[A-DX] WWV und der "Kammerton A" und....

[Roger]

Celebrating 100 years of WWV

http://wwv100.com/index.php/history

.......
1935, February – 20kW on 10MHz and 15MHz.
1936, August – 440Hz tone added at the request of several music
organizations.   <=== "A"
1940, November 6 – Fire destroys WWV facilities, but frequency standards
survive.
.......
.......
2000 to present – NIST WWVB enhancements with phase-modulated time code,
wide-spread commercial automated clocks, internal upgrades to WWV
transmitters, NIST-F1, NIST-F2, and much more.
........
2019, October 1 – WWV, the oldest continuously operating radio station
in the world, licensed for 100 years.
Special event station WW0WWV commemorates this event for the amateur
community.

https://www.nist.gov/pml/story-old-timer-phase-modulation-pm
"....New phase modulation layout
First we increased the depth of the amplitude modulation. This increased
the reception capability by a few db - but didn't solve the interference
problem from Rugby. An East coast station operating at 40 kHz at the
Redstone Arsenal in Huntsville, Alabama was attempted but didn't get
completed. So then we took a new approach. We added phase modulation to
the existing broadcast while keeping the existing AM modulation intact
so that all existing devices continued to work.
The new modulation modifications became permanent in October of 2012.
The changes improved reception by 14 db with several more db possible
using extended reception techniques.
New products are now coming out using this much improved technique. Time
will tell how widely this gets used!..."

"......Die neuen Modulationsmodifikationen wurden im Oktober 2012
permanent. Die Änderungen verbesserten den Empfang um 14 dB, wobei
mehrere weitere dB unter Verwendung erweiterter Empfangstechniken
möglich waren."



roger


<http://wwv100.com/>