13 Jan 19

Paul Horowitz

At age 8, Horowitz achieved distinction as the world’s youngest amateur radio operator. He went on to study physics at Harvard University (B.A., 1965; M.A., 1967; Ph.D., 1970), where he has also spent all of his subsequent career. His early work was on scanning microscopy (using both protons and X-rays). Horowitz has also conducted astrophysical research on pulsars and investigations in biophysics. His interest in practical electronics has led to a handful of inventions, including an automated voting machine and an acoustic mechanism for landmine detection. Since 1974 he has taught a practical course in electronics whose lecture notes became one of the best known textbooks in the field: The Art of Electronics (coauthored with Winfield Hill).

Source, Wikipedia


10 Jan 19

At night, solar radiation ceases and the free electrons recombine with their host molecules. The D-layer completely disappears and offers no signal loss. The E/F layers merge into a single layer, but remain reflective to HF signals.

However, this combined layer has a lower electron density than daytime levels, lowering the MUF. Astronomers call these ionization layers plasma layers and the lowest frequency that escapes into space the plasma frequency, fp. QRPers look at it just opposite – what is the highest frequency that does not escape into space?

We call this the maximum usable frequency or MUF. In reality, the MUF and plasma frequency are exactly the same.

7 Jan 19

Built by AT&T in Houlton Maine, this array of 4 phased beverage antennas was used for the first transatlantic phone system which began operation on the 7th of January 1927… The first conversation took place betweenWalter S Gifford, the president of AT&T, in NY, and Sir Evelyn Murray, the Secretary of the General Post Office, which managed the British telephone system at the time.

History Channel… The First Transatlantic Conversation (1 minute commercial before it starts) 

Wikipedia … Good source for Beverage antenna history and more….

EDN Network … Good article with links on the first transatlantic phone call