NI4CE regional linked repeater system


A Little Perspective

Are You Prepared?

By The Numbers


Emperical Evidence

The Ham Radio Repeater (Part 1)

The Ham Radio Repeater (Part 2)

The Importance of Digital Radio

The Power of APRS

Your First Radio (Part 1)

Your First Radio (Part 2)

Your First Radio (Part 3)

Your First Radio (Part 4)

Your First Radio (Part 5)

Why SKYWARN Is Important

By Paul Toth-NB9X

If you live in Florida, anywhere in Florida, the last week has been extraordinary. For many, life is getting back to “normal”, if you define “normal” as electricity from a power utility, air conditioning, a hot shower and most if not all the other conveniences of life prior to Hurricane Irma. For many others, however, “normal” is still an elusive target. And Hurricane Season still has a long way to go.

The last time Florida experienced a storm that ran up the center of the state and affected so many people was Hurricane Donna, exactly sixty-seven years ago. I wasn’t living in Florida at the time. But those who experienced Donna first-hand did not have the satellite imagery, the Tropical Cyclone forecasting and the other technology now in place to prepare them for what was about to change their lives. A couple Donna survivors I have talked with have told me the impact of Irma was much worse. I wonder if the all the pre-storm anxiety, the long lines at gas stations, food stores, Home Depot, Lowes and other stores wasn’t part of their assessment.

Floridians in 1960 did not have the vast communications resources and networks we have today, either There were no cell phones, Facebook, Twitter and the like to share the experience with others. Heck, Ham Radio and SKYWARN had barely met in 1960 to provide real-time information on the storm, where it was going and who would be impacted the most. Of course, there were a lot fewer people in Florida in 1960 than today. It was a simpler time and place.

We are not going to know the full extent of just how bad Irma was for a few months. For those of us who lost our utilities and were inconvenienced for a few days, the impact will be far more fleeting than those whose homes are flooded or otherwise severely damaged. I can only hope that whatever Irma’s impact was on your neighborhood, you took the opportunity to get to know your neighbors a little better and help them out if you could. And I hope everyone will take this experience and acknowledge what worked, what needs improvement and be better prepared for the next storm that will barge into our lives.

I want to take a moment to acknowledge some extraordinary efforts that helped keep people informed before, during and after the storm. A tip of the hat to Evans Mitchell-KD4EFM and Jason Triolo-KD4ACG for their efforts both collecting and disseminating information about Irma on NI4CE. They kept the SKYWARN Net running under very tough circumstances. Another tip of the hat to our partners at Cox Media Group, iHeart Radio, American Tower Corp. and Polk Co Emergency Management for keeping the generators running, allowing the NI4CE system to remain on the air and available for the Ham Radio community. Downed trees and power lines at the Holiday site made re-fueling the generators there a real exercise in “adapt, improvise and overcome”. And a big thumbs up for the Hams who manned shelters and are aiding in the recovery effort.

Hurricanes like Harvey, Irma and Jose and all those that preceded them serve a necessary purpose, that is, to evacuate an extraordinary amount of heat and energy from the surface of our planet. Hurricanes have been doing this long time, long before all the chatter about climate change. It is part of Mother Nature’s grand schema to keep out eco-system in balance. It is unfortunate so many lives must be disrupted in the process.

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By Paul Toth-NB9X

I have written before about Digital Two-Way Radio, the several flavors of digital radio that are currently available. I have also discussed what some of the differences between these Common Air Interfaces (CAI) are and why the West Central Florida Group, Inc. made NXDN as its choice for the digital repeaters we operate.

One thing I have not gotten into is WHY digital two-way radio for VHF and UHF is important to the Amateur Radio community here in West Central Florida and for that matter, to Hams everywhere. Once you understand that, I think you will agree it is something we all need to take seriously.

Hams have not been mandated by the FCC (or any other body yet) to go Narrowband on VHF and UHF. We have been allowed to continue operating with 25 KHz, wideband FM (WBFM) signals on these two important bands, unlike commercial, Land Mobile Radio operators. But don’t believe for a minute that 12.5 KHz Narrowband FM (NBFM) operations will never come. Many newer “Ham” radio products will operate in NBFM mode. It is not s matter of “if” but rather a matter of “when” this will occur.

What is narrowbanding all about? It is simple: Doing More With Less. Narrowband FM operations can enable up to twice as many radio channels for both repeater and simplex operations. But there are some significant drawbacks with Narrowbanding many Ham have yet to discover. One big drawback is loss of coverage. Narrowband repeaters generally experience a twenty-five percent or more loss of their coverage footprint versus their current WBFM operation. That’s HUGE! This loss of coverage will cause more instances of weak signal reception and loss of reception altogether. Another downside is the impact of more repeaters on the air. More repeaters can increase the probability of Intermod, when two or more signals from different sources mix to create a spurious signal.

So WHY is digital so important? And WHY should Hams start paying more attention to DIGITAL? Again it’s all about “doing more with less”.

NI4CE selected NXDN as the digital mode we would support for several reasons. NXDN radios operate with 6.25 KHz channel bandwidth. But instead of suffering a loss of coverage, NXDN actually provides a ten percent or more increase in coverage when compared with a WBFM signal. NXDN voice is clear, no static, no “snap-crackle-pop” even when the received signal strength in analog would be noisy and unreadable. NXDN radios can also be used to deliver text messaging and GPS location data. And the process of connecting NXDN repeaters over IP / Internet to form a repeater network is very simple and straightforward.

End user NXDN radios are readily available and feature rich, There is more than one manufacturer producing NXDN radios. And support for the development of applications for the Ham community is also available.

To help Hams in West Central Florida know more about NXDN, we have set up the NI4CE-NXDN email group. You can join the discussion by sending an email to We will be happy to add you to the list. And watch the website for news about a NXDN Net on the NI4CE NXDN Repeaters coming soon.

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By Paul Toth-NB9X

As we, once again, celebrate the Fourth of July and the freedoms we enjoy here in the United States, it is easy to be reminded that freedom (and all good things for that matter) is something we cannot become complacent about. Freedom is a precious commodity something we must work at every day. It does not just happen all by itself.

Ham radio and the freedom to communicate freely is the same way. No one, to the best of my knowledge, was born with the knowledge and skills needed to use technology, any technology, to convey ideas, solve problems or just “shoot the breeze”. Using wireless technology, including Ham Radio equipment, is a learned process. If you don’t believe me just tune in to any repeater system and witness the number of key-ups or “kerchunks” followed by dead silence. Those of us who are Volunteer Examiners were called on to administer Morse Code tests to evaluate the ability of Ham Radio license candidates to operate with Morse Code. I sometimes think we need some sort of Phone Proficiency exam as part of the testing process to make sure that operators actually know what to do once they have pressed the Push-To-Talk button.

But back to the topic of “complacency”. It has been thirteen years since those of us on the West Coast of Florida experienced a major disaster. Someone said to me the other day we need a good hurricane or some other type of disaster event to shake everyone out of their complacency and not take everything for granted. By nature, humans, including those of us with an Amateur Radio license, tend to get into a “comfort zone” and stay there because it is the easy thing to do. We avoid taking on challenges or thinking outside the box unless it is something we are really motivated to do.

Unfortunately, we live in a world where the challenges are growing in scope and in number. There are the natural threats (like severe weather and hurricanes) that we can get some prior warning about. And then there are the manmade threats for which we will receive almost no prior warning.

One threat we need to take seriously is EMP – Electro Magnetic Pulse. EMP can occur naturally, the result of sunspot solar flare activity and lightning. EMP can also be manmade on a scale that can range from something very localized to a catastrophic, existential event. The loss of the electric power grid and most electronic communications (including Ham Radio) that we rely on daily could have an enormous impact.

There are several actions you can take to mitigate the threat from EMP. First, protect your radio equipment with EMP-rated devices, like PolyPhasor Lightning Protectors. The West Central Florida Group, Inc. has been using EMP-rated lightning protection for over a decade at our several NI4CE repeater sites. Second, build a Faraday Cage and place one or more radios into it for safe keeping. Third, think about all the things you need electricity for and what you would do if the lights went out. You will find this goes well beyond communications. Finally, raise your voice with your elected representatives and electric power provider about the work that needs to be done to shore up the Electric Power Grid in the United States. Several studies conducted over the last two decades have concluded the electric grid is at significant risk from an EMP event. One of these studies has determined the power grid can be strengthened and made more secure at a cost of around $2 billion. Complacency about this problem and its potential impact, however, has led to inaction. Not good enough!

Take stock of the freedoms we enjoy this Independence Day Week. And if you will be cooking some burgers on the grill, I’ll take mine medium rare!

By Paul Toth-NB9X

For those of you who may have missed the Tech Net last Thursday evening on the NI4CE Repeater System, I thought I would share some comments I made concerning an equipment heating issue we recently solved.

The problem first showed its ugly head several months ago when we installed a new RF power amplifier at the Verna Repeater Site. The new amp boosts the output power of the 145.430 MHz VHF repeater there. To achieve the rated power output of the amplifier, we needed to feed it with two watts from the repeater. Sounds simple enough, just dial back the power output and all is good.

Shortly after the amplifier went into service, problems began cropping up. During a Net where both the repeater and the amplifier were in transmit mode for an extended period of time, the output power dropped to almost zero. The symptoms suggested an overheating problem. Was it the repeater or the amplifier? Since the repeater had been in service for an extended period of time and without incident, it was logical to suspect the amp. A fan was placed in front of the heat sink to provide additional heat dissipation. That seemed to work for a while.

But alas after a few weeks, the problem showed up again. And this time, it persisted.

Troubleshooting the repeater got a lot easier with the development of a Windows app and direct IP connectivity that allowed us to monitor the repeater’s core temperature in real time. It did not take long to conclude the repeater, in fact, was where the heat issue resided. The temperature inside the repeater chassis rose quickly during Nets and other periods of extended transmit operations.

To provide better heat dissipation, one of the WCFG Board members (and a retired engineer) Paul Knupke-N4PK, resurrected a desire that has been in place for several years at the NI4CE Riverview site. He modified a rackmount shelf and attached two high volume four inch fans that would blow air across the heat sink and chassis of the VHF and its companion UHF repeater. We tested the impact of the additional air flow in a controlled environment similar to the Verna Communications Room. The data collected confirmed this design worked keeping both repeaters within their published operating temperature. Since this modification has been installed, both repeaters are operating within normal parameters, even during extended transmit periods.

The important take away from this experience is the importance of gathering empirical data to support your troubleshooting hypothesis. In this instance, the problem was excessive heat generation. But the initial culprit, the external power amplifier, was not the culprit. It was the repeater, a piece of equipment that operating within its rated one hundred percent duty cycle power output. Had we not been able to measure the internal core temperature of the repeater, we might still be chasing the problem.

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By Paul Toth-NB9X

Most Hams, particularly those operators new to Ham Radio, use one or more VHF or UHF repeaters to communicate with their local Ham Radio friends. The repeater is that magic box that enables you to communicate more than a mile or two, particularly if you are using a portable radio.

So what is a repeater? How does it work? Why do some repeaters cover more territory than others?

First, let’s talk about the radio side of the repeater. Most portable and mobile radios operate in half duplex mode. That is, they transmit and receive but not simultaneously. That’s called Half Duplex mode operation and is the “norm” for two-way radio. Repeaters, on the other hand, receive an incoming signal (uplink) and then immediately re-transmit that signal (downlink) on a different frequency. In the VHF band, the uplink signal is usually 600 KHz above or below the downlink signal. In the UHF band, there is usually a 5 MHz difference between the uplink (mobile and portable user) and the downlink (repeater output).

A repeater can use one antenna to receive the uplink signal and a separate antenna to transmit the downlink (repeater output). The antennas usually require some amount of vertical separation, usually 20 feet for UHF, 30 feet or more for VHF. If that vertical separation cannot be achieved, a single antenna can be used to receive the uplink signal and transmit the downlink repeater output. In order to keep the local transmit signal from causing interference and feedback into the repeater’s receiver, a set of RF filters, called a duplexer, is now part of the repeater system.

Duplexers come in various shapes sizes and configurations. The filters are tuned to pass the specific frequency that is being received or transmitted, nothing more, nothing less. Most duplexers consist of four filters, two for receive and two for transmit. As you increase the power output of the transmitted signal, more RF filtering is usually required on both the receive and transmit side of the equation.

A repeater system can incorporate a receive Pre-amp. This boosts the strength of the incoming uplink signal by 15 dB or more. To boost the strength of the repeater’s output (downlink), an external Power Amplifier can be used.

Many Ham repeaters use an external Repeater Controller to enable Station IDs, announcements and connections with link radios or other audio sources like a Weather Alert radio.

All of the active components (e.g. repeater, controller, receiver pre-amp, RF power amplifier) all require electrical power to operate. That’s where a 13.8 VDC Power Supply (sometimes with a Battery Backup) comes into the picture.

Finally, there is the transmission line and Lightning Protection. If the repeater is on a building top, like an apartment or condo building, a hospital or a tall office building, your cable can be relatively short. However, if your antenna is mounted in a tower, your cable can be quite long and lose a lot of signal along the way.

We’ll discuss the challenges of operating a repeater in our next post.

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By Paul Toth-NB9X

In our last post, we detailed the several different components that make up a typical Ham Radio repeater. If you were not aware of how many working parts there are in most repeaters, don’t feel bad. Most Hams just think of a repeater as a “black box” and never get into the intimate details to appreciate the complexity.

One of the questions we posed in our last post was what determines the geographic area a repeater covers. The downlink transmit power of a repeater is one determining factor. Another factor is the efficiency of the coax cable and antenna. What determines the Effective Radiated Power (ERP) or a repeater is a complex equation: Transmitter Power Output – (Duplexer Loss + Coax Cable Loss) + Antenna Gain. For example, if your repeater output is 50 watts, Duplexer Loss=3 dB plus Coax Loss=3 dB, with an Antenna Gain of 3dBd, your Effective Radiated Power will be 25 watts.

The biggest determining factor of just how far a repeater will be able to receive and transmit is Antenna Height. An antenna located one hundred feet above ground level (AGL) will have a line-of-sight horizon line of 11.89 miles. By comparison, a repeater antenna located at 1,000 feet (AGL) will have a line-of-sight horizon line of 37.60 miles, quite a difference. The formula for determining the horizon line for a repeater is SQRT(1.414*Ant Ht (in feet)). Because radio waves can go beyond the line-of-sight horizon, the formula for determining the Radio Horizon is SQRT(1.414*Ant HT)*1.333.

The NI4CE system is much more than a collection of stand-alone repeaters. Our five sites are strategically located and constructed to optimize coverage. But more importantly, by linking the five sites together, many parts of West Central Florida’s most densely populated counties enjoy overlapping coverage from two or more sites. This design is not by accident and affords many operators the ability to access the system from more than one site.

Building and maintaining a repeater system, whether it is a one site system or the five site system that is NI4CE, is a challenging and costly endeavor. But without repeaters, like NI4CE, Ham Radio’s ability to use of the 2 meter (VHF) and 70 cm (UHF) bands would be severely limited. Now that you know what goes into a repeater system, we think you will have a much better appreciation of all the repeaters that are on the air here in West Central Florida and the role they play in your Ham Radio life.

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The Power of APRS
By Paul Toth-NB9X

Ham Radio is sometimes more about the technology than applying available technology to solve a problem or a need. It has also been, over the years, a proving ground for many of the communications technologies we now use in everyday life. This article is about a Ham Radio technology that is a very practical solution that benefits everyone.

We know this technology by its four letter acronym, APRS. That’s short for Automatic Position Reporting System. APRS is a mix GPS technology, mapping software and Ham Radio. Its roots date back to the early 1990s at the U.S. Naval Academy in Annapolis MD where Professor Bob Bruninga was looking for a low cost method for tracking Midshipmen as they conducted maneuvers on the water.

Today, in the commercial world, the practical application of APRS allows transportation companies to track their fleets, provides firefighters and other in Public Safety situational awareness at events large and small and pizza drivers the needed information to get you your pie while it is still hot.

But APRS has turned into much more. In 1997, twin identical brothers, Keith (WU2Z) and Mark (KB2ICI) Sproul, teamed up with another Ham Radio operator who was heavily involved with the National Weather Service SKYWARN program in New Jersey to expand APRS’ mission. They were the first to bring the transmission of live weather telemetry to APRS as a practical transport. Hundreds of Amateur Radio weather stations beacon temperature, wind, barometric pressure and rainfall data in real time to enhance the SKYWARN program. The data from these weather stations also supplement data from NOAA sensors to help forecasters plot tomorrow’s forecast.

APRS weather station data can provide accurate, real time information on rainfall and wind speed and direction to trigger severe weather warnings. That data is also used to tell forecasters whether radar estimates of precipitation are accurate. And sometimes, that data can be used to track a storm. Such was the case in 2004 when APRS weather stations here in West Central Florida provided a means of tracking Hurricane Francis when other instrument data was offline because of the storm.

The West Central Florida Group operates a number of APRS Weather Stations and Digipeaters to support the network here. Other Hams, including Dave-KG4YZY in Pasco County, Polk County Emergency Management and Highlands Co. Emergency Management have joined the effort. And so can you. All you need is a weather instrument sensor package (some of the most popular are from Peet Brothers in St. Cloud, FL and Davis Instruments), a two meter radio to operate on 144.390 MHz, a TNC, like the Kantronics KPC-3+ or the new WX3in! controller and an antenna system. Once your station is on the air, you will want to register it with the National Weather Service’s Community Weather Observer Program (CWOP). You can do so online at

If you are a licensed Ham and are operating a weather station on the Internet only, exercise your operating privileges and put your station on the air.

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By Paul Toth-NB9X

The 2017 Hurricane Season officially begins this week.  Unofficially, it got underway several weeks ago with a bona fide Tropical Storm that spun for several days in the Central Atlantic.  And if the forecasters at the National Hurricane Center are to be believed, we may be in for an above average season, possibly the most active since 2005.

A few weeks ago, I was re-discovering a portable radio I purchased about ten years ago.  When I acquired my Kenwood TH-F6A, my motivation was to have a Ham Radio transceiver that could transmit and receive on 2 meters (VHF), the 222 MHz band and 70 cm (UHF).  At the time, I knew a couple other Hams who had purchased the radio and were happy with how it operated.  So, I took the plunge.

While re-discovering the radio and what it could do, I was pleasantly reminded the F6A had a really cool feature that every Ham operator needs to have at their fingertips, particularly during large scale emergencies.  That feature is the ability to receive Broadcast AM and Broadcast FM stations.  The F6A also tunes the three domestic Broadcast Television bands, too, although the migration of TV stations to digital now makes this capability a moot point.

Why is the ability to receive AM and FM broadcast stations so important?  In a large scale emergency, broadcast stations, particularly those who are the designated EAS LP1 and LP2 stations, are an authoritative resource for information vital to the community.  These broadcasters have direct links to local and State Emergency Managers and other authorities whose job it is to mitigate the disaster, whatever it is.  This includes information on road closures, power outages, emergency ice and water resources and much more, including the weather forecast.  These broadcast stations can operate for as long as necessary on generator-based backup power.

After the Hurricane Charley disaster thirteen years ago, I spent a day serving as a liaison between Charlotte Co. Emergency Management and the local AM-FM broadcast station in Charlotte County.  My task was to convey information transmitted to me via Ham Radio to the radio station so they could then relay it to the general public and those most severely impacted by the storm.  It didn’t hurt that I am an ex-broadcast journalist and could take raw information and turn it into an easy to read script.

As our society has become more cellular and wireless data centric, we need to be reminded these resources will be the first one to go down in a large scale disaster.  That’s why having a battery-powered radio capable of receiving local AM and FM broadcast stations is vitally important.  Much to my delight, that capability is part of my multi-band Ham Radio transceiver that is always close by.

Should a tropical weather system threaten West Central Florida, the NI4CE Repeater System also stands ready as a communications and information resource you can count on.

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By Paul Toth-NB9X

Even though Ham Radio is all about “wireless communications”, getting the RF signal from the radio to the antenna efficiently and effectively requires using the right cable. That sounds easy and it is. But it requires a bit of education and some calculation to come up with the numbers and the right cable selection.

First, let’s shine a little light on your cable options. There are many different kinds of coaxial cable on the market. Two-way radio for Ham and commercial use is designed to use fifty ohm cable. That will provide your radio with the best impedance match, lowest power loss and lowest reflected power.

There are lots of different fifty ohm cables to choose from. Let’s focus on some of the more popular cables. They include RG-58U, RG-8X, RG8U, RG-213, LMR-400, Belden 9913 and LMR-600.

Most mobile installations require a cable that is relatively thin, flexibility and something that will not break easily. RG-58U and RG-8X are most often used because they use a stranded center conducted. These two cable types work because the length of cable required is usually short, less than twenty feet. Even at that length, the loss you can expect from RG-58 is typically 2 dB. Using RG-8X nets a loss of 1.6 dB. If you are using a quarter wave antenna with a gain of 3 dBi or 0 dBd, you will experience a NET LOSS.

RG-58 and RG-8X are not the most efficient cables to use for a Base Station application. Here, you want something beefier. A fifty foot run of RG-8 will net you a loss of 1.2 db at 146 MHz, 2.2 db at 446 MHz. RG-213 has similar loss numbers. Time Mirror LMR-400 lowers the loss at 146 MHz to 0.8 db, at 446 MHz to 1.3 db. Belden 9913’s numbers are similar. If you are looking for even lower loss, LMR-600 reduces the loss at 146 MH to 0.6 db and at 446 MHz to 0.9 db.

What makes one cable type better than another? The most dramatic feature is the gauge of the center conductor. RG-58 is a stranded, 20 AWG (0.033”) wire. By comparison, LMR-400 and Belden 9913 uses a solid core center conductor that is 0.108” in diameter, 10 AWG or what is used for most 20A electrical circuits in your home.

Times Mirror has an easy to use Cable Performance Calculator on their website that makes it easy to determine which cable type is best for your application. Go to:

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By Paul Toth – NB9X

When I was first licensed over twenty years ago, I was faced with the same daunting challenge that every new Amateur Radio operator faces: “What should new FIRST Amateur Radio purchase be?” Should my first radio be a Portable I can take everywhere? Should it be a Mobile radio that I can use as a Base Station (with a power supply) or in the car? Decisions, decisions, decisions. Well, here is what I decided.

My first radio was (wait for it) a MOBILE radio. A curious choice you are thinking. But in retrospect, if I had to do it again, I would make the same choice. Here’s why.

Portable radios, no matter the brand or model, are limited in their power output. Now, if the repeater you are trying to talk through has an output of fifty watts and the portable radio you have chosen transmits at five watts, you will be operating at a distinct disadvantage. That difference in power output is 10 dB. That may not sound like a big difference. But believe me, it is. Now, let’s compare Antenna Gain. The repeater is probably using a high gain antenna to boost the Effective Radiated Power by 6 dBd to 10 dBd, maybe even more. But comparison, most portable radios are outfitted with antennas that have a negative gain maybe as much as -4.0 dBd. Now, add up the differential and, as you can see, that portable radio you are trying to use has a -20 dBd or more disadvantage. And just got good measure, let’s say you are trying to use your portable radio inside a vehicle or a well built structure. You can tack on -15 dBd to the RF hole you are in.

By comparison, most VHF mobile radios transmit at up to 50 watts. UHF radios can transmit at up to 45 watts maximum output. Most mobile antennas will offer a gain factor that will offset any losses introduced by the coax cable needed to connect the antenna to the radio. And because your mobile antenna is located on the exterior of your vehicle and the radio is powered by the vehicle’s alternator, you will not be added to the losses described above with a portable radio. Base Station antennas may actually offer you enough gain to increase your Effective Radio Power (ERP) by a factor of two or more. And a Base Station antenna will likely be mounted at some elevation that will allow you to eliminate losses from trees, buildings and other vertical obstructions.

Why is all this important for a new Ham? You have heard the saying “Success begets success!” A successful first radio experience will encourage and motivate a new Ham (and, for that matter, any Ham) to want to do more. Ham Radio is not a spectator hobby. You learn by doing. And the more you do, the better you will be.

More on your First Radio in my next post.

By Paul toth-NB9X

In my first post on this subject, I discussed my rationale for selecting a MOBILE radio as my first Ham Radio. When I added up the numbers including Transmit Power Output and Antennas Gain and factored in other losses I could expect using a Portable radio, it just made more sense to make that first radio a MOBILE radio.

But there were other important criteria I took into consideration for that first purchase. Many new Hams will purchase a VHF, single band radio. It is less expensive than many VHF+UHF dual band models. And, in many parts of the country, there is more activity on the VHF (Two Meter) band or so many people believe. But even though a dual band, VHF-UHF radio was going to cost more, I thought going that direction was worth the every investment. And that decision turned out to be a good one.

Another factor was audio quality. Once again, the MOBILE radios I had been exposed to before making that first purchase just sounded cleaner and more full bodied than their Portable Radio counterparts. That still holds true today for most ANALOG radios. Digital Mobiles and Portables (e.g. NXDN, DMR, P25, Fusion, etc.) tend to have virtually identical audio quality. There are other factors, including the Speaker/Mic you may be using and the digital format itself, that make once format better than another. More on this topic in another post.

Perhaps the most important item I factored into my first radio purchase was how I wanted to use the radio. Did I want to talk with other Hams going to and from work? YES! Did I want to participate in Nets? YES! Did I want to get involved with emergency/public service activities, like SKYWARN and ARES? YES! How about Club activities? YES! With those criteria in mind, a MOBILE radio made the most sense.

Now, in all fairness and in full disclosure, it became pretty clear within three months that a VHF-UHF dual band Portable radio was going to be in my immediate future. Ultimately, an active, energized, engaged Ham is going to have at least one MOBILE and one PORTABLE radio.

More on DIGITAL Ham Radio in my next post.

By Paul Toth-NB9X

A new Ham in the 1990s had some important choices to make when selecting his/her first radio. Was it going to be an ICOM, Kenwood, Yaseu, Alinco or one from a handful of lesser known brands, like Standard or Azden. Or maybe, you knew someone who could convert an old Motorola or GE mobile or portable that had been used by a commercial user.

Twenty years later, the choices are a lot more numerous. Yes, the Big Four in Ham Radio are still around and still innovating with radios that include color LCD screens, PL+CTCSS+DTCS tone control, voice compression and more. Many of the lesser known brands have been replaced by radios from Chinese manufacturers who have flooded the market with low cost (and, in some cases, dubious quality product).

While most ANALOG Amateur Radio repeaters still operate Wide Band FM, that is with a 25 KHz channel bandwidth, the Narrowband Mandate (12.5 KHz bandwidth) imposed on commercial and government users in 2013 has dried up the availability of commercial radios capable of 25 KHz operation. We are also seeing older WBFM repeaters now being replaced by new models that must operate at 12.5 KHz NBFM.

The FCC mandate for commercial radio has also brought with it new DIGITAL operating modes that some Hams are experimenting with. P25, NXDN, DMR, Fusion, TERTA and D-Star are just some of the DIGITAL modes out there. All but D-Star and Fusion (which are Ham Radio only) are gaining prominence in commercial and government use. All of these DIGITAL modes are feature rich. Some allow multiple VHF and UHF repeaters to be connected via IP. Interoperability, one mode to another and one manufacturer to another, is still a problem (just as computer networking was twenty years ago). And each mode has its strengths and weaknesses. No two modes are created equally.

I personally like NXDN, created by ICOM and Kenwood jointly in 2005. Each manufacturer’s radios are interoperable. The repeaters can be networked easily. And equipment is readily available from dealers and on the Internet. I also happen to like the range and clarity of NXDN radios, which rivals WBFM despite the fact they use one quarter the bandwidth of WBFM.

DMR offers two talk paths per RF carrier, a feature some Hams find desirable and fascinating, although you can only talk on one at a time. DMR repeaters tend not to cover the same amount of real estate as NXDN repeater do. And there have been some interoperability issues between Type 2 and Type 3 formats. Yet, DMR is popular in many areas, in part because of the availability of product.

P25 has two versions, the older Phase 1 mode and the newer Phase 2 mode. Both are designed for the Public Safety market and, as a result, P25 radios are a lot more expensive than most other Digital radios.

More on the Ham Radio only DIGITAL modes in my next post…..

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By Paul Toth-NB9X

In my last post, we started talking about DIGITAL two-way radio, why it exists and why you should seriously consider a DIGITAL radio.  Let’s expand on that with a look at the several DIGITAL radio protocols and radios that are available.

First, no two digital modes are created alike.  Each of the several CAI (Common Air Interface) has their strengths and weaknesses.  NXDN is the only mode that meets all of the FCC’s 2004 engineering mandates for Ultra Narrow Band Digital.  In a Report and Order issued in December, 2004, the FCC told the radio manufacturers they wanted to see radios that used 6.25 KHz bandwidth, FDMA modulation and a data rate of 4800 baud.  That is what NXDN, jointly created by ICOM and Kenwood, is.

In that same R&O, however, the FCC gave manufacturers like Motorola some wiggle room allowing their two channel TDMA mode to operate.  DMR radios, the generic term for TDMA, uses 12.5 KHz bandwidth with two simultaneous voice paths.  Some early DMR offerings are not compatible with the newer Type 3 radios that include products from Hytera, Tait and others.

P25, the modes (there are two) adopted by APCO for Public Safety are also 12.5 KHz.  P25 Phase 1 uses a FDMA modulation schema while the new P25 Phase 2 mode is a two voice path TDMA offering that uses one modulation type for the uplink (radio to the repeater) and a different modulation schema for the downlink (repeater to radio).

Radios using all these operating modes have been created primarily for commercial and government use.  But they are also is use on Amateur Radio bands.  Why?  What are the benefits of DIGITAL?

ANALOG transmissions are subject to all kinds of noise and disruption.  Weak signal analog voice transmissions are often difficult to copy because of the inherent noise that is part of the signal.  Then, add to that “snap, crackle pop” from atmospherics in the area, disruptions caused by multipath, trees and other vertical obstacles.  In short, analog transmissions have drawbacks that can make communications difficult.

DIGITAL transmissions are usually much cleaner, clearer and easier to comprehend.  That’s because the transmitting radio turns your voice into a stream of “zeroes and ones”, sends them over the air to the receiving radio that decodes the stream and re-creates the voice communications.  With some exceptions, digital voice is far more stable than analog voice.  Digital voice transmissions are generally usable at RF signal strengths up to 20 dBm weaker than analog signals.  Most digital radios also feature ambient noise reduction to eliminate or substantially reduce road noise.

One drawback with most of the commercially available digital radios:  they are single band only. 

More on DIGITAL radio in our next post….

By Paul Toth-NB9X

Some of you have heard me state that “Amateur Radio was the FIRST Social Media”.  That is a rather bold statement given all the other Social Media offerings that now grace the digital landscape.  The fact that Ham Radio, in Analog or Digital mode, is still a relevant Social Media, is pretty remarkable.
Let’s close the loop on DIGITAL radio before we get too far off topic.  Here are some thoughts on the several DIGITAL modes available to all Hams.
I personally like NXDN, created by ICOM and Kenwood jointly in 2005.  The radios from both manufacturers are interoperable.  The repeaters can be networked over IP easily.  And equipment is readily available from commercial dealers and on the Internet.  I also happen to like the range and clarity of NXDN radios, which rivals WBFM despite the fact they use one-quarter the bandwidth of WBFM.   NXDN radios also support Text Messaging and GPS.
DMR offers two talk paths per RF carrier, a feature some Hams find desirable and fascinating, although you can only talk on one at a time.  DMR repeaters tend to come up short on coverage compared to NXDN and P25 Phase 1, a product of their modulation schema.  And there have been some interoperability issues between Type 2 and Type 3 formats.  Yet, DMR is popular in many areas, in part because of product availability and local dealer support.  There is also the Motorola name recognition that has helped popularize DMR.
P25 has two versions, the older Phase 1 mode and the newer Phase 2 mode.  Both are designed for the Public Safety market and, as a result, P25 radios are a lot more expensive than most other Digital radios.
There are two digital products that are “Ham Only”:  ICOM’s D-Star and Yaesu’s Fusion.  D-Star remains ICOM’s prominent Ham Radio offering, even though its GMSK modulation schema is hardly state of the art.  The end user D-Star radios will do both analog and digital modes. D-Star repeaters are digital only.  D-Star has become less of a “proprietary” mode thanks to the proliferation of D-Star dongles that turn your computer into a virtual radio.  Still, if you want to operate wirelessly, ICOM is your radio source.
Fusion, from Yaesu, is a ‘proprietary’ created only for Ham Radio product.  Its C4FM modulation schema has some P25 Phase 1 characteristics.  Fusion radios support both analog and digital mode operations.  And Fusion repeaters can be programmed to automatically convert analog to digital and vice versa.  Fusion has gained a foothold with some Ham Radio Clubs, in part, because of an early marketing campaign that made Fusion repeaters available at Fire Sale prices.  Yaesu’s success with Fusion may also be based on a belief that the majority of Hams will only buy Ham-class radios.
The West Central Florida Group, Inc. currently has two NXDN repeaters in operation at our Riverview and Verna repeater sites.  Like our analog repeaters, the NXDN repeaters are linked full time to create a large coverage footprint along Florida’s West Coast.

By Paul Toth-NB9X

When the NI4CE Repeater was first conceived sixteen years ago, it had two primary objectives:  Provide a VHF-UHF platform that ALL Hams in West Central Florida could communicate through.  This included support for the several Nets the ARRL West Central Florida Section conducts each week.  The second objective was to provide a VHF-UHF communications platform to support the National Weather Service’s SKYWARN severe weather spotter program.
Ham Radio has played an integral and vital role since the SKYWARN program first started in the late 1950’s in “Tornado Alley”.  Trained Ham operators were the eye and ears of the NWS during severe weather outbreaks in Kansas, Oklahoma and Texas using their radio communications privileges to report severe weather directly to NWS meteorologist.  It wasn’t until the 1970s when the program was rolled out nationwide.  In the 1990s, when the Weather Service was downsized and re-organized into the 118 offices it now operates from, SKYWARN took on an even more important role.
The technology used by the National Weather Service has changed dramatically since the early days of the SKYWARN program.  Forecasters now have geo-synchronous satellites and 3D Doppler radar to help predict severe weather and issue warnings to keep all of us safe.  Spotters who were limited to telephone and Ham Radio now have a plethora of social media and email to send in reports, including still images and video.
So, why is Ham Radio still relevant to the SKYWARN program and to the general public?  The answer is simple.  Ham radio does not require the Internet, a working telephone or any other technology (other than a portable or mobile radio) to get severe weather reports from spotters to the NWS forecasters.  Moreover, that same Ham Radio link can also be used by the forecasters to push out severe weather warnings and other guidance to all the SKYWARN Hams as needed in a timely manner.
Let’s turn the question around.  Is SKYWARN still relevant to Ham Radio?  Absolutely!!!  SKYWARN is a year-round opportunity for Ham Radio operators to demonstrate our importance at a time when society is cell phone and Internet centric, so much so that many people think Ham Radio, the original “social media”, is a thing of the past.  And SKYWARN participation is a great opportunity to fulfill one of the prime justifications for the Amateur Radio Service’s existence.
2017 has the potential to be a very active Hurricane and Severe Weather year, maybe the most active since the 2004 and 2005 seasons.  Now is the time to get ready.  Attend an upcoming SKYWARN Training session scheduled for your area or take the online SKYWARN training offered by the National Weather Service.  Participate in the SKYWARN Information Net every Tuesday night at 9:00 PM on NI4CE.  Be ready to be part of the solution when severe weather threatens your county, your neighborhood.  And when you finish reading this article and feel so motivated, find the PayPal “Contribute” buttons on our main webpage to help keep NI4CE on the air and ready for whatever Mother Nature will throw at us this year.
A correction to my comment about ICOM being the sole source for D-Star radios in my last column.  Kenwood’s TH-D74 portable now provides Hams with a second source for operating in D-Star mode wirelessly.