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After Hertz received his professorship at Karlsruhe he was experimenting with a pair of Riess spirals in the autumn of 1886 when he noticed that discharging a Leyden jar into one of these coils would produce a spark in the other coil. With an idea on how to build an apparatus, Hertz now had a way to proceed with the “Berlin Prize” problem of 1879 on proving Maxwell’s theory (although the actual prize had expired uncollected in 1882). He used a Ruhmkorff coil-driven spark gap and one-meter wire pair as a radiator. Capacity spheres were present at the ends for circuit resonance adjustments. His receiver was a simple half-wave dipole antenna with a micrometer spark gap between the elements. This experiment produced and received what are now called radio waves in the very high frequency range.
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In every amplifier circuit, the input resistor is critical. Any noise at the input signal will be amplified to the full gain. It is therefore of high importance to choose a low-noise resistor at the first stage, as well as a low resistance value. This is however not valid for a load resistor, since the gain that is obtained from a high resistance value outweighs the higher noise level. Because thermal noise is temperature dependent, it is very effective to cool the input stages to reach a low-noise performance.
Noise is an unwanted phenomenon for resistors. For some applications the noise properties are important. Examples are high gain amplifiers, charge amplifiers and low-level signals. Resistor noise is often specified as micro-volt, noise per volt of applied voltage, for a 1 MHz bandwidth. Thermal noise is the predominant source of noise for resistors. It is dependent on three variables: resistance, temperature and bandwidth.Johnson_noise_intro
E.T Krenkel was an avid Amature Radio operator and was Chairman of the Central Radio Club until his death. He gave lectures around Russia on amateur radio as well as he was the editor of the radio magazine for Russia. Born in 1903 and died in 1971, in 2008 a medal was named in his honer which is awarded in 2 categories, Please See The E T Krenkel Medal Website… For more on E T Krenkel (Wikipedia) Here you will find a list of his expeditions and other posts as a radio operator…
It all began with one man…Frank Dawson Bliley. In 1930, one year into the greatest economic collapse our country has ever experienced, the young engineer was struggling to find steady work.
Bliley Technologies Inc. was originally founded as the Bliley Piezo-Electric Company in 1930. Initially, we manufactured quartz crystals for the amateur radio market. In the mid-1930s, our customers and products soon broadened to match the interests of the burgeoning military and commercial communications fields and our name was changed to Bliley Electric Company. In 1939 we were the largest Crystal Company with 11 employees.
This was an excerpt from the Bliley History from the Bliley website…..