Vertical (tower) antennas measured in degrees?

[KM1H]

You better check with the FCC directly and not rely on a CE that is not that familiar with all the rules.

In case of a partially destroyed radial field due to industrial or other enroachment the FCC may OK a power change and the actual amount is their call. They may also require a power reduction at dusk/dark to reduce the skywave back to original levels.

They have also given approval to an elevated radial system which often requires a reduction in power.

[k4kyv]

Those are special cases.  In the case of accidental damage to the ground system, it's more like a STA to keep the station on the air until the system can be brought back up to specs, but no doubt the FCC would give the station a deadline to get everything back in order.  Regarding elevated radials, those systems were FCC certified for permanent operation and included in the licensing data for the station, and the FCC may impose whatever standards they deem appropriate, at their own whim. In the past the FCC licence certificate that hung on the wall stated the type of antenna, including the degrees of height, power output and the permitted range of base current, the length and number of radials, and details of how the tower is fed.

The FCC has approved at least one low profile vertical monopole that is much shorter than 90°, using a short fat radiator.  I forget its name, but they have recently run ads in several of the broadcast rags. It uses a full radial system, but the radiator is more like four short inverted-Ls arranged back-to-back to each other, and the horizontal sections act like a top hat.  They claim nearly the same efficiency as a conventional 90° vertical. They have grabbed a lot of attention in response to the anti-tower and anti-antenna sentiments that have permeated in recent years.

OTOH, the FCC wouldn't authorise the E-H and Cross-Field antennas, and I haven't seen anything about them lately. I'm not sure if the FCC ever gave anyone the go-ahead to even try one of those antennas experimentally.  Of course, a licensed amateur could have built one for 160m and reported the results, but I never heard of anyone doing that.

[KM1H]

Regarding elevated radials, those systems were FCC certified for permanent operation and included in the licensing data for the station, and the FCC may impose whatever standards they deem appropriate, at their own whim.

Im talking about as replacements for buried radials, not new construction. A new certification was required and as I said there were often power reductions required.

[R. Fry SWL]

Im talking about as replacements for buried radials, not new construction. A new certification was required and as I said there were often power reductions required.

Could you please post the specifics (call letters, links to FCC documentation etc ) supporting your statement?

The FCC requires minimum r.m.s.field intensities at 1 km for the classes of AM stations, but I'm not aware of any maximum field intensity for a given licensed power.

A class C "graveyard" AM station (1 kW, non-directional, 24/7) can produce its minimum field using a monopole of less than 90 degrees and an r-f ground of 120 x 1/4-wave buried radials, but is not prohibited from installing a 1/2-wave or 5/8-wave monopole that, for the same applied power could produce a field at 1 km that is over 1.5X  the minimum value required by the FCC.

Decades ago I was the CE of such a station (1 kW non-D on 1400 kHz), which used a 1/2-wave monopole.