ALPHA ANTENNA ProMaster Antenna User Guide
- June 3, 2024
- ALPHA ANTENNA
Table of Contents
ALPHA ANTENNA ProMaster Antenna
REPORTING ERRORS AND RECOMMENDING IMPROVEMENTS
You can help improve this manual. If you find any mistakes or if you know of a
way to improve the procedures, please let us know. Mail or email us a marked
copy to the contact information on the last page of this manual.
REPORTING EQUIPMENT IMPROVEMENT RECOMMENDATIONS (EIR)
If your Alpha ProMaster antenna needs improvement, let us know. You, the user,
are the only one who can tell us what you don’t like about your equipment.
Mail or email us an EIR to the contact information on the last page of this
manual.
Safety Information
When installing or operating this antenna or any other antenna/tower, please
observe the following safety tips. High voltages are present when
transmitting, no matter how much or little power is applied. Do not touch any
part of the antenna while transmitting.
NOTE – Never Loosen any of the Bolts, Washers, Nuts, or Caps on the Alpha
Match.
WARNING: INSTALLATION OR OPERATION OF THIS PRODUCT NEAR POWER LINES IS
DANGEROUS! FOR YOUR SAFETY, FOLLOW THE ENCLOSED INSTALLATION DIRECTIONS.
THOUGH THIS ANTENNA IS CONSTRUCTED WITH INSULATEDMATERIALS, PROPER CARE MUST
BE TAKEN DURING INSTALLATION. INSTALLER ASSUMES ALL LIABILITY FOR PROPERTY AND
LIFE SAFETY.
YOU, YOUR ANTENNA, AND SAFETY
Each year, hundreds of people are killed, mutilated, or receive severe and
permanent injuries when attempting to install an antenna. In many of these
cases, the victim was aware of the danger of electrocution, but did not take
adequate steps to avoid the hazard. For your safety, and to help you achieve a
good installation, please READ and FOLLOW the safety precautions below. THEY
MAY SAVE YOUR LIFE!
- If you are installing an antenna for the first time, please, for your own safety as well as others, seek PROFESSIONAL ASSISTANCE.
- Select your installation site with safety, as well as performance, in mind. REMEMBER: ELECTRIC POWER LINES AND PHONE LINES LOOK ALIKE. FOR YOUR SAFETY, ASSUME THAT ANY OVERHEAD LINES CAN KILL YOU.
- Call your electric power company. Tell them your plans and ask them to come take a look at your proposed installation. This is a small inconvenience, considering YOUR LIFE IS AT STAKE.
- Plan your installation procedure carefully and completely before you begin. Successful raising of a mast or tower is largely a matter of coordination. Each person should be assigned a specific task, and should know what to do and when to do it. One person should be designated as the leader/coordinator of the operation to call out instructions and watch for signs of trouble.
- When installing your antenna, REMEMBER: DO NOT USE A METAL LADDER. DO NOT WORK ON A WET OR WINDY DAY. DO DRESS PROPERLY: shoes with rubber soles and heels, rubber gloves, long sleeved shirt or jacket.
- If the assembly starts to drop, get away from it and let it fall. Remember, the antenna, mast, cable and metal guy wires are all excellent conductors of electrical current. Even the slightest touch of any of these parts to a power line completes an electrical path through the antenna and the installer – THAT’S YOU!
- If ANY PART of the antenna system should come in contact with a power line, DON’T TOUCH IT OR TRY TO REMOVE IT YOURSELF. CALL YOUR LOCAL POWER COMPANY. They will remove it safely. If an accident should occur with the power lines, call for qualified emergency help IMMEDIATELY.
Excess RF Exposure Warning
In the United States, the Federal Communications Commission has established
guidelines for human exposure to Radio Frequency (RF) electromagnetic fields.
The commission’s requirements are detailed in parts 1 & 2 of the FCC’s rules
and regulations {47 CFR, 1.1307(b), 1.1310, 22.1091, 2.1093}. It is the
responsibility of the owner/operator of this device to follow all applicable
warnings and precautions regarding human exposure to RF fields.
The FCC Office of Engineering Technology (OET) Bulletin 65, Supplement B,
Evaluating Compliance with FCC Guidelines for Human Exposure to Radio
frequency Electromagnetic Fields directly concerns the use and operations of
all Alpha Antenna systems. This bulletin establishes safe operating distances
from antennas associated power levels in order to permit the operator and
persons who may be impacted by operation to exist in a safe environment.
Guidelines for Maximum Permissible Exposure, or MPE, are defined in Supplement
B of the bulletin.
IMPORTANT NOTE:
Refer to the above mentioned Supplement B along with FCC OET Bulletin 65,
Version 97-01. The information in the supplement provides additional details
that are used for evaluating compliance of amateur radio stations with FCC
guidelines for exposure to radio frequency electromagnetic fields. Supplement
B users should, however, also consult Bulletin 65 for complete information on
FCC policies, guidelines, and compliance related issues. Definitions of terms
used in this supplements appear in Bulletin 65. Bulletin 65 can be viewed and
downloaded from the FCC’s Office of Engineering and Technology’s web site at:
http://www.fcc.gov/oet/rfsafety
Concept of Operation
The ProMaster is a balanced limited space (permanent base or transportable) antenna that maximizes effective radiated power (ERP) while maintaining an acceptable SWR.
- The system will cover 3.5-29.7 MHz when deployed in the default configuration using 1 NVIS, 1 Vertical and 1 Grounded counterpoise element.
- For an omnidirectional signal pattern, to improve low band performance, and to enhance NVIS characteristics from 1.8 to 30 MHz, four optional 35 foot NVIS elements can be installed in place of the single 25 foot NVIS element.
- Alternatively, these optional four (or even 3 of the 4) 35 foot elements can be used as counterpoise elements. This configuration will lower the take-off angle of the radiated signals on 7-29.7MHz, which will thereby enhance the DX characteristics.
DETAILS
Many short-range HF communication system use vertical elements that are not
directional. With these antennas, communications are achieved on very short
ranges by ground-wave (surface-wave propagation), and longer paths are
achieved by sky-wave propagation. An inherent characteristic of radio-wave
propagation that is missing when vertical antennas are used is the zone of
silence (skip zone) between the point where the ground-wave signal becomes
unusable and where the sky-wave signal starts to become usable (Ref. Radio
Amateur’s Handbook, Ionospheric Propagation, most editions). Depending upon
terrain, ground conductivity, operating frequency, noise levels, etc., ground-
wave signals are usable up to about 70 miles over average soil. Also, minimum
distances for sky-wave paths when using vertical elements are generally 200
miles (E-layer) during the day and 400 miles (F-layer) at night.
While the skip zone, described above, severely limits the usefulness of
vertical antennas for short-range communications, conditions become even worse
for the skip zone in an adverse environment, such as a hilly or forest-type
terrain. This occurs because of the restricted range for ground-wave signals
in these environments.
Additional considerations should include soil conductivity, where the soil
conductivity decreases or as the foliage increases, the signal strength at a
distance decreases rapidly. The strongest practical signals occur over
seawater. The important consideration for signal strength is not the value of
signal level, but the signal-to-noise ratio, which is an important
characteristic of this antenna. Good ground-wave communications are expected
at 25 miles at any time of the day for good ground conditions, and the range
may be as much as 100 miles for a couple of hours at midday. However, if the
environment is dense forest instead of good ground, the maximum ground-wave
communication range may be 1 mile or less.
From the above discussion, it is clear that a skip zone is present when
vertical antennas are used. The extent of the skip zone is dependent upon soil
conditions and the surrounding physical environment. For average conditions,
the skip zone lies between 70 and 200/300 miles; however, in extreme
environments, it may include the range from 1 to 200/300 miles. The skip zone
is of a very critical range for most tactical communication systems. Most
tactical requirements necessitate good communications in the 0 to 300-mile
range. If HF communications are to be effective in this range, different
antennas and propagation modes are necessary.
The solution to the short-range communication problem is the use of sky-wave
instead of ground-wave propagation on the short paths. This requires radiation
patterns from the antenna at very high elevation angles NVIS (near vertical
incidence sky-wave). This is accomplished by deploying the vertical element
simultaneously with the horizontally sloped NVIS element. Radiation pattern
characteristics of the vertical element enhance DX, while radiation pattern
characteristics of the NVIS type are achieved through the use of the NVIS
element. Such radiation characteristics are omnidirectional in azimuth and
provide an l-hop range of about 300 miles. The antenna gain varies mainly with
the height of the antenna above ground.
Because it is highly desirable to have minimum height and weight for tactical
antennas, the immediate problem becomes one of determining the minimum
effective antenna height required. In order to determine the required minimum
antenna height, a minimum acceptable level of performance is established as
necessary to permit communications.
The required effective height of the antenna is found by considering the
following; when a horizontal antenna is close to ground, energy is radiated in
two modes. 1) The desired NVIS mode produces radiation with a maximum in the
vertical direction. 2) The undesirable Beverage mode creates a vertical
electric field between the conductor and ground, producing vertically
polarized ground-wave signal with a maximum pattern in the direction off the
NVIS wire end. Due to the proximity of the antenna to ground, this latter mode
has an efficiency that is generally poorer than a whip. To negate the
undesirable mode, the vertical element is deployed simultaneously with the
NVIS element.
The shape of the radiation pattern of the horizontally sloped NVIS element is
essentially constant for heights not exceeding one-quarter wavelength. For a
fixed height above ground, the amount of the input power radiated
proportionately in each of these modes is a function of the relative
percentage of the antenna input resistance characterizing each mode. Each of
these, in turn, is a function of the height above ground. The total input
resistance is that portion due to the NVIS mode as the NVIS height is varied.
As the height increases, a larger part of the input signal is radiated in the
NVIS mode. These resistances are typical of these encountered over average
ground.
For example, an antenna at an effective height of 0.070 wavelength is about 5
feet at 7.000 MHz. The result of this example enables an effective height for
a signal at 0.070 wavelength to be achieved by elevating the horizontal NVIS
element so that is mounted between two 5-foot supports where the NVIS element
is horizontally mounted, or by a sloping the NVIS element so that it is
connected at between 5-7 feet on the top bolt of the Alpha Match and sloped
down to the ground in the same manner that a guy wire would be deployed. An
advantage of the sloping NVIS configuration is the vertically polarized
component, which produces desired affects at low frequencies and also permits
compatibility with the vertical element to enable DX propagation.
System Overview
Equipment Description
Deployable by one person in less than 10 minutes, the ProMaster system is a complete wide-band transportable base antenna systems that provide for low noise receive and supports wide-band transmission that is useful for spread- spectrum communications or quickly switching between bands.
Equipment Characteristics
Low noise receive characteristics occur due to the entire antenna system being
placed close to the earth. This balanced system requires no additional
components be added to maintain a maximum SWR of 3:1 during transmission when
measured at the antenna, no coax insertion. Once coax is connected, operators
may find that a choke balun can be useful, but do not add one unless it is
determined that it’s needed.
The ProMaster antenna is designed to simultaneously provide directional high-
angle radiation (near vertical incidence – NVIS) and low-angle radiation
(long-range and DX) propagation. The directionality of the default system is
controlled by the placement of your NVIS element. Where your signal will
launch opposite the direction of the NVIS element, which will be in the
direction your Ground wire is run. The NVIS element also enhances short-range
sky wave propagation, which varies from 0 to 300 miles, the Vertical element
in tandem with the NVIS element enables long-range & DX propagation for
distances greater than 300 miles.
For an omnidirectional signal pattern, you may replace the 25 foot NVIS
element with four 35 foot NVIS elements, which may alternatively be used as
counterpoise elements. Each configuration has its’ own frequency coverage and
signal pattern discussed earlier in this document. No matter which
configuration you deploy, an external antenna tuner can be used if your
antenna is installed over a poor ground or not placed in a clear area.
Site Selection
For maximum antenna operating efficiency, the ProMaster antenna should be located in the center of a clear area. Installation of the antenna near any tall metal object or under heavy foliage should be avoided. Under no circumstances should structures come in contact with the antenna.
Maintenance
Yearly – Inspect connection points and tighten any loose connections.
Triennially – Disassemble and clean all connection points of corrosion and
reassemble.
Maintenance Log | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 |
---|---|---|---|---|---|---|---|---|---|---|---|---|
Yearly | ||||||||||||
Triennial |
Leading Particulars
Leading particulars and equipment for the ProMaster antenna are listed in Tables 1-2. Operators should become thoroughly familiar with data and procedures contained in the entire technical manual before working on or using the antenna.
Table 1-2 Leading Particulars
ITEM| LEADING PARTICULARS
ProMaster Frequency range/Power rating in watts When deployed with one 25 foot
NVIS element and one 8 foot grounded counterpoise element.|
3.5-30 MHz , 250 PEP SSB, 125 CW, or 25 watts for digital modes
When deployed with for 25 foot NVIS elements and one 8 foot grounded
counterpoise element.| 1.8-30MHz, 250 PEP SSB, 125 CW, or 25 watts for digital
modes Horizontal and Vertical polarization
Polarization| 50 ohms
Input impedance|
Azimuth
Elevation| Omnidirectional/Semi-Directional NVIS & DX
Wind and ice
Maximum Height erected| System survives 85 MPH wind with no ice.
24 Feet when mounted on the optional tripod or user supplied mast.
Maximum Length
Maximum Diameter| 42 inches
Less than 9 inches
Deployment
Quick Installation Overview
NOTE – Never loosen any of the bolts, washers, nuts, or caps on the match.
- Install your mast or optional tripod away from power lines.
- Place the ground wire ring connector over the bottom bolt on the match
- Install the mounting plate on your mast.
- Push the stake on the ground wire into an earth ground.
- Place the NVIS element’s ring connector(s) over the top bolt on the match.
- Assemble the vertical element, and install it on the mounting plate.
- Attach your coax from your tuner to the SO-239 on the match.
Detailed Assembly Instructions
-
Prepare your mounting installation with a) galvanized 1 3/8” fence rail placed 3-4 feet in ground, b) Steel tripod from Alpha Antenna, or c) any other similar conductive or non-conductive mast that is no larger than 1 3/8” in diameter.
-
Lay the 6 tapered vertical antenna elements end to end flat on the ground. Insert each section into the next until each element passes the slit of the other by ¼ inch, and secure each section with a stainless steel clamp.
-
Place aluminum mounting plate hardware onto the supporting item in Step 1 & tighten the U-Bolts that are circled below.
-
Mount the vertical antenna element into the U-Bolts opposite of those used to mount the aluminum mounting plate. Here is where you will place the included rubber offsets circled around the vertical element and under the associated U-Bolts on the mounting plate that are circled below.
-
Place the o-ring connector that has red shrink tube, which feeds the Vertical element, over the top bolt on the Alpha Match.
Place the o-ring connector that has red shrink tube, which feeds the single 25’ NVIS element (or four 35’ NVIS elements, but without the 25’ NVIS element), over the top bolt on the Alpha Match.
Secure the ring connectors in place with the included nut. Then pull these out as though they were guy wires, and do not allow them the lay flat on the ground. -
Attach the 1 o-ring connector of the Grounded Counterpoise element that has black shrink tube to the bottom bolt on the Alpha Match, as circled below. b) Secure the ring connector in place with the included nut.
-
Mount the aluminum hardware with fully assembled vertical element onto the mounting installation that was prepared in Step 1, then drive the Ground wire’s stake into the ground at least 4 inches.
-
Attach your coaxial feedline to the SO-239 on the Alpha Match.
Support
If you have questions about your antenna, please feel free to email us at alphaantenna@gmail.com
References
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