Putting a VHF or UHF antenna on a metal balcony is not a simple
matter. There are many things that will limit what you do, especially if
you are not on the top floor of the building. Beams are almost always
too big or too cumbersome and their mounting structures often take over
your whole balcony. Base type verticals are usually way too tall to fit.
Magnetic mount antennas don't really have enough metal to stick to and
may fall. So, unless you have permission to go beyond the balcony
railing, you end up stuck with indoor antennas or using your HT on the
balcony. The "Balcony Buddy" offers a very simple
and flexible solution to the problem. It can be mounted to any vertical
metal bar on your balcony or fire escape and, because it is so compact
it will be almost invisible from the ground, making it a "near stealth"
For new hams this design also offers an
extremely easy first antenna project. It is made entirely from
commercially available bits and pieces that you can get at your local
ham shop and hardware stores. The only tools you will need are a small
screwdriver, an adjustable wrench, a pair of pliers, a measuring tape
and a fine cut file. Tuning is simple; accomplished through adjusting
the length of the radiator.
The antenna itself is a basic 1/4 wave
monopole that uses the metal structure of the balcony as it's
groundplane. Gain is unity (+6 DBi) but that is better than most indoor
or rubber ducky antennas achieve, so you will almost certainly see some
improvement in performance by getting your antenna outdoors; especially
if you live in a "concrete cliff".
What You Need
On the left you see a shot of everything you
need to build a balcony buddy. In the picture are a mounting bracket,
SM-1 mounting bolt, AS-1 adaptor, a length of 3/16" tempered aluminium
rod and a run of RG-8X coax with PL-259 connectors installed. All these
parts, except the aluminium rod, should be available at any ham or CB
Not pictured is a dollop of liquid silicone
rubber (fish tank sealer recommended) needed to waterproof the bracket
You can probably find the 3/16" aluminium rod
in 3 and 6 foot lengths at your local hardware store. It can also be
purchased in 12 foot lengths from metals suppliers for a couple of
dollars each. Make sure you get tempered aluminium, the regular
stuff is way too soft and might bend in the wind.
the right we see a model RV-1, one of many possible mounting brackets
you can use. These are readily available at most ham radio and CB radio
dealers, even some truck stops carry them. Durham Radio shows a good
selection in their online catalogue; everything from modified vice grips
all the way to fancy dual mounts for making HF dipoles.
Your choices will depend on the structure of
your balcony. To determine which mount is best for you it is wise to do
a bit of measuring and reckoning in advance. A bracket that's too small
to fit over your railing is no use to you at all. Also stay away from
cheap stamped steel brackets, use cast aluminium whenever possible. The
cheapies may look ok but many rust and some will bend in strong winds.
we see the SM-1 antenna mounting studs on the right. I've taken one
apart to show you the components. The connector end shown in the
foreground goes under your bracket and is where your coax connects. The
plastic washer is an insulator that sits on top of the bracket and
prevents the live center stud from shorting to the bracket. The lock
washer and 3/8-24 nut sit on top of the insulator providing the mount
point for the antenna.
Also note there are two types of SM-1
mounting bolts. The one in the foreground is brass and is generally
strong enough for most VHF and UHF antennas. However the stainless steel
"SM-1s" in the background is far less likely to react against the
aluminium brackets, causing corrosion, and is recommended for anything
more than short term use.
we see the AS-1 whip adaptors, again on the right. They are threaded on
one end with a 3/8-24 thread that fits into the SM-1 mounting stud. They
are drilled right through with a 3/16" hole that is the perfect size for
aluminium or brass rods. There are also 2 setscrews on the sides that
make the antenna adjustable up and down about 15mm, for fine tuning. If
you build more than one antenna you will find lots of uses for these
The last part is the coax. I suggest RG-8x
for balcony/apartment use. It's a relatively low loss cable that is more
than suitable for short runs on VHF and UHF. It is a thin cable (1/4"
diameter) like RG-58 but with 5 times the power handling and
considerably less signal loss. It is also very flexible making it easy
to route out an air conditioner box or through a small window opening.
For runs up to about 12 metres it's every bit as good as the more