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**KN3U** · September 30, 2019

When I hear this question, I find myself trying to provide some context first. First and foremost, I am dismayed by the fragmentation of our relatively small Amatuer Radio market by three (or more) competing technologies whose similarities outweigh their differences. This seems counter-productive.

Second, although digital modes are sometimes promoted as beng useful for emcomm, it's hard to see that digital voice is a net plus, at least until there is some kind of convergence. For emcomm, we want the broadest pool of available operators, the widest degree of interoperability, and minimal reliance on commercial infrastructure. Admittedly, some of the tools, like the optional camera that works with some Fusion radios, could be useful for damage assessment.

Third, linked repeaters may be useful in some georgraphies and for some purposes, but in an emergency, it might be counter-productive to tie up multiple repeaters that could be better utilized for parallel communications.

That said, pick the mode that your friends or other local hams are using. If your primary operating interest is ragchewing, it's hard to see how you could go wrong with any of them. I'll leave it to others to argue the technical merits of the competing technologies.

73,

Al, KN3U

**K3MRI** · October 1, 2019

11 hours ago, KN3U said:

When I hear this question, I find myself trying to provide some context first. First and foremost, I am dismayed by the fragmentation of our relatively small Amatuer Radio market by three (or more) competing technologies whose similarities outweigh their differences. This seems counter-productive.

Second, although digital modes are sometimes promoted as beng useful for emcomm, it's hard to see that digital voice is a net plus, at least until there is some kind of convergence. For emcomm, we want the broadest pool of available operators, the widest degree of interoperability, and minimal reliance on commercial infrastructure. Admittedly, some of the tools, like the optional camera that works with some Fusion radios, could be useful for damage assessment.

Third, linked repeaters may be useful in some georgraphies and for some purposes, but in an emergency, it might be counter-productive to tie up multiple repeaters that could be better utilized for parallel communications.

That said, pick the mode that your friends or other local hams are using. If your primary operating interest is ragchewing, it's hard to see how you could go wrong with any of them. I'll leave it to others to argue the technical merits of the competing technologies.

73,

Al, KN3U

I'll expand later with my own thoughts, but for now I just wanted to say about @KN3U's comment... what he said! 👍🏻

**KW4TO** · October 2, 2019

My current choice would be DMR.

I love the fact DMR is open source, with inexpensive mass produced hardware.

The proprietary modes by specific manufacturers limits the scalability, and interoperability.

Recently I see lots of DMR growth, probably for these reasons.

W3ICK · October 19, 2019

I own a D-Star handheld and it works great. I just bought a Yaesu mobile that I’m going to install this weekend and get my feet wet with Fusion. I’ll let you know how it turns out.

My biggest hurdle where I live, is that there are no D-Star repeaters in my area, and I have to rely on a hotspot. For QTH operations, that’s not really an issue, but when it comes to mobile operations, I either have to use a hotspot connected to the wifi on my phone, or stay in analog mode. There are a lot more Fusion repeaters in my area, so I’m going to give it a try.

**AE2A** · February 10, 2020

You need to look at your available bandwidth for connecting to the digital network of your choice. DMR does require about double the throughput bandwidth of D-STAR due to the inherent coding (DMR is a ~9600 baud throughput while D-STAR is about 4800 baud). Fusion is dependent on the mode you are using and can vary. Fusion has become popular because Yaesu seeded the market with low cost repeaters and many clubs jumped on the bandwagon hoping to replace agin repeaters at a bargain price. The initial entry into the Fusion environment had its startup problems and now after a few years of operation, the Fusion product/protocols are well established and the networking issues have been worked out.

With the advent of the newer hotspots which support multiple modes, the choice of what type radio is pretty much up to you and who you wish to QSO with. Many of the newer hotspots allow you to utilize a feature called "cross-mode" where your radio can be DMR and you can "cross-mode" to Fusion or NXDN. The newest hotspots can actually "cross-mode" to any and all of the modes from any other mode! This feature (software magic) has made the choice of which mode (and by association- the choice of radio) a moot point. Obviously, each OP will have personal brand choices for many reasons, but you are now able to join any network with almost any radio.

If you will be using mostly mobile operation in an area with limited or no repeaters, the cellular tethered by WiFi to a hotspot option is usually a good choice! Depending on your selection of cellular provider and the "customer profile" will be the limiting factors. I mention "customer profile" for a specific reason. Your rate plan determines the amount of data you can use and its end cost, but you should always be aware that the lowest cost plans may also subject you to lower network priority and "throttling" your actual throughput. Prime customers (those that pay the premium prices) are generally not subject to lower network priority and throttling. If you are familiar with how the major carriers work, there may be many resellers of one of the major carrier networks. Each has its own set of "customer profiles" with an unknown priority and throttling threshold! Bargain resellers such as Walmart or Consumer Cellular (or any other reseller) don't actually own an cellular infrastructure (towers or networks) but instead they "resell" network access to one of the major network providers. These resellers, provide you with service for a fee that is generally less than the rate charged to "direct" customers in exchange for a lower grade of service. This is how the resellers can offer service for a lower cost. Be aware that even the direct customers can be sold a lower grade of service advertised as "the 55 plus rate" or some other non-prime rate plan. These are generally non-primary rate plans and carry the same lower grade of service along with lower priority and more throttling during time of heavy network loading! Depending on the area your are in, the provider network, and time of day, your own experience will vary! In my case being in a college town and near the campus and residences, I was forced to change fom the "55 plus" plan to an "unlimited" plan (for $10 a month more) which resolved a whole host of issues.

With all of the above in mind - "Your Mileage May Vary"!

**K3MRI** · February 10, 2020

@AE2A, I am about to promote this response to an editorial pick because it does, indeed, explain the digital voice options all so clearly. Thanks for this.

NN0M · April 9, 2020

For DV to be appealing it needs to be easy to implement, offer advantages over analog, and be inexpensive.

So which DV system does one choose?

DV is a digital mode. The underlying issue with all digital modes is that the A/D and D/A conversions have to
implimented either:
1. on a computer which is seperate from the radio, or else
2. they have to be an embedded system within the radio.
So which of these 2 models is the most practical to impliment for your applications and which implimentation will
meet the criterions. The answer to this question will influence which DV options are viable for you in a profound
manner.

If you want portable radios; an embedded implimentation will be your go-to.

If you need to communicate information over great distances; then the external computer/sound-card
implimentation will probably your starting point.

Many of the embedded DV systems which Hams are experimenting with or adopting are limited with regard to off-
the-shelf radios to either the 2 meter VHF band and/or the 440 UHF band. Not being able to use these DV
implementations on HF is a substantial barrier to becoming adopted and used by a substantial number of Hams.

DMR relies on time-slicing and requires a hardware implementation. Few radios with the exception of those that
operate only on the 2 meter VHF band or the 440 UHF band support DMR. So except for these 2 bands it is for the
moment not very appealing to experiment with. I got an MD-380 and experimented with it; and was underwhelmed.
DMR linking is for now lacking any substantial established RF backbone and relies on commercial internet providers;
it is a nifty toy but not currently robust and reliable enough to be suitable for EComm situations.

I see mobile amps advertised which claim to be compatible with DMR. I tend to be wary of these claims given the
short length of the time slices. So for this reson I am wary of even suggesting that an external amp could give an HT
some help if used in a mobile environment. With DMR I feel that if you need more power you probably need a
different radio.

P25 (Project-25) commercially available radios like DMR also are too rare to be of interest to most Hams except on the
VHF and UHF bands.

D-Star uses a codec which requires a license fee to experiment with much less use widely on a variety of bands. So the
$200 price point for a DV-Dongle; which is the lowest entry price-point for people that want to experiment with this
mode. $200 for an experiment will be off-putting to many Hams.

I have not explored C4FM nor the proprietary System Fusion implementation of it. So I can not offer an informed
opinion about its strengths and weaknesses. It is my perception that C4FM is also pretty much only implemented on
2 meters and 440. I know that the Kenwood repeaters are limited to these bands. I am unaware of any radios which
support System Fusion on 6 meter VHF.

FreeDV has the right price-point to make it worth experimenting with. It is implemented on a computer which
interfaces to a sound card. So it can be tested and utilized on any band with any radio which can be interfaced to the
sound card. As Ham's; for majority of us that means it can be used on any radio we own. The exception to this is
vintage radios for which the original connectors are hard to get; In EComm situations using modern radios often
makes more sense because those radios tend to be much lighter in weight and they tend to require less power to
operate. Modern radios which use less power can operate longer from a battery which has a given number number of
amp hours. Running off of a generator with a modern and more energy efficient transceiver can mean that you can
use a smaller and presumably lighter weight generator to keep you radio operating.

- NN0M

KF7JAF · May 9, 2021

I live in the Las Vegas valley, in Southern Nevada.

We are pretty much stuck with what is available locally, in terms of infrastructure like repeaters. If there is a serious power outage or other natural disaster, (forest fire, flood, tornado, hurricane, etc.) a lot of this infrastructure will stop working. One of my local repeaters experienced a localized power failure recently. The battery backup lasted about 12 hours. That same repeater is linked to other repeaters and the Allstar network via a microwave link to the local internet. This link failed, and we were able to reconnect using a mesh network. It required a trip up a mountain via 4 wheel drive to reset breakers and get it all working again.

All of this stuff is primarily analog. Our local club is putting a D-Star repeater up on a mountain in the next week or two. Another club already has a couple of C4FM repeaters. There are also a couple DMR repeaters. Considering that all the clubs here are volunteer operated, repeater networks are built with donated and scrounged equipment, we've managed to accomplish a lot.

The basic problem is that none of these digital protocols are compatible with each other. Inexpensive DMR radios are becoming more available, but other formats are more expensive. I've not seen an HT with FreeDV but that may change with the increase of inexpensive imports from Asia. I'm waiting to find out what the new Icom D-Star HT will cost, before I decide what I'm going to do. It looks like some kind of hotspot will be a necessity for maximum utility, regardless of which format I decide to go with.

That's my two cents worth, anyway.

Dave

KF7JAF

**K3MRI** · May 9, 2021

11 minutes ago, KF7JAF said:

The basic problem is that none of these digital protocols are compatible with each other.

Hi Dave. Everything you say just makes me more frustrated with choice. Don't get me wrong, choice is a good thing, but look at something as simple as an electric plug. Imagine if we had not standardized the prongs (I know, there are multiple other standards in other countries). But of course, if one says standardize, someone else says monopoly. Who knows (thinking out loud) maybe some day there will be some sort of packaging that can virtualize digital systems, much like we can set up virtual Windows, Linux or Mac systems one into the other. Al little like the 'keys' that Uniden makes available for the different systems (including DMR).

As @KN3U said above, this is the very reason why digital is absolutely not adapted to emcomm. Just imagine an expeditionary force going out with three or four different systems 😥

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