Re: [Discuss-gnuradio] Active Radar Hardware

[Jason Hecker]

Hi

> I have zero experience building a system like this. I'll be thinking a
> lot more about it, and looking for better parts, but I've learned to ask
> the experts early ;) Any ideas?

I used to write software for a radar.  It used separate antennas for transmit 
and receive for several reasons though the RX and TX antennas were located 
right next to each other.  This arrangement works very well.  If you are 
concerned about too much power entering the RX stage you could use a 
switchable attenuator using a voltage signal and PIN diode.  Actually, if you 
want any sensible readings and a signal that has good dynamic range at the 
ADC you will need a controllable attenuator that increases the RX gain over 
time (in a logarithmic way) as the return signal gets weaker with the squared 
square of the distance (R^4 !).  You'll always get overload signal for a 
certain close-in range anyway.  Not much you can do about that.

Regards
Jason Hecker