"Walter Maxwell" wrote:
When reviewing these data, please keep in mind that as the field strength
approaches 194.5 mv/meter the effective ground is approaching perfect
ground, which means that the conductivity of the ground in which the
radials are planted is irrelevant, only the ground external to the radial
system is relevant with respect to conductivity.

BL&E measured the groundwave field strength generated by a 200 milliwatt
carrier 0.3 miles from a vertical radiator. This value was converted to
equivalent field for 1 kW of radiated power at a distance of 1 mile. With
this technique, and with 113 each 0.412-wave radials, they found that their
measured/converted field was less than 0.1124 dB below the theoretical value
for it over a perfect ground plane. These results demonstrate that the
consideration of ground conductivity during this study over this short path
was unnecessary (REG, please note).

It should also be kept in mind that the energy in the EM fields
surrounding the vertical radiator diminishes with distance from the
radiator. Thus the displacement currents entering the ground diminish
proportionately with distance. Consequently, there is a distance from the
radiator after which the currents become too small to be significant to
the conservation of power radiated. This fact determines the maximum
length of the radials necessary to reach the point where the law of
diminishing returns prevails. The measurements reported in the BLE paper
show this distance to be between 0.4 and 0.5 wavelengths.

And that was for 113 radials. If only a few radials are used, BL&E report
that it is pointless to extend them that far.

RF

"Richard Fry" wrote in message
...
"Walter Maxwell" wrote:
When reviewing these data, please keep in mind that as the field strength
approaches 194.5 mv/meter the effective ground is approaching perfect ground,
which means that the conductivity of the ground in which the radials are
planted is irrelevant, only the ground external to the radial system is
relevant with respect to conductivity.

BL&E measured the groundwave field strength generated by a 200 milliwatt
carrier 0.3 miles from a vertical radiator. This value was converted to
equivalent field for 1 kW of radiated power at a distance of 1 mile. With
this technique, and with 113 each 0.412-wave radials, they found that their
measured/converted field was less than 0.1124 dB below the theoretical value
for it over a perfect ground plane. These results demonstrate that the
consideration of ground conductivity during this study over this short path
was unnecessary (REG, please note).

It should also be kept in mind that the energy in the EM fields surrounding
the vertical radiator diminishes with distance from the radiator. Thus the
displacement currents entering the ground diminish proportionately with
distance. Consequently, there is a distance from the radiator after which the
currents become too small to be significant to the conservation of power
radiated. This fact determines the maximum length of the radials necessary to
reach the point where the law of diminishing returns prevails. The
measurements reported in the BLE paper show this distance to be between 0.4
and 0.5 wavelengths.

And that was for 113 radials. If only a few radials are used, BL&E report
that it is pointless to extend them that far.

RF

Correct on both counts, Richard, thanks for reminding Reg, I forgot to. Did I
mention that I had the privilege of working at Brown's RCA antenna lab along
side Epstein for several years? Bob Lewis had left RCA when I arrived, but I
knew him later as a ham, W2EBS.

Walt, W2DU

"Walter Maxwell"
Correct on both counts, Richard, thanks for reminding Reg, I forgot to.
Did I mention that I had the privilege of working at Brown's RCA antenna
lab along side Epstein for several years? Bob Lewis had left RCA when I
arrived, but I knew him later as a ham, W2EBS.
_______________

That would have been a privilege. When with RCA I worked a bit with Matti
Siukola, Oded Ben-Dov, Nick Nikolayuk and others at the RCA broadcast
antenna design center and test range at Gibbsboro, NJ . Great facility in
those days.

RF

"Richard Fry" wrote in message
...
"Walter Maxwell"
Correct on both counts, Richard, thanks for reminding Reg, I forgot to. Did I
mention that I had the privilege of working at Brown's RCA antenna lab along
side Epstein for several years? Bob Lewis had left RCA when I arrived, but I
knew him later as a ham, W2EBS.
_______________

That would have been a privilege. When with RCA I worked a bit with Matti
Siukola, Oded Ben-Dov, Nick Nikolayuk and others at the RCA broadcast antenna
design center and test range at Gibbsboro, NJ . Great facility in those days.

RF
______________

Very interesting, Richard, of all the years I've been on this NG you are the
first RCA person I've met on the NG. What years were you with RCA?

While at the RCA Princeton Labs I also worked with O.M. (Woody) Woodward, Bruce
Rankin, and Don Peterson. Perhaps you knew them. I joined RCA in 1949,
transferred to the antenna lab in 1957, and later originated the antenna lab at
the then new Astro-Electronics Division in Hightstown. Was located there until I
retired to DeLand, Florida in 1980. While at Princeton I developed the entire
antenna system for TIROS 1, the World's first weather satellite.

I never had the pleasure of meeting any of the guys at Gibbsboro, but the names
of Matti and Oded came up quite often. I heard Woody and Jess Epstein talking
with them on the phone quite frequently.

I also spent some time at Cherry Hill as part of a three-man team developing the
3.6 GHz dish used on Lunar Rover, the moon buggy. I performed all the final
impedance and antenna pattern measurements on the three dishes prior to delivery
to NASA.

Perhaps we can meet some day and discuss our experiences at RCA. I consider
myself fortunate to have been there during the early days of space exploration,
they were truly exciting days.

Walt, W2DU

Walter Maxwell wrote:
Very interesting, Richard, of all the years I've been on this NG you are the
first RCA person I've met on the NG.

But Walt, I was once W6RCA. :-)
--
73, Cecil http://www.qsl.net/w5dxp


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"Cecil Moore" wrote in message
...
Walter Maxwell wrote:
Very interesting, Richard, of all the years I've been on this NG you are the
first RCA person I've met on the NG.

But Walt, I was once W6RCA. :-)
--
73, Cecil http://www.qsl.net/w5dxp

'ya know, Cecil, yer right, how could I have overlooked you. In fact, I've
always wondered why you gave up that illustrious call sign.

Walt, W2DU

Walter Maxwell wrote:
'ya know, Cecil, yer right, how could I have overlooked you. In fact, I've
always wondered why you gave up that illustrious call sign.

A land of fruits and nuts call didn't fit very well in
Texas, :-) just kidding. I was first licensed as WN5DXP
in 1952 and just couldn't resist getting my old call
back when I moved back to the same land as I lived
on then, land homesteaded by my grandfather before
the 20th century.
--
73, Cecil http://www.qsl.net/w5dxp


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Since the name of Dr. George H. Brown, of Brown, Lewis and Epstein is not well
known in the amateur community, I would like to acquaint you with some of his
other accomplishments that are well known in the engineering community,
especially in the AM-FM-TV broadcast community. His name deserves attention in
the amateur community as well.



In addition to his work that established the ground radial standards for AM
broadcasting, he discovered the reason the early diamond-shaped tower radiators
produced undesirable radiation characteristics, and proved experimentally that
towers of uniform cross section solved the problem. As a result of his
experimental proof, the FCC denied further use of the diamond shape tower, and
has since required all AM BC antenna towers be of uniform cross section. He also
developed sectionalized radiators for control of the elevation pattern.



He invented the ground-plane antenna for VHF/UHF use. He found that two radials
were sufficient, but marketing people convinced him that the antennas would sell
better with four.



With his famous 1937 paper, 'Directional Antennas' he established the basis for
directional arrays used in thousands of AM broadcast stations.



He worked closely with John Kraus in the early days, and showed Kraus the
importance of close spacing of elements in an array to increase the gain over
that obtained with quarter-wave spacing. The result was Kraus' close spaced beam
known as the 'W8JK' beam. Kraus gave this credit to Brown in his book,
"Antennas."



He developed a method for RF heating, especially for the joining, or 'sewing' of
plastic sheet material, a method that led to the development of microwave ovens.



As lead engineer in RCA's color television lab at the RCA Laboratories in
Princeton, he successfully led the development of the present system color
system used in all US tv operations, the NTSC system that permitted black and
white receivers to see color transmissions in black and white, overturning the
original FCC acceptance of the CBS spinning wheel system that would not permit
black and white receivers to receive color transmissions.



George Brown retired as an Executive Vice President of RCA.



These are just a few of his noteworthy accomplishments as an extraordinary
engineer.



Walt, W2DU

On Sat, 2 Jul 2005 10:03:11 -0400, "Walter Maxwell"
wrote:

These are just a few of his noteworthy accomplishments as an extraordinary
engineer.

Yes Walter, luckily I have a copy of his autobiography "and part of
which I was" publish in the early 1980s. He surely had a full and
fruitful life.

Danny, K6MHE

"Walter Maxwell" wrote:
Very interesting, Richard, of all the years I've been on this NG you are
the first RCA person I've met on the NG. What years were you with RCA?

1965-1980. My position certainly was not as exalted as that of
Epstein/Lewis/Siukola/Maxwell/et al, but I was fortunate enough to work with
Siukola and Ben-Dov of Gibbsboro in developing and proving RCA's RF Pulse
test equipment system used to evaluate and optimize broadcast TV antenna
systems. This test system may be thought of as a "narrow-band TDR," in that
it duplicates the spectrum of the standard TV signal, rather than using a
bandwidth of maybe 100X that of the TV channel. Excess test bandwidth gives
high pulse returns outside the TV channel -- which are valid, but
unimportant to the performance of the antenna system.

RF