I have PC boards available once again for the high-performance Double-Quadrature (DQ) Radiolocation receiver and for the Class-E underground beacon.
The cost for a 3-board set, including the 2 receiver boards, plus a beacon board with a special toroid and wire to wind it, has dropped to $29.00 US plus shipping. A separate beacon board with toroid and wire is $9.00 US plus shipping. I am selling at my cost as a service. PayPal accepted. See http://radiolocation.tripod.com