[BC] IBOC Radios

[Mark Humphrey]

On 8/27/06, Dave Dunsmoor <mrfixit at min.midco.net> wrote:
>
>
>     I started to consider this as a project a short while back, but balked
> at the price of the CP6XX series
> FET prices. $14.70 each. I may try it with another readily available FET,
> and see what I think of it's
> performance. If poor, then might shell out the $15+ for a "good one".

You might try substituting a U310 or J310 (42 cents in unit quantities
from Mouser) and bias it for 30 mA, which will eliminate the need for
the heat sink.  For details, see this FAQ page:

http://www.amrad.org/projects/lf/actant/faq.htm

Another good website for broadband receiving loops, whips, and preamps
is maintained by Mark Connelly, WA1ION.  Here's a schematic for a
balanced loop preamp, using inexpensive MPF102s:

http://www.qsl.net/wa1ion/loop/bfe_c.htm

See also his tri-mode buffer amp box, which can be switched between a
whip, terminated loop, and broadband loop.  This uses an IC amplifier,
such as an LM6221N:

http://www.qsl.net/wa1ion/tmb-1/tmb-1.htm

Have fun!

Mark