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Original thread:
Post 8 made on Wednesday November 10, 2004 at 13:44
mr2channel
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August 2002
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On 11/10/04 17:32 ET, Ernie Bornn-Gilman said...
I just finished reading this. I should have just
said "don't get me started." I didn't.

I started out in this industry as a hobbyist listening
to AM radio...used to get, in Southern California,
KOA in Denver, KOB in Albuquerque, sometimes WLS
in Chicago, occasionally WWL in New Orleans....

Right. When I started in HiFi in 1970, I got
the impression that once manufacturers could put
high fidelity FM tuners into their products, they
decided to only spend about a buck twenty on an
AM tuner. After all, there is no way it can be
hifi (in this modern profit-driven world)! Unless
you buy one that actually pushes its AM reception,
the AM section is likely to be crap.

OEM car tuners are better because they are designed
to be used all across the country (see the section
on distance below). I recently drove from northern
Arizona to Los Angeles around four in the morning,
and I was clearly receiving a station in Norman,
OK while in Arizona. After that I switched to
a San Francisco station.

Most car HiFi radios have poor AM sections, just
like home HiFi. Same principle.

This seems like a nice wish. You can wake up
to FM and it sounds better, so there is no reason
for a clock radio to have a good AM section.
After all, loud static will wake you up, right?

Are you saying you have found this to be true,
or are you theorizing?

Unfortunately, pure bunk.

RG-6 is fine if your AM antenna has a 75 ohm output.
RG-6 will work well with amplitude modulated signals.
Analog TV signals have AM picture and FM sound.
It is not the type of modulation, but the frequency,
that determines the possible reception distance.
At AM frequencies, there is a "ground wave" that
hugs the earth, so reception is possible beyond
where the curvature of the earth would eliminate
it. FM, at 100 mHz, is line-of -sight. Transmitters
on mountains can send FM signals (100 mHz signals,
that is) more than a hundred miles, but 100 mHz.
transmitters at ground level are limited to around
100 miles.

AM signals go along the ground, attenuating as
they spread. They also are radiated up into the
air, and actually bounce off the ionosphere before
returning to earth. There is a distance between
where the ground wave is too weak and where the
ionospheric bounce returns the signal to earth;
in this range you cannot receive an AM (oops,
I mean 1 mHz) signal. The ionosphere is calmer
when the sun is not shining on it, making a better
reflecting "surface," so 1 mHz reception is much
better at night.

Yeah, the old 1948 RCA consoloe I had as a teenager
had a loop. About 12" wide, 30" high, and 2"
thick. You had to orient it for best reception
of each station...which is a drawback to this
day with any AM reception (1 mHz, really).

I once had an early 1930s Philco radio (it had
a tube in it with a label saying that it had been
installed as a replacement in 1935). This radio
took one ground wire and one wire tossed out the
window, or as long as you could get it. It did
not work with a loop. Lops are not the only possible
antenna type for 1 mHz recetpion.

It is the best AM antenna I have seen, and that
is saying a lot since I have hated Terk for looking
good but performing like junk since day One.

In fact, I have one. You rotate it for best orientation
each time you change stations, and there is a
tuning knob that can peak the signal or "unpeak"
an interfering signal. It is awesome but it does
not lend itself to use in a customer's home unless
they want ONE AM station or they are willing to
mess with it all the time.

This antenna does not even need to be connected:
just place it near the radio's AM antenna and
its internal resonating coil/capacitor system
will aid the radio.

I don't think Winegard has anything to offer for
AM, although you are RIGHT ON about their other
products.

Basically,an AM antenna needs two wires, similar
to an FM one, but the frequency difference makes
the rest of it dissimilar. You should use the
loop that comes with the reciever, remembering
you have to orient it to maximize a station you
are listening for or minimize an interfering station.

When you use the loop, the AM section of the radio
is matched to a type of circuit it wants to see.
You can then augment this by connecting one terminal
to GROUND. I mean the earth, planet, dirt, wet
sand, wormtown, whatever, not the closest electrical
ground. Amplitude Modulation is exactly the type
of signal put out by motors and fluorescent fixtures,
so going to ground without going to the electrical
fixture ground will be quieter.

Then, put up a wire connected to the other AM
antenna terminal. A long one. In fact, "long
wire" is a technical name for a type of AM (oops,
1 mHz) antenna (google "long wire antenna")!
Basically, run it out the window, up to the chimney,
out to the tree, across to the neighbor's house...the
longer it is, the better. Longer means more signal
pickup, which means the fluorescent noise will
fade more into the background. Longer also means
less directional for some reason, so you don't
have to worry about reorienting your sixty to
one hundred foot antenna.

Oh, yeah, and don't forget to keep this NOT connected
to the ground.

good to know I know so little...and learn a little more.

One question though Ernie if the antenna is not grounded (for better performance) how can you stay up to code (NEC) since all "antenna's" are required to be grounded?
What part of "A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed." do you not understand?


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