protected]> wrote: > I always figured that using Google Earth for lat/lon and ground elevation > is as accurate as I'm going to realistically get with any method that's > available to me (yeah, I suppose I could pay a surveyor to go out there and > get me better numbers, but that's not really going to happen). As long as I > check a few points around the area and don't find any drastic (unexpected) > differences in elevation, I figure it's pretty accurate. > > Making a mistake in mounting height on the tower seems like a bigger > concern to me... on smaller towers, I should be able to get within a few > inches by counting tower sections, or even dropping a tape measure, but if > you're up a few hundred feet, that can get a lot trickier. > > On Mon, Dec 28, 2020 at 12:07 PM Ken Hohhof <[email protected]> wrote: > >> IANAL but if I wanted to do an audit, I’d just check against Google Earth >> for lat/lon and ground elevation. That’s close enough nobody will care >> about the difference. >> >> >> >> For azimuth, if you have the lat/lon of each end, you can calculate >> azimuth, assuming the antennas were aligned properly. If the RSSI is >> within a few dB of target, they were aligned properly. You can find >> azimuth by drawing a line on Google Earth, or using something like >> LinkPlanner. >> >> >> >> I’d mostly be worried about xmt freq, channel width, and xmt power >> matching the license. It would be easy to miss the fact that frequency >> coordination showed you needed to dial back the xmt power, or to make a >> mistake and be on the wrong frequency. Those would be bad errors. >> >> >> >> Tougher one to audit would be AGL. You coordinate the link, apply for >> your license, then tell the tower guys to mount the dish at 100 feet. But >> how do they determine 100 feet? Count tower sections? Foot markers on >> cable? Tape drop? Laser rangefinder? Maybe there’s a beacon light at the >> 100 feet so they put it at 90 or 110. Or there’s a nice abandoned mount at >> 120 feet so they put it there. >> >> >> >> >> >> *From:* AF <[email protected]> *On Behalf Of *Steve Jones >> *Sent:* Monday, December 28, 2020 11:44 AM >> *To:* AnimalFarm Microwave Users Group <[email protected]> >> *Subject:* Re: [AFMUG] FCC coordinate verification >> >> >> >> hypothetical, If FCC was coming I would be freaking out. I just spend a >> lot of time nervous about all our licensed links and one day finding out we >> are just outside the margin, particularly on amsl. We use the smart >> aligner now to verify the coordinate, but I assume FCC has more accurate >> meter than me. Or I'm completely off and FCC equates to whoever FCC >> contract to come. >> >> >> >> I can look at tolerance charts all day, but If I dont know what the >> tolerance is measured against, what value is it. Like if I want to get >> super accurate on weights I can go steal one of the ones in the jars and >> compare it to my weights >> >> >> >> On Mon, Dec 28, 2020 at 11:02 AM Ken Hohhof <[email protected]> wrote: >> >> When I had our frequency coordinator do an FAA application for us >> (licensed link on tower near airport) and mentioned the discussion here >> about 2C surveys, they acted like I was crazy. Are you sure this is >> required? >> >> >> >> Steve, is this hypothetical, or is the FCC paying you a visit? >> >> >> >> I know one time I discovered the commercial tower we were on had the >> lat/lon wrong on the ASR. For us to fix out license, they had to also fix >> the ASR. It was just a matter of filing a modification. I also seem to >> remember something about it wasn’t significant unless it was off by at >> least 1 second or something. >> >> >> >> Honestly I just use the numbers from my Garmin 64st, same as for CPI data >> for CBRS. Given several minutes it will usually state accuracy within <10 >> feet. I check it against Google Earth and they usually match to better >> than that. Even the elevation AMSL usually matches. If there was a need >> for a survey I would think it would have to be for AMSL, there’s just no >> rational reason to need a surveyor to certify the lat/lon these days. >> >> >> >> >> >> *From:* AF <[email protected]> *On Behalf Of *Steve Jones >> *Sent:* Monday, December 28, 2020 10:41 AM >> *To:* AnimalFarm Microwave Users Group <[email protected]> >> *Subject:* Re: [AFMUG] FCC coordinate verification >> >> >> >> im asking about if you get nailed by the FCC, not application >> >> >> >> On Mon, Dec 28, 2020 at 10:13 AM Cameron Crum <[email protected]> >> wrote: >> >> Typically if you are filing for FAA or FCC you have to supply coordinates >> from a 2C survey mimium. They assume a certified survey is good enough. >> >> >> >> >> >> On Mon, Dec 28, 2020 at 10:02 AM Steve Jones <[email protected]> >> wrote: >> >> Have any of you guys ever had the FCC verify your transmitter data? >> >> What equipment do they use to verify elevation and coordinate? >> >> -- >> AF mailing list >> [email protected] >> http://af.afmug.com/mailman/listinfo/af_af.afmug.com >> >> -- >> AF mailing list >> [email protected] >> http://af.afmug.com/mailman/listinfo/af_af.afmug.com >> >> -- >> AF mailing list >> [email protected] >> http://af.afmug.com/mailman/listinfo/af_af.afmug.com >> >> -- >> AF mailing list >> [email protected] >> http://af.afmug.com/mailman/listinfo/af_af.afmug.com >> > -- > AF mailing list > [email protected] > http://af.afmug.com/mailman/listinfo/af_af.afmug.com >
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