4 ms·

Mobile devices tend to operate in the 700 to 900 MHz range which translates to a wavelengths of several inches, so it's quite possible the geometry of the drink

by snorkel 16y ago

Mobile devices tend to operate in the 700 to 900 MHz range which translates to a wavelengths of several inches, so it's quite possible the geometry of the drinking glass is providing a bit of focus to the signal.

peterwwillis 16y ago
Just skimming some sites, I found this one: http://www.squidoo.com/antenna-advice-and-information http://www.squidoo.com/antenna-advice-and-information It points out that some antennas for PCBs are built at 1/4 wavelength (from 2.75 to 1.3 inches for GSM networks). Something to do with this combined with how waves are either reflected or refracted when hitting a surface like glass could explain how (depending on the angle of the glass and its length) you could see a portion of the signal actually directed upward or just in a different direction. Maybe combined with a flat metal table as a shoddy groundplane? Whatever is going on it's probably limited to the signal inside and above the glass, as going through non-tinted glass is (iirc) supposed to have a -3dB reduction in signal. More reading: http://setup-wireless.blogspot.com/2008/11/radio-frequency-behaviors.html http://setup-wireless.blogspot.com/2008/11/radio-frequency-b... http://docs.google.com/viewer?a=v&q=cache:FGiX56l9G3MJ:www.compendium.pl/files/rfandradiotechnologyfundamentals.pdf+rf+reflection+vs+refraction&hl=en&gl=us&pid=bl&srcid=ADGEESiIoIsYUN1939u9-deoTpG5VtFnq3uphxAi6uPFRCZFAbfG5zSQXEJYQ1GTVovYAeUq6WAqZbmlyfvP3ttEp9_sAUQucFeKso78Pw02Yr1zM4dKp9iZVDDIbbi33sohtvKdsp73&sig=AHIEtbTPOkM2VDKBg6pb3jKCz0HpZ1_mhg http://docs.google.com/viewer?a=v&q=cache:FGiX56l9G3MJ:w... http://www.wifi-doc.com/Cisco.Press-802.11.Wireless.Ne/1587051648/ch02lev1sec6.html http://www.wifi-doc.com/Cisco.Press-802.11.Wireless.Ne/15870... (i really wish an RF/electrical engineer would comment!)

4 ms·

Mobile devices tend to operate in the 700 to 900 MHz range which translates to a wavelengths of several inches, so it's quite possible the geometry of the drink

by snorkel 16y ago

peterwwillis 16y ago
Just skimming some sites, I found this one: http://www.squidoo.com/antenna-advice-and-information http://www.squidoo.com/antenna-advice-and-information It points out that some antennas for PCBs are built at 1/4 wavelength (from 2.75 to 1.3 inches for GSM networks). Something to do with this combined with how waves are either reflected or refracted when hitting a surface like glass could explain how (depending on the angle of the glass and its length) you could see a portion of the signal actually directed upward or just in a different direction. Maybe combined with a flat metal table as a shoddy groundplane? Whatever is going on it's probably limited to the signal inside and above the glass, as going through non-tinted glass is (iirc) supposed to have a -3dB reduction in signal. More reading: http://setup-wireless.blogspot.com/2008/11/radio-frequency-behaviors.html http://setup-wireless.blogspot.com/2008/11/radio-frequency-b... http://docs.google.com/viewer?a=v&q=cache:FGiX56l9G3MJ:www.compendium.pl/files/rfandradiotechnologyfundamentals.pdf+rf+reflection+vs+refraction&hl=en&gl=us&pid=bl&srcid=ADGEESiIoIsYUN1939u9-deoTpG5VtFnq3uphxAi6uPFRCZFAbfG5zSQXEJYQ1GTVovYAeUq6WAqZbmlyfvP3ttEp9_sAUQucFeKso78Pw02Yr1zM4dKp9iZVDDIbbi33sohtvKdsp73&sig=AHIEtbTPOkM2VDKBg6pb3jKCz0HpZ1_mhg http://docs.google.com/viewer?a=v&q=cache:FGiX56l9G3MJ:w... http://www.wifi-doc.com/Cisco.Press-802.11.Wireless.Ne/1587051648/ch02lev1sec6.html http://www.wifi-doc.com/Cisco.Press-802.11.Wireless.Ne/15870... (i really wish an RF/electrical engineer would comment!)