The Mountain Topper II is the second antenna I designed
specifically for operating from the summits of mountains. (PHOTO
Its lightweight, completely self-supporting (no trees or guy lines required),
works all bands, and sets up in two or three minutes.
When disassembled, (PHOTO
MT 2) it is a small package about 20 long and 2.5 in diameter
(depending on what you come up with for a carrying case).
When assembled, it is a 9-foot radiator consisting of a 3-foot mast, a
loading coil, and a 6-foot telescoping stinger.
The antenna is supported by a tripod made from a music stand the
type used by kids in high school band. The antenna has one coil for 20
and 17 meters, a coil each for 40, 30 and 15 meters, and 10 meters is
tuned without using a coil.
All antenna pieces are made from two different sizes of brass tubing which
slide together to make a tight friction fit so that no tools are required
for assembly. The pieces are simply pushed together.
Changing bands requires changing coils but that process is very, very
simple because of the way the pieces fit together. Fine-tuning the antenna
for SWR is done by adjusting the telescoping whip at the top of the antenna.
Radials are attached to the antenna using alligator clips. The tripod
elevates the antenna to about 3-feet off the ground. This gets the radials
just far enough off the ground that they act as resonant, elevated radials
and provide a pretty efficient ground plane with only a small number.
My solution to radials is to cut four radials each for 40, 30, 20, 15
and 10. When I put the antenna up, if I intend to operate only one band,
I put all four radials for that band on. If I intend to operate more than
one band, I put two radials on for each band I intend to operate.
Performance seems to be excellent on the upper bands 20 meters
and higher. On 40 and 30 it is definitely a compromise antenna because
it is short and because the radials are not as elevated in relation to
The antenna is composed of the following pieces: tripod (PHOTO
MT 3), base mount and feed point (PHOTO
MT 4), three-foot mast made of two 18-inch brass tubes (PHOTO
MT 5), loading coils (PHOTO
MT 6) and six-foot stinger (PHOTO
MT 7). See Figure 1 for the layout (PHOTO
The project started with a music stand that I picked up at the flea market
for 50 cents. I knew I could turn that baby into an antenna.
Shortly after that, I discovered a rack of 3-foot brass tubes in a variety
of small sizes at the local hardware store. Amazingly, each of the different
sizes telescoped very snugly into the sizes above and below it (amazing
because its indeed seldom that things go right at the hardware store
for the antenna homebrewer). Ive seen this tubing at a couple of
small hardware stores since then, so I think if you check a few stores
you can find it. I found it at a local Ace hardware and a local True Value.
It is made by K&S engineering and the rack will say so. The tubes
are 3-feet long and vary in diameter from about one-eighth inch to a half
inch. Ive found a place on-line that sells something similar, but
you have to buy it in packs of five tubes.
I got three tubes. Two of them were 5/16 and two were 11/32.
These sizes telescope perfectly. The idea is that all parts of the antenna
(base, mast, coil and stinger) have an 11/32 top and a 5/16
bottom and can all be simply pushed together when it is time to build
the antenna. No screws no nothing to fasten together.
Once you find the music stand and the brass rods, the rest is easy. Heres
the parts needed (and estimated costs to buy new):
* 2 - 5/16 K&S engineering brass tubes ( $8)
* 1 - 11/32 K&S engineering brass tube ($4)
* 1 1 hardwood dowel (2 or 3 foot) ($4)
* 1 6-foot Radio Shack telescoping antenna ($5)
* Bunch of No. 14 building wire depends on how many loading coils
you want to build ($5)
* 12 1.25 X No. 6 machine screws with 2 nuts ($1.20)
* 2 half-inch X No. 6 machine screws with 1 nut (.20)
* 2 2 X No. 6 machines screws with nuts (.20)
* Stuff for radials (see description below)
* 6 to 10 feet of coax with a BNC on one end. I used the mini coax to
make it more compact. Yes, I know it has got a lot of loss, but not much
in only 6 feet!
* Used music stand ($ - who knows?)
** TOTAL COST: $27.60
Here's the tools needed:
* Drill (I used a drill press but I THINK I could have done it with a
hand drill. Theres a possibility the antenna would have looked a
little crooked when assembled, though)
* Tap for No. 6 screws (probably $10 if you dont have one) (PHOTO
* Drill bits (5/16, 11/32 and 7/64 the 7/64
is used for drilling the hole for the tap for the No. 6 screw. Work with
your hardware store to make sure this is the right size)
* Screw Drivers and Pliers
* Propane torch (optional - about $15 if you need to buy one)
* Tubing cutter ($5 if you need to buy one) (PHOTO
* Some kind of saw for the dowel
Heres the instructions to build this thing:
First, build the three-foot mast. It is made of two 18-inch telescoping
* Cut one of the larger (11/32) tubes in to 2 18 pieces
* Cut 2 4 pieces from the smaller (5/16 tubes)
* The 18 pieces will probably need to be reamed out on the end that
was cut so that the smaller tubes will slide in to the end. If this is
necessary, the tubing cutter usually will have a reaming tool built into
the cutter (PHOTO
MT 12). It is simply a triangular shaped piece of metal designed to
scrape the inside of the tube to enlarge it.
* Now fasten one of the smaller 4 tubes inside the larger tubes
at a depth of about 2. I did this by soldering the small tube into
the large with the propane torch. This is done just like a plumber sweating
a fitting on to copper pipe. Put a little soldering paste on the little
tube before sliding it in. Then, heat the larger tube with the torch and
after it has had a good chance to warm up touch some solder to the joint.
If all goes well, the solder will melt and be sucked right into the seam.
Another way that is just as good as soldering is to drill a hole through
the tubes for a No. 6 machine screw and fasten them together with half-inch
X No. 6 screw. If you elect this method, add 2 screws and nuts per coil
to the parts list.
* Slide the two 18 pieces together to make the three-foot mast.
* Build one or more coils (PHOTO
MT 13). A coil is made of a 4.5 piece of dowel with a piece
of 11/32 tube attached to one end and a piece of 5/16 tube
attached to the other end. Screws that are 1.25-inches long are run through
the dowel and into the brass pieces. Wire is coiled around the dowel and
attached to the screws to form the electrical part of the loading coil.
* Cut one or more 4.5 pieces from the 1 dowel, one for each
* Drill a 5/16 hole in one end of the dowel about 2 deep,
make sure its as straight as you can make it. I used a drill press
and eye-balled it and was able to get these holes pretty straight. I think
you can use a hand drill, but its possible the antenna will look
a little off kilter when its assembled.
* Drill a 11/32 hole in the other end of the down about 2
* Cut a 4 piece from the 11/32 tube and a 4 piece from
the 5/16 tube. Ream out the 11/32 tube so that it will accept
a smaller tube in the end.
* Stick the two 4 pieces into the ends of the dowel
* Drill a 7/64 hole through the dowel and the brass rod at each
* Use the No. 6 tap and put threads in the just drilled holes. If youve
never done this, its very simple just screw the tap into
the hole and it will cut threads as it goes.
* Screw a 1.25 machine screw through each hole and put two nuts
on the end. Dont tighten the nuts too hard on the screw. I had one
coil actually lose the connection to the brass rod after I had screwed
it too tight. After that experience, Ive always been scared that
one of my coils would suddenly lose electrical connection with the brass
tube but it has never happened. Nonetheless, Id be more comfortable
with a better way of making this connection. In the meantime, this method
has not yet failed me.
* Coil No. 14 wire on the dowel as per the following chart for different
coils (Ive made coils for 30 and 40 also, but ended up using very
light (No. 22) wire and am not terribly happy with them. If I had used
No. 14 wire I would have needed longer coil forms (dowels) and Im
afraid the weight would be too much for the antenna. I plan to experiment
more with this and hopefully Ill add more coil data later) You may
want to add one turn. If the coil is slightly too large, its easy
to tune the antenna by shortening the whip. Experimentation is the best
way to find what you like:
10 Meters No coil needed
15 Meters 6 turns
20 Meters 25 turns
17 Meters 25 turns
* Tie the wire ends to the bolts on the coil form.
* Wait until after you have tuned the antenna to wrap the coils with electrical
tape. The tape will hold the coils securely in place but you may need
to adjust the coils during tuning so its best not to wrap them with
* Push the coil into the three-foot mast (PHOTO
* Build the six-foot stinger. (PHOTO
MT 16). The telescoping mast needs a piece of 5/16 tubing attached
MT 17) so that it will slide into the top of the coil.
* Cut a 4 piece from the 5/16 brass tube
* Drill a 7/64 hole down the brass tube and the tap the hole to
create threads for a No. 6 bolt
* The telescoping mast will have a hole slightly smaller than 7/64
in the end (PHOTO
MT 18). Drill that hole out to 7/64 and tap it to create threads.
* Now you should be able to thread a No. 6 screw through the tube and
into the threaded hole in the telescoping mast
* Push the stinger into the top of the loading coil.
* Build the base (PHOTO
MT 20). The base is constructed to accept the 5/16 tube from
the 3-foot mast on the upper side. The lower end of the base will depend
on your tripod (music stand). I put another piece of 5/16 tubing
on the bottom of the base and it slid into the tripod. The base also has
two bolts that are used to attach the feedline and radials (PHOTO
* Cut a 4 piece from the 11/32 tube and ream it out so it
will accept a 5/16 tube
* Cut a 6 piece from the 1 dowel
* Drill an 11/32 hole about 2 deep into the 6 dowel
* Push the 4 brass tube into the just-drilled hole
* Figure out how you will mount the base to the tripod. I inserted another
piece of 5/16 tubing into the bottom of the base and this was a
perfect size to slip into the telescoping portion of the music stand.
You might want to just drill the hole the appropriate size for sliding
over the top of the music stand.
* Drill a 7/64 hole about 1 from the end of the dowel that
contains the brass tube so that it goes through the brass tube.
* Drill another 7/64 hole far enough from the other end so that
it DOESNT go through the hole you drilled for the tripod to slip
into. You dont want the bolt that goes in this hole to make electrical
contact with the tripod.
* Tap both of the 7/64 holes for a No. 6 bolt and insert the bolts
* Attach the middle of your coax to the upper bolt and the shield to the
lower bolt. I arranged the lower bolt so it would stick out a little on
both sides (PHOTO
MT 23). This makes it easier to attach radials.
* Securely tape the coax to the dowel with electrical tape. This acts
as tension relief for the coax so the leads wont break off.
* Slide the mast onto the base (PHOTO
* Prepare the music stand tripod. I had to cut the top off of the tripod
mast because it was bent. I also had to modify the tripod a little so
that it spread out a little further than the standard music stand. This
stuff will depend on the music stand you end up with.
* Mount the base to the tripod (PHOTO
* Construct radials (PHOTO
MT 26). I have cut 4 radials for each band Im interested in.
I use very lightweight (No. 22) solid wire that I happened to get a hot
deal on at the flea market. I think you can buy the same wire cheap at
the hardware store. It comes as 2 wire twisted pair, but is easy to untwist.
I really like sold wire because its easy to roll up and holds in
a coil without having to wind it on something or having wire ties
to hold it in place. I use small rubber grommets for insulators and attached
a 3-foot piece of wire on the end of the radial. This helps keep the radial
itself from touching the ground. This is pretty important in order to
maintain a consistent SWR every time you put it up. If youre on
a mountain where you cant drive a stake, just find a small rock
and wrap the end of the wire around it to hold it in place. I attach two
radials to one alligator clip. If Im expecting to work just one
band, I attach all four radials for that band. If I expect to work more
then one band, I attach two radials for each band I'll be using.
* Attach the radials and youre ready to tune the antenna.
* I found that the coils sizes listed above made the antenna resonant
on 10/15/20 with the telescoping whip fully extended which is very
convenient. For 17 meters, I used the 20 meter coil and shortened the
whip by 28. For 10 meters, use no coil and shorten the whip
by 6. In the field, its easy to adjust the whip because each
section is 12. If you need to reduce by 6, just push one section
half way in.
* Since the whip can only be shortened, not lengthened, you may want to
make the coils listed above 1 turn more than my recommendation. That way
you have a better chance of the antenna being able to be tuned by shortening
* If you don't have an antenna analyzer and need some help tuning the
antenna using your transceiver and an SWR meter, send me an e-mail at
firstname.lastname@example.org and I'll give you a description of how to do it.
* * * * * * * * * *
Gary Slagel, NØSXX, is an expert outdoorsman, QRPer and builder
living in Conifer, CO.