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Old September 16th 03, 12:27 AM
Reg Edwards
 
Posts: n/a
Default Mostly of Entertainment value - Questions & Answers.

Q1
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How is large-scale ground conductivity determined ?

A1
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You set up a 1 Kw transmitter using a vertical antenna above 120 ground
radials and measure the ground-wave field strength at a number of
geographical locations at various distances up to 100 miles in daylight.
You then use Sommerfeld's (corrected) formulae to estimate average ground
conductivity for the region.

Q2
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What is this knowledge of ground conductivity used for ?

A2
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With Sommerfeld's (corrected) formula it is used to estimate the ground-wave
field strength received at various distances up to 100 miles from a 1 KW
transmitter in daylight. Refer to program GRNDWAV3.

Q3
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How is a reflection-coefficient determined ?

A3
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Its modulus and angle is calculated from complex impedance measurements.

Q4
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What is knowledge of the reflection-coefficient used for ?

A4
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After discarding half of the information it contains, then tossing a coin to
select one of two possible formulae, it is used to calculate the imaginary
SWR on a non-existent transmission line.

Q5
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What is the value of the SWR used for ?

A5
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It has no use except as the subject of magazine articles to fill in gaps
between the adverts.

Q6
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What is a TLI ?

A6
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It is a useful little instrument which indicates whether or not the load on
the transmitter is sufficiently near to a resistive 50 ohms. That is, of
course, if your particular transmitter happens to work best with such an
arbitrary value. (TLI = Transmitter Loading Indicator formally incorrectly
recognised as a swaaarrr meter.)

Q7
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What plonk is being imbibed tonight ?

A7
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Vintage 2002, Medium White, from a vinyard located in the beautiful Central
Valley at the foot of the Sierra Mountain Range in the State of California,
one of the United States of North America. Good stuff ! I should have
grabbed another bottle at my local supermarket.

----
Yours, Grandad Reg, G4FGQ.

PS: Station is located on the outskirts of the original Great Manufacturing
City of Birmingham, where Boulton and Watt built their immense condensing
steam engines, and where the microwave-oven cavity-magnetron was invented
and constructed, 1940-41, during the air-raids, and generously given to the
World.

Present all-band antenna is a 40-feet sloping 18-gauge wire extending from
the kitchen window, near the extractor fan, to a TV antenna mast, without
the TV antenna, mounted on the house chimney. An automatic tuner is located
under the kitchen sink very conveniently near to the one and only ground
radial - the incoming domestic water supply lead pipe. It does however
extend 5 miles to the area's water reservoir and pumping station.