Item 5.1 - Workshop on Amateur Radio Antenna Regulations,t OF POLY
�Y City of Poway
TyF roq ��¢� COUNCIL AGENDA REPORT
C,I IN THE CO
DATE: February 18, 2014
APPROVED
APPROVED AS AMENDED
❑
(SEE MINUTES)
DENIED
❑
REMOVED
❑
CONTINUED
Resolution No.
TO: Honorable Mayor and Members of the City Council
FROM: Tina White, Interim City Manager (l,
INITIATED BY: Robert J. Manis, Director of Development ServicesP4
Rich Whipple, City Planner
Jason Martin, Senior Planner
SUBJECT: Workshop on Amateur Radio Antenna Regulations
Summary:
On October 15, 2013, the City Council approved a staff work plan to evaluate potential
regulations for amateur radio antennas that could be incorporated into the Poway
Municipal Code (PMC). Since then, City staff has met with representatives from the local
amateur radio community and other community members that are interested in the topic.
The purpose of this workshop is to discuss the potential updated regulations.
Recommended Action:
It is recommended that the City Council direct staff to return to the City Council with an
Ordinance amending the PMC with updated amateur radio antenna regulations.
Background:
The Federal Communications Commission (FCC) has regulatory and licensing oversight
responsibility for amateur radio operators. California Government Code Section
65850.3 codifies in State law that the FCC has a limited pre - emption over local
regulations governing amateur radio antenna facilities. FCC standards, however, do not
fully pre -empt the City's ability to regulate amateur radio antennas under its local zoning
authority. The degree to which a local jurisdiction can regulate under its zoning
authority has been the subject of an FCC issued order ( "PRB -1 "), FCC issued
clarifications of PRB -1, and numerous court cases. Ultimately, it has been concluded
that a jurisdiction must make "reasonable accommodations" for amateur radio operators
and installations.
Amateur radio antennas, which are commonly referred to as "ham" radio antennas, are
currently allowed in the City as accessory uses in all residential and commercial zones,
as well as the Business Park, and are subject to the development standards and
procedural requirements of Chapters 17.37 and 17.52 of the PMC. Additionally,
amateur radio antennas are subject to the standards of the underlying zoning district in
which they are located. A Minor Development Review Application (MDRA) is required
to establish an amateur radio antenna that has a dimension greater than six feet in
height or length.
1 of 30 February 18, 2014 Item # .7.1
Workshop on Amateur Radio Antenna Regulations
February 18, 2014
Page 2
On December 6, 2005, City staff brought forward to the City Council a proposed PMC
amendment to add/update regulations for amateur radio antennas. Staff had developed
the PMC amendment in consultation with the City Attorney and with l input from
representatives from the local amateur radio community. At the December 2005 public
hearing, the City Council took no action on the proposed PMC amendment.
On September 3, 2013, the City Council discussed the potential waiver of the MDRA
processing fee for amateur radio antennas. The City Council acknowledged the
benefits of amateur radios during emergencies when other forms of communication fail,
and the assistance that the City and region receive in disaster preparedness. During
the discussion on the MDRA fee waiver, a number of speakers raised the issue of
regulations for amateur radio antennas. At the conclusion of the discussion; the City
Council directed staff to prepare a Resolution amending the Master Fee Schedule to
waive the MDRA fee for amateur radio antennas and directed staff to prepare a work
plan to evaluate potential regulations for amateur radio antennas that would be in an
amendment to the PMC.
On October 15, 2013, the City Council approved a Resolution to waive the MDRA fee
for amateur radio antennas and approved the workplan to evaluate regulations. Staff
met with representatives from the local amateur radio community and with other
community members that have expressed interest in the matter in January 2014.
Findings:
Current Regulations and Procedures
Current regulations require that proposed amateur radio antennas that have a
dimension greater than six feet in height or length be processed through a MDRA, with
staff level approval. Through the MDRA process it is verified that the installation will
comply with all applicable regulations, which include specific setback requirements from
property lines and a 35 -foot maximum height limit. Additionally, through the process,
staff works with the applicant to ensure that the installation is sited such that its visibility
is limited to the maximum extent possible by placing the antenna behind existing
structures or landscaping, or providing additional landscaping. The MDRA process
includes a notice to adjacent property owners. It has been staff's experience that as a
result of the noticing process, or after an approved facility is installed, nearby residents
have expressed concerns regarding negative visual impacts to the neighborhood since
the antennas cannot be fully screened. Representatives from the local amateur radio
community and the City Attorney have indicated that the current regulations should be
updated to comply with FCC standards.
Regulations In Other Jurisdictions
Staff has surveyed other jurisdictions in San Diego County regarding their regulations.
The survey of other jurisdictions is included as Attachment A. Some of the jurisdictions
surveyed have limited regulations regarding amateur radio antenna installation, others
2 of 30 February 18, 2014 Item # 5,
Workshop on Amateur Radio Antenna Regulations
February 18, 2014
Page 3
have more stringent regulations. For example, the cities of Carlsbad, Escondido, Vista,
Encinitas, San Diego, and Chula Vista, and the County of San Diego, allow antennas
with no specified height limit (or a relatively high limit of 100 feet or greater) without
requiring any type of discretionary permit review. Others, such as Coronado, San
Marcos, Santee, La Mesa, Oceanside, and Solana Beach, allow antennas up to a
specified height (ranging from 15 feet to 66 feet, depending on the city) with no required
discretionary review. For installations beyond the specified height limit in these cities,
some type of discretionary review is required, but no maximum height limit is identified.
The City of Del Mar requires discretionary permits for all antenna installations
regardless of height, and has a height limit of 36 feet. Nearly all the surveyed
jurisdictions do not allow installations in the required building setbacks of the subject
zone, and do not have a limit on the number of antennas allowed on a site.
Updated Regulations
In updating/ adding amateur radio antenna regulations, the City is interested in input
from not only the amateur radio community, but also other community members.
Additionally, the City is interested in having the regulations necessary to preserve the
visual qualities of the City, while still ensuring the reasonable accommodation of
amateur radio operations. In meeting with representatives from the amateur radio
community and other community members, staff used the draft PMC amendment from
2005 as a basis for discussion. The proposed 2005 PMC amendment would have
allowed certain types of antennas with no discretionary permit review; others with an
MDRA; and others with a Minor Conditional Use Permit.
The proposed 2005 PMC amendment included the following:
• Establishment of a category of exempt antennas that require no review or permit
from the City, but are subject to placement requirements and are limited to three
in number. The exempt antennas are characteristically slender, with a diameter
of four inches or less, and are not supported by a structure (although guy wires
may be used in some instances). Some of these vertical antennas could have
slender horizontal antennas also. They are similar in appearance to roof -
mounted television antennas. They would comply with the 35 -foot height limit,
be outside of required setbacks for the zone, and be located on the site to
minimize their appearance. A primary objective in developing the list of exempt
antennas was to meet the needs of many amateur radio operators, and thereby
create a situation where a typical operator would not have to go through any City
discretionary process.
• Require an MDRA for non - exempt antennas /support structures up to a height of
35 feet.
• Clarify the development standards for these antennas /support structures.
• Require a Minor Conditional Use Permit (MCUP) for antennas higher than 35
feet, up to 50 feet. The MCUP process would also allow an applicant to request
an antenna/support structure higher than 50 feet, upon demonstration that the
3 of 30 February 18, 2014 Item # 5-, I
Workshop on Amateur Radio Antenna Regulations
February 18, 2014
Page 4
regulations prevent reception of a signal of acceptable quality and with special
findings to be made by the City Council.
At the January 2014 meeting with representatives from the local amateur radio
community, which included their attorney, they indicated their belief that the 2005
proposed PMC amendment was too stringent and burdensome to amateur radio
antenna operators. They questioned the fees for MDRAs and MCUPs. Prior to the City
Council waiving of the MDRA fee for amateur radio antennas it was $719. The MCUP
fee is currently $1,542, plus additional environmental fees which may be necessary
based on the particular project.
Additionally they questioned whether the regulations would be compliant with the FCC
requirements and requested several modifications. They submitted a proposal for
amendments to the PMC, which is included as Attachment B. In support of their
proposal they submitted a technical analysis, which is included as Attachment C.
The local amateur radio antenna community proposal includes the following:
® Distinguishing between the actual antenna and the antenna support structure as
it pertains to height and setbacks. The antennas are typically long and slender,
can be either vertically or horizontally oriented, are sometimes- comprised of an
array or clustered, and sometimes will be adjusted to change the direction the
antennas are pointing. The antennas are attached to a support structure which
can be a simple pole or sometimes will be a more substantial lattice style tower.
Sometimes the antenna support structure can be raised or lowered to change the
height of the antennas.
a Exempting antennas from any height limit and setback requirement regardless of
the antenna support structure height or location.
Requiring antenna support structures to comply with setback requirements of the
applicable zone but the antennas themselves can project to the property line.
• Allowing, without a MDRA, antenna support structures up to 65 feet in height.
® Allowing, with a MDRA, antenna support structures over 65 feet in height.
o No limit on number of antennas.
At the meeting with other community members, they acknowledged the need for the
City to comply with the FCC requirements and indicated a general support for the
regulations that were included in the proposed 2005 PMC amendment. They did agree,
however, that the number limit on exempted antennas, which was three, be eliminated.
They agreed that antenna support structures must comply with the setback requirement,
but that the antennas could be allowed to encroach up to 20% into the side and /or rear
yard setback. They also agreed that a roof mounted antenna/antenna support structure
that is no more than 35 feet (combined total) in height measured from ground be
allowed with no MDRA.
4 of 30 February 18, 2014 Item # 51
Workshop on Amateur Radio Antenna Regulations
February 18, 2014
Page 5
The staff proposal includes revisions to the proposed 2005 PMC amendment that were
made in response to the input received from the local amateur radio antenna community
and other community members that met with staff. A summary of the City's existing
regulations, the staff recommended regulations, the proposal by the representatives
from the local amateur radio community, and the input from other community members
are shown in the table included as Attachment D.
City Council options include the following:
1. Direct staff to return to City Council with an Ordinance to amend the PMC with
updated regulations, pursuant to the staff recommendations outlined in this report.
2. Direct staff to return to City Council with an Ordinance to amend the PMC with
updated regulations with modifications discussed at this workshop.
3. Direct staff to discontinue work on this matter.
Environmental Review
The matter of this workshop discussion is not subject to the California Environmental
Quality Act (CEQA). Any subsequent action by the City Council to amend the PMC
would be subject to additional environmental review.
Fiscal Impact:
None.
Public Notification:
Notice of this Workshop was published in the Poway News Chieftain and sent to
representatives from the local amateur radio antenna community and other community
members that met with staff on this matter, individuals who have expressed interest in
this matter to the City in writing, individuals that have spoken on this matter at past City
Council meetings, and the current contact person for Home Owners Associations which
are known to be active.
Attachments:
A. Survey of Regulations in Other Jurisdictions
B. Proposal From the Local Amateur Radio Antenna Community
C. Technical Report On Amateur Radio Antennas
D. Summary of Existing Regulations, Staff Proposal, Local Amateur Radio
Antenna Community Proposal, and Other Community Member Input
Wplanning \14 Reports \Workshop\amateur radio \rpt.docx
5 of 30 February 18, 2014 Item # S, I
Amateur Radio Antenna Standards in San Diego County
6 of 30 ATTACHMENT A February 18, 2014 Item # S.t
Type of Discretionary
City
Permits
He! ht
Location
Number
Carlsbad
None
No Limit
Not in required
No limit
building
setbacks
Coronado
None for antennas up to 66 feet
No Limit
Not in required
No limit
in height, Special Use Permit for
building
over 66 feet
setbacks
Chula Vista
None
No limit
No locational
No limit
requirements
Del Mar
Design Review Permit
26' ground,
Subject to
Design
36' roof
Design Review
Review
Encinitas
None for antennas up to 100
No Limit
Not in required
No limit
feet in height, Major Use Permit
front yard
MUP if over 100 feet
setback
Escondido
None
No Limit
Not in required
No limit
building
setbacks
La Mesa
None for antennas up to 15 feet
No Limit
Not in required
No limit
in height, CUP for over 15 ft.
front yard
setback
Lemon
None for antennas up to 100
No Limit
Not in required
No limit
Grove
feet in height, CUP if over 100
front yard
feet
setback
Oceanside
None for freestanding antennas
No Limit
Not in required
No limit
up to 51 feet and roof- mounted
building
antennas up to 15 feet, CUP for
setbacks
over 51 feet freestanding /over
15 feet on roof - mounted
San Diego
None
No limit
Not in required
No limit
(City)
building
setbacks
San Diego
None for antennas up to 200
No limit
Not in required
No limit
County
feet in height, MUP for over 200
building
feet
setbacks
San Marcos
None for antennas up to 60 feet
No Limit
Not in required
No limit
in height, CUP for over 60 feet
building
setbacks
Santee
None for antennas up to 50 feet
No Limit
Not in required
No limit
in height, CUP for over 50 feet
building
setbacks
Solana
None for antennas to 40 feet in
No Limit
Not.in required
One over
Beach
height, CUP if over 40 feet
building
30 feet
setbacks
Vista
None
100 feet
Not in required
No limit
building
setbacks
6 of 30 ATTACHMENT A February 18, 2014 Item # S.t
ORDINANCE NO.
AN ORDINANCE OF THE CITY OF POWAY, CALIFORNIA, CREATING CHAPTER _
OF THE POWAY MUNICIPAL CODE CONCERNING AMATEUR RADIO ANTENNAS
(ZONING ORDINANCE AMENDMENT_--)
WHEREAS, amateur (HAM) radio is recognized as a reliable emergency communication
system, a valuable method of supporting international and regional goodwill, and a low -
cost tool to encourage technology education and innovation by authorized amateur radio
operators pursuant to 47 US Code of Federal Regulations Part 97;
WHEREAS, the City Council prepared this Chapter in o1 to provide standards
that are more specific to amateur radio antenna installations; a,
WHEREAS, on 20_, the City Cou c1 eld§ a duly a Q Vertised public
hearing to solicit comments from the public, both pro a.. . con, relative to this application.
NOW, THEREFORE, THE CITY COUNCIL OF T t JTY OF `I3 WAY DOES 0 -' '� N AS
FOLLOWS:
Section 1: The City Council finds that the adopfir n of this Ordinance is exempt
from the provisions of the California Environmental Qual't ct (CEQA), pursuant to
Section 15061(b)(3) of the CEQA Guidelines,, because the Ordinance entails the update of
existing regulations involving procedural chnges, and other de etopment standards that
would allow amateur radio (HAM) antennas as limited ccesso I structures that would
comply with height and setback requirements. A term s t a.t do not comply with the
standards would be subject o fher discretion permit and environmental review.
C. To reasonablyeaccommodate effective amateur radio communications, and to
impose no unreasonable cost on the amateur radio operators.
D. To provide the minimum practical regulation necessary to satisfy the aesthetic, health,
safety and welfare concerns that have prompted these minimal restrictions on amateur
radio antennas and their supporting structures.
7 of 30 ATTACHMENT B February 18, 2014 Item # S•(
17. .020 Amateur Radio Antennas
Amateur radio antennas may be installed, erected and maintained within all zones in the City in
accordance with the following provisions contained in this Section.
A. Definitions. Whenever, in this Chapter, the following terms are used they shall have the
meaning ascribed to them in this Section.
1. "Amateur radio antenna" means any antenna that is used for the purpose of
transmitting and receiving radio signals in con).unction with an amateur
radio station licensed by the Federal Communications Commission.
"Antenna '9 -,1
2. Antenna structure means an amateur radio antenna s supporting mast or
tower, if any.
3. "Reasonably effective radiac m unicatio.ns" refers to a ninety percent
(90 %) minimum rate of successfu amat ur adio signal transmission and
reception under the changing variab" "lest at impact such communications.
B. Amateur radio antennas and ante na structures are a empt from the standard height
limitations described for each zone in Title 17 of the Poway M n ^icipal Code and shall be
subject solely to the provisions of this Chapter 17.
C. Installation of an antenna structure up to height 65 `feet requires a building permit.
An electrical permit sha;l also be req ' ed for anya tenna structure operating on 25
volts of power or more:
D. Installation of an antenna Structure excee J, 5 feet in height, shall require approval of
a minor develop t r vie.
E. Develop ,1 e § t Standa - All antenn structure installations shall comply with the
following unies, otherwise specified in this Chapter.
1. Permitted Heig 151r' e height of any antenna structure described in this
Section shall be measured from the natural grade at the point the antenna
structure touches, or if extended would touch, the ground.
2. Siting /Setbacks. An amateur radio antenna and /or an antenna structure
shall bsconsidered to satisfy siting and setback criteria if:
No portion of the amateur radio antenna or the antenna structure is
permanently located within any required setback area.
b. The amateur radio antenna and the antenna structure are located on
the property to minimize its visibility from the street, while allowing
reasonably effective radio communications from the installation.
F. Application for Permit. When a minor development review permit is required, submittal
8 of 30 February 18, 2014 Item # S.I
G
H
shall be on a form supplied by the Development Services Department and shall be
accompanied by the following information, maps and plans:
1. A scale drawing showing the proposed location of the amateur radio
antenna and antenna structure, if applicable, in relation to property lines.
2. Manufacturer's specifications of the amateur radio antenna and antenna
structure, if applicable, including the wind loa AS the manufacturer's
specifications are not available, applicant may alternatively provide the
specifications in a report signed and stamped by a California licensed civil or
structural engineer.
3. Elevations drawn to scale.
Installations over 65 feet. The Director sha l grant a minor develop men review permit
for an antenna structure over 65 eet in' , height upon 4 Ii i that:
1. The requested height of the insta I'ation i§ necessary to 4ccommodate
reasonably effective radio communicaf
'on on the site;
2. The installation is located in such a mann " as to minimize visibility to the
closest public street I wn possible, fam adj "scent property owners.
Where screening is equ'rretl by the Director it may not substantially
interfere with reasonably effective radio communications; and
3. There ire no other reaso ably feasib a alternatives. Alternatives which
wo d su atantially increase the cost oinstallation shall not be considered
reasonably easible alternatives.
The appiicant s
�find:inas can be r
evidtnce necessary to document that the above
�mpt AMINO , The fiol owing types of antennas shall be exempt from the permit
uirements of this Section p {pvided all the conditions identified below are met:
1. Antennas legally established prior to the effective date of this Ordinance.
Very gh Frequency (VHF) and Ultra High Frequency (UHF) antennas,
whetter roof or ground mounted.
3. ,Vertical amateur radio antennas. Antennas of any type, whether roof or
ground mounted, substantially projecting solely in the vertical plane.
4. Temporary antennas. Antennas of any type, whether supported, attached
or otherwise affixed in, on or to a tree, wire, cord, or other non - permanent
structure. Antennas which are regularly permanently affixed are not
exempt under this Section.
9 of 30 February 18, 2014 Item # E. (
Amateur Radio Use. The use of amateur radio communications shall be deemed a
permitted accessory use in all zones in the City.
J. Binding Effect. This Ordinance shall apply throughout the City of Poway but shall in no
way supersede any covenants, conditions, and restrictions relating to antenna
placement or height on a given lot.
EFFECTIVE DATE: This Ordinance shall take effect and be in fora thirty (30) days after
the date of this passage; and before the expiration of fifteen (15 da s after its passage, it
shall be published once with the names and members votin 'fo, and against the same in
the Poway News Chieftain, a newspaper of general circuf do ublished in the City of
Poway.
Introduced and first read at a regular meeting of the C t ouncil of the Cit. of Poway held
this day of 2014 and therea461 SSED AND ADOPTED at a regular
meeting of said City Council held the d 20_, by the fo lowing roll
call vote.
AYES:
ison, Mayor
10 of 30 February 18, 2014 Item # S.
EFFECTIVE AMATEUR RADIO COMMUNICATIONS IN POWAY
By Charles Ristorcelli, NN3V
Executive Summary-
This technical analysis identifies the minimum antenna height. needed for effective
amateur radio communications in Poway, by analyzing the principal factors impacting
long range radio communications.
Effective communications are a 90% probability of achieving the desired communication.
The analysis describes the components needed for a typical amateur radio station,
identifies how environmental factors - influence radio propagation, and then studies the
technical decisions and component selection for the radio station that lead to a
compromise antenna height for a licensed amateur radio operator (Ham) to effectively
communicate.
The analysis is centered on a Poway Ham living on a standard lot size property, erecting
at least a single permitted antenna, and desiring to operate the amateur radio station as a
hobby, for experimentation, and as an. emergency communication service for Poway and
San Diego County residents in event of a natural or man made disaster
The uncontrollable laws of physics impacting the probability of achieving effective
communications are examined and are considered that they "are what they are ".
A radio station's elevation above sea level impacts long distance effective communication
To study all possible radio location elevations in Poway, the analysis would. have to
address - innumerable locations. Therefore, the analysis uses a 's eta. earth"
a ptio -The impact of the assumption in effect lowers the analytical antenna height.
This is considered a reasonable compromise.
Antenna height is the core issue of concern surrounding the City of Poway proposed
amateur radio antenna ordinance. This study .proves antenna height is the single most
important controllable variable influencing effective communications at long distance,
and technically specifies the needed compromise height.
The analysis proves that the compromise antenna height needed for effective
communication in Poway is 65 feet.
11 of 30 ATTACHMENT C February 18, 2014 Item # S.(
Discussion
"Effective radio communication" is achieved when there is a 90% probability of
completing the communication.
In the, aggregate of all possible factors influencing this situation, this is ultimately driven
by four factors: the radiated power of the transmitting station antenna in the direction of
the intended receiving antenna, the ionosphere, the receiver sensitivity, and the receiver
selectivity
The Electroma_grzetic Reciprocity Theorem states that the transmitted characteristics of an
electromagnetic wave mirror those influencing its reception (Reference 1). This analysis
concentrates on the transmitted signal and relies on reciprocity to apply the analysis to the
received signal.
The ionosphere is a region of the upper atmosphere lying between 55 miles and 370 miles
above sea level. The ionosphere contains atoms and molecules that are highly charged by
solar incidence and activity.
The dominant influence on radio wave propagation is the ionosphere' -s condition. The
ionosphere is not controllable; therefore the radio operator must be aware of its condition
and choose a radio frequency suitable for the conditions and the target communication.
The ionosphere reflects and refracts HF/VHF radio waves, permitting long range
communication as illustrated in Figure 1.
2
12 of 30 February 18, 2014 Item # 5'• l
Figure 1. - Radio signal propagation paths.
Wrong Frequency
Earth 'N
As shown above, the ionosphere bends the transmitted wave directing it back to earth.
Choosing the wrong frequency for a specific time of day and condition of the ionosphere
does not bend the transmitted wave enough, so the signal escapes, as shown in Fig 1.
With proper choices; the signal bends-back down, creating one or possibly many hops.
Each hop covers a "skip distance " of about 2,500 miles. Multiple hops result in even
greater communication range. The "critical angle " is the largest angle at which
a radio wave of a specified frequency can be returned to Earth by the ionosphere.
HF/VHF radio waves departing the antenna at or near tangent to the earth are more likely
to provide the longest communication range. In the illustration in Figure 1, the signal that
departs the transmitter tangent to the earth's surface is said to depart at "zero elevation
ate. It travels the farthest to reach the ionosphere.
Many other factors influence transmitted radio signals. Soil conductivity, moisture in the
atmosphere, objects in the near and far fields of the propagation envelope, passing
automobiles, lightning, etc. are not practically controllable by the operator. They too "are
what they are" and must be tolerated.
Topography influences propagation. While Poway presents innumerable hills and valleys,
analyzing every possible location for a transmitter in Poway represents an
insurmountable task. This analysis assumes a smooth earth surface. This is a routine
assumption for propagation studies. For the objective of this study, this results in an
acceptable compromise.
13 of 30 February 18, 2014 Item # S • (
Conditions at the radio station intended as the receiver "are what they are ". It is
presumed the receiver operator has carried out a careful selection of components, and
consequently maximized the receiver station sensitivity and selectivity.
Operationally, the Poway Ham operator will use amateur radio for long range, ground
based, terrestrial, point -to -point communication. The communication will be performed
without assistance from other communications technologies i.e. intereet, telephony and
relay points. The transmitter will be operated within its modulation and power limits.
Living in the city, this operator will be situated permanently on a regular size city lot, and
will design a modest cost amateur radio station.
The steps in this analysis- consider the controllable environmental and operational factors
influencing radio wave transmission. The Poway Ham must deal with these influences to
achieve effective communications.
Five fundamental factors must be considered to maximize any effective radio
communications capability
Antenna Type
o Antenna installation height
o Operating Radio Frequency
e Maximum Effective Transmitted Power
o Time of Day
As a hobby or experimenter, the Poway Ham can choose any time to operate. However,
we said there is interest in assuring the radio station is able to assist Poway residents with
communications in the event of an emergency or disaster (major earthquake, fire, terrorist
act, etc.). So the communication may have to be at any time (365 x 24 x 7), on the
amateur radio bands most commonly used for communications within the United States,
or to other countries.
With limited residential property size, and considering practical and affordable amateur
radio installations, this means operation on the 40 through 6 Meter amateur radio bands
(HFNHF) using at least one permitted antenna.
This is the most common amateur radio station configuration in the - world.
Long range HFNHF communication is analogous to trying to illuminate an outdoor
scene at night. You need the brightest possible light beam pointed only toward the scene,
without illuminating objects outside the scene, or between the light and the scene.
E
14 of 30 February 18, 2014 Item # S• l
There are three things the Poway Ham can do to achieve effective communications:
1. Avoid terrain interference of the signal transmitted toward the receiver. This
means avoiding hills, trees in the face of the antenna, large metal barns in front of
the property, etc.
2. Maximize the station's effective transmitted signal power in the direction of the
intended receiver. This is achieved by delivering the maximum possible
transmitter power to the antenna, and ensuring the antenna can focus the
transmitted power towards the intended receiver.
3. Minimize the departure angle of the transmitted signal radio wave toward the
horizon. This is accomplished by ensuring the antenna is at the proper height
above ground for the chosen operating frequency.
The technical design, and operational decisions needed to-achieve the above are analyzed
in detail in what follows.
ANTENNA
Points where "Impedance"
must be matched
RADIO
TRANSMITTER - - - - - -= —
COAXIAL CABLE
Figure 1. - An amateur radio station
Figure 1 is representative of a simple amateur radio station.
To avoid propagation interference, the station should be at the highest point possible,
devoid of hills, trees, and obstacles in the desired direction of propagation. For this
analysis those factors are considered to be whatever they are, and we presume a smooth
earth. The effect on the analysis at best is no impact, and at worst is to require 'a higher
antenna installation. This is a reasonable compromise.
15 of 30 February 18, 2014 Item #5-
Maximum radio signal power in the direction of an intended receiver is achieved by three
conditions: ensuring that maximum power generated by the transmitter is transferred to
the transmission line (wire) to the antenna; minimizing the loss of that power along the
transmission line; and selecting an appropriate antenna for maximum directive gain
towards the receiver.
Power loss between the radio transmitter and antenna is minimized through proper
transmitter design; transmission line choice; and minimum Standing Wave Ratio (SWR)
on the transmission line.
A standard, commercially available amateur radio transmitter manufactured to current
technology standards is the basis of the analysis. The transmitter must transfer all of its
power to the antenna.
The key to this power transfer is the transmitter output impedance. All commonly
available amateur radio transmitters and transceivers are manufactured with an output
impedance of 50 ohms.
The electromg netic maximum power transfer theorem shows that maximum power is
transferred between a generator (transmitter) and a load (transmission line plus antenna)
when the transmitter output impedance is equal to the load impedance. (Reference 2).
In this case, the load impedance is the impedance seen by the transmitter at the
transmission line input. This is a combination of the transmission line characteristic
impedance plus the antenna impedance. Given the transmitter construction stated earlier,
to transfer maximum power, the load impedance must be 50 ohms.
There are many available choices for connecting a transmitter to an antenna. The
conditions specified for this case narrow the selection. -A low visibility, easily installed,
multi band capable transmission-line is needed. A coaxial transmission cable fills this
need. Given that the transmitter output impedance is 50 ohms, the installation requires a
50 ohm coaxial cable. Two of the most common 50 ohm coax types are RG -58 and RG -8.
Electromagnetic wave propagation along a coaxial cable will create what is known as a
"standing wave " (Reference 3). The measure of the amount of standing wave present on
a transmission line is known as the Standing Wave Ratio (SWR). SWR is a measure of the
efficiency of power transfer, and is determined with a commercially and readily available
instrument.
While the effects of a standing wave on the operation of a transceiver and antenna are
very complex, they can be best summarized by recognizing that the lower the SWR, the
higher the transmitted power and the more effective communication.
16 of 30 February 18, 2014 Item # 5 , I
Maximum power transfer to the antenna is achieved as shown in Reference 3 when the
SWR on the line is 1 to 1 (a minimum). This takes place as predicted by the maximum
power transfer theorem, when the coaxial cable characteristic impedance matches the
load (in this case the antenna) impedance. The antenna needed must present 50 ohm input
impedance.
The antenna is the amateur radio station component with the greatest impact on effective
communications, and antenna choices are truly innumerable. (Reference 4)
For this case, the choices are conveniently limited by the operating constraints. The
antenna must be multi -band capable, in the HFNHF range. Its characteristic impedance
must match the transmission line impedance (50 ohms), and it must direct the transmitted
signal toward the intended receiver.
The most common and popular antenna in amateur radio is the 1/2 wave center -fed dipole
(Reference 4). It consists of a wire parallel to the ground, split in the center where the,
feed line from the transmitter is attached. The length of the wire is 1/2 the wavelength at
the specifically transmitted frequency. An example is seen in Figure 2
Length (L)
Figure 2. - Illustration of a 1/2 wave center fed dipole antenna
While not capable of satisfying the operational need for multiband operation for the
Poway Ham, it serves to illustrate important antenna properties. At resonance, as shown
in the figure, the impedance presented by the antenna at the coax to the transmitter is 50
ohms. Again, by matching impedance, the antenna will accept all the power delivered by
the transmitter to the coaxial feed line.
Figure 3 shows the radiation pattern of a 1/2 wave center fed dipole antenna. This is a
representation of the energy dispersed from the antenna suspended in free space.
7
17 of 30 February 18, 2014 Item # S.
Signal energy
Signal energy
ran
NIV
Figure 3. Half wave center fed dipole radiation pattern in free space. (Reference 5)
The transmitted signal energy leaves the antenna in a doughnut shaped pattern, with
maximum power travelling at right angles to, and minimum power along, the antenna
wire.
Concentrating the signal power in a specific direction is what is known as "antenna
directive gain ".
Antenna directive gain is a measure of the power effectively transmitted by the antenna in
the intended direction of transmission (Po), relative to the power delivered by the
transmission line (Pi). It is measured in "decibels " abbreviated "db ". It is a logarithmic
ratio of the output to the input power given by the formula:
Gain = 10 log Po / Pi (Reference 4)
If the directive gain of an antenna as given by the formula is 3 db, the radiated power
from the antenna in the intended direction is twice the input power.
Antenna gain is calculated in many ways. One way is to apply electromagnetic
propagation theorems to antenna numerical models on the assumption they are in free
space. This leads to the isotropic measure of gain, and is abbreviated dbi.
The gain of a center fed i/2 wave dipole antenna is 2.15 dbi (Reference 4). Therefore the
transmitted power in the maximum gain direction is 1.64 times greater than the power
produced by the transmitter and delivered to the antenna.
8
18 of 30 February 18, 2014 Item # S.
Without -the ground's influence, the '/2 wave dipole's radiation pattern is shaped like a
pair of balloons (Figure 3, right). Proximity to the ground "squeezes the balloon ". As the
balloon is squeezed, it collapses in some areas, and expands in others. The extent of the
squeeze will vary with the height of the antenna over the ground (Reference 6). A half
wave center fed dipole at %2 wavelength above ground has one lobe at 30 degrees. A half
wave center fed dipole at, one wavelength above ground shows two lobes of radiation,
one at 50 degrees elevation and the other at about 15 degrees.
The ground effect is such that the higher the antenna is placed above ground, the closer
the lowest lobe of radiation will be to the best departure angle for longest propagation
distance. The effect is shown in Figure 4.
Dspole, = -Wave High 0. dB
-1 :") `M eve High
0 deg.
Figure 4. - Pattern of radio signal energy transmitted into the ionosphere from two 1/2
wave center fed dipole antennas, each at a different suspension height above ground.
(Reference 6)
19 of 30 February 18, 2014 Item # S.1
Analysis of all antennas reveals two important facts (Reference 6):
1. The departure angle at which a wave leaves the antenna is the key factor
determining effective communication distances beyond line -of- sight: It is directly
related to antenna height. The higher the antenna, the lower the departure angle,
and the longer the resulting skip distance. For maximum long distance, the
departure angle must be as low as possible.
2. In general, placing an amateur antenna system higher in the air enhances
communication capabilities and also reduces electromagnetic interference with
neighbors.
Figure 1 illustrated the effect of the ionosphere on radio wave propagation. It showed that
a radio wave leaving the antenna at the lowest departure angle is the one that propagates
farthest. This is the effect the Poway Ham needs to achieve'. Figure 4 illustrates how a
higher- antenna - produces a lower lobe. Consequently the higher an antenna is placed
above ground, the- farther it will communicate because of the resulting lower radiation
angle.
Theoretical analysis, and millions of hours of communication operations show that a
center fed '/z wave dipole antenna is not the most effective antenna for reliable 24x7x365
day multi -band communications. It is only resonant on one frequency band, creating high
SWR values if operated at non - resonant frequencies, and -only provides modest gain in
many directions, where a high gain in a single direction is needed.
To transmit,a strong signal toward a chosen direction requires rotating the antenna. In the
case of the center -fed %2 wave dipole, this requires antenna disassembly and
repositioning, with all the attendant installation complications.
Engineering research and design considerations have proven that multiple '/2 wave
dipoles can be combined in various configurations to increase gain and directivity. The
analogy of the balloon applies. The more dipoles, the greater the number of radiation
pattern balloons, and the greater the squeezing effect of the ground.
Obviously assembling multiple %2 wave center fed wire dipoles, of long lengths of wire,
is very impractical.
10
20 of 30 February 18, 2014 Item # s. I
This led to the design of what are called "directive beam antennas ". There are many
commercially available for reasonable prices. They all offer increased gain, enhanced
directivity, ease of erection and installation, and 50 ohm input impedance.
One particularly well known type of beam antenna is called a Yagi, named after one of its
Japanese inventors. The common television antenna is an example. Second to the Y2 wave
center fed dipole, the yagi is the most popular amateur radio antenna (Reference 4). A 3
element yagi is illustrated in Figure 5.
Figure 5. Three element yagi antenna consisting of the reflector element (far left),
the feed element (middle), and the director element (far right)
Depending on design, the yagi combines number of elements of varying lengths,
separated by varying distances along a support boom. Electromagnetic design principles,
too complex to describe here, allow multi -band operation (HFNHF) capability with an
input impedance of 50 ohms.
The antenna radiation patterns, vertical and horizontal, of a 4 element yagi antenna above
ground are shown in Figure 6. The figure illustrates the directional gain achieved by a
typical yagi antenna, in both the vertical and horizontal planes of radiation.
�4.
E _
Vertical
Ili:
Horizontal
Figure 6. Yagi antenna radiation patterns.
no
D
am
11
21 of 30 February 18, 2014 Item # 57•1
22 of 30
The construction of a yagi eliminates the disadvantages associated with' /2 wave center
fed dipoles. Common commercially available yagi antennas are rugged, lightweight, and
low profile. They can easily be rotated to aim their primary transmitted lobe in any
direction. Their input impedance of 50 ohms meets our criteria for matched impedance
and minimum SWR. In the IVNHF frequency range they produce horizontal
polarization.
Figure 7 shows a commercially available 4 element yagi antenna.
f
1 J
1 '
Figure 7- Four element Yagi multi -band antenna designed to operate on the 40 — 6 meter
amateur radio band. The second and third elements from the left are one continuous loop,
and are the feed point for the antenna.
12
February 18, 2014 Item # S. I
23 of 30
Table 1 presents the performance specifications for the yagi shown in Figure 7.
Performance for ]Licensed
'Bands
4E
Gain
4>E ]Front to
30/40 Option
30/40 option
Front to Rear,
amateur radio operator
gDlBn
DBi
][dear, ➢Dl$
gain, lDBi
DB
40M[
n/a
n/a
1.8
n/a
30M[
n/a
n/a
2.1
n/a
20M[
9.5
21
17M[
10
20
15M1
10.2
27
12M[
10.4
21
10M[
10.6
11
6M[ — 4 elements
7.8
4
Table 1. - Performance specifications of the yagi antenna shown in Figure 7.
http://ww--,v.steppir.com/4-element-yagi
The table shows that depending on the operating frequency, the antenna produces modest
to substantial directive gain. In the case here illustrated for example, we find that:
1. In the 40 meter band, the antenna produces a gain of 1.8 dbi (1.5 times
power gain)
2. In the 20 meter band, the antenna produces a gain of 9.5 dbi (8.9 times
power gain)
3. In the 6 meter band, the antenna produces a gain of 7.8 dbi (6:0 times
power gain)
There are many other commercially available directional beam HFNHF multi band
antennas besides the Yagi. Their application to an amateur radio station and the analysis
of how their operation will satisfy the conditions we imposed for this analysis is the same
as carried out above. The resulting hei ght for antenna installation is independent of
antenna type, however different antennas will show variations in gain on some bands
(depending on nature of the feed element or reflecting elements), the size of the boom on
which the elements are attached, etc.
Up to this point, the analysis has shown all the important technical decisions the Poway
Ham must make in assembling an amateur radio station that delivers the requisite signal
to a directive multi band antenna.
13
February 18, 2014 Item # 5.1
24 of 30
The final decision needed is a choice of the antenna support structure.
The question is: Given the equipment selected,
what is the minimum acceptable antenna heijeht for effective worldwide
communications from Poway?
As stated earlier, the best height must result in the lowest radiation departure angle, and
that is frequency dependent. This poses a challenge. For the multi -band capability
needed, different antenna heights are needed for each band.
One might envision a structure that would raise and lower the antenna as a function of
operating frequency. Such a structure would seem to be the commercially available
"crank -up tower ". Unfortunately they are not built for that purpose. Instead they are
intended to occasionally raise and lower the antenna for maintenance or experimentation
Furthermore, any antenna selected for use as described would not survive the vibration
stresses induced by the continued raising and lowering of the structure, and the apparatus
used to raise and lower the antenna would have to be of special design to assure
reliability. Neither is commercially available.
So how can the necessary antenna height for 90% communications effectiveness on the
HFNHF bands be decided?
A compromise solution is to choose an antenna height optimized for the lowest departure
angle at the highest HF frequency of operation.
In this case that is the l Om meter band.
The rationale for doing so will be explained in what follows.
At the transmitting antenna, a detailed study of departure angles requires dealing with the
effects of the "near field radiation pattern ". That is much too complex for this analysis.
Fortunately, the near field effects disappear in the far field, where the receiving station is
located.
The earlier cited electromagnetic reciprocity theorem shows that the effects at the
receiving antenna are identical to the effects at the transmitting antenna.
Figure 8 shows a simplified view of the electromagnetic field effects at the receive
antenna, "the far field "..
14
February 18, 2014 Item # S• I
Arrival angle, T
® o
o
®v
- T0
Dc
Reflection point Standing
A
X
W
R
wave
Figure 8. Simplified depiction of incident (transmitted) electromagnetic energy arriving
(departing) a receive (transmit) antenna.
By analyzing the effect of the propagation path on the signal arriving at the receiving
antenna, we get an understanding of the antenna height needed at the origin and reception
antennas in order to achieve 90% communication effectiveness.
The analysis must consider two electromagnetic waves. The wave arriving directly from
reflecting off the ionosphere, and the wave bouncing from the earth's surface.
Depending on the antenna height, the waves will arrive in or out of phase at various
heights above ground, reinforcing or cancelling the resulting received signal. The effect
creates a standing wave surrounding the antenna as illustrated by the sinusoidal pattern
shown at the right of figure 8. Highest SWR (the humps to the right in the sinusoid) will
vary in height depending on the frequency of operation. The antenna must not be placed
at a height of maximum SWR, as that will minimize the received signal.
The antenna installation height must also consider the radio wave arrival angles. The
lower the angle of arrival, the longer the propagation from where the wave originated.
The angles will also vary by operating frequency.
Expected arrival angles for waves direct from the ionosphere for HF propagation are
listed in Reference 8. They show that half the arrival angles are less than 6 °, and that 90%
of the arrival angles are smaller than 16 °.
15
25 of 30 February 18, 2014 Item # 5.1
For multi -band HF signals, to achieve 90% probability of communication, the
transmission and reception antennas must be at heights that exploit arrival angles up to 16
o.
The Poway Ham must optimize the antenna height accordingly.
The optimum heights to achieve minimum elevation angles for various frequency bands
between 7 and 54 MHz are shown in Figure 9. The curves show four different minimum
angles. The green curve shows optima for a V arrival angle, the red curve for 2 °, the blue
curve for 3 °, and the black curve for 4 °. Increasing angles very scale somewhat with
frequency, but not linearly.
80
60
50
40
30
20
10
Antenna height,
7 10 14 20 30 40 50 60
Frequency, MHz
Figure 9 — Optimum antenna heights over even terrain for various frequencies.
As shown above (Reference 7), to operate with the lowest possible arrival angle on the 10
meter band, the antenna height should be 19.9 Meters (65 feet).
10 Meters is the amateur radio band that, under satisfactory ionosphere conditions allows
the longest range communications with the lowest necessary effective transmitted power
(Reference 5).
16
26 of 30 February 18, 2014 Item # S.
32 in I
`�.---
-- — — - — — — —
- -. - --
----- - - - - --
Best .Height
I
- Tmim.um —
15 m
1 deg
2 deg
deg deg
7 10 14 20 30 40 50 60
Frequency, MHz
Figure 9 — Optimum antenna heights over even terrain for various frequencies.
As shown above (Reference 7), to operate with the lowest possible arrival angle on the 10
meter band, the antenna height should be 19.9 Meters (65 feet).
10 Meters is the amateur radio band that, under satisfactory ionosphere conditions allows
the longest range communications with the lowest necessary effective transmitted power
(Reference 5).
16
26 of 30 February 18, 2014 Item # S.
Studying Figure 9 shows that as the operating band is lowered, the antenna height to
achieve the lower angles rises. However, even when operating on the 20 meter band with
an antenna height of 654 feet, an arrival angle of 4 degrees is achieved. That is an
acceptable compromise, as other ionosphere factors compensate with multi -hop paths at
the lower frequencies.
The analysis does not ignore the lower 40 — 30 meter bands. While an antenna height of
65 feet leads to higher direct arrival angles (implying shorter propagation path), the utility
of the bands for emergency communications are enhanced for medium range distances.
Additionally, the utility of the lower bands during daylight for hobby operation is limited
by the high ambient noise created by the ionosphere condition.
Thus, with 65 ft antenna height, the Poway Ham achieves a station design that
accomplishes, with a compromise to lower antenna height, a 90% probability of success
for long range communications any time of day or night, regardless of the ionosphere
condition.
The Poway Hann should install the multi -band BF/VHF antenna at a compromise
height of 65 feet.
17
27 of 30 February 18, 2014 Item # 5• I
Reference 1. - Wikipedia.
http:Hen.wikipedia.or- /wild /Reciprocity %28electromagnetism %o29
Reference 2. - Wikipedia
http: / /en.,,viki edp ia.org /wiki /Maximum power transfer theorem
Reference 3. ARRL Handbook For Radio Communications, Chapter 20, Section 20.1
Reference 4. - ARRL Handbook For Radio Communications, Chapter 21, Section 21.1
Reference 5. - ARRL Handbook For Radio Communications, Chapter 21, Section 21.2.1
Reference 6. - "Antenna Height and Communications Effectiveness ", Second Edition, by
R. Dean Straw, N6BV, and Gerald A. Hall, K1 TV,
Reference 7. - "An Optimum Height for an Elevated HFAntenna ", QEX May 2011, by
Kazimierz "Kai" Siwiak, KE4PT
Reference 8. - The ARRL Antenna Book, 18th. Edition, April 1997, Chapter 20.
About the author. - Mr. Ristorcelli has been a Licensed amateur radio operator radio
operator (NN3V) since 1976. A graduate engineer; he holds a B.S.E.E, M.S.E.E. and
M.S.C.S, and the Degree Electrical Engineer (PhD, ABD) specializing in electromagnetic
propagation and communication systems. During 35 years as a U.S. Navy officer he
commanded ships, and was the Commanding Officer of Naval Electronics Systems
Engineering Center, Portsmouth . Virginia, responsible for the procurement, installation,
and maintenance of the Navy's worldwide communication system. During the last 8
years of Navy service as the Director of Navy Electronic Combat Surveillance Systems,
he was responsible for the design, procurement, installation, and maintenance of the
Navy's afloat and ashore HF/VHF/UHF surveillance network.
18
28 of 30 February 18, 2014 Item # 5.1
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30 of 30 February 18, 2014 Item # S, I