Yes. A long time ago on the engineering crew at KSBY-TV, the station
would rent us out to some of the AM stations who did not have a resident
engineer, usually when something quit or when their PoP came due.
Mostly 5 and 10 kW, usually directional, at least at night. These
stations were required to have at least 120 radials. They were also
required to have those 120 radials connected to the matching network
ground. It was common to have a conductive grid out from the base of
the tower(s) with the radials connected to the outer edge since 120 to
a single point is a bit hard physically. Each tower had it's own grid
and radial field. After a few visits, I discovered:
1. They usually didn't want to me to go out to the tower(s) to inspect
it/them and the matching network(s). "Snakes" was the excuse.
2. After insisting on going and that someone accompany me or we
couldn't complete the PoP, I usually found that no one had been out
there in years, the matching/phasing networks were full of bugs, webs,
weeds, and corrosion, and of the radials I could find, some were
connected, some had corroded away from the connection, and some couldn't
be found. Never encountered a snake.
I guess they were faking their PoP's, and maybe continued to do so
because we weren't hired again by a couple of them.
73,
Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County
Jim Brown wrote on 1/17/2022 12:44 PM:
Just out of high school, I had a summer job at WSAZ, a 5-kw with a
4-tower array, with the same ground screen/raidal configuration on
each tower, silver-soldering those radials.
120 radials was a legal requirement of FCC Rules, and was primarily
for standardization of performance.
73, Jim K9YC
On 1/17/2022 9:28 AM, George Danner wrote:
Mike,
When I was an AM radio broadcast engineer in the 60s & 70s, we used a
copper screen for the first 20' to 50' around the tower base and silver
soldered all the 1/4 wavelength radials to the common point straps and
several places along the screen. This was in Florida with sandy soil. I
seemed to remember from my 1st Phone exam that 120 radials were
required.
--
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