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, fenders, 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″ & 58″ COMPACtenna models
20M/2M/440, 10M/2M/440, 6M/2M/440, CB/2M/440, SW & 40M/20M/10M/6M/2M/440 (aka 40Mthru440)
Most antennas require large ground planes with large ground/counterpoise lengths
all-around the antenna.
The 20″ & 58″ 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 problems
such as 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.
40M/20M/10M/6M/2M/440 aka 40Mthru440
These 20″ & 58″ 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**:
* Caution – Corners, edges; some people use duct tape around the edges/corners
** If used outside, support (wind load) especially the 58″ model, such as with non-conducting guy lines