In a message dated 10/30/2004 2:42:11 PM Eastern Standard Time,
k5uj@hotmail.com writes:
it turns out these people invest in apparently expensive elaborate audio
gear for AM transmitters that operate in the higher portion of the bc band
with 100 mw carriers fed to 108" steel whips. The whips are elevated and the
tx
mounts directly under it in a weatherproof box on the mast. I know the
range of low power
10 watt carrier stations (class Ds with night-time authorization) is
surprisingly good
due to their use of their regular full-size systems but I can't imagine the
service area
of 100 mw on a whip will be more than a few blocks. To invest in so much
high grade
audio gear for such a thing is bizarre.
rob/k5uj
I experimented with a few 100 milliwatt part 15 AM transmitters on 1640 KHz
about 10-15 years ago before the expanded AM BC band was populated. I used a 10
foot elevated vertical mast with tophat over an elevated/tuned radial ground
system mounted on the roof of a house about 20 ft.above ground. It would put
out a very respectable groundwave signal out to about a 1/2 mile radius and
could be heard well out to about 2 miles distance on a good car radio. With
just
a 102" whip the range would be less - it would be stretching things to get out
much more than a 1-mile radius and maybe 1/4 mile radius strong groundwave.
It would take 4 of them to blanket a square mile but it could be done. It would
be just the thing to cover a theme park or maybe a fairgrounds. A $48,000
studio and satellite receiving building seems to be going a little overboard to
cover a square mile or two though. It would be a nice setup for LPFM. 73 Todd
Roberts WD4NGG.
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