DB18 Yagi Antenna

DB18 Yagi antenna uses loop elements for 30 and 40M performance.  The DB18 and DB18E are the most popular antennas in the DB line, due to their performance vs. size profile.  The loop elements used for 40 and 30m are 40% shorter than a full size element would be, with very little sacrifice in performance (-0.4dB).

The DB18 uses an integral coax switch to select which one of the three elements are driven to give equal performance in forward and reverse directions. The control of the Antenna and Coax switch is integrated into the SDA100 controller (standard on DB18) for effortless tuning.

The only difference between the DB18 and the DB18E is on 30m – the DB18 has two elements on 30m, making it a wide spaced high gain dipole with very little front to rear.  The DB18E has 3 elements on 30m, making it an optimally spaced Yagi with solid gain and excellent front-to-rear ratios.


Martin EA3PW DB18
ARS Martin EA3PW DB18
Specification DB18 DB18 w/6m option
Boom Length 19 ft / 5.79 sq m same
Boom Diameter 1.75 in – 2.0 in
4.45 cm – 5.08 cm
Longest Element 39 ft / 11.9 m same
Turning Radius 21.58 ft / 6.57 m same
Weight 96 lb / 43.5 kg 97.75 lb / 44.35 kg
Mast clamps
1.75 in – 3.0 in
4.45 cm – 7.6 cm
Wind Load
18.02 sq ft
21.62 sq ft (Rev F & G)
12.01 sq ft (Rev C)
18.36 sq ft
22.03 sq ft (Rev F & G)
12.24 sq ft (Rev C)
Wind rating 100 MPH (EIA-222-C) same
Adjustable elements 3 same
Power Rating 3 KW same
Feed points 3 same
Frequency coverage 6.8 – 54 MHz same
Tuning Rate 1.3 ft per sec same
Control Cable 16 wire 22 AWG shielded same


Performance for Ham Bands DB18 Gain DBi DB18 Front to Rear, DB
40M 6.2 20
30M 5.4 0
20M 7.4 25
17M 8.3 25
15M 8.5 20
12M 8.8 15
10M 9.0 11
6M – 3 elements 6.2 4
6M – w/ opt. passive
element 50.000 – 50.350 MHz
10.1 30



Product Features


(click for  detail)
 DB18  00432 DB18 40m-6m:  DB18 Yagi antenna, includes 2x 39 ft loop elements, 1x 36 ft straight element, 19 ft boom, 99 lb, 6.9Mhz – 54Mhz continuous frequency coverage; Includes basic SDA100 electronic controller
 SDA 100  09128 SDA100 Controller: Standard for all antenna models; Basic controller includes: 180 degree mode, bi-directional mode, auto-retract, manual band change, manual adjustment of elements.   CLICK HERE   for the Electronic Controller Information page
Transceiver interface  01321 OPTIONAL Transceiver Interface for SDA100 controller:  Automatically adjusts each element of the antenna as the radio tunes.  Requires a transceiver interface cable.  CLICK HERE to see which interface cable you will require for your radio.
 Tuning Relay  01322 OPTIONAL Tuning Relay for SDA100 controller:  Lock-out relay connects via PTT cable to RF power source and prevents the amplfier from transmitting while the SteppIR antenna is being tuned.  Helps prevent potential mismatch issues that could damage the antenna.
 ALP Module  09130 OPTIONAL Advanced Lightning Protection (ALP) Module for SDA 100 electronic controller:  Each driver chip has a relay in front of it that protects against lightning, nearby lightning incident and dead shorts.  Module will only work if the antenna is not in the process of adjusting when the event occurs.
 Remote Driver Board  09132 OPTIONAL Remote Driver Board for SDA 100 electronic controller:  The remote driver board is mounted near the tower base.  16 conductor control cable is run from antenna to the remote driver board, and then CAT5e cable can be used to connect from remote driver board to hamshack, up to 2000 feet away.  Requires a power source.  Advanced lightning protection (ALP) module is included with this option.  Remote driver board comes with an aluminum mounting plate but does not come with an enclosure.
 Boom Truss 01606  OPTIONAL Boom truss kit: The boom truss kit is recommended for areas of the country that have significant potential for snow or ice loading.  The kit consists of a truss mast that mounts on the mast plate and Phillystran rope that connects to the boom via eye-bolts.  Tunbuckle tensioners are included.
 Element truss kit 01604  OPTIONAL Element truss kit, end elements: Element trusses for loop element.  Because the loop elements droop lower than the non-loop elements, this option allows a more uniform appearance of all the elements. Does not improve wind or ice load limits. For appearance only.  There are two sets of trusses for this kit.
stock photo
03322 Control Cable: 16 wire 22 AWG shielded control cable, outdoor rated, NON-buriable.  Available in 1 foot increments.  Lengths over 200 feet require the 33v power supply or the remote driver board option.
 25 pin dsub  03650 DB25 dsub Field Splice: The db25 field splice is used to connect the control cable to the SDA 100 electronic controller. The field splice consists of 3 terminal headers that are mounted to a PCB board, which is in turn connected to a male DB25 connector.  The control cable is connected to the splice using the included wiring diagram.  Having the field splice allows for exact lengths of control cable, with lengths available to the nearest foot.  In addition, if the cable is being run into a conduit, it eliminates the need to cut off the connector.
 16 wire Voltage Suppressor  06116 OPTIONAL Voltage Suppressor: Line filter (16 conductor) for filtering ESD and other unwanted voltages from the Control cable. Made by Array Solutions.  A better option would be the 09130 Advanced Lightning Protection (ALP) module, which internally protects the SDA 100 controller by relaying out the driver chips in case of a lightning strike, near incident event or a dead short.
stock photo
 01504 OPTIONAL Connector Junction Box: Replaces the standard cylindrical plastic housing; The standard antenna comes with a cylindrical plastic housing (affectionately referred to by many as the “pipe bomb”, due to its looks) with plastic caps on each end.  The control cable wires are connected to terminal strips, which are then placed into the plastic housing.  The connector junction box is a hinged enclosure that has female terminal headers mounted inside.  The control cable and EHU cables are then connected to a male terminal plug, creating a pluggable/unpluggable connection for the antenna wiring.  The connector junction box also includes a 25 pin female dsub mounted inside, for testing the antenna at the point of installation.  Highly recommended!
 33v power supply  01101 33v Power Supply Upgrade: For control cable lengths over 200 feet;  This can be an upgrade on new purchases and a standalone purchase for existing antennas.  For cable runs over 300 feet we recommend the Remote Driver Board (see controller information page).  The remote driver board allows you to run cat5e cable up to 2000 feet away from the tower base (power required at tower for this option)



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