All:
 Original article from: Wayne Sarosi 
 Reposted by Rob Dennis,Moderator HAM_TECH,for use of the FIDO HAM_TECH echo.
  THIS POST/SERIES NOT TO BE USED IN ANY CDROM COMPILATIONS FOR COMMERCIAL
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SUBJECT: VHF & UHF Hidden antennas for PUDs/CONDOs/APARTMENTs
         Part 2
INSTALLATION OUTSIDE: continued
 Next,I'll discuss the 1/4,3/4 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,3/4
wave antennas are built in the same manor except the vertical element is 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 
Ps.
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 Discones have been used outside in restricted areas. Hiding one can present 

problem because of the dimentions.
 I would suggest using these antennas indoors and will discuss them later.
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 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.
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 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 placed 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 factor in approaching the 50 ohm
impedance required by amateur radio gear today. Please keep that in mind.
 Geometric shapes in a natural setting tend to 1stick 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 
pecific
direction is required. Remember the chimney? Good place to start.
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 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, 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'll be dealing
with. The formula use does not always relfect the exact length of the 
ntennas
involed, but is to be used for sizing only.
       1/4     3/4         f
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 6m  | 4.73'   14.19' @   52.0 MHz
 2m  | 1.68'   5.05'  @  146.0 MHz
1.25m| 1.1'    3.3'   @  223.5 MHz
70cm | 0.55'   1.65'  @  445.0 MHz
33cm | 0.27'   0.806' @  915.0 MHz
23cm | 0.194'  0.581' @ 1270.0 MHz
73,Wayne KB4YLY
--- GoldED 2.42.G1219
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