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Tuesday, February 3, 2009
RADIO PIONEER: GROTE REBER
Grote Reber has always been a hero of mine. Above you can see the dish that he built in his backyard to conduct radio astronomy in the 1930's. Read more about OM Grote here: http://www.nrao.edu/whatisra/hist_reber.shtml
Thanks, Bill! Incredible he could build such a huge antenna on his own nickel.
I wondered what his call was and found this excellent ham history page at NRAO: http://www.nrao.edu/whatisra/hist_ham.shtml
"In 1997, the National Radio Astronomy Observatory Amateur Radio Club obtained a license from the Federal Communications Commission for an amateur radio station with the callsign W9GFZ, Grote Reber's callsign in the 1930s. No longer active as a ham, Reber still expressed pleasure that his old callsign would be preserved by NRAO's hams. The NRAO club plans to use the callsign W9GFZ on the air for special events connected with radio astronomy."
Also a fine article on the Wikipedia: http://en.wikipedia.org/wiki/Grote_Reber
About your voice distortion problem: It has been a completely different problem!
In former times you used a 16 kHz sampling rate. Consider the A/D converter as some kind of 16 kHz mixer and what the lower sideband might sound like. On Soldermoke #99 and #100 you used a sampling rate of 32 kHz. Now consider where the lower sideband of this "mixer" lands!
Normally you have lowpass filters in front of the A/D converter AND after the D/A converter at the receiver to suppress this folded spectrum.
Thanks, Bill! Incredible he could build such a huge antenna on his own nickel.
ReplyDeleteI wondered what his call was and found this excellent ham history page at NRAO:
http://www.nrao.edu/whatisra/hist_ham.shtml
"In 1997, the National Radio Astronomy Observatory Amateur Radio Club obtained a license from the Federal Communications Commission for an amateur radio station with the callsign W9GFZ, Grote Reber's callsign in the 1930s. No longer active as a ham, Reber still expressed pleasure that his old callsign would be preserved by NRAO's hams. The NRAO club plans to use the callsign W9GFZ on the air for special events connected with radio astronomy."
Also a fine article on the Wikipedia:
http://en.wikipedia.org/wiki/Grote_Reber
73 de KC7IT
Hello Bill,
ReplyDeleteAbout your voice distortion problem: It has been a completely different problem!
In former times you used a 16 kHz sampling rate. Consider the A/D converter as some kind of 16 kHz mixer and what the lower sideband might sound like. On Soldermoke #99 and #100 you used a sampling rate of 32 kHz. Now consider where the lower sideband of this "mixer" lands!
Normally you have lowpass filters in front of the A/D converter AND after the D/A converter at the receiver to suppress this folded spectrum.
vy 73,
Alexander
DL4NO