wrote:

http://www.wellbrook.uk.com/ALA100b.html
With a bit of hacking, the Wellbrook ALA 100 is as good as any of the
shortwave antennas they sell. It is just the amplifier. You have to
roll your own loop. The ALA100 is the lowest cost welbrook. At the
current exchange rate, the ala100 is a over $200.

I have made a few loops with this amp. I have a 2ftx2ft out of copper
pipe for direction finding. I have 4ft x 6ft copper pipe for regular
use. It's really stupid big and will eventually be reduced to the
original 4ftx4ft. I have a few portable designs that are around 40ft
worth of wire.

The wellbrook loops are just amazing. All that said, the ATS909
probably can't handle that much signal. It would make sense to use
one with a portable shortwave radio.

Has anyone ever successfully reverse engineered the pre-amp of a
Wellbrook loop? It might be possible to dissolve the encapsulating
material (epoxy?) to reveal the PCB and componants. Otherwise a medical
scanner (seriously) might reveal some useful information.