DB42 MonstIR Pro Yagi Antenna

The DB42 Monstir Pro is currently the largest of the Dream Beam series of  Yagi antennas, with 5 elements on 20m-6m and 3 elements on 40/30. For those who aspire to the pinnacle of performance, the DB42 provides coverage from 80m through 6m (with optional 80m dipole kit). The DB42 has a 49 ft looped driven element.  This patented design allows us to make the end loop elements only 39 feet long, yet the performance is as if all 3 of the loop elements are 49 feet long.  The folded dipole loop technology lets the footprint be 40% less than that of a full size yagi,  losing only 0.4dB in gain performance.

The DB42 has a optional 80M dipole that works with the SDA100 controller for effortless tuning throughout the entire 80M band.  The dipole runs parallel to the boom and uses the end elements as capacity hats, creating zero interaction with the rest of the antenna.

The 6m passive element option for the DB42 adds 3x fixed elements to the antenna, for a total of 8 elements on 6m.  With no interaction or wind load added to the antenna, this option creates a 6m Yagi with 14.0 dBi of gain and 25 dB of front to rear!


DB42 Stack
Craig Thompson K9CT DB42 Stack



Specification DB42 DB42 with 80m
Dipole Option
Boom Length 42.5 feet / 13.0 m same
Boom 1.75 to 3 inch/4.45-7.6 cm (tapered) same
Longest Element 49 feet / 14.9 m same
Turning Radius 29 feet / 8.8 m same
Weight 238 Lb / 108 Kg 242 Lb / 109 Kg
Wind Load 19.9 ft^2/ 1.85 sq. m same
Wind rating 100 mph same
Adjustable elements 5 same
Power Rating 3 KW continuous 80m – 1.5KW; otherwise 3KW
Feed points 3 same
Frequency coverage 6.95 – 54 MHz 3.5 – 4 MHz, 5.3 MHz, 6.95 – 54 MHz
Tuning Rate 1.3 ft/sec same
Control Cable 25 conductor 22 gauge 25 conductor 22 gauge


Performance for Ham Bands DB42 Forward Dir
Gain DBi
DB42 Forward Dir
Front to Rear, DB
DB42 Reverse Dir
Gain DBi
DB42 Reverse Dir
Front to Rear, DB
80M (option)
1.7 n/a 1.7 NA
40M 8.0 25.5 8.0 23.2
30M 9.0 12.4 9.0 12.3
20M 10.1 22.0 10.0 23.2
17M 10.8 22.2 10.7 21.9
15M 11.0 25.7 10.6 20.0
12M 11.9 24.1 10.4 8.9
10M 12.2 20.0 10.5 11.7
6M – 5 elements 5.0 2 5 2.0
6M – with optional passive
element 50.0 – 50.3 MHz
14.0 25 NA NA

Product Features


(click for  detail)
 DB42  00442 DB42 40m-6m:  DB42 Yagi antenna, includes 2x 39 ft loop elements, 1x 49 ft loop element, 2x 36 ft straight element, 42 ft boom, 238 lb, 6.95 Mhz – 54 Mhz continuous frequency coverage; Includes basic SDA100 electronic controller, advanced lightning protection (ALP) board, connector junction box and power supply with cable.  Optional 80m dipole available.
 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.  24 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.
 80m Dipole DB42 01811  OPTIONAL 80m Dipole kit: This option adds a wire dipole that runs parallel to the boom, using the end loop elements for capacity hats.  Adds coverage for 3.5-4 MHz & 5.3 MHz. Performance is only 0.8dB down in gain from a full sized 80m dipole and there is zero interaction with antenna and no wind load added.
 Element truss kit 01603  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
03624 Control Cable: 24 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. NOTE:   you will also need the 06108 8 wire line filter in conjunction with this 16 wire line filter for a total of 24 wires.
stock photo
 01502 Connector Junction Box: Standard on the DB42 Yagi, 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.   



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