Probably an inv L or T antenna as high as
possible for TX is the best solution for 9 kcs. Base load the antenna
with the necessary inductance for resonance and if necessary add
another small inductor in series to ground and adjust with taps up from
ground to get a 1 : 1 match with the coax feed from the TX, readjust
the main inductor to maintain resonance if necessary.
This system has never failed me on 73, 137 and
500 kcs and this would be my approach on 9 kcs.
RX is a different matter and there are a
variety of antennas suitable.
I can RX the Alpha signals around 12 kcs at
good strength using my 500 kcs 1/4 wave inv L and weaker on the 40m loop
both antennas not resonated for 9 kcs.
Obviously if resonated the signals would be
very strong with these antennas.
9 kcs is a lot easier to get going than the
other LF/MF bands because there is an abundance of LF generators and
high power audio amplifiers about,
I would suggest modifying a audio amp output to
50 ohms with a suitable transformer then use existing station equipment for
monitoring and measuring.
Suggested approach for making a large inductor
to resonate antenna.
Get several slotted laundry baskets size diam
600mm, height about the same, stiff plastic material. Wind some wire on a
few and connect in series with antenna and check for resonance, then add
baskets as necessary to resonate at desired frequency These baskets fit into
one another and look tidy.
Use the largest diam wire possible to
achieve the desired inductance. If using a vy small inv L with lots of
Henries required then go for the water butt coil former.
Do not forget some earth radials and
rods.
I could probably manage about 4 inv L antennas
in parallel, 500 kcs size, loaded against ground and would hope the
signal would travel some hundreds of miles.
If only I had the time.
de mal/g3kev
