Tape Measure Antenna
The tape measure 2 meter antenna is a common, easy
project for amateur radio operators. A great design is
online at http://home.att.net/~jleggio/projects/rdf/tape_bm.htm
This antenna uses schedule 40 PVC pipe. The PVC frame
(with tees at both ends, not a cross at one end) weighs 152
grams (5.4 oz).
a standard PVC antenna frame
Since this antenna is often used in backpacking, it would
be nice to make this of 1/2" CPVC, a pipe material with smaller
mechanical dimensions and, thus, the possibility of lighter
This has been investigated by others, but apparently, no
CPVC crosses are manufactured. (See
no real sources exist. If you can find one, please let
So, the trade-off seems to be that a 1/2" CPVC design
would require an extra tee and a non-linear design.
a standard PVC antenna with tape measure elements held by rubber bands
Two versions have been developed and built. Their weights
are 128 grams and 127 grams (4.6 oz). Thus, about 1 oz
can be saved with these designs.
For the designs, open this drawing.
The rest of the construction uses the instructions at
Note that at my local Ace Hardware, the CPVC tees
and 45º elbows for around 99 cents each. As of May
2010, my local Ace reduce the price to 49 cents. The local
Orchard Supply Hardware had the same for around
39 cents each, so shop around! The farm supply
store also had these for 49 cents. A nominal 10' piece of
CPVC 1/2" pipe is $3 to $4. Home Depot doesn't
carry CPVC at all!
the 128 gram design
The PVC pipe is 0.84" in outside diameter, while the
CPVC pipe is 0.63" in diameter. The PVC pipe has
a wall thickness of 0.06" and the CPVC has a wall
thickness of 0.08", so the CPVC is a stronger pipe.
The original PVC model could be built using schedule
80 pipe instead of schedule 40, but that would add
the 127 gram design
It is possible to make the traditional, straight design using CPVC
by making a bushing so that a 1/2" PVC cross can be used. Two
pieces of 1/2" schedule 80 PVC pipe will work. The CPVC pipe
needs to be sanded to fit inside the schedule 80 bushings. The weight
of this is also 127 grams.
One ham has taken a lathe and cut a PVC to make it a cross. The total
weight of this assembly is 102 grams. So, we've saved 50 grams, nearly
2 oz. John Breckenridge will make these for fellow hams for $5 each. If
you want one, email AD6YB@ARRL.net.
Comments and suggestions are welcome to AD6YB@ARRL.net.
Good building and 73s!
the design with the 1/2" PVC tee and two home-made bushings
the design with a CPVC cross made from a CPVC tee
weight on the frame is 102 grams
last updated: 08/05/11 01:01:11 AM