Stealth Antennas

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Stealth Antennas
Stealth Antennas
Johan Reinalda, WG7J
Johan's Antenna Motto
ANY antenna
is better then
NO antenna
aka. HOA dwellers dilemma
Let’s discuss some ideas on how to simply experiment
with simple antennas • on HF
• on VHF / UHF
This is not a technical discussion on antenna design,
construction and performance ...
(Note: if you have done a lot of antenna
design and building, you will
probably be bored ...
Safety First !
Make sure you are safe with your experiments:
Field strength, physical and electrical safety
first!
What stealth antenna’s are NOT!
Typically stealth antenna’s are compromised
antenna, in size and location, and are thus NOT
great performers. But don’t despair, see slide 2!
While you won’t have a pile-up causing signal, you
will work many DX with the right amount of
patience and operating skills !
Some ideas to discuss
• Stealth vs. Temporary
• Verticals
• Ham sticks,and the likes
• Random wires
• Attic antennas, and around-the-house-or-trees loops
• Magnetic Loops
• Handhelds
• Others ?
My favorite materials
• Fishing poles (fiberglass, non inductive) to raise wires or hold
small vertical. Commercial and surplus pole products available.
• Regular antenna wire (even speaker wires from home project
stores will work just fine)
• PVC pipe, lots of use for raising or shaping the antenna (eg. Wire
quad)
• Aluminum AC duct tape, with hose clamps!
Great for taping around PCV shapes (eg. Dipole or magnetic
loops)
• (soft or hard) Aluminum and Copper tubing (expensive)
• Alligator clips to clip vertical and ground wires to chassis
connector on end of cable run.
• Wood for booms (especially. V/UHF yagis)
HF antenna’s
Stealth:
Frequently permanent, hidden antennas in unsuspecting places:
Flagpoles, atticks, wires in or to tree, around house eve,
etc.
Temporary:
raise to use, and remove then done.
Let’s have a look…
My HF antenna – 20m vertical, and
temporary 6m dual element quad
Temporary HF antenna: fiberglass fishing pole on umbrella
base, ground radials laid out in yard
40m 1/4 wave vertical, put up in the
evening, or
Temporary VHF/UHF:
Same pole, with dual band 1/4 wave
3m/440 vertical
(used for repeater and satellite)
HF vertical hidden in many shapes
• Flag poles
• Fishing poles in trees
• Hamstick verticals in trees,
or in set on fiberglass fishing
poles on balcony, etc.
• Be creative
• Can be cheap
(eg. Fishpoles with wire, 10m with RadioShack 102” whip)
Hidden HF dipoles
House S of 59th and Union Hills
Hide in attic, around
outside of house, or
wherever you have space.
Use traps/tuner for multiband.
HF Long Wires
• Run “Long Wire”
from shack to a
nearby tree, or
around side of
house. Use tuner,
and make sure are
safe.
• This hummingbird
feeder hides a
loading coil!
Temporary Dipoles or Verticals
• Commercial hamstick dipole mounts, Buddipoles, etc.
• Temp. mag.mount with HF verticals (hamstick variety)
• Classic ¼ ground plane with hamstick
on pole with radials (screw vert
element off and be below fence!)
• Cubical Quad on
higher HF bands
(possible on 10m)
• Caveat: know vertical vs.
low dipole performance
All kinds of shortened HF antennas
(more complicated)
• Compact loops
• Loaded dipoles
• Trapped multiband dipoles
HF Magnetic Loops
• Don’t need grounding, have low radiation angle,
typically low noise, but can have high magnetic
fields!
• Commercial or homebrew!
V/UFH
• Things are smaller and easier, and just as much
fun
• Think RDF, distant repeaters, Sporadic-E,
Satellites, etc.
VHF/UHF verticals
hide permanently or hang up when needed
• J-poles, coat-hanger ¼ wave verticals,
collinears, etc
• Lots of commercials verts:
- hang in trees
- mount on temp. poles
- on back side of house
- in bird house
- whatever you can think off
A variation on the classic project!
My 5th grade daughter, W7BCR,
loved building this!
Images from Eham, see resources
Cheap (portable) Yagi’s from WA5VJB
Use for terrestrial
(Es, repeaters,…)
or satellite …
• Simple Halo’s (ie hor. full wave loop)
• To more complicated
multi-element quads
Simple LEO satellite antennas
WA5VJB cheap yagi’s (see earlier)
Turnstiles
Quadrafilar Helix
And more…
Lindenblad
Resources
ARRL's books:
Antenna Book
Small Antennas for Small Spaces (new 2011!)
AC6V antenna pages:
http://www.ac6v.com/antprojects.htm
Various links:
http://kd6tlf.fortunecity.com/stealthantennas.html
2m/440 ¼ wave vertical: http://www.eham.net/articles/7005
WA5VJF cheap yagis:
http://www.wa5vjb.com/references.html
Google Searches on "stealth antenna“, etc.
(and much, much more…)
Questions, Comments, Thoughts ?
If time permits,
a little extra on next few slides
WG7J’s GridMapper
• Upload your log file in ADIF format,
and see your worked Grids on a map
or Google Earth!
What I’ve worked with stealth since 2002
(All-bands. Map created by WG7J GridMapper v1.0)
And on 6m only (2009 – 2011) with 2 ele. Quad shown.
(not meant to brag, but to show that steath can be fun!)
Google Earth “KML” download
(still buggy)