Foundations of Amateur Radio #202:
April 20, 2019
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Antennas out of sight and out of mind
Previously I've spoken about the dynamic
nature of your station. Even if from day to
day use, nothing changes, things around you
are always in flux. Propagation changes,
power fluctuates and the environment in which
your antenna operates is dynamic. Mobile
stations even more so.
A few days ago we had a gale come through,
strong enough to do some major damage, rip
off some roofs, break some trees, cause
flooding, cause power outages, plummeting
temperatures, the first of the Winter Storms.
Obviously, checking out your antenna after
such an event is expected. Better still,
stowing your gear before the event is even
Such extreme weather events are an obvious
trigger to attending to antenna health and
well being, not to mention, maintenance and
The thing is, it's not the only time you
should check out your antenna. Every day it's
subject to change. The sun rises in the East,
follows its path along the sky and eventually
sets in the West. The temperature and
humidity change throughout the day and
continue to change through the night and the
next day it starts all over again.
Peppered with sun, rain, snow, salt,
corrosion, expansion and contraction, your
faithful antenna sits there ready for you to
get on air and make noise, until one day it
You could just wait until it falls down,
dies, perhaps becomes a hazard to anyone
within gravity range, not to mention, destroy
your radio when you key it up. Or you could
check your antenna regularly and look after
it. Inspect and test it regularly, run you
analyser across it every couple of months,
you know the drill.
Most antennas are out of sight for most of
their life, but they should never be out of
During the weekly F-troop net we started
discussing this - as well as an in depth
conversation about launching wire into trees
- and there were several suggestions worth
One amateur pointed out that the level of
complexity in the air dictates the amount of
maintenance. A log periodic antenna on a
rotator needs more Tender Loving Care than a
wire hanging off a tree.
Another suggested that you should regularly
check the tower supports - technically the
mast supports - a tower is self-standing and
a mast is not - the best way to remember is
that is the Eiffel Tower doesn't have any guy
Before a storm, if you have warning, you
should check the supports, wind down anything
that goes up and down and you should think
about how you're going to earth the coax.
I've previously covered the weirdness that
lightning and charge represents, even at
distance, so don't wait until it's overhead.
There were suggestions of using spark plugs
and Mason Jars, but I've got no supporting
evidence either way. My geek background is
sceptical, but I'm open to learning more.
I've seen installations where a coax switch
is used where the antenna is switched to a
shorted socket, so the inner and outer braid
of the coax are connected to each other.
One amateur suggested that an antenna tuner
is cheaper than a radio, and that if you
leave it in place during a storm, blowing
that up is cheaper than blowing up a radio,
but your mileage may vary. Also, if you have
spare cash to burn, I'm happy to take your
donation and relieve you of that fire hazard.
It's interesting in and of itself that
antenna maintenance is often discussed in
terms of extremes, lighting, storm, wind,
ice, etc. and less so in terms of regular
Finally, if you're only using a temporary
antenna, you're not exempt from this. You're
actually likely to have more failure, since
the act of erecting and lowering of the
antenna is likely to cause more wear and
The antenna is the final part of the
transmission chain and it should be treated
with the same respect as the power supply at
the other end.
I'm Onno VK6FLAB
TL;DR This is the transcript of the weekly
'Foundations of Amateur Radio' podcast - for
other episodes, see http://vk6flab.com/
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