On 7 January 2011 14:13, James Moritz <[email protected]> wrote:

Dear LF Group,

A quote from JA Fleming, Marconi's technical advisor:

"The wavelength of the electric waves sent out from Poldhu Marconi station in 1901 was not measured because I did not invent my cymometer or wavemeter until October 1904. The height of the original aerial (1901) was 200 feet, but then there was a coil of a transformer or "jiggeroo" as we called it in series with it. My estimate was that the original wavelength must have been not less than about 3,000 feet, but it was considerably lengthened later on. I knew at that time that the diffraction or bending of the rays around the earth would be increased by increasing the wavelength and after the first success I was continually urging Marconi to lengthen the wavelength, and that was done when commercial transmission began. I remember I designed special cymometers to measure up to 20,000 feet or so".

A "cymometer" was an early absorbtion wavemeter - I remember there used to be one in the Science Museum in London - I think the scale was calibrated in feet...

Cheers, Jim Moritz
73 de M0BMU