SUBJECT:               o  Hidden Apartment HF Antenna


 Bottom floor dwellers have some advantages over dwellers on other floors
 concerning HF antennas. Single unit condo & PUD dwellers fall into this
 area.

 Dwellers in the mid-floor(s) have it the toughest. And top floor dwellers
 have other advantages the first two don't.


 HF antennas are large and trying to hide one can be like trying to hide an
elephant. Many hams try different configurations, snap together antennas,
wires, and flag poles to conceal their antennas. Some work out, but most
get caught in the end.

 First, let's look at what you can and can't have. Most restrictive housing
areas have a long list of items you can't have. Clothlines, TV antennas,
sheds, flags, BBQ grills, etc. And most of all, the all important HF
antenna. It has something to do with nice surroundings.

Make a list of these items and place them in a column on the left side of
the page. Next, list what you can have and list them in the center of
the page. Next, list the items that are readly available in the area of
your home. Such items are trees, gutters, vents, fences, etc. Look closely
and don't leave anything out.

A hidden HF antenna must be just that, hidden to the naked eye, even at
a point blank range.

Next, list the areas that you have a ready access to. If you can get to the
roof, write it down. How about the attic, basement, trees, etc, without much
notice by your neighbors. Most HF antennas are discovered not because of
their design or placement, but rather a neighbor spies the ham installing
the antenna or at least doing something out of the ordinary.

EX: Creeping around on the roof, on a Saturday afternoon, is going to
draw attention. Flinging wires over trees is sure to draw some attention.

The big point here is not to install the antenna by looking like your
installing an antenna or doing something out of the ordinary.

There are some new designs out on the market such as PVC vent pipe antennas
for 2m. But for now we'll stick to HF. Most contracts for condo / PUD
dwellers will allow bird feeders. And even apartment dwellers on the bottom
floor can benifit from this design.

I'll give a brief description here of the Bird Feeder antenna and discuss it
further in later postings. The Bird Feeder HF antenna is a vertical cage
wire antenna. A 'What?' you might ask. Imagine if you will eight flexible
wires, evenly spaced in a circular pattern, much like a ground plane. Draw
these wires vertically to form a wire 'tube' and connect them together with
a ring at the top. Now imagine these wires inside a telescoping PVC mast.
Top that off with a bird feeder. Now, instead of a ground plane system with
radials you have to put in (the neighbors are watching), you have this
'wire tube' constructed as a vertical dipole. At 10m, the Bird Feeder
antenna is a mere 17' tall when raised. What would the neighbors say? Or
for that matter the manager?

       "I raise it up for the birds to get into and it keeps the squirels
out too. And look, I can take it out when I'm not using it or the weather
is bad. Boy, I really like watching the birds from my window. Did you know
that ..."

And then go on about some rare, but not unbelievable birds that frequent
the feeder. Buy a book on the subject with some pages tagged to show them
what you've seen so far. At worst, they'll think you're a flake and leave
you alone. Next, go in and tune up 10m and catch some rare DX instead.

What do you have to actually put into the ground? Your coax and a PVC
pipe to hold the mast up. Make it low in the ground and cap it so the
mower doesn't take it off. For te most part, you can leave it up.

But do remember to put so seed in the feeder once in a while!

I'll give the details next posting and tell you about another right out in
the open totally hidden antenna.

This one is getting a bit long.

**************************************************************************

SUBJECT: Part 2, Bird Feeder Antenna

Now, I admit, this design sounds a bit far fetched, but it works. The
vertical dipole, inside the PVC push-up, is invisable. It moves up and
down and can be removed without drawing attention to the fact that it
contains an antenna. The flagpole design has some problems. Not all PUDs,
condos, or apartments allow flagpoles. They represent a permanent fixture.
Not all associations or managers are that patriotic.

Although you can pack a good vertical in a flagpole, there is the problem
of radials. You can run the vertical without radials, but that's another
compromise.

The design for the Bird Feeder Antenna is very simple. Drawing it here is
another problem. Ascii Graphics really do not exist, so a description is
in order.

You can build the vertical dipole without much trouble. The dipole consists
of up to 16 wire 1/4 wave elements. There are eight on each leg of the dipole.
You may use less, it's up to you. You know the bandwidth of a wire dipole and
you know the band spread on 10m. If you are a general or above, you will
want the extra wire elements to give you the bandwidth you need.

First, let's look at the PVC tubular mast / bird feeder support. Most hardware
and home improvement center have PVC tubing. Like the steel counterparts,
the mast will be graduated (large at the bottom and smaller at the top.
I'm not going to recommend any sizes here as availability at your store is
going to dictate what sizes you will need. I will state the the top tube
should be 2" in diameter or better. You will need that size to support the
bird feeder and give the mast some strength.
                                ___
                                | | <-------  Attach upper ring
                                | |           inside
                                | |
                                | |
                                |_| <-------  Attach next ring
                               |   |          inside
                               |   |
                               |   |
                               |   |
                               |___| <------- Attach feed ring inside
                              |     |<------- Attach feed ring inside
                              |     |
                              |     |
                              |     |
                              |_____| <------ Attach feed ring
                             |       |        inside
                             |       |
                             |       |
                             |       |
                             |       |
                             |_______| <------ Attach bottom ring inside

                   Figure one.


The wire elements are attached in a ring format, evenly spaced, in a 360
degree pattern. Locations are noted in figure one. This allows the dipole
to be folded up when the mast is lowered. More than eight wires on each
leg of the dipole tends toward snags when raising and lowering.

Dipole wire element sizes are calculated by 246 / f Mhz. But I recommend
shorter lengths if eight elements are used.

A BALUN can be inserted, but is not necessary. I feeder coax is needed from
the dipole feed to the base of the mast. A UHF bullet (female to female) to
attach your coax to.

NEXT: How to lay the coax without looking like you're doing it and Bird
Feeder mast install.


NEXT ANTENNA: Mobile resonators and hiding them.

***************************************************************************

SUBJECT: HF Bird Feeder Antenna, Part three

Installing the antenna:

The base piece for the bird feeder mast should be one size larger than
the bottom section of the mast. The mast should be able to side in a
snug fashion, but not too tight. Since you are installing a 'bird feeder',
you shouldn't have any problem explaining what you are doing. Simply
lay the bird feeder and mast right out in the open. Your nosey neighbors
will know exactly what you're doing (almost). The coax is the tough part.

Trenches are out of the question. Use a sidewalk edger (manual) and make a
thin cut in the grass. If you have other obsticles, you will have to deal
with that when you come to it. The object is to do it when the neighbors are
not going to notice. The thin cut in the lawn will not be seen and will
'heal' quickly. A tricky technique is to use a wheelblade on a handle. It
will look like you are using a measuring device. The cable can be laid into
the cut at dawn, when you are filling the bird feeder. Stepping on the cut
lawn on the way back seals the cut. Now you're in business.


If you have any questions, drop me a line here.


Next: Mobile resonators for HF. Their small, they work and they hide well
in places you would overlook. And they can be placed right out in the open.

************************************************************************

SUBJECT: VHF & UHF Hidden antennas for PUDs/Condos/Apartments

These antennas are much easier to hide because of their size.
I'll get into some high level design concepts here and expound on
them later.

I'll be discussing the following antennas:

               o       Stealth Verticals
               o       Stealth Beams
               o       Indoor Antennas
               o       Indoor/Outdoor use of Mobile Antennas
               o       Field Day / Portable

-+-------------------------------------------------------------

Stealth Verticals:

This type of VHF / UHF antenna is very popular with amateurs. The are
easy to build and install. Many commercial antennas are available, but
for the dollar, an amateur can build a superior VHF or UHF antenna for
the base or mobile use. For the PUD/Condo/Apartment user, even a simple
vertical can be a major problem to install. Location in an apartment may
be one of the biggest problems facing an amateur when antennas are
prohibited.

There are large multi-element verticals on the market such as Comet and
Diamond. The size of these antennas makes these a bit more difficult to
install. There are other homebrew antennas that can be installed however.
These antennas will be discussed here.


                       J-Pole

The J-Pole is an exceptionally good antenna and easy to build if the
directions in the ARRL handbook are followed correctly. One modification
I recomend for the J-Pole is to solder the tuning connections after the
SWR is set. This allows for 'no maintenance' on the J-pole and no
surprizes with SWR changes due to corrosion.


            1/4, 1/2, 3/4 wave ground planes

These ground planes offer unity, 2dB, and 3dB respecfully. These antennas
do not need coils or tuning circuits to accomplish their action.


                      Discones

This antenna can be homebrewed or bought commercially. The discone is an
excellent antenna, but has it's drawbacks in hiding. The antenna has unity
gain and can be used on multiple bands.


                   Vertical Dipole

This antenna can be put together in various configurations with various
matching devices. The dipole is a halfwave.


                   Full Wave Loop

This antenna can be configured to vertical polarization. It is not omni, but
exhibits good gain in a bidirectional pattern.


There are many more antennas that exist. Some are larger, some don't have
the bandwidth, and still others require coils & capacitors to make them
work. The aboved mentioned antennas are easy to homebrew and make for
good antennas that can be used by PUD / Condo / Apartment dwellers. All
the above antennas are in the ARRL antenna book. The design and
construction of these antennas is easy if the directions are followed in the
book. What I intend to accomplish here is placing the antennas such that
they go unseen by all.

-+---------------------------------------------------------------------

                  INSTALLATION OUTSIDE

Let's look at the first one: The J-Pole. Gain wise, this antenna does not
have a lot of gain on transmit, but the antenna has an easy 3dB gain on
receive. If you make your J-Pole from brass rod or like material, placement
of the antenna should be accomplished fairly easy. You should remember not
to install the antenna near other metal objects or fixtures. Give it about
three feet of room from conducting surfaces.

The best hidden J-Pole I've seen was painted to match the chimney brick work.
Everything that went with the antenna was matched to the chimney. The coax
was painted to match not only the chimney, but the roof and then the paint
color on the side of this PUD home. The J-Pole was bent to the contours of
the brickwork and masonery. The amateur installed the antenna under the cover
of cleaning and repairing the chimney. His plan worked well.

Another J-Pole I've (almost) seen was mounted to side of a tree at thirty
feet. It too was painted to match the bark of the tree.

I designed and built a J-Pole for a friend that looked and matched the
foliage of a white pine. I used artificial plastic Christmas tree elements
to match a branch on the pine tree. If you didn't see where it was installed,
you couldn't tell it from the rest of the tree.

Another design was mounted to a swing out arm which was installed under
a window sill at thirty feet. The Ham painted the J-Pole to match the
natural wood finish on the condo. At night, he would swing the J-Pole
out from the window and talk on the local repeaters. The dark color of
the J-Pole, helped the amateur, by blending the antenna against the
night sky.

Next, I'll discuss the 1/4, 1/2, 3/4 wave ground planes. These antennas have
various gains, but all have one thing in common. Each antenna requires no
tuning or matching elements. Like the 1/4 wave, the 1/2 and 3/4 wave antennas
are built in the same manor except the vertical element is either 1/2 or
3/4 wave. The Quarter wave 2m antenna can be cut so that it is a 3/4 antenna
on the 440-450 MHz band. Thus, a dual band antenna. A 1/4 wave on 222-225 MHz
can be cut for a half wave on 440-450 MHz, another dual bander. These dual
band antennas will not have the complete range over the secondary band, but
will give a piece of it at low SWR.

Each antenna will cover the entire primary band it was cut for. I use brass
rod for my ground planes. They do not rust and solder easy with a good
soldering iron.

Hiding these antenna takes a little more foresight. The ground plane shape
tends to make the posibilities of a good hiding spot a bit less. But the
thin material tends good for trees. They can be hidden as part of the tree
with plastic leaves and a blending color paint job. Their size is a good
contributing factor. UHF vertical ground planes (VGP) tend to hide themselves.
A UHF 1/4 wave VGP is a mere 9 inches from the base of the ground plane to
the tip of the vertical element. I wouldn't leave them out in the open, but
little will have to be done to hide one of these UHF VGPs.

-+--------------------------------------------------------------------

Discones have been used outside in restricted areas. Hiding one can present
a problem because of the dimentions. I would suggest using these antennas
indoors and will discuss them later.

-+--------------------------------------------------------------------

The Vertical Dipole is an easy antenna to hide. The shape is easy to bend
in with surrounding objects and matching can be accomplished by many means
as listed in the ARRL antenna handbook. My favorite is the gamma match.
I would recommend this for the 2m and 1.25m antennas. At this point, I must
say the gamma match works fine, but at UHF frequencies, a Tee match is
better. The gamma tend to loose the bandwidth required up on the 440-450 MHz
band.

It can be hidden in the same manner as the J-Pole.

-+--------------------------------------------------------------------

The Full Wave Loop is another favorite. Although this antenna has the best
gain of the previously mentioned antennas, it can present a problem in band
width and placement. When palced against a building, the SWR goes up.
Cutting and tuning a loop to a band may also present some problems. The
bandwidth of a loop may not cover all the frequencies desired if operating
the repeaters.

The circular loop is the best, followed by the square loop. Triangular loops
work well also. The area enclosed by the loop is the main facter in
approaching the 50 ohm impeadance required by amateur radio gear today.
Please keep that in mind. Geometric shapes in a natural setting tend to
'stick out' to the human eye. Hiding the antenna will require a crafty
plan on the part of the amateur. The bidirectional pattern from the loop
my hinder the placement if a specific direction is required. Remember
the chimney? Good place to start.

-+--------------------------------------------------------------------


Enough for now. Next, I will discuss the VHF/UHF hidden beam antenna.
I have not discussed 6m, 33cm, or 23cm antennas, but the same application
holds.

Here's some info on 1/4, 1/2, and 3/4 wave lengths for the bands 6m, 2m,
1.25m, 70cm, 33cm, & 23cm to give you an idea on the size of the antennas
you will be dealing with. The formula use does not always relfect the exact
length of the antennas involed, but is to be used for sizing only.

       1/4     1/2     3/4         f
-+----------------------------------------
 6m  | 4.73'   9.46'   14.19' @   52.0 MHz
 2m  | 1.68'   3.37'   5.05'  @  146.0 MHz
1.25m| 1.1'    2.2'    3.3'   @  223.5 MHz
70cm | 0.55'   1.1'    1.65'  @  445.0 MHz
33cm | 0.27'   0.54'   0.806' @  915.0 MHz
23cm | 0.194'  0.387'  0.581' @ 1270.0 MHz




SUBJECT: VHF/UHF stealth beam antennas

Let's look at a couple of points here first. From my last posting, the
relative sizes of the different antennas show that hiding a 6m antenna
can be a lot more difficult than hiding a 70cm antenna.

6m beams can be large and hard to explain as a TV antenna. Many PUDs/Condos/
Apartments do not permit TV antennas at all.

For places that allow TV antennas, I have some tricks that you can do inorder
to play on the bands. These tricks will be discussed later.

Beams are a necessity in some locations. The gain achieved on a beam can mean
the difference between getting in the repeater, digi-node, making a simplex
or SSB contact. The easiest installation would be in an attic, but most
hams can figure that out.

Unless you only require a fixed position, a beam will require a rotor to
fully utilize the quality the a beam can provide. Beams are generally single
band antennas when used above 10m. I would recommend a log periodic for use
on the VHF/UHF frequencies to provide the ham with multi-band operations.

There are some problem that must be addressed when working with beams.
First, different polarities are required for different operations. FM and
packet use vertical while SSB and CW require horizontal. Space communications
requires a combination of the two or circular polarization.

Second, hiding a beam and it's associated support equipment can be a pain in
the butt when the QTH says no antennas. Anything that must rotate is going
to draw attention. Fixed beams can be hidden. Rotating beams are going to
require a bit more.

-+-----------------------------------------------------------------------

Remember that size plays a big point when stealth is employed. I'll look
at the 2m beam for the examples here and the relation can be applied to
the other bands.

       Horizontal operation: This is the easiest beam to hide. Be sure you
know all the rules of your association or apartment before attempting to
install a beam. The beam, because of it's polarity, is flat. It can be
passed off as a TV antenna for a specific channel. Most people wouldn't
know the difference. The outside installation can be accomplished with
the basic TV installation. By adding a second rotor, such as an elevation
rotor, both vertical and horizontal polarization can be accomplished.
I recommend the vertical operation for night time use only. It eliminates
the question; "Why is your TV antenna like that?"

       Stealth operation:
You may not be able to put up a TV antenna and must totally hide the beam.
Attics are an easy hiding place. Upper rooms are good too. Telescoping
elements for portable operation work well. I would like to relate some
unique installations to overcome the no antenna rules.

       This Amateur had a bad time trying to locate any antenna at
his dwelling. He lives in an apartment complex. His apartment is on the
inside, second floor, of a four story apartment building that is shaped
into a large rectangle.

               -----------------------------------------
               |                                       |
               |                                       |
               |      ---------------------------      |
               |      |                         |      |
               |      |                         |      |
               |      |                         |      |
               |      |                         |      |
               |      ---------------------------      |
               |                  X                    |
               |                                       |
               -----------------------------------------

The X indicates where the apartment is located. There is an apartment on
the outside of his. Like I mentioned, he was on the second of four floors.
No antennas are allowed outside the apartment. He had a couple of options.
One, he could move, but funds weren't there. Two, he could use his noodle
to figure out how to beat the system.

This ham enjoys UHF operations from 440-450. He also works 2m packet from
time to time. Most people would stick to stamp collecting at this point.

There are additional problems facing this ham. Windows on the upper floors
would expose him to masts, cables and devices to raise or lower his antennas.
On top of that, the roof of the building is steeply sloped. Mounting anything
up there, let alone getting up there was a problem.

    A steeply sloped roof means a large attic. The ham in question is an
    electrician, by trade, and was employed by the owners of the building to
    rewire part of the top floor hallway lighting. The job was to take place
    in a weeks time. It was all the time he required to assemble a set of
    beams, with rotor control. The coax and control cables were to be run
    down next to the electrical conduit into his apartment. He purchased
    two beams, a 2m and a 70cm, to facilitate his requirements. A TV rotor
    was employed to rotate the set and the antennas were mounted side by side.
    The 2m beam was a simple four element model and the 70cm model was an
    eleven element model. In addition to the beams, he also installed two
    omni directional antennas. The total set was mounted to a short mast and
    base. It took a mere two hours to assemble the system and one hour extra
    to run the cables. He was in business. He mounted the system over a
    stairwell and service closet. He also mounted the base over a foam pad to
    inhibit the rotor noise. This ham is in the Central Florida area. He is
    a Technician Class operator and has been operating this way for over
    three years now.


This is an example of fixed beam installation:

    This ham lives in a condo complex south of a large city. No antennas are
    allowed. His unit is on the second floor of a two floor unit. This ham
    enjoys 2m SSB. Since he owns the condo, this ham was able to modify the
    roof of his screened in porch to accommodate a unique masting system that
    can be raised and lowered from inside the porch. He employed a three
    section mast made from aluminum tubing. The eleven element 2m beam was
    fitted with rubber feet under all the elements and the boom. After that,
    the beam was painted a dark flat grey to blend in with the night sky, even
    under full moon conditions. The upper mast sections were also painted
    in the same manner. During the daylight hours, the beam was lowered
    against the aluminum roof and was well out of sight from the neighbors.
    At night, the beam was raised enough to clear the top of his roof.

    Raising the antenna mast took a bit of planning. The roof of the porch
    was 7'6" above the deck. A pulley system, similar to a patio umbrella
    device was employed to raise the mast sections. The mast was placed in the
    center of the roof and a table supported the base. A plastic vine type
    plant was used to disguise the bottom section along with a planter to
    finish off the stealth set-up. The coax was run to the planter and then
    connected to another coax when it was to be used. The ham in question
    has been operating this way for a few years with good success.

The installation of a beam requires thought and planning. I can not give
plans for every installation. This is mostly dependent on the amateur. But
these ideas may give you some ideas on how to beat the rules and enjoy
your hobby.

73, Wayne KB4YLY, EMLab, KSC, FL