https://urgentcomm.com/wp-content/themes/ucm_child/assets/images/logo/footer-new-logo.png
  • Home
  • News
  • Multimedia
    • Back
    • Multimedia
    • Video
    • Podcasts
    • Galleries
  • Commentary
    • Back
    • Commentary
    • Urgent Matters
    • View From The Top
    • All Things IWCE
    • Legal Matters
  • Resources
    • Back
    • Resources
    • Webinars
    • White Papers
    • Reprints & Reuse
  • IWCE
    • Back
    • IWCE
    • Conference
    • Special Events
    • Exhibitor Listings
    • Premier Partners
    • Floor Plan
    • Exhibiting Information
    • Register for IWCE
  • About Us
    • Back
    • About Us
    • Contact Us
    • Advertise
    • Terms of Service
    • Privacy Statement
    • Cookies Policy
  • Related Sites
    • Back
    • American City & County
    • IWCE
    • Light Reading
    • IOT World Today
    • Mission Critical Technologies
    • Microwave/RF
    • T&D World
    • TU-Auto
  • In the field
    • Back
    • In the field
    • Broadband Push-to-X
    • Internet of Things
    • Project 25
    • Public-Safety Broadband/FirstNet
    • Virtual/Augmented Reality
    • Land Mobile Radio
    • Long Term Evolution (LTE)
    • Applications
    • Drones/Robots
    • IoT/Smart X
    • Software
    • Subscriber Devices
    • Video
  • Call Center/Command
    • Back
    • Call Center/Command
    • Artificial Intelligence
    • NG911
    • Alerting Systems
    • Analytics
    • Dispatch/Call-taking
    • Incident Command/Situational Awareness
    • Tracking, Monitoring & Control
  • Network Tech
    • Back
    • Network Tech
    • Interoperability
    • LMR 100
    • LMR 200
    • Backhaul
    • Deployables
    • Power
    • Tower & Site
    • Wireless Networks
    • Coverage/Interference
    • Security
    • System Design
    • System Installation
    • System Operation
    • Test & Measurement
  • Operations
    • Back
    • Operations
    • Critical Infrastructure
    • Enterprise
    • Federal Government/Military
    • Public Safety
    • State & Local Government
    • Training
  • Regulations
    • Back
    • Regulations
    • Narrowbanding
    • T-Band
    • Rebanding
    • TV White Spaces
    • None
    • Funding
    • Policy
    • Regional Coordination
    • Standards
  • Organizations
    • Back
    • Organizations
    • AASHTO
    • APCO
    • DHS
    • DMR Association
    • ETA
    • EWA
    • FCC
    • IWCE
    • NASEMSO
    • NATE
    • NXDN Forum
    • NENA
    • NIST/PSCR
    • NPSTC
    • NTIA/FirstNet
    • P25 TIG
    • TETRA + CCA
    • UTC
Urgent Communications
  • NEWSLETTER
  • Home
  • News
  • Multimedia
    • Back
    • Video
    • Podcasts
    • Omdia Crit Comms Circle Podcast
    • Galleries
    • IWCE’s Video Showcase
  • Commentary
    • Back
    • All Things IWCE
    • Urgent Matters
    • View From The Top
    • Legal Matters
  • Resources
    • Back
    • Webinars
    • White Papers
    • Reprints & Reuse
    • UC eZines
    • Sponsored content
  • IWCE
    • Back
    • Conference
    • Why Attend
    • Exhibitor Listing
    • Floor Plan
    • Exhibiting Information
    • Join the Event Mailing List
  • About Us
    • Back
    • About Us
    • Contact Us
    • Advertise
    • Terms of Service
    • Privacy Statement
    • Cookies Policy
  • Related Sites
    • Back
    • American City & County
    • IWCE
    • Light Reading
    • IOT World Today
    • TU-Auto
  • newsletter
  • In the field
    • Back
    • Internet of Things
    • Broadband Push-to-X
    • Project 25
    • Public-Safety Broadband/FirstNet
    • Virtual/Augmented Reality
    • Land Mobile Radio
    • Long Term Evolution (LTE)
    • Applications
    • Drones/Robots
    • IoT/Smart X
    • Software
    • Subscriber Devices
    • Video
  • Call Center/Command
    • Back
    • Artificial Intelligence
    • NG911
    • Alerting Systems
    • Analytics
    • Dispatch/Call-taking
    • Incident Command/Situational Awareness
    • Tracking, Monitoring & Control
  • Network Tech
    • Back
    • Cybersecurity
    • Interoperability
    • LMR 100
    • LMR 200
    • Backhaul
    • Deployables
    • Power
    • Tower & Site
    • Wireless Networks
    • Coverage/Interference
    • Security
    • System Design
    • System Installation
    • System Operation
    • Test & Measurement
  • Operations
    • Back
    • Critical Infrastructure
    • Enterprise
    • Federal Government/Military
    • Public Safety
    • State & Local Government
    • Training
  • Regulations
    • Back
    • Narrowbanding
    • T-Band
    • Rebanding
    • TV White Spaces
    • None
    • Funding
    • Policy
    • Regional Coordination
    • Standards
  • Organizations
    • Back
    • AASHTO
    • APCO
    • DHS
    • DMR Association
    • ETA
    • EWA
    • FCC
    • IWCE
    • NASEMSO
    • NATE
    • NXDN Forum
    • NENA
    • NIST/PSCR
    • NPSTC
    • NTIA/FirstNet
    • P25 TIG
    • TETRA + CCA
    • UTC
acc.com

Here’s the perfect antenna

Here’s the perfect antenna

  • Written by raidee
  • 1st October 2018

High-frequency communications (3-30 MHz) require large antennas. Multiple antenna lengths and/or tuning capability also are needed in order to change bands or use different channels (frequencies) in the same band.  In the world of HF, the ability to change bands or channels within a band is a necessity because no one frequency can be used to reliably communicate from Point A to Point B at all times.  As myriad factors change—e.g., day transitioning to night, the eruption of sunspots—one must choose appropriate bands (frequencies) to ensure a reliable working path for long- or short-range communications. Consequently, 50-130 feet of space is needed for the HF antenna.

The directivity of HF antennas is another concern.  In some circumstances, directivity is altered in order to null out interference; however, the desired stations that you want to communicate with occasionally fall in this same null pattern.  Also, when using a horizontal dipole, you will have main lobes perpendicular to the direction of the antenna lines, and no signal toward the end of the lines.  Conversely, if you are using a vertical antenna, then you will have a good signal going toward the horizon in all directions, but little signal going straight up for close-range communications that bounce off the ionosphere—a propagation method known as Near Vertical Incidence Skyway, or NVIS.

If you designed a perfect antenna, it would be an isotropic radiator with no nulls; it also would be able to work on multiple bands and have a wide bandwidth, so that antenna changes would be unnecessary as you change channels or bands.  It would be compact in size (4-feet tall x 4-feet long x 1-foot wide) and not disturbed by metal or structures in close proximity to the antenna.  Additionally, it would have a natural immunity to noise and other manmade interference.

In other words, you would have the EH antenna manufactured by Madison, Miss.-based Alpha Cognetics. Recently, we were hired by its inventor, Ted Hart, to evaluate the antenna and determine its radiation pattern. Here’s what we discovered.

Tags:

Related Content

  • Here’s the perfect antenna
    Newscan: Joint alert: advanced hackers have tool targeting industrial-control systems
  • IWCE 2022: FirstNet more than 95% complete; new tech advances adoption
  • T-Mobile sues Florida school district over 5G
  • Russian group Sandworm foiled in attempt to disrupt Ukraine power grid

Commentary


LTE and liability: Why the fire service must move forward with digital incident command

  • 2
6th May 2022

Partnership and collaboration must be the foundation for emergency communications

18th April 2022

FirstNet success means no hypothetical ‘shots’ need to be fired, Swenson says

22nd February 2022
view all

Events


UC Ezines


IWCE 2019 Wrap Up

13th May 2019
view all

Twitter


UrgentComm

Sesame Solar leverages mobile solar, hydrogen to power efforts beyond the grid dlvr.it/ST8m3K

1st July 2022
UrgentComm

Newscan: On front lines, communications breakdowns prove costly for Ukraine dlvr.it/ST7fnC

30th June 2022
UrgentComm

China-backed APT pwns building-automation systems with ProxyLogon dlvr.it/ST6q7m

30th June 2022
UrgentComm

Samsung fills its 2G hole in new challenge to Ericsson and Nokia dlvr.it/ST6hBK

30th June 2022
UrgentComm

Militarized drone swarms coming dlvr.it/ST6dNz

30th June 2022
UrgentComm

Take American City & County’s budgeting survey dlvr.it/ST6Yxb

30th June 2022
UrgentComm

Final cases made about Airwave, ESN, before CMA issues provisional decision on Motorola Solutions dlvr.it/ST4Q6X

29th June 2022
UrgentComm

Polaris Wireless: Manlio Allegra talks 911 Z-axis tech, future IoT opportunities dlvr.it/ST1384

28th June 2022

Newsletter

Sign up for UrgentComm’s newsletters to receive regular news and information updates about Communications and Technology.

Expert Commentary

Learn from experts about the latest technology in automation, machine-learning, big data and cybersecurity.

Business Media

Find the latest videos and media from the market leaders.

Media Kit and Advertising

Want to reach our digital and print audiences? Learn more here.

DISCOVER MORE FROM INFORMA TECH

  • American City & County
  • IWCE
  • Light Reading
  • IOT World Today
  • Mission Critical Technologies
  • Microwave/RF
  • T&D World
  • TU-Auto

WORKING WITH US

  • About Us
  • Contact Us
  • Events
  • Careers

FOLLOW Urgent Comms ON SOCIAL

  • Privacy
  • CCPA: “Do Not Sell My Data”
  • Cookies Policy
  • Terms
Copyright © 2022 Informa PLC. Informa PLC is registered in England and Wales with company number 8860726 whose registered and Head office is 5 Howick Place, London, SW1P 1WG.
This website uses cookies, including third party ones, to allow for analysis of how people use our website in order to improve your experience and our services. By continuing to use our website, you agree to the use of such cookies. Click here for more information on our Cookie Policy and Privacy Policy.
X