DX Engineering DXE-PS-2B Instructions manual

Pro-Stack Broadband

Two Antenna

Phasing System

DXE-PS-2B-P

DXE-PS-2B-P-INS Revision 2b

© DX Engineering 2021

1200 Southeast Ave. - Tallmadge, OH 44278

Phone: [phone] ∙ Tech Support and International: [phone]

Fax: [phone] ∙ E-mail: [e-mail]

- 1 -

Introduction

The DXE-PS-2B-P Pro-Stack Broadband Two Antenna Phasing System is primarily designed to
combine two identical Yagi, log periodic or vertical antennas in a phasing arrangement. The DXE-
PS-2B-P is a frequency independent broadband phasing system that operates with two mono-band
antennas on any band, from 160 through 10 meters. It is a 50Ω system that is switched by applying
12 to 15 volts dc to three control wires. The unit can be used for other applications requiring the
following four basic antenna feed selections:

 Both antenna ports in-phase
 Both antenna ports out-of-phase
 Antenna port 1 only
 Antenna port 2 only

Default is both antenna ports in-phase. To ensure lowest SWR, impedance matching automatically

changes when any antenna is disabled.

Information on the appropriate distances for the separation between the two stacked Yagis, to create
a versatile, high performance array, is discussed fully in the “ARRL Antenna Book”, 20th Edition.
Generally, stacked Yagi antennas are separated vertically greater than 1/2-wavelength, free space.
The bottom antenna should generally be as high above ground as the stack spacing distance.
Optimum spacing is generally around one wavelength.

Features

 Power Handling up to 5 kW
 Broad band coverage on 160-10 meters
 Proven DX Engineering RF Relays - high performance
 Safe 12 volt dc relay operation
 MOV surge protection on control lines
 RoHS compliant assembly
 High-RF tolerant, silver - PTFE UHF connectors

Using Antenna Pattern to your Advantage

Signals arrive at your antenna from different azimuth directions and different elevation angles,
depending on many variables. The ability to steer the major lobe of an antenna (or array of
antennas) in both planes moves the major lobe and nulls, not just the major lobe. Typically two dB
or slightly more is gained by stacking a second antenna. The largest advantage is not necessarily
additional gain, but the ability to move harmful pattern nulls away from primary signal arrival
angles. While gain makes a marginal improvement, moving a null can be a phenomenal change,

- 2 -

sometimes the difference between barely readable and having a strong signal which can provide the
performance edge needed to work rare DX and win contests.

It is therefore desirable to not only change azimuthal direction by rotating the antenna, but also
elevation angle by switching between antennas at different heights above ground and/or changing
the phase relationship between multiple antennas. The old standard system in stacks was to activate
or disable specific antennas in the stack to change pattern. In general, gain remains higher when all
antennas are driven and phase is changed. This system allows either phase inversion or completely
disabling any antenna.

The DXE-PS-2B-P Pro-Stack Broadband Two Antenna Phasing System provides the greatest
flexibility from two identical antennas. This system contains a broad-bandwidth high-power 2:1
impedance matching transformer. This eliminates common requirements of using mixtures of 75Ω
and 50 Ω cables for impedance matching.

A central stack-box location is best. Feedlines to each antenna from any stack-box should match
the antenna system impedance and have the same electrical length. Feedlines need only be long
enough to reach comfortably from each antenna to the stack-box. While it is best to have feedlines
equal electrical lengths, total errors of twenty electrical degrees or less have only a minor impact on
system performance. With such wide tolerances in cable lengths, cutting similar cables to equal
lengths will suffice. There is no need to closely phase-match cables.

Larger Array Building Blocks

The DXE-PS-2B-P Pro-Stack Broadband Two Antenna Phasing System control box works in
conjunction with identical boxes, or in combinations with 3-stack boxes, to build larger stacked
arrays. For example, four antennas are stacked using three DXE-PS-2B-P boxes. In this example,
two PS-2Bs would be centrally located; one between the upper and lower antenna pairs, and each
antenna would be fed through equal length cables. A single PS-2B located in the middle of the stack
feeds the upper and lower boxes through equal lengths cables. This would allow the user to take any
antenna or combination of antennas off-line, or feed any antenna or combination of antennas out-of­phase. Keep in mind out-of-phase systems generally have more gain than systems that disable
antennas.

The best arrangement for larger stacked systems is feeding antennas in pairs, with the pairs fed from
other stacking boxes. This is a distributed or branched feed system. All cables at any branch level
should be equal length. While it is best to avoid length errors, accumulated errors totaling 20­degrees or less have a minimal affect on gain and positioning of lobes. With such wide tolerances in
cable lengths, cutting similar cables to equal lengths will suffice. There is no need to closely phase­match cables.

Multiple antenna arrays require modeling with software such as “EZNEC” by W7EL to examine the
multiple patterns possible by reversing phase and dropping antennas in a large system.

- 3 -

This unit is RoHS (Reduction of Hazardous Substances) compliant. The components,
including the solder used are all lead free. If you decide to do any modifications or internal
repairs, you should use only lead free solder and lead free soldering tools. Lead free solder
melts approximately 100 degrees (F) higher than the old leaded solder, so you may need to
upgrade your current soldering system.

Manual Updates

Every effort is made to supply the latest manual revision with each product. Occasionally a manual
will be updated between the time your DX Engineering product is shipped and when you receive it.
Please check the DX Engineering web site (www.dxengineering.com) for the latest revision manual.

Additional Material Needed but not Supplied:

 JTL-12555 - Jet-Lube SS-30 anti-seize compound – must be used on the threads of

Stainless Steel Hardware to prevent galling and aid in proper tightening torque.

 Two electrically equal length 50 Ω coaxial cables to run from the DXE-PS-2B to each of the

identical Yagi antennas.

 4-Wire Control Cable - COM-CW4 Control Cable is ideal.
 LCT-37534 Dielectric Grease

- 4 -

1 - Stacking Yagis

In-phase

 The greatest gain increase comes from the

first pair of antennas.

 Optimum spacing is usually around one-

wavelength stack spacing.

 Lower heights produce a cleaner pattern.

Avoiding nulls in the middle of useful
propagation angles is often more important
than a small gain improvement.

Note that increased heights result in maximum
stack gain improvement (maximum gain still
occurs at about 1 wavelength antenna-to-antenna
spacing) and lower wave angles. The lowest
antenna should generally be significantly higher
than the antenna-to-antenna spacing above ground
for maximum stacking gain. Greatly increased
height produces more minor lobes and stronger
minor lobes.

Neglecting feedline losses, over medium soil two
stacked Hy-Gain model 205CA 20 meter antennas
have the following in-phase gain improvement:

Figure 1

70 feet = 1 wavelength

Height

35+70 ft

52+104 ft

70+140

Optimum

87.5+175

110+180ft

Gain / angle

15.41dBi

@ 15 deg

16.89 dBi
@ 11 deg

17.27dBi
@ 8 deg

17.17

@ 7 deg

17.87 dBi
@ 6 deg

Stack

spacing

0.5 wave

.75 wave

1 wave

1.25 wave

1 wave

Reference

Figures

Figure 1
Figure 2

Figure 3