On 7/29/2014 10:58 PM, Lostgallifreyan wrote:
Lostgallifreyan wrote in
:

A small FM aerial amplifier built around a MAR-6 IC works to boost the
signal for direct connection, but can it also be used to drive a
1/4-wave dipole for the immediate locality?

I found that old amp and a 1mH choke and 12VDC source so I tried it. The
answer is NO. Radiated power is so tiny that I think it would take a 5 grans
bit of test gear to analyse why in meaningful detail. I saw no difference
whether the power was on or off. The quickly-cobbled dipole itself was fine,
even as an indoor aerial wired directly to the input of an AR-3000 it was
excellent, nearly as good as outside, but it's the wires I want to avoid,
eventually.....

If I feel like trying again it will be with one of those legal
microtransmitters sometime, just the RF gain part, and probably with the
indoor radiating dipole horizontal to reduce coupling to the vertical one
outside.


The problem with what you're trying to do is you can easily get RF
feedback between the output antenna and the input antenna, causing
oscillations. And those oscillations may not be in the FM band - they
may be on an adjacent band (like aircraft, which is just above the FM band).

But the amplifier you're trying to use is meant to feed a receiver
directly, not another antenna. So output is going to be very low (on
the order of microwatts) - much lower than any amplifier which feeds an
antenna.

--
==================
Remove the "x" from my email address
Jerry, AI0K

==================