Radio Communication 201: Short Range HAM Radio Operation

Introduction

In our primer on radio communications, we began a discussion on how to communicate when telephone service (especially cellular) gets overwhelmed during emergencies or is otherwise unavailable. This is the first in a two part series in which we will narrow our focus to Amateur Radio, also known as HAM radio. While there are a variety of formats and frequencies available within ham radio to transmit and receive information and voice, today we will focus on shorter range formats that are commonly referred to as “line of sight” communications.

Most ham radio use in the US and Canada takes place on two bands in the VHF (Very High Frequency) and UHF (Ultra High Frequency) ranges that are referred to as the 2m and 70cm bands. These refer to the wavelength of those frequency ranges, or the distance from peak to peak on the oscillation of the radio “wave.” Basic in Canada, and Technician in the US, have access to all amateur frequencies above 30MHz, but most use falls into these two bands. The 2m band in ITU (International Telecommunications Union) Region 2, which encompasses North America, runs from 144-148MHz, while the 70cm band runs from 420-450MHz in the US, and 430-450 in Canada. Almost everyone who gets started in ham radio at the very least gets a 2m radio, and many go ahead and get “dual band” radios – those that allow you to transmit and receive on both 2 meter and 70cm.
Most repeaters run on these two bands. 

Worth noting is that there are also a fair number of radios that are capable of operating on the 220MHz (1.25m) band as well. These are more common in areas where there is significant interference on 2m bands, and those same areas tend to have repeaters operating on the 900MHz band as well (which requires modifying public safety and business radios). The 6m band (50-54MHz), while still within VHF, and being accessible to all amateurs in the US and Canada, often shows characteristics of HF (High Frequency) and lower bands, and many HF radios have 6m capabilities as well. There are still a small handful of 6m repeaters in the US as well, but interference from various electronics prevalent in society has led to a decline in the use of 6m FM.

Within these frequency ranges, We will cover FM and three digital modes (DMR, D-Star, and System Fusion). While there are ham repeaters utilizing NXDN and P25 standards, they’re not nearly as widespread, whereas you can find at least one of the other three in most populated areas. 

Frequency Modulation (FM)

FM is by far the most commonly used voice format on the bands we’re discussing. Almost every ham radio on the market designed for these frequencies has FM as an available mode, if not the only mode. Most of these radios also have data ports that can be utilized for transmitting data (such as APRS), which we will cover later. The majority of repeaters in North America are also on FM. There are also segments of the band that are dedicated to simplex operation (transmitting and receiving on the same frequency). 146.52MHz is considered the “national calling frequency” on 2m, and 446.000 serves the same purpose on 70cm. While simplex operations are fairly common among convoys or other short range communications, most use of these bands are done on repeaters. 

The biggest disadvantage of FM is the static that can garble transmissions, especially when at the outer edges of range. Also, with the prevalence of electrical interference in the atmosphere, the wider bandwidth used with ham FM makes it susceptible to interference that impacts the quality of the transmission. The single biggest advantage here in an emergency situation is that there are radios and repeaters everywhere that can utilize this format.

Digital Mobile Radio (DMR)

DMR is a voice format originally developed in Europe for business use. While it is an open source format, none of the purpose built ham radios have options to use the format. It has quickly become one of the most prevalent formats in amateur radio, however, due to the proliferation of business radios (particularly Motorola/Kenwood and companies such as Hytera and TYT). Most DMR ham repeaters are linked via internet, and are affiliated either with DMR-MARC or Brandmeister. This connectivity, in conjunction with being able to program individual talkgroups into each radio, allows worldwide communication with other hams around the world. I personally use DMR extensively, and have made contacts covering most of Europe, parts of Asia, Austrailia, and even areas in the Middle East such as Saudi Arabia. With the use of hotspots using wireless internet sources, I’ve been able to use it on the road where no repeater is available.

One thing to note is that some NWS offices have begun to take advantage of the ability of DMR repeaters within their areas to easily be interconnected. While FM SKYWARN repeaters are still the norm, some offices are now integrating DMR operations into their SKYWARN nets, in conjunction with ARES in those areas. The Memphis WFO (Weather Forecast Office) is one of the more notable ones to do this, and repeaters within their CWA (County Warning Area) have specified talkgroups for SKYWARN operations. Oklahoma ARES is working on a plan to intergrate this resource as well for use in the Norman and Tulsa CWAs, although it’s only in the planning stages currently. Even in local repeater and simplex modes, DMR is an excellent alternative to FM analog that offers significant advantages in voice quality. As such, more and more emergency oriented ham organizations are at the very least including it as an available resource to use during emergency situations.

The biggest disadvantage of DMR is that the radios are not ham specific, and as such, do not allow for front panel programming without modification. Programming is done via computer software. Software for MotoTRBO (the Motorola branded DMR equipment) in particular is expensive, although the radios are rock solid in terms of reliability. With that said, when purchasing Motorola radios for the UHF range, the R1 (403-470MHz) range is what is desired. While R2 (450-520MHz) radios can be hex edited down to 440MHz, this is an added level of complexity for a novice operator. Kenwood programming software is less expensive, but since the radios involved are much newer, and usually include NXDN as a format, they’re typically more expensive. The cheapest option to get into DMR is primarily through the various Chinese manufacturers. Of these, the Hytera and TYT radios are the only ones that are generally considered reliable, and the TYT is going to be the only reliable option for a dual band DMR radio.

D-STAR (Digital Smart Technologies for Amateur Radio)

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D-Star is one of the early digital formats, and one that was created specifically for amateur radio use. Created by the Japanese Amateur Radio League, it spread into worldwide use even before DMR was created. While it can be used in simplex or in local repeater operation in the manner that DMR and other modes are used, it is primarily used in conjunction with internet linked repeaters. Much like the DMR standard described above, there are repeaters (and hotspots) in use all over the world, and linking with the right “reflector” enables worldwide communication. 

While it is exclusively used in ham radio, there are only two companies currently making D-Star compatible radios, Icom and Kenwood. With the limited number of compatible models, the entry price for D-Star tends to be more expensive than with other modes. Voice quality tends to be slightly lower due to age of the format, although better than FM analog in most cases. Much like the DMR radios that we’ve already discussed, and the System Fusion that we’ll discuss next, radios are able to operate either in digital voice mode or in FM analog. 

Unfortunately, the linking and unlinking of reflectors can be a complicated process, and all but the most experienced operators have to keep a manual handy to help keep things straight. With that said, much like DMR, it is utilized during emergency situations at times, most notably, during the preparation for landfall of a tropical system. Both DMR and D-Star have talkgroups (or reflectors in the case of D-Star) set up solely for tropical cyclone nets in the United States.

Yaesu Sustem Fusion (YSF)

YSF is one of the more recent additions to the arena of digital radio formats. Much like D-Star, it was created exclusively for amateur radio operation. Being a new format (introduced in 2013), there aren’t as many compatible radio models available as there are for other modes, but it does offer some of the best voice quality that can be had on a digital mode. Unlike D-Star, most YSF use is on local repeaters, although most are connected to the internet. The single biggest benefit of the actual repeater equipment with YSF is the ability to run both analog and digital. While DMR and D-Star repeaters are limited to their respective modes (even though the radios themselves are not), YSF repeaters can switch between FM analog and YSF, either by manually setting the repeater or by letting it decided based on the transmissions that it receives. The radios can be set in a similar manner, and I generally allow both of my YSF radios to automatically detect what mode it is receiving. 

The primary downfall to YSF is the fact that is a proprietary format created by Yaesu. To our knowledge, there are no plans on their part to even allow other manufacturers to build compatible radios, let alone companies that would like to do so. As a result, entry price can be rather high. Older YSF radios, as well as some with less features (such as the FTM-100) can be bought for lower prices, although the APRS capable radios will certainly be more expensive, which is true for any APRS capable radio. 

Automatic Packet Reporting System (APRS)

This is the final format that we’re going to cover today. Contrary to popular belief among hams, APRS is not a position reporting format. It is a full two way communication system that enables hams to quickly relate information to one another, and to even query fixed stations for information. Early on in my storm chasing career, before mobile internet (and the easy access to METARS information that came with it) I was able to use APRS to query stations (primarily airports) for weather information. While time consuming, it allowed manual plotting of surface observations and the drawing of a surface map to understand what the atmosphere was doing on that particular day. Each region in the world has a set frequency that has been agreed upon for APRS use. In all of North America, 144.390MHz is the designated freq for 2m. 

APRS also allows for messaging individual operators. While APRS repeaters (referred to as digipeaters) are linked to the internet, they primarily function as a relay system. Radio A sends a signal that’s picked up by digipeater A, which is relayed to digipeater B, which is relayed to radio B. In an emergency situation, even if internet is down, messages can be relayed well outside of the range of VHF and UHF voice communications. For some radios, the TNC (Terminal Node Controller) can be linked up to a GPS, tablet, or even a computer to display and (in the case of the tablet and computer) to input data for transmission. 

As useful as APRS can be, radios that having built in GPSs and TNCs are expensive. The Kenwood D710G is considered the gold standard for APRS, as it as an unlocked TNC that can be accessed by a computer. The downside is that the radio itself is analog only, so none of the aforementioned digital modes can be utilized. The earlier D700 also has an unlocked TNC, but it’s more difficult to find and has limited memory vs the newer D710G, which unfortunately is also the most expensive mobile APRS offering as well. The Yaesu FTM-400 series radios are YSF compatible and have built in APRS capabilities, but the TNC is locked. That said, there are ways to at least display the information onto a map, and it’s not hard to connect an external TNC to one as well. With that said, any radio can be used for APRS with use of an external GPS and TNC. However, most radios cannot do dual monitor or transmit, so using such a radio limits you almost exclusively to APRS use for that particular radio.

What radio should I buy?

This is ultimately a personal decision that every operator has to make on their own. Some (like myself) have preferences of one brand or another. Among the “Big 3” (Yaesu, Kenwood, Icom), however, that’s all it is, preference. Any radio from those three brands will be excellent choices. Alinco has also emerged as a brand that makes quality equipment, as has Hytera. Note that DMR requires the use of commercial radios, and of those Motorola, Kenwood, and Hytera are the three best options in our opinion. We strongly recommend against Baofeng, as they have numerous issues with quality control and spurious emissions. Many repeater owners have prohibited the use of Baofeng radios on their repeaters for that reason. As a storm chaser, I find it more useful to utilize commercial radios for SKYWARN repeater use, as frequencies can be organized into zones (in this case, each zone represents an NWS County Warning Area, or CWA). That means two separate radios are utilized, one for 2m and one for 70cm, but it’s also much easier to find the appropriate frequency based on location. The Motorola XPR4550 I use on 70cm also allows use of DMR, which is increasingly utilized by SKYWARN organizations. Ultimately, each person needs to evaluate what modes are most common in their area and choose a radio that utilizes those modes.

Just as important as the radio though, is the antenna and the coaxial cable that connects the two. I highly recommend no less than RG58 coax, preferably in as short of a length as you can run. The shorter the run, the less loss you have between radio and antenna. For dual band antennas, Comet or Diamond is the way to go. While NMO mounts are preferable, there’s nothing wrong with the traditional UHF mount unless space is an issue, or you prefer to mount an antenna directly on the roof or trunk lid. We cannot in good conscience recommend any mag mount antennas. At best, they ruin the paint on the roof and negatively impact the ability to receive and transmit, especially at longer ranges.

Conclusion

As we mentioned in our primer on radio communications, ham radio can be an invaluable resource when traditional communications, particularly cellular, are down. It is also utilized as a primary means for reporting things such as severe weather. Most emergency management organizations, as well as NWS offices, have amateur radio capabilities. Ham radio has been a critical part of responding to emergencies such as 9/11, Hurricanes Katrina and Maria, and other significant events that required a large scale response. At the very least, obtaining a technician license is something that we would recommend to anyone who subscribes to the ISG mindset. Everything that this article touches on is accessible to Technician level ham operators (or Basic in Canada). Find a local club, study and test, and get on the airwaves to hone your new craft. 

Best to everyone,

Drew

Drew is a 12 year veteran of the US Army who has had a lifelong fascination with weather and the outdoors. Growing up in Northeast Oklahoma, he learned at an early age how to work with cattle and horses, and began riding even before he was tall enough to climb up himself. During his time in the Army, he gained experience in mounted operations and in logistics as part of Armor and later Cavalry units, as well as managing communications under operational conditions. A long time HAM operator and veteran storm chaser, he’s observed and called in numerous severe weather events, is a member of ARRL, and active within local ARES and local ham radio clubs.

His interests include working on various types of vehicles (both old and new), shooting, archery, sports medicine, martial arts, weather forecasting/chasing, and radio communications (especially with regards to emergency management). He also enjoys photography (both digital and film), as well as working with computers. He has a special affinity for the land stemming from childhood, and enjoys hunting and fishing, in addition to working with horses and cattle.

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