When an aircraft is overhead it’s fairly close and line of sight and you could probably talk to it using a paper clip as an antenna. An aircraft at 35,000ft directly overhead is about 6.6NM away and if it’s 10NM down range it’s still very line of sight. At about that point you should be within the very broad pattern of a low gain airport base antenna and you want any gain at the horizon when the aircraft is far away like 100+mi.How do they get the transmission to radiate upwards? The ATC antennas look like ordinary antennas. Do they (ATC) use special antennas?
Are the RTR sites pretty much the same set up as an RCAG? My closest airport, MKE, has two on site, but the RCAG is like 3 miles south of the airport. I'm thinking they belong to the MKE TRACON?ctadam12...you can read all about the antennas they use:
VHF Archives - Antenna Products
www.antennas.com
Depends on the site, some will be mounted on metal poles to pull down the lobes, like an RTR and on RCAG sites they use fiberglass poles to try and fill in the doughnut hole(at least make it smaller) at 40000 feet.
I said all the photos I posted were FAA sites--I took all those photos that were linked to in the other thread (I have visited dozens and done similar). In fact, at one, the first photo, I talked to the FAA maintenance person while there. I am not sure what you are trying to tell me or correct me.dlwtrunked, all the pictures you linked to are probably FAA sites. For AM, you will never see co-located utilities, well you shouldn't except for ads-b/c, most of the time, maybe, depends...
ctadam12, RTR's, RCAG's, RCO's BUEC's pretty much all look the same. RTR's are usually on the airport property.
ind224, you know if you file a long form you can get tax credits for ten years but the depreciation schedule the IRS uses sucks.