COMPACtenna … COMPACT antenna
SMALL antennas NO tuning (of antenna structure) SMALL ground plane HIGH Performance
COMPACtenna requires a ground plane/counterpoise as other antennas, BUT LESS.
Allowing greater flexibility in installations/locations.
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7″ & 9″ COMPACtenna models
2M/220/440 (7″) 2M/440 (7″) SCAN-III (9″)
With many antennas, the single center-of-roof placement (with no sunroof) is strongly encouraged.
All the corners of a vehicle roof/trunk lid are considered undesirable for these ‘standard technology’ antennas.
Not true with COMPACtenna Science & Technology… Those many locations are actually very desirable for the COMPACtenna,
providing many appreciated options.
The COMPACtenna effectively utilizes the side-metal of the vehicle
(quarter panels, pillars, doors) as a ~ ‘sloping’ counterpoise allowing greater flexibility and ease for varieties of installations.
The center-of-roof location can cause reduced resistance and increased (V)SWR especially at
VHF frequencies with short antennas due to the high voltage point of the antenna
being so close to extensive ground plane/counterpoise all around it.
But with substantial downward-projecting metal the resistance
beneficially increases with counterpoise signal enhancement
effect such that the numerous corner of roof/trunk
locations become excellent potential
installation site choices.
[As a receiving antenna, model SCAN-III performs excellently at any position on metal roof/trunk lid/fender.]
Here are photos of the 7″/9″ models on NMO magnet mounts:
*** STEEL SOLDIERS, RAM TRUCKS, GM Trucks, & TOYOTA 4X4’s
with 7″ COMPACtennas at bottom of page. ***
Base Station Application
Base Station Antenna ground radials kits work very well with the VHF/UHF COMPACtennas
with the ground plane counterpoise elements bent downward to 70 degrees below the horizon.
7″ & 9″ models Available at:
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20″ & 46″ COMPACtenna models
20M/2M/440 10M/2M/440 6M/2M/440 CB/2M/440 SW HamR-7 Series
Most antennas require large ground planes
with large ground/counterpoise lengths all-around the antenna.
The 20″ & 46″ COMPACtennas require only a small ~ 3′ x 3′ metal sheet below it.
When antennas have inadequate ground plane/counterpoises, there is a problem… RF ‘comes back down’ the OUTSIDE of the
shield of the coax, causing distorted signal (radiation) pattern and potential problems with the (transmitting) radio.
In operation, one recognizes problems like these by seeing changes in signal reception and (V)SWR
while moving ones hand (wrapped around the coax) along the length of the coaxial cable.
Standard antenna technology typically requires large ground plane/counterpoises
and all-around/in all directions to avoid these ‘inadequate’
ground plane/counterpoise problems.
Yet the COMPACtenna with only a small ~ 3′ x 3′ metal sheet or perforated sheet/mesh/screen below it
exhibits no changes in signal nor (V)SWR while moving ones hand
along the length of the coaxial cable.
HamR-7 HamR-7Digi HamR-7WARC
These 20″ & 46″ small antenna models work well with a small ground plane counterpoise
such as shown here using a 3/8″-24 thread 5″ diameter magnet mount on a small
(only 3′ x 4′) commonly available galvanized steel flat (flashing) sheet*
(such as from Home Depot) in a closet or attic**,
or on a steel table such as in an
enclosed patio or shed:
* Caution – Corners, edges; some people use duct tape around the edges/corners
** Ambient temperature rating 110 degrees fahrenheit