I am building a SDR type radio using a microprocessor and self contained radio IC. The frequencies will be limited for sure as the datasheet claims reception at 153kHz ~ 279kHz, 520kHz ~ 1.71MHz, 2.3MHz ~ 26.1MHz, 64MHz ~ 108MHz. I want to be able to listen to a frequency and constantly scan signal strengths and create a chart for each listenable frequency. I am thinking of using two Si4735 chips(one for listening and one for scanning) and a parallax propeller to send and receive the commands to the Si4735. I am wondering about how to implement the antenna setup. I think I need two antenna's. But if I combine the two antennas somehow I am thinking I can improve reception for both applications at the same time. I have no experience with SDR radio's. Are they able to scan signal strengths in the background? Or are they blocking functions(you can only do one at a time)? The propeller chip will do TV out and I don't think the RF out will be a problem because all the output circuitry is on the chip die. The only external components are the 75-ohm 3-bit dac. Also being SDR, I will implement a USB serial interface and write a .net C# program to control from a computer. I ideally want 2 whip antenna's(like the ones on wireless routers) on either side of the project enclosure. Is there anything I should do to multiplex the antennas or would one antenna be fine for both? I want a real time band scan for all the frequencies on one side of the screen and a reciever interface on the other to select the bands and frequencies. This is just a serial or i2c interface to the microprocessor. The whole project depends on getting the best reception using small indoor antennas. So any ideas on how to implement an antenna system. If it helps the traces from the antenna to the chips will probably be small as the project box won't be much bigger than 4x6x2". I can't depend on using the project board to run traces to act as an antenna. I am not opposed to using a MFJ type active antenna, but I don't want to have to manually select a band on the antenna. And this is just shortwave reception I am worried about.