Antenna Polarization
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Our recent NVIS (Near Incidence Vertical Skywave) experiments brought to light a discussion of antenna polarization. Does it matter? Does it impact NVIS? Absolutely and absolutely.
First, lets talk about polarization on VHF. We all generally run vertical antennas when running VHF-FM. It works well when reaching out to repeaters or attempting point-to-point simplex communications. However, if two operators are attempting to communicate VHF-FM and one is horizontal and one is vertical, they will have issues. The E-fields are oriented perpendicular ("cross-ways", so to speak), and the loss of 10db-20db, signal degradation to 1/10th to 1/100th, is the result. It's just the nature of how radio signals are picked up by the antenna. In this case, compatible orientation is vital.
Things are a little different with NVIS, and there are other considerations with HF. If you are running NVIS then horizontal polarization is effectively required. A dipole will radiate signals overhead and to the horizon, and the closer to the ground then antenna is the less towards the horizon the signal goes, deflecting a larger and larger percentage of radiated signals vertically.
NVIS is typically a 80M-40M bands method, because the higher the frequency the less likely you'll be to get the signal to reflect off the overhead atmosphere. If you run a vertical antenna then your signal is going to be vertically polarized and be headed towards the horizon, not straight up. Verticals just won't work for transmitting NVIS. But, unlike VHF-FM, polarization isn't a complete show-stopper.
An operator using a vertical can communicate with someone operating NVIS. Once the signal hits the atmosphere polarization goes out the window. The reflected signals are scattered and disorganized - oriented in all directions. Therefore, a more distant station will be more likely to pick up a transmission once it has been reflected back to Earth. Likewise, that vertical-antenna station will also have its signals scattered in such a way that a NVIS/dipole operator could receive their signals! It isn't necessarily optimal, but it happens.
In close quarters (less than 50 miles from each other), as most of our stations operated in our NVIS test, you see more effects of attempting horizontal-to-vertical communications. With enough power and/or other obstacles for a signal to bounce off of, we will see "random" local contacts that don't seem to follow the rules. But these will be the result of reflections off ground objects or ground-wave as a general rule.
So, while HF is more forgiving of polarization differences, it is not immune. The fact that polarization becomes less of an issue once the signal reflects off the Ionosphere is great for our purposes; it extends our ability to communicate to more stations at the outer reaches of our NVIS coverage area, allowing us greater ability to communicate during an emergency.
Amateur Radio, ARES, and RACES
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In previous ARES presentations I have made reference to other entities that either provide Emergency Communications services, or need the ability to utilize them during an emergency.
While we focus on the Amateur Radio Emergency Service (ARES), sponsored by the ARRL, for providing emergency communications, the only entity recognized formally in FCC regulations is the Radio Amateur Civil Emergency Service (RACES). So what is RACES, and why do we hear so little about it?
QRP And Amateur Radio
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While many operators tend to operate using the 100W or 200W their radio provides, and yet others use external amplifiers to run hundreds, even more than 1KW, there are others who operate at the other end of the spectrum, 5-10 Watts.
QRP operation is often practiced by operators participating in Parks On The Air (POTA) or Summits On The Air (SOTA), who are often hiking or backpacking their equipment to the operating location, carrying their power source with them. Naturally, packing a Marine Battery would be a bit of a challenge, so smaller and lighter batteries with lower power capacity are used.
Due to limitations in available power the operators naturally run less power, usually 20W or less. QRP is generally considered 5-10W, but even 20W is possible with more efficient modern equipment and Lithium batteries.
Disaster Preparedness Month 2025
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September is National Preparedness month, and we'll continue our discussion of preparedness. It is fitting we cover the topic as a group, but even more so at home with your family.
Recent discussions have included a variety of people volunteering information about their preparation efforts (or lack of). The most recent West Georgia Amateur Radio Society (WGARS) featured a discussion between Sierra (K4SBE) and John (WD8LQT) regarding her deployments to disaster areas. That discussion focused on catastrophic events where, quite frankly, there is little any of us could do beyond wait for help (i.e. houses destroyed, infrastructure inoperable, etc). Probably the best advice for these types of events, especially if we know they are coming, is to wear a full set of clothes, even when going to sleep - so if something does happen you have some basic personal protection from the elements! We hope to have a video of that discussion available soon.
Third Party Traffic
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When we discuss Amateur Radio and handling traffic, either formal or informal, we tend to think of actual Amateur Radio Operators at the microphone, key, or computer passing information. However, particularly when moving tactical traffic, it may be beneficial to let the third party have the microphone, or type the message into a Winlink email.
Section 97.115 provides for allowing third party traffic as long as the control operator, a licensed Amateur Radio Operator, is in control of the station and monitoring the activity. All requirements that would apply to a typical contact would apply (identifying at proper intervals and at end of communication, use of non-coded communication, avoiding profanity, etc).
Will We Or Won't We (Deploy)?
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During Field Day (2025) a discussion of work being done outfitting the WGARS communications trailer digressed into a debate of whether Amateur Radio operators would ever really be deployed in a local emergency. One operator insisted it would never happen, while another acknowledged the probability was low, but it was not outside the realm of possibility.
The discussion was mostly centered around the fact that post 911/Katrina government communications systems are better integrated, allow various levels of inter-department and inter-agency communications
Deployable Antenna Support Systems
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We've spent a lot of time discussing training for deployment, what personal supplies we'd bring to a deployment, and what radio gear we would bring along, but what to do for antennas?
Yes, roll-up or J-pole antennas have been discussed often for years; to a lesser extent we have discussed low-flying HF (NVIS) antennas. We never know where our deployments may send us, and in many cases trees or other antenna supports may be some distance away, so extra coax and/or rope will be handy in those instances.
NTS and ICS-213 Messages
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Note: Images may be clicked for enlarged view
The National Traffic System (NTS) has provided a means of passing messages (usually referred to as traffic) via Radiograms for almost as long as amateur radio has existed. Before long distance telephone was common, and until the
Should You Use UTC Or Local Time?
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The use of "local", Universal Time Coordinated (UTC/Zulu/GMT), or a specific time zone (like Eastern) when specifying the time a message was created or a net is scheduled, or even passing the current time over the net can create confusion for all involved, especially when nets or message traffic cross time zones.
Here, in Carroll County, Georgia, we are close enough to the Central time zone that their and our VHF net times are "one hour off" from each other.
Other Benefits Of Field Day
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We've discussed the usefulness of Field Day as an EMCOMM training exercise as well as a fun weekend event. We've talked about the benefits of having deployment ready equipment, especially antennas and patch cables. The same equipment used on field day can be easily deployed to ad-hoc shelters, hospitals, or other locations. Field Day preparation, setup, and operation allows for testing, debugging, and finally operating equipment, ensuring the equipment is actually functional and ready for use during an emergency.
There are other benefits of Field Day beyond those above, some only marginally applicable to Emergency Communications, but still very useful. These include educational sessions and, in some cases, other activities.
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