[Milsurplus] Aeronautical Marker Beacons

[aGEnuine ham]

Group:

If my records were any better, I should be sending this to an individual,
but don't remember with whom I was having this discussion a couple of
years ago.  So I apologize for the bandwidth, but maybe someone else is
interested in ancient history.

75 MHz marker beacons (initially called Z Markers) were comissioned on
Jan 1, 1939 in the continental U. S.   
From the text book: "Principles of Aeronautical Radio Engineering" by
Sandretto, first edition, 1942, pages 150 to 167.  While this book
contains numerous factual and typographic errors, I believe this
statement is accurate from the context and references to CAA test dates
in 1938, and it is mentioned several times in different discussions.  The
75 MHz "Z marker" beacons replaced the so called "cone of silence"
beacons on 278 kHz which had been installed in association with the
original LF radio range stations. 

So, it is unlikely that Amelia Earhart had any 75 MHz beacon equipment on
board for an international flight in 1937.  I have found no further
references to beacon implementation overseas, but beyond those deployed
by the military during WW2, I suspect it was well into the late 40s
before they were common world wide.

George W5VPQ
________________________________________________________________
GET INTERNET ACCESS FROM JUNO!
Juno offers FREE or PREMIUM Internet access for less!
Join Juno today!  For your FREE software, visit:
http://dl.www.juno.com/get/web/.