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.

– – – – – – – – – 

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 unfavorable
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 vertical/sloping counterpoise
allowing greater flexibility in varieties of placements and ease of installation.

The center-of-roof location can cause reduced resistance and increased (V)SWR especially at
VHF frequencies with short antennas due to the antenna high voltage point
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:
COMPACtenna Website 2M-(220-)440 & SCAN-III Vehicle Photos

COMPACtenna Installation 2M-220-440 Mount Types

Submitted by John. W0RS:
COMPACtenna 2M-220-440 Photo W0RS Mobile Installation Photo 2 with SWR's  COMPACtenna 2M-220-440 Photo W0RS Mobile Installation Photo 1

COMPACtenna Installation NMO Bracket Mount for Railing, Ladder

Tim Bauer’s Truck Stake Pocket Bracket for NMO Mount (Athens, AL):

COMPACtenna Installation - Tim Baurer's Stake Pocket Bracket for NMO Mount (Athens, AL)


Base Station Application

[Follow local building codes including NEC grounding/lightning/etc. and NFPA guidelines.]
[See SAR below.]
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.
COMPACtenna Installation 7 inch models on BSAKIT

COMPACtenna Installation 7in File Cabinet, Steel Table

7″ & 9″ models Available at:

COMPACtenna model 2M/220/440 at Universal Radio
COMPACtenna model 2M/220/440 at Ham Radio Outlet
COMPACtenna model 2M/220/440 at DX Engineering
COMPACtenna model 2M/220/440 at KB Cubed Hamfests
Heartland Radio   —   eBay affiliate

COMPACtenna model 2M/440 at Universal Radio
COMPACtenna model 2M/440 at Ham Radio Outlet
COMPACtenna model 2M/440 at DX Engineering
Heartland Radio   —   eBay affiliate

COMPACtenna model SCAN-III at Universal Radio
COMPACtenna model SCAN-III at Ham Radio Outlet
COMPACtenna model SCAN-III at DX Engineering
Heartland Radio   —   eBay affiliate

– – – – – – – – – 

20″  &  46″  COMPACtenna models

20M/2M/440   10M/2M/440   6M/2M/440   CB/2M/440   SW      HamR-7 Series
[Follow local building codes including NEC grounding/lightning/etc. and NFPA guidelines.]
[See SAR below.]

Small Ground Plane/Counterpoise

Most antennas require large ground planes
with lengthy ground/counterpoise radials all-around the antenna.
The 20″ & 46″ COMPACtennas require only a small, minimum 3′ x 3′ metal sheet/mesh/grating below it.
[Smaller overlapping sheets may be used.]

46″ Models:

HamR-7    HamR-7Digi    HamR-7WARC

20″ Models:






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

COMPACtenna 20M-2M-440 on floor in house  COMPACtenna 20in ATTIC PHOTO - CROPPED       COMPACtenna Installation - Enclosed Patio - 20 in. antenna on Patio Table  COMPACtenna HamR-7 Photo Resized and Trimmed

COMPACtenna HF 20&46in Antennas 3.8in-24 mount, PL-259 PHOTO

Surrounding Metal Structures

can affect SWR

Proximity of Transmitting Antennas to Radios

can lead to disturbances in SWR measurements,
ability of (particularly internal) tuners to function well,
audio distortion, as well as (other) feedback/resonance issues.
These issues may be mitigated by:
Increasing separation of radio and antenna
which also leads to decreased SAR (Specific Absorption Rate),
Ferrite beads/chokes on coaxial cable/wire leads of radio

Magnet Mounts & Coaxial Connections

A number of pleased customers of
the 20″(models 20M/2M/440, SW, etc.) & 46″ (HamR-7) COMPACtennas
reported that some of the magnet mounts
don’t have soldered connections inside.
The braid of the coaxial cable termination inside, for example
is in some cases simply pressed against metal.
It can be bad (unreliable connection/continuity) from the start,
or if the inside gets a little “twist” in antenna-mount assembly
the connection may slide off (partially) inside.
Additionally some have reported that
not all PL-259’s mate well/reliably with all SO-239’s.
(Some coaxial jumpers with PL-259’s
don’t even connect well into the SO-239 connector of their radios!)
Limiting the number of connections is a good policy:

COMPACtenna HF 20&46in Antennas Coaxial Jumper with SO-239 at one end Photo


COMPACtenna HF 20&46in Antennas Coaxial Jumper with SO-239 Barrel Adapter Photo

Example SAR Calculator
   Example calculation:  
COMPACtenna SAR Calculation Example 7.4.20

20″/46″ models Available at:

6M/2M/440 at Universal Radio
6M/2M/440 at Ham Radio Outlet
6M/2M/440 at DX Engineering

10M/2M/440 at Universal Radio
10M/2M/440 at Ham Radio Outlet
10M/2M/440 at DX Engineering

20M/2M/440 at Universal Radio
20M/2M/440 at Ham Radio Outlet
20M/2M/440 at DX Engineering

ShortWave Radio at Universal Radio
ShortWave Radio at Ham Radio Outlet
ShortWave Radio at DX Engineering
Heartland Radio   —   eBay affiliate

CB/2M/440 at Universal Radio
CB/2M/440 at Ham Radio Outlet
CB/2M/440 at DX Engineering
Heartland Radio   —   eBay affiliate

HamR-7 — at Universal Radio
HamR-7 — at Ham Radio Outlet
HamR-7 — at DX Engineering

HamR-7Digi — at Ham Radio Outlet
HamR-7Digi — at DX Engineering

HamR-7WARC — at Ham Radio Outlet
HamR-7WARC — at DX Engineering