Analyzing Frequencies + Logic Probe circuit

http://www.youtube.com/watch?v=ZuRcaxpbYCw

http://en.wikipedia.org/wiki/Ionosphere

http://en.wikipedia.org/wiki/Aircraft_Communications_Addressing_and_Reporting_System

http://www.rtty.com/

http://books.google.com/books?id=jKA8AAAAIAAJ&pg=PA106&lpg=PA106&dq=5460+khz&source=bl&ots=4ihZ-KGUTF&sig=TsifV-lxZYDCZcjJuQo7Fp034j8&hl=en&sa=X&ei=Jvl_UZe3Mte84AP8loDACA&ved=0CEgQ6AEwAw#v=onepage&q=5460%20khz&f=false

http://www.wavecom.ch/

http://maps.spench.net/aviation/

https://en.wikipedia.org/wiki/LIDAR

http://en.wikipedia.org/wiki/Orthogonal_frequency-division_multiplexing

http://www.spectrumservers.com/ssproducts/pc/viewCategories.asp

http://thepartsplace.k5nwa.com/

http://wb5rvz.com/sdr/

http://www.oz9aec.net/index.php/gnu-radio/gqrx-sdr

http://sourceforge.net/projects/gqrx/

http://www.amazon.com/RTL-SDR-DVB-T-Stick-RTL2832U-R820T/dp/B00CCQMTCM/ref=sr_1_3?ie=UTF8&qid=1367343564&sr=8-3&keywords=usb+digital+tv+rtl

http://www.amazon.com/digital-Stick-RTL-SDR-Receiver-RTL2832U/dp/B00CE2GMHC/ref=sr_1_7?ie=UTF8&qid=1367343564&sr=8-7&keywords=usb+digital+tv+rtl

http://erosenthal.com/NYUITP/Session_13.html - Logic Probe