[DisasterRadio] Learning about antennas and impedance matching

I created a page on the wiki with some learning resources for getting up to speed on the work we're starting to do on antenna design and impedance matching networks: https://github.com/sudomesh/disaster-radio/wiki/Antennas-and-impedance-matc… Since we'll need a VNA for this work I included a comparison of different affordable VNAs. Tomorrow evening we'll probably spend some time building a simple test setup with two computers displaying the RSSI from the RFM95 modules. -- marc/juul