Using commercially-available equipment is cheating anyway. What does it
take to modify PCS cellular phone firmware for digital communication on
902? Is it just a matter of firmware or isn't the RF section able to tune
that far out of band?

At the time, cell phone equipment was not readily available.

To oversimplify a bit: Low frequencies (like AM broadcast) pass through
the body without being absorbed. Microwave frequencies bounce off the body
without being absorbed.

ROTFFL!!!

Why not PROVE your ridiculous theory by putting your head into a microwave oven!

........yeah. I didn't think so.

"Bob Haberkost" wrote in message
...

"David Eduardo" wrote in message
...

Huh? AM stations essentially always have vertical radiators, especially
in
Europe where there are so many high powered stations.

In general, AMs don't work very well otherwise.

This concludes your antenna theory class for the day. ;-)

Very interesting discussion. Thanks.

How about introducing the masses to franklin antennas, such as the system
still in use at KFBK in Sacramento. I believe KDKA once had one, too. I saw
one in South America that had no real ground system, just the two elements
of the Frnklin and a ground mat at the base.

"Richard Fry" wrote in message ...

"Bob Haberkost" wrote

Huh? AM stations essentially always have vertical radiators,
especially in Europe where there are so many high powered
stations. In general, AMs don't work very well otherwise.

H-Pol radiators have little to no ground wave.

H-pol would not be used on VHF and above (FM/TV broadcast etc) if that was
true. A linear, horizontal dipole antenna at MW or any other band generates
its maximum field strength at all angles perpendicular to its longitudinal
centerline -- which includes all angles from below the antenna out to the
radio horizon; i.e., a "ground" wave. [Free-space radiation with respect to
the dipole itself is the same whether its axis is horizontal or vertical.]

H-Pol is used on VHF, such as TV and FM, not because there's no ground wave (which
there still isn't) but because, in historical times, the antennas used to receive TV
and FM were H-Pol (most still are, if you look around). However, vhf broadcasters
(you know?) have been allowed to used V-Pol (to the limits of the H-Pol
authorisation) or elliptical or C-Pol as well since the early 70s, due to the number
of portable receivers coming into use at the time whose antennas are, frequently,
vertically-oriented. And while all dipole radiators have the characteristic
radiation pattern you describe, this isn't a "ground" wave since there's no bias for
radiation along the horizontal plane when the radiator is oriented horizontally -
it's only when this radiator is vertical that the omnidirectional radiation
perpendicular to the centreline is a "ground" wave, as significantly less power goes
skyward, in conformance with your description. Further, since medium wave radiation
has a significantly larger wavelength when compared to the size of the earth, the
diffractive effects make for over-the-horizon transmission, further enhancing the
phenomena called "ground wave propagation".

The reason h-pol is not used for MW is because path losses are much higher
for h-pol than v-pol in that part of the radio spectrum.

And, as noted above, because for the same amount of coverage, more power would be
necessary, since well over half of the radiated power goes uselessly skyward.

This is why a vertical radiator is sometimes called a "ground plane"
antenna, snip for those installations on the ground, this counterpoise
is usually buried.


The radial ground system used with MW broadcast antennas reduces antenna
system losses (I^2R), and keeps maximum radiation directed more toward the
the horizontal plane, rather than at some elevation angle above the
horizontal. The FCC defines the minimum efficiency of radiators licensed
for MW broadcast in terms of producing a field strength of so many mV/m at 1
km from the antenna, per kW of antenna input power. These efficiencies
cannot be met without using a good ground system.

Right....but how is this information inconsistent with my description, which is to
say that a vertical radiator needs a ground plane? You also fail to note that the
rules specify different minimum efficiencies for differring antenna lengths.

Those familiar with 11-meter Citizens Band know this antenna
in its 27MHz form, snip the reason why this particular configuration has
these radials at a 45-degree angle from the horizontal is because a ground
plane antenna has an intrinsic impedance of about 30 ohms....the farther
towards being vertical, the more it's like a dipole, with a dipole's
characteristic 72 ohm impedance. Thus, at 45 degrees or so, the
ground planes typically used for C-Band are about 50 ohms without
the need for a matching network.)


Possibly more important is the point that drooping the radials also tends to
lower the angle of maximum radiation, which can improve field strength for
receiving antenna sites at/near ground level.

Perhaps. But isn't it interesting that the angle selected is the same angle as what
produces a 50-ohm impedance? If the effect were more pronounced at a different
angle, one would think that that angle would be preferred, and then using a matching
network, bring it back to 50 ohms. Of course, there would be some loss in that
network, which might overwhelm the additional advantage gained by dragging down the
lobe.

The nice thing about the low radiating impedance of a vertical radiator is
that the high base current necessary for a given power means that the
magnetic vector is bigger than the electrostatic vector, and since
ferrite loops used in most AM radios respond to the magnetic
vector, the "connection" is more intimate.

?? The table below shows the efficiencies for MW vertical radiators with a
good ground system. The self-impedance of a 90 degree vertical is about 50
ohms, and for a 180 degree vertical it is over 100 ohms. So for the same
input power, base current is lower in a 180 degree radiator than in a 90
degree radiator. Yet the efficiency of the 180 degree radiator is higher --
the opposite of the above quote statement.

The ground wave field strength of a MW vertical radiator per kilowatt of
input power is related only to the current distribution in the radiator, not
its base impedance. Whatever the base impedance is, it can be matched to 50
ohm line at the tower base, using the right network. But the network doesn't
affect the relative field radiation pattern of that radiator.

But....I've seen (and fortunately NOT had to deal with) antenna systems with very
high base impedances (one, if my memory serves me correctly, was 800 ohms! Not much
current, but do the math...any appreciable power, like 3 or 4 kW, and there's a real
danger of getting tangled in with some pretty high voltages). While it's not a
scientific survey, I can tell you that those systems, watt-for-watt, perform worse
than lower impedance systems, and that's not even counting the difficulties in having
1kV base voltages!

And it's more than just current distribution that affects efficiencies. It's the
integral of the loop currents, which is why your chart shows better efficiencies for
those taller radiators. The larger fields generated by the longer radiators makes
for more power transferred (which also explains why a taller radiator has a higher
intrinsic impedance, as you have above, so 1kW into a 90 degree stick will be about
half as effective as a 180 degree stick (actually, shy of twice, due to the
I-squared-R losses you mention..

AM Radiator Efficiencies, 1kW input

Twr Hgt, Deg Effic
70 182mV/m
90 190
100 195
180 237
190 246
225 274

Note here that "efficiency" is the FCC definition for MW broadcast.
Efficiency falls for short radiators because the ohmic loss even in the best
ground system becomes a bigger percentage of the resistive term of the
radiators base impedance.

I appreciate the effort and time you've made trying to teach me something about
antenna theory, but be assured that there's not much more that need to know, and I
sincerely doubt that going into much more detail than this is warranted for this
particular thread.
--
-----------------------------------------------------------------------------
If there's nothing that offends you in your community, then you know you're not
living in a free society.
Kim Campbell - ex-Prime Minister of Canada - 2004
-----------------------------------------------------------------------------
For direct replies, take out the contents between the hyphens. -Really!-

Mister Fact wrote:

Certainly my reply was not related to any physical
harm which might result from radio waves themselves-
but since the message board has to do with radio
broadcasting in general- I thought it would be a good
opportunity to inject ANOTHER TYPE OF MEDICAL HARM
which I see inherent in AM broadcasting today.

Isn't that what Rush Limbaugh was doing? Injecting another
type of harmful medicine?
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Within these hallowed halls, Truth of added the
following to the collective conscience:
To oversimplify a bit: Low frequencies (like AM broadcast) pass
through the body without being absorbed. Microwave frequencies
bounce off the body without being absorbed.

ROTFFL!!!

Why not PROVE your ridiculous theory by putting your head into a
microwave oven!

.......yeah. I didn't think so.

I was actually wondering what this post of yours had to do with
broadcasting. Even if
it was off topic but informative or entertaining, it would have been better
than just
being a post about being rude to someone.

"Bob Haberkost" wrote in message
...

But....I've seen (and fortunately NOT had to deal with) antenna systems
with very
high base impedances (one, if my memory serves me correctly, was 800 ohms!
Not much
current, but do the math...any appreciable power, like 3 or 4 kW, and
there's a real
danger of getting tangled in with some pretty high voltages). While it's
not a
scientific survey, I can tell you that those systems, watt-for-watt,
perform worse
than lower impedance systems, and that's not even counting the
difficulties in having
1kV base voltages!

At medium wave (AM Broadcast) many Class A stations (formerly "clear
channel") use antennas of about 190 or 200 degrees tall. The FCC requires a
minimum antenna effectiveness for that class which is higher than for the
other classes of stations. The base impedance of these sticks near a
half-wave tall is going to be pretty high - and all but one US Class A
station run 50 kW. One of the factors in deciding AM tower height is to
place the first null in the vertical pattern such that the nighttime skywave
interferes as little as possible with the ground wave toward the edges of
the groundwave coverage.

Of course Class A AM stations are a Big Deal and generally have very good
ground systems.

"Bob Haberkost" wrote these clips:

The larger fields generated by the longer radiators makes
for more power transferred (which also explains why a taller
radiator has a higher intrinsic impedance,

Have to disagree with that. The reason that a 180 degree MW vertical
generates a stronger ground wave than a 90 degree vertical (other conditions
equal) is due SOLELY to the shape of their respective elevation patterns.
Their radiation efficiency or "power transferred" has nothing to do with
their base impedances.

If properly matched to their transmission lines, both of them radiate the
same total power. But the elevation pattern of the 180 degree radiator has
more intrinsic gain in the horizontal plane -- which produces the stronger
ground wave of the two.

so 1kW into a 90 degree stick will be about half as effective
as a 180 degree stick.)

Not following that conclusion. Using the FCC's numbers, a 180 degree MW
radiator with 1 kW input produces a groundwave field of 237 mV/m at one
mile, while a 90 degree radiator produces 190 mV/m. So for same input power
and other conditions, the 90 degree radiator produces 80% of the field
strength of the 180 degree radiator.

Put another way, the input power to the 90 degree radiator would have to be
increased about 1.56X in order to produce the same ground wave field at one
mile as the 180 degree radiator.

RF

Truth wrote:
Harris wrote:
To oversimplify a bit: Low frequencies (like AM broadcast) pass through
the body without being absorbed. Microwave frequencies bounce off the body
without being absorbed.

ROTFFL!!!

Why not PROVE your ridiculous theory by putting your head into a microwave oven!

I said this was a simplification. The point is that maximum absorption
occurs in the 30 to 300 MHz range. Microwave frequencies are used for
cooking because they are more practical to produce, not because they
are more effective at heating.

See the ANSI (American National Standards Institute) exposure limits
curve below:

http://www-training.llnl.gov/wbt/hc/.../slide34lg.gif

Greatest rf absorption (minimum allowable exposure) is in the 30 to
300 MHz range.

Art H.

At medium wave (AM Broadcast) many Class A stations (formerly "clear channel")
use antennas of about 190 or 200 degrees tall.


A Clear Channel is a Clear Channel is a Clear Channel. Any of 540, 640, 650,
660, etcetera.

The average height over all ND-U Class As is 195 degrees.

The real goal here is to get 400 mVm/kW at 1 km, or better, without also having
high-angle radiation which could cancel the groundwave in the fringe area ...
that area where the primary service area ends and the secondary service area
begins.

Taller than about 200 degrees requires sectionalization to do this.

225 degrees is a real killer for a Class A, but is perfectly fine for a Class B
or C, which doesn't have a large primary service area, anyway.

The best performing Standard Broadcast radiator is 360 degrees tall, and
consists of a 180 degree bottom section, and a 180 degree top section.



The FCC requires a minimum antenna effectiveness for that class which is higher
than for the other classes of stations.


362.10 mV/m/kW at 1 km for Class A.

281.63 mV/m/kW at 1 km for Class B and D.

241.40 mV/m/kW at 1 km for Class C.

Of all lower 48 Class As, two don't have conforming radiators, and both of
these are in San Francisco.

Of all Alaska Class As, only one has a conforming radiator.



The base impedance of these sticks near a half-wave tall is going to be pretty
high - and all but one US Class A
station run 50 kW.


The only such Class A in the lower 48 is 1560 in Bakersfield, CA.

There are numerous such Class As in Alaska.

"Richard Fry" wrote in message ...
"Bob Haberkost" wrote these clips:

The larger fields generated by the longer radiators makes
for more power transferred (which also explains why a taller
radiator has a higher intrinsic impedance,

Have to disagree with that. The reason that a 180 degree MW vertical
generates a stronger ground wave than a 90 degree vertical (other conditions
equal) is due SOLELY to the shape of their respective elevation patterns.
Their radiation efficiency or "power transferred" has nothing to do with
their base impedances.

And yet it does. How, if I may ask, do you think that the radiation pattern of a 180
degree vertical element is lower than a 90 degree radiator? As you mention, it's
current distribution, but it's not as simple as you've characterised. The field is
generated by the summation of the currents over the length of that antenna that
combine to provide the "pull-down" effect you mention, and in the process, since the
infinitesimal slices of the radiator, each contributing its own part to the overall
field, also interact with each other in much the same way as separate elements in a
directional array interact, the phasing and amplitude over the length of the radiator
serve to enhance the direction towards the horizon and reduce radiation towards the
sky. Now, the reason why the base impedances are different for these two examples is
the same as why the effective impedance for one element in a directional array
changes when a second element is introduced into the nearspace around that first
element, because the interactions between the infinitesimal slices serve to increase
the "coupling" of the radiator to space. It's all calculus, with a heaping serving
of trigonometry thrown in for good measure.

If properly matched to their transmission lines, both of them radiate the
same total power. But the elevation pattern of the 180 degree radiator has
more intrinsic gain in the horizontal plane -- which produces the stronger
ground wave of the two.

I long ago recognised that, in the physical world, you don't get something for
nothing (a concept which, it's pretty clear, the current administration in Washington
doesn't get...or maybe they do?). Nothing in what I've discussed is ignorant of
this, although admittedly it's not explicitly stated. We broadcast engineers tend to
look at radiation patterns as they relate to the potential audience, knowing that the
areas we've pulled power from won't miss it, and then pat ourselves on the backs for
having designed an antenna system with "gain."

so 1kW into a 90 degree stick will be about half as effective
as a 180 degree stick.)

Not following that conclusion. Using the FCC's numbers, a 180 degree MW
radiator with 1 kW input produces a groundwave field of 237 mV/m at one
mile, while a 90 degree radiator produces 190 mV/m. So for same input power
and other conditions, the 90 degree radiator produces 80% of the field
strength of the 180 degree radiator.

Put another way, the input power to the 90 degree radiator would have to be
increased about 1.56X in order to produce the same ground wave field at one
mile as the 180 degree radiator.

Well, there you have it. 1.56 times, while not exactly 2, is closer to 2 than it is
to one. Consider that, since radiated field is over an area for our purposes, a
radiator half as effective as the reference would have 70.7% as much field, or the
reciprocal of the square root of two. It was a gross approximation, Richard. From
what I've seen of broadcast engineers, many have only a practical knowledge of the
underlying theoretical concepts...whether it's the understanding of modulation theory
(how many people do you know who think that amplitude modulation actually manipulates
the amplitude of the carrier? Or that FM actually changes the centre frequency?) or
antenna design, or solid state theory...never mind quantum theory. I don't believe
that getting down to this level would serve any practical purpose in this newsgroup,
however, especially since I'm not prepared to start introducing mathematical
equations into a text-based format.
--
-----------------------------------------------------------------------------
If there's nothing that offends you in your community, then you know you're not
living in a free society.
Kim Campbell - ex-Prime Minister of Canada - 2004
-----------------------------------------------------------------------------
For direct replies, take out the contents between the hyphens. -Really!-

Sequence #1...

B. Haberkost:
The larger fields generated by the longer radiators makes
for more power transferred (which also explains why a taller
radiator has a higher intrinsic impedance,
R. Fry:
Have to disagree with that. The reason that a 180 degree MW vertical
generates a stronger ground wave than a 90 degree vertical (other
conditions
equal) is due SOLELY to the shape of their respective elevation
patterns.
Their radiation efficiency or "power transferred" has nothing to do with
their base impedances.
B. Haberkost:
And yet it does. How, if I may ask, do you think that the radiation
pattern of a 180
degree vertical element is lower than a 90 degree radiator? etc

Not because of any change in base impedance. The electrical height of the
tower determines BOTH the elevation pattern it produces, AND the base
impedance of that tower. Base impedance is an effect, not a cause.

If base impedance determined efficiency and "power transferred," then a 90
degree tower should have very nearly the same elevation pattern as a 245
degree tower, because the base impedance for those two heights are very
similar (90 degree is about 63+j105 ohms; 245 degree is about 64 +j50
ohms). Yet the elevation patterns for these two verticals are greatly
different. The elevation pattern of a 245 degree vertical has two distinct
major lobes; one centered on the horizontal plane, and one at about 45
degrees. The 90 degree tower produces an elevation pattern with a single
lobe centered on the horizontal plane.

These verticals can be computer-modeled to show their shapes and intrinisic
gains in dBi. I'll e-mail you a graphic I generated in NEC to compare them
for you.

Sequence #2...

R. Fry:
Put another way, the input power to the 90 degree radiator would have to
be
increased about 1.56X in order to produce the same ground wave field at
one
mile as the 180 degree radiator.
B. Haberkost:
Well, there you have it. 1.56 times, while not exactly 2, is closer to 2
than it is
to one. Consider that, since radiated field is over an area for our
purposes, a
radiator half as effective as the reference would have 70.7% as much
field, or the
reciprocal of the square root of two. It was a gross approximation,
Richard.

To help you compare geographic areas covered by a 90 degree vs a 180 degree
radiator, here are the numbers using the FCC's MW coverage program. For 1kW
input power to the tower base, a 1,000 kHz carrier, and conductivity of
8mS/m, the radial distance to the 2mV/m contour is 25.6 miles from 90 degree
tower, and 28.5 miles from the 180 degree tower. The areas covered are
2,058 mi² and 2,550 mi² respectively. So the 90 degree vertical covers
about 80% of the area served by the 180 degree vertical. Not very close to
a 2:1 difference at all.

Sequence #3:

From what I've seen of broadcast engineers, many have only a
practical knowledge of the underlying theoretical concepts...whether it's
the understanding of modulation theory (how many people do you know
who think that amplitude modulation actually manipulates
the amplitude of the carrier? Or that FM actually changes the
centre frequency?)

The instantaneous frequency DOES change with frequency modulation, although
the average center frequency stays close to the unmodulated value. In fact,
a very common FM exciter design uses the incoming program audio to change
the resonant frequency of the frequency-determining components of an RF
oscillator, whose resting frequency is the stations licensed carrier
frequency.

RF

Visit http://rfry.org for FM broadcast RF system papers.

"Bob Haberkost" wrote (clip):
The nice thing about the low radiating impedance
of a vertical radiator is that the high base current
necessary for a given power means that the magnetic
vector is bigger than the electrostatic vector, and since
ferrite loops used in most AM radios respond to the
magnetic vector, the "connection" is more intimate.

This concludes your antenna theory class for the day. ;-)
____________________

The above calls for a bit of discussion, IMO

The base current of a MW vertical radiator depends on the resistive term of
the base impedance of that radiator, according to the equation I =
sqrt(P/R), where P is the applied power and R is the base resistance.

However current is not uniform over the height of the radiator. It must
satisfy the physical reality that a current node (minimum) always must exist
at the top of the tower. Other current nodes occur at 1/2 -wave intervals
below the top, if the tower is tall enough.

Between the nodes, current rises to a loop, or maximum, at intervals of 1/4
wave. The maximum current present at the loop(s) is a function of the
amount of power applied to the base of the radiator -- not to the base
impedance of the radiator.

So for a given input power, the same absolute value of current will be
present starting 1/4 wave below the tower top, and repeating every 1/2 wave
below that -- regardless of the base impedance of the radiator.

Far-field radiated EM waves from MW vertical radiators of any height are
identical in that they all have equal electric and magnetic vectors at right
angles to each other. A ferrite receiving antenna performs well on MW
frequencies for reasons unrelated to the ratio of the E & H fields in which
it is immersed.

RF

Visit http://rfry.org for FM broadcast RF system papers.

900 MHz are NOT microwaves

Interesting. Especially since the older microwave ovens operated on 800 and
900 Mhz.

Why are people who are uneducated in certain subjects always the first to jump
in on a conversation and tell everyone else how they think things really are?

To oversimplify a bit: Low frequencies (like AM broadcast) pass through
the body without being absorbed. Microwave frequencies bounce off the body
without being absorbed.

ROTFFL!!!

Why not PROVE your ridiculous theory by putting your head into a microwave oven!

I once worked with a guy who claimed he could hear microwaves. He said
that he could tell when the radar system was in operation and when it
wasn't by the sound. We did a simple blind test up on the roof, and it
became pretty clear that he could tell.

Turns out that what he was hearing was conducted noise from his skull
expanding due to heating effects. Admittedly this was with well over a
megawatt ERP. But it was definitely being absorbed.

What a very bright individual. It frightens me that someone like that was allowed
to get close to that equipment in the first place. They put all the rest of us at
risk.

SOME microwave frequencies get absorbed very well by water, some do not.
The body being mostly water,

Especially the EYES in our heads, so close to the cell phone antennas.

Truth wrote:

900 MHz are NOT microwaves


Interesting. Especially since the older microwave ovens operated on 800 and
900 Mhz.

Why are people who are uneducated in certain subjects always the first to jump
in on a conversation and tell everyone else how they think things really are?



Because they want to appear educated.

"Truth" wrote in message ...
900 MHz are NOT microwaves

Interesting. Especially since the older microwave ovens operated on 800
and
900 Mhz.

Why are people who are uneducated in certain subjects always the first to
jump
in on a conversation and tell everyone else how they think things really
are?


ref http://www.naval.com/radio-bands.htm


ref
http://chemindustry.intota.com/multi...ve%20frequency

ref http://www.k5rmg.org/A-soup.html

in most definitions microwaves start at 1GHz or 30CM

what frequencies "microwave ovens" use is irrelevant as marketers can pretty
much name anything what they want.

"Truth" wrote in message ...
900 MHz are NOT microwaves

Interesting. Especially since the older microwave ovens operated on 800 and
900 Mhz.

Why are people who are uneducated in certain subjects always the first to jump
in on a conversation and tell everyone else how they think things really are?

Yeah, why is that?

http://en.wikipedia.org/wiki/Microwave

(For the non-curious, the paragraph of interest says:

Microwaves, also known as Super High Frequency (SHF) signals, have wavelengths
approximately in the range of 30 cm (1 GHz) to 1 mm (300 GHz).

)
--
-----------------------------------------------------------------------------
If there's nothing that offends you in your community, then you know you're not
living in a free society.
Kim Campbell - ex-Prime Minister of Canada - 2004
-----------------------------------------------------------------------------
For direct replies, take out the contents between the hyphens. -Really!-

Is AM Radio Harmful? Only if you listen to it.

Microwaves, also known as Super High Frequency (SHF) signals, have wavelengths
approximately in the range of 30 cm (1 GHz) to 1 mm (300 GHz).

This is a pathetic attempt to avoid the real issue and turn the argument another way
to avoid the statement they were unable to dispute.

Saying microwaves magically start at 1000 Mhz, and saying 999 Mhz is not, and 800
Mhz is not, is bull**** talk.

Regardless of where you want to call it, the FACT remains that Microwave Ovens were
manufactured that cooked your food with frequencies in the 800 Mhz region.

So, since we can cook food and heat at 800 Mhz, and since cell phones are using the
same frequency range, we can make a definite connection here.

Any attempt to shift the discussion to one about where we now want to classify the
word "microwaves" to be appropriate is just childish and ignorant, and nothing more
than diversion from the point about cell phones being dangerous.

LEGAL exposure to certain RF in Russia can be different than the LEGAL limits in the
US. As if RF follows any of these laws, or as if a cell phone is not going to harm
you just because you change the definition of what can be legally called microwaves.

What was considered low blood pressure a decade ago, is now being called high blood
pressure in an attempt to sell more medication and make more money. Just the AMA
changing the imaginary boundary line did not make us all suddenly have high blood
pressure, just as your changing what is now considered microwaves has no effect on
this issue either.

-----------------------------------------------------------------------------
If there's nothing that offends you in your community, then you know you're not
living in a free society.

If there is nothing that offends you in your community, then you ALSO know you're
not living in a dictatorship either.

This is a stupid play on words that is meaningless!

You can NEVER have any society in which nothing offends anyone! Not under ANY
government.

Idiots.

Truth wrote:

Regardless of where you want to call it, the FACT remains that Microwave Ovens were
manufactured that cooked your food with frequencies in the 800 Mhz region.

So, since we can cook food and heat at 800 Mhz, and since cell phones are using the
same frequency range, we can make a definite connection here.


Three things:

1) You need to recheck the frequency of the magnetrons in microwave
ovens.
2) You need to recompare the power levels between microwave ovens and
cell phones (*cough* 0.3 W v. 1500 W, a factor of 5000 difference
*cough*)
3) *Plonk*

So, since we can cook food and heat at 800 Mhz, and since cell phones are
using the
same frequency range, we can make a definite connection here.

since we will die if we walk into a blast furnace we has best not even light
a candle.
great logic

Any attempt to shift the discussion to one about where we now want to
classify the
word "microwaves" to be appropriate is just childish and ignorant, and
nothing more
than diversion from the point about cell phones being dangerous.

cell phones don't even make good blunt instrument any more, just too light.


LEGAL exposure to certain RF in Russia can be different than the LEGAL
limits in the
US. As if RF follows any of these laws, or as if a cell phone is not
going to harm
you just because you change the definition of what can be legally called
microwaves.

your wild allegations are unsupported by any credible sources.


What was considered low blood pressure a decade ago, is now being called
high blood
pressure in an attempt to sell more medication and make more money.

an unwarranted assumption

Just the AMA
changing the imaginary boundary line did not make us all suddenly have
high blood
pressure, just as your changing what is now considered microwaves has no
effect on
this issue either.


since the dawn if time he earth has been drenched in radio waves and
radiation. since the advent of electromagnetic telecommunications and power
grid distribution mans lifespan has dramatically increased. therefore radio
waves are good for you.

"Truth" wrote in message ...

So, since we can cook food and heat at 800 Mhz, and since cell phones are
using the
same frequency range, we can make a definite connection here.

Where is the scientific data on this? Cite? Link?


--
McWebber
No email replies read
If someone tells you to forward an email to all your friends
please forget that I'm your friend.

"Truth" wrote in message ...
What if the government issues a statement that smoking cigarettes is
good for you
and gets rid of cholesterol? Would you start smoking?

Uhhhhhh.... yes?

How sad for you. Go have another Diet Coke with Aspartame.

What's wrong with aspartame?

Just wait until all the kids using cell phones today don't live to even
get to
retirement age.

There are people using cell phones now that have been using them for more
than 20 years in Japan. How long do you think it will take for the epidemic
to show up?


--
McWebber
No email replies read
If someone tells you to forward an email to all your friends
please forget that I'm your friend.

Tim Perry wrote:
since the dawn if time he earth has been drenched in radio waves and
radiation. since the advent of electromagnetic telecommunications and power
grid distribution mans lifespan has dramatically increased. therefore radio
waves are good for you.

By that reasoning, so are carbon dioxide and feces.

--
"The Democrats are all over this. Democratic strategists feel John Kerry's
war record means he can beat Bush. They say when it comes down to it, voters
will always vote for a war hero over someone who tried to get out of the war.
I'll be sure to mention that to Bob Dole when I see him." -- Jay Leno

Truth wrote:

To oversimplify a bit: Low frequencies (like AM broadcast) pass through
the body without being absorbed. Microwave frequencies bounce off the body
without being absorbed.


ROTFFL!!!

Why not PROVE your ridiculous theory by putting your head into a microwave oven!

.......yeah. I didn't think so.


.....or by leaning against a 50,000 watt AM antenna while standing on the
ground.

McWebber wrote:
"Truth" wrote in message ...

What if the government issues a statement that smoking cigarettes is

good for you

and gets rid of cholesterol? Would you start smoking?

Uhhhhhh.... yes?

How sad for you. Go have another Diet Coke with Aspartame.


What's wrong with aspartame?


Just wait until all the kids using cell phones today don't live to even

get to

retirement age.


There are people using cell phones now that have been using them for more
than 20 years in Japan. How long do you think it will take for the epidemic
to show up?


No one knows.

Scott Dorsey wrote:

Mister Fact wrote:

Certainly my reply was not related to any physical
harm which might result from radio waves themselves-
but since the message board has to do with radio
broadcasting in general- I thought it would be a good
opportunity to inject ANOTHER TYPE OF MEDICAL HARM
which I see inherent in AM broadcasting today.


Isn't that what Rush Limbaugh was doing? Injecting another
type of harmful medicine?
--scott

The thread is a bit ambiguous. I think AM radio can be harmful if talk
show hosts thereon are dividing peoples.

Tim Perry wrote:

"Truth" wrote in message ...

There is still no commercially-available equipment for the 902 MHz

amateur

band that I am aware of.

Using commercially-available equipment is cheating anyway. What does it
take to modify PCS cellular phone firmware for digital communication on
902? Is it just a matter of firmware or isn't the RF section able to

tune

that far out of band?

Think of it this way. When you have an FM broadcast antenna and

transmitter, it

makes quite a difference when switching within the same band from 88 Mhz

to 100

Mhz. (only 12 Mhz)

Now you want to take something from around 850 Mhz to 902 Mhz (52 Mhz
difference)

Plus the higher up you go, the more critical the circuitry. Even in

the 440

band you are already dealing with microsurgery when using the miniature

surface

mount components.


pretty might the same for all hand held electronics these days


Besides, working with microwaves is never a good idea.


everyone has to have a hobby... 900 MHz are NOT microwaves (we call it
microwave in brroadcast, but it is a slang term for high UHF)

Might as well just take

up smoking cigarettes instead.

I would play with mercury and use lead paint in my home no problem, but I

would

not ever build a transmitter and use microwave frequencies.



gunplexers are friendly... bi-directional line-of-sight audio




How did a disussion about AM radio (later microwave RF) change to audio?

David Eduardo wrote:

"Bob Haberkost" wrote in message
...

"David Eduardo" wrote in message
...

Huh? AM stations essentially always have vertical radiators, especially
in
Europe where there are so many high powered stations.

In general, AMs don't work very well otherwise.


This concludes your antenna theory class for the day. ;-)


Very interesting discussion. Thanks.

How about introducing the masses to franklin antennas, such as the system
still in use at KFBK in Sacramento. I believe KDKA once had one, too. I saw
one in South America that had no real ground system, just the two elements
of the Frnklin and a ground mat at the base.


There's a Franklin at N 41.6 and w 93.3:

http://www.desmoinesbroadcasting.com...use _9867.jpg

Sir Circumference wrote:
Is AM Radio Harmful? Only if you listen to it.

Oh, yeah? Try dropping a Satellite 800 on your foot.

--
"The Democrats are all over this. Democratic strategists feel John Kerry's
war record means he can beat Bush. They say when it comes down to it, voters
will always vote for a war hero over someone who tried to get out of the war.
I'll be sure to mention that to Bob Dole when I see him." -- Jay Leno

"Dan Robbins" wrote in message
...

There's a Franklin at N 41.6 and w 93.3:

http://www.desmoinesbroadcasting.com...use _9867.jpg


I don't know if it still exists, but KELO 1320 used to even advertise it had
a Franklin.

On 8 Sep 2004 19:00:59 GMT, clifto wrote:

Tim Perry wrote:
since the dawn if time he earth has been drenched in radio waves and
radiation. since the advent of electromagnetic telecommunications and power
grid distribution mans lifespan has dramatically increased. therefore radio
waves are good for you.

By that reasoning, so are carbon dioxide and feces.

No carbon dioxide, no plants, little oxygen.

No feces, little agriculture. Well, some places anyway. :-)

OTOH, no feces, very few politicians.

"clifto" wrote in message
...
Tim Perry wrote:
since the dawn if time he earth has been drenched in radio waves and
radiation. since the advent of electromagnetic telecommunications and
power
grid distribution mans lifespan has dramatically increased. therefore
radio
waves are good for you.

By that reasoning, so are carbon dioxide and feces.


by George i think hes got it!


consider: CO2 is necessary for tree/plant life. human/animal waste products
enrich the soil, which aids plant growth. which provides healthy food, which
gives us humans more time to build and operate radio stations for the
enjoyment of the multitudes. the more people the more the cume and TSL
therefore the more cash flow and life is wonderful.

searching back trying to find who added all these freaking cross posts...
this thread just started out in
alt.radio,alt.radio.broadcasting

"clifto" wrote in message
...
Tim Perry wrote:
since the dawn if time he earth has been drenched in radio waves and
radiation. since the advent of electromagnetic telecommunications and
power
grid distribution mans lifespan has dramatically increased. therefore
radio
waves are good for you.

By that reasoning, so are carbon dioxide and feces.


Read what he was replying to. That's his point. The reasoning doesn't hold
water.

--
McWebber
"Richter points to the lack of legal action against his company as proof
that he's operating appropriately."
Information Week, November 10, 2003

"David Eduardo" wrote in message
...

"Dan Robbins" wrote in message
...

There's a Franklin at N 41.6 and w 93.3:


http://www.desmoinesbroadcasting.com...use _9867.jpg


I don't know if it still exists, but KELO 1320 used to even advertise it had
a Franklin.

In deference to Steve who says the previous thread is dead, let me answer David's
question about KDKA's "Franklin"....but only to say that KDKA's Franklin wasn't truly
that. A Franklin radiator looks like two self-supporting towers, one inverted on top
the other, fat ends touching. The one such that I remember (and I'd have to think
that most of us have seen the picture) is WLW's tower that participated in the
superpower experiments in the 30s. KDKA's radiator was simply described in the
license as a center-fed vertical radiator, where the base impedance and input power
was determined through quasi-indirect means at the input to the balun necessary to
match the balanced feed point with the unbalanced transmission line (in years past,
this stick was fed with balanced feed line, not unlike VHF twin lead on acid...hams
know this feed line as "ladder" feedline, because of the characteristic cylindrical
insulators placed at regular lengths along the conductors to maintain the correct
separation between those conductors).

KDKA's antenna was fairly broadbanded, which if I remember correctly is a feature of
center-fed radiators. But WLW's Franklin, because of the larger cross-section where
current was higher, had a very nice, minimally-sloped reactance curve, and thus a
very consistent, symmetrical impedance...if you ever heard WLW when they played music
in the 70s, it really sounded great. KDKA's system had, of course, a ground system,
to help pull down the skywave, but due to the fact that my manager (who shall go
nameless to protect the embarassed) let the neighborhood kids ride their BMX
motorcycles on the property (she thought that the presence of life on the transmitter
grounds would deter vandalism), breaking a significant number of radials that were
exposed by rutting after heavy rains dredged out the BMX paths, it didn't work all
that well...on solar max periods, we'd often get fading well within our local metro
coverage area because so much power went skyward and came back down, just slightly
out-of-phase with the ground wave.

The antenna I had direct experience with was replaced in the mid 90s, but from what
I've heard the only thing that was changed was the steel....the basic design was
retained, and the counterpoise was repaired.
--
-----------------------------------------------------------------------------
If there's nothing that offends you in your community, then you know you're not
living in a free society.
Kim Campbell - ex-Prime Minister of Canada - 2004
-----------------------------------------------------------------------------
For direct replies, take out the contents between the hyphens. -Really!-

A Franklin radiator looks like two self-supporting towers, one inverted on top
the other, fat ends touching.


Nope.

A Franklin is defined as a center-fed sectional, which is 180 degrees over 180
degrees. The base of the bottom section is connected to the ground system by an
impedance, usually a capacitor.

KSTP's Franklin is not a Frankin on account it is 179 degrees over 179 degrees.

A true Franklin has an efficiency of 510 mV/m/kW at 1 km.

KSTP's certainly equals that, although it is classified by the FCC as a
conventional sectional.

KDKA's sectional is just that.

As was WOAI's. 120 degrees over 120 degrees.

WHO's radiator isn't a Franklin, either, it is a "WHO Type", and is so
classified by the FCC. It is 300 degrees tall.

A true Franklin has the best horizontal field of any radiator.

A WHO-type radiator probably has the best anti-fading performance of any
radiator.

A Franklin radiator looks like two self-supporting towers, one inverted on top
the other, fat ends touching.


Naw ... that's a Blaw-Knox, named for the company which manufactured them.

Not many still standing today.

Peter H. wrote:


A Franklin radiator looks like two self-supporting towers, one inverted on top
the other, fat ends touching.


Nope.

A Franklin is defined as a center-fed sectional, which is 180 degrees over 180
degrees. The base of the bottom section is connected to the ground system by an
impedance, usually a capacitor.

So it is asymmetric, with the two sections slightly different lengths, or the
base capacitor is used to compensate for that?

If it were in free air, it would simply be a vertical dipole, but since the
ground is below it, the electrical lengths of the bottom leg is changed,
right?

KSTP's Franklin is not a Frankin on account it is 179 degrees over 179 degrees.

What does this do to the pattern in real terms?
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

"Peter H." wrote in message
...


A Franklin radiator looks like two self-supporting towers, one inverted on
top
the other, fat ends touching.


Naw ... that's a Blaw-Knox, named for the company which manufactured them.

Not many still standing today.

I think there are a couple. New Hampshire (WFEA?), WSM, WLW, and the WBT
installation. WADO took theirs down when the new 50 kw DA was built 3-4
years ago.