Digital Voice Radio

Background

As you know, I love digital radio. I acknowledge my bias but that doesn’t mean that I’m blind to the realities. Watch any YouTube channel and they will say, “It sounds like you are right next to me.” While I’m on System Fusion and most of the rooms are cross linked with DMR, I have not heard a voice that sounds like they are right next to me. There is always that digital compression. So why use digital voice? Because it isn’t about the voice. It is about all the other information that is passed along when using voice.

Repeaters

There are DMR, D-Star, and YSF repeaters. Personally, I use the local YSF repeater. Why? Because both my wife and I have Yaesu radios. Have we ever used digital? Every so often. The problem with digital repeaters is the problem with analog repeaters. They are quiet. When I use the YSF repeater, I get no response in digital mode. “Well that may be because not everyone has a Fusion radio.” So why do I also get no response when using analog FM on the same repeater? On top of that, there is no other incentive to use the YSF repeater. It does analog FM and C4FM. That is it. No IRLP. No Echolink. It isn’t even on the internet for WIRES-X. This means that it is another local repeater that goes silent. There are 3 repeaters in town that are primarily used. Don’t get me wrong. I tried. I would monitor the YSF repeater. I would answer any call and put my call out when I was listening, but I didn’t get any response. So not, I monitor the other active repeaters. I didn’t get into radio to listen. I want to learn, and learning means communicating with those that have more experience. One operator said on the repeater a few days ago, “This is the best time to be a ham. I remember the old radios I used in the 60s and 70s. They were terrible. You had to have so much stuff to make it work and even more to keep it working. It was constant maintenance. The new radios are the greatest things made.” While I agree with that 99%, it doesn’t help if the new features in radio are never used.

Extra Data

Early, I said the point of digital voice isn’t the voice, it is the extra information that is passed along. How many times have you talked to someone and forgot a call sign? How many times have you blanked on a name? All of this can be transmitted with digital voice. When I talk, you can hear my voice along with an on-screen text reading my name and call. It will appear as “KD9NRT – ADAM.”

In addition to broadcasting callsign, you can also opt to have your position reported. This can either be reported to those within the group or to APRS.fi, provided the repeater/node is connected to the internet. This is helpful when coordinating an event, reporting a problem, declaring an emergency, or updating someone on your location. I usually have this option enabled by default, though you do need a GPS for this to work. While I use this with my FT3DR and FTM-400XDR, it cannot be used on my FT-991a or my wife’s FT-70DR. There is the option to plug my FT3DR into my FT-991a and leverage that GPS or add on an external GPS. Personally, I use the FT3DR. I say this knowing that I almost never use this function as there isn’t anyone else in my area that uses it. I have tested it using an openSpot 3 node and it works well.

Wide Voice

There is also the option to drop this extra data completely and use the entire bandwidth for voice. This gives you better voice quality. This is useful in situations where the extra data isn’t needed. I’m a regular member on the AMSAT node. I could drop the extra data for improved voice quality. While I don’t do this, it isn’t because I don’t want the other users to enjoy the sweet melody of my voice. It does present problems I’ll explain later.

Wide voice is also useful in situations where it is difficult to hear/be heard. Let’s say you are working another station on simplex and that other station is in a car. Using wide voice may be helpful to overcome some of the road noise. Wide voice is also helpful for those new to digital voice. Digital voice has the standard voice compression sound. This is done to save bandwidth. If you want to hear this, listen to any DMR radio. DMR has the poorest sound and it is obvious what the compressed voice sounds like. It does take some time to get used to this. When I first started with digital voice, I struggled to understand other users, especially those with DMR, poorly setup hotspots, poor internet connections, or all the above. Wide voice can help with some of these.

DMR

DMR is the lowest cost digital mode. It is open source, meaning that the code is available to everyone. This means that nearly all the lower end radio manufacturers can implement DMR into their radio. This is why you see it in a lot of the Chinese brands but not in the major Japanese brands. Popular DMR radios are made by Anytone, Alinco, and Bridgecom. I have personal experience with Alinco, though I rarely use DMR. A DMR radio can be purchased for around $150, which is appealing for anyone who wants to get into digital voice. Remember when I talked about why I don’t like Baofeng radios. The major appeal is the low cost. The same goes for DMR. Most of the time, digital voice means DMR. That doesn’t mean it is bad. It offers digital voice for a low price. I said low cost, not low quality. I always distinguish between cheap and inexpensive. Cheap means lower quality. Inexpensive means an affordable option. DMR is inexpensive, yet it does lack some of the features the other modes have.

How does DMR work? This is where it gets complicated. Rather than dividing up the bandwidth, it divides up the timing. That sounds odd. Let’s say you are transmitting for 30 seconds on DMR. You are only sending for 15 seconds, even though 30 seconds has passed on the clock. DMR transmits for 30 ms and off for 30 ms. These are referred to as time slots. We will use the following picture.

DMR - Longer Battery Life

The guy on the left in the black shirt wants to talk to the guy on the right in the blue shirt. Left guy is on time slot 1. He will transmit. Right guy is also on time slot 1, meaning he can hear left guy. They have a conversation about the weather, since that is pretty much all ham radio operators talk about. While they are talking, the radio switches from transmit to stand-by every 30 ms. It is so fast that it is difficult to notice. This leaves time slot 2 open for another conversation to happen. DMR allows for two conversations at once. This is really oversimplified. There are also color codes and a bunch of other stuff that makes DMR complicated. DMR is more difficult to setup. The appeal is the price, not the ease of use.

IMPORTANT: In order to use DMR, you must sign up for a DMR ID at this link. You will need an official copy of your license, not the reference copy. Everyone should apply for this, even if you are not going to use DMR. Let me repeat that. If you plan to use Fusion or D-Star, register for a DMR ID. I understand that you may never use DMR. However, there are crosslinked nodes, like the AMSAT node I use, that is Fusion linked with DMR. The DMR users will never hear you if you don’t register. When I first started using the AMSAT node, I could only reach two guys. They were the two Fusion guys. The others couldn’t hear me. I registered my DMR ID and everyone can hear me. You will also need to save the email you get from your registration. The DMR system doesn’t see your callsign, it sees your ID. It links your ID to your callsign. When you setup your radio, you will need to put in your ID.

DMR also has another issue. It cannot use Wide Voice. If you have Wide Voice enabled on your radio, your signal will cut in and out for nodes linked to DMR. Be aware of this. It is best to just leave your radio in standard digital mode and only use wide voice when in simplex with other uses that can use wide voice. Back to the AMSAT node. The DMR users, most of them, have me cut in and out if I use wide voice. It is a common complaint for America Link as well. Many of the America Link users have DMR radios and configure their hotspots to crosslink for them. Wide Voice gives them issues. This is something to be aware of.

Hotspots

I’m going to be honest. I’m not a fan of digital node hotspots. At the same time, I love what they have provided. So why the love/hate? Because they work okay but not great. Let’s start with the negative so I can end on a positive note.

Most users have no idea how to setup a hotspot. Setting up a hotspot in more than just plugging it in and putting in your call and location. To avoid conjestion/interference, you need to search APRS.fi to look for other nearby hotspots and their frequency and set your hotspot accordingly. You don’t want overlapping frequencies. The purpose of a personal node isn’t to have a mesh network with your neighbors, though this would be cool. It does bear note that if a community is thinking of setting up a mesh network using hotspots, a proper repeater would be better. In a mesh network, the individual radios would need to be strong enough to control all of the hotspots at once. There is also the chance of interference and other issues. It is best not to do it. It is okay to run multiple hotspots in one house, just ensure they are set to different frequencies. I do this with my Pi-Star and my openSpot 3. The newest nodes with the newest software can handle multiple modes on one hotspot.

Another issue is bit error rate. Even though your radio says it is set to 438.800 MHz doesn’t mean the exact frequency is 438.800 MHz. There is a small amount of error. This is corrected in the menus. Switch your channel to Parrot, which just repeats your voice so you don’t need to constantly do radio checks in busy rooms. Find you bit error rate, sometimes labeled as BER, and transmit for around 5 seconds. It will give you a percent. The goal is to have this under 2% though under 5% is fine. Ideally, it should be under 0.5%. My Pi-Star gives me 0.1%. You have to adjust your offset slightly. There is a great YouTube video by W1MSG. This explains how to setup the offset. For me, it took around 15 minutes to get it dialed in. Again, the newest hotspots with the newest software can do this automatically. My FT-991a, FT3DR, FTM-400XDR, and my wife’s FT-70DR all have different offsets. This gives different BER each time. Updating to the newest software that adjusts this automatically has helped out since we get the same quality each time. This is how I have a BER of 0.1% each time.

Not all hotspots are created equal. Rugged Spot, for example, has a great case and a screen but also advertise/sell using counterfeit Diamond antennas. I’m not sure how you can call yourself the Rolls Royce of hotspots when you sell counterfeit items. Last I checked, Rolls Royce doesn’t come with laminate wood or imitation leather. Other hotspots come in beautiful machined aluminum cases. Some are compatible with Pi Zero or Pi 3/4. Some work with all of them. You can also custom build your own. You can purchase the MMDVM hat, the Raspberry Pi (or other compatible board), case, and antenna all separate. I personally use the DVMega hotspot, which isn’t bad. I think it provides everything I need. It doesn’t have a screen, which isn’t a deal breaker for me since I interface with it through my radio. It is held back by the software, though Pi-Star v4 fixed many of the issues I had. I would not have recommended a Pi-Star hotspot until software v4 came out. Now, I would recommend it to anyone. Just don’t use Rugged Spot’s counterfeit antennas.

Side Note: I want to explain some of my grief toward Rugged Spot for their antennas. I like their hotspots and debated getting one, though I think they are slightly overpriced. You can purchase the fake antenna for $20 and the real one for $27 through DX Engineering. There is also another short antenna from Diamond for $22. I personally use the $22 antenna and it works well. I get coverage of my hotspot for about a city block, which is far more than I need. It covers my property, which is primarily what I need. I can also access my hotspot from my FTM-400XDR when my car is parked in my garage. It is only $7 more for the real antenna, only $2 if you want a different version. Please don’t support the counterfeit industry. Spend the extra $2.

Some positives. The openSpot 3 is the Rolls Royce of hotspots. Actually, Rolls Royce is about style and luxury. The openSpot 3 is a Lamborghini. It it small, portable, versatile, and looks pretty cool. It also has an integrated antenna, meaning if you don’t want people to see it, you can hide it away. I walk around with it in my pocket all the time. Having a built in antenna may limit the range, but I haven’t tested it. I might do that this week. I usually use my hotspot around the house so range isn’t a big issue for me. I just need to to work at my garage, which is the furthest point from it.

The customization of hotspots is incredible. I’ll break that into two categories, the software and the hardware. I’ll cover the hardware first. For some people, they have their callsign everywhere. You can get your callsign engraved on a hotspot. You can get your case made from wood, plastic, or metal. You can pick the wood type and stain it anyway you want. You can get different colors of plastic. You can get plastic that screws together or stacked layers. The metal can come in different colors and styles. It is pretty much open to how you want to customize it. That is the nice part about it. Same with the antenna. If you have a signal story house, you can get an antenna that covers just your house. Same for a multi-story house. I have my hotspot on the first floor next to my WiFi router and use the flexible $22 Diamond antenna I linked above. I guess I can link it again. There you go. I’ve also used a high gain Diamond antenna that I had sitting around. It probably had better range but it is hard to tell. I didn’t test it, which I should. Hotspots are so low power (10 mW) that it is tough to extend the range. They use less power than WiFi routers. You can also have dual-band hotspots that run either 2m or 70 cm. You can have duplex routers that function like repeaters, though you need two antennas.

For software, the most popular is Pi-Star, which was trash until v4 released. It is now more stable and offers more features. I would highly recommend v4. The openSpot uses its own software, which is easier to use than the Pi-Star but offers the same features. The openSpot in a lot more plug-and-play. The setup is extremely simple. There is less restarting and confusion. You really need a guide to help set everything up, which there are plenty of online. In the software, you have plenty of options. You can set the hotspot frequency. Check your nearby area and your repeater council for the frequency that you should use. The low power digital hotspots are close to the satellite frequencies so avoid those since it will interfere with their operation. The option exists to put the hotspot on an APRS map, which I suggest you do so others can see what frequency you are on and adjust their hotspot accordingly. You can also add information about your hotspot. I have power setting, antenna height, the model, and my website. You don’t have to add any information at all, in which case it will just show the set frequency and offset for duplex/repeater mode. There is also the option to push out APRS info for transmitting radios. I also have this option on, though the only radio it would be useful for would be my FT3DR, since I sometime walk around the neighborhood with it. This is also useful if you use your hotspot mobile, i.e. in a vehicle. You can set it to your phone’s WiFi and have a portable node. With this, you will probably want to disable your APRS for the hotspot as it will display your set location rather than your current location.

Side note: I have attempted to standardize all of my APRS information. I use the format (Model) | Power XX W | HAAT XX ft | http://www.kd9nrt.com for everything. HAAT is only used on stationary objects like my hotspots and iGate. For my FT3DR and FTM-400XDR, I just skip that. This makes everything standardized for me so the relevant information is present.

The last positive is the ability to connect to any room your choose. For example, my local repeater is connected to the local node. This is so you can talk back here, even if you are traveling. My wife likes to participate in a YL net. Rather than asking if the repeater is busy, asking to switch the node, switching the node, doing the net, and switching it back to local, all she has to do is switch our hotspot. She doesn’t need ask if it is busy, since we are the only two that use it. She doesn’t need to ask to switch the node, since we are the only two here. She doesn’t need to worry about time, since no one else is waiting to use it. She doesn’t need to worry about switching it back, since I can easily switch it to another room when I use it. This can, however, cause individuals to discontinue use a digital repeater, but there are still a fair number of operators that use the repeaters as the hotspots are not cheap. For the bare minimum, you are looking at around $100 without a case and assuming you have a spare antenna. That may not seem like a lot considering the cost that ham radio can be, but it may be quite a bit for just digital voice in your house. Think of it like if voice only Discord, Teamspeak, or Skype was $100. For some, this is too much for very little. So what do you get for the money? Convenience. Once it is said and done, you have a digital node in your house. Not just a digital node, your digital node. In my area, we don’t have a WIRES-X repeater. My hotspot allows me to connect to WIRES-X.

Application

This is not a rally to get everyone onboard with a hotspot, even though most of this post is about hotspots. This is more of the use of digital voice. How can this help everyone? It provides a mode of communication that is superior to analog voice through the application of data. I’ll use Skywarn as an example. You are leading a Skywarn net due to severe weather. Everyone uses digital voice with location services. The net control operator is doing check-ins. My transmission is as follows. “This is KD9NRT, Adam, located near Foster Park on the southern part of Fort Wayne near the intersection of Fairfield and Rudisill.” My broadcast could be, “This is KD9NRT, Adam, located near Foster Park.” I would show up on his radio with my callsign, name, and location. If he forgets, the information will be displayed again the next time I broadcast. He can also set his radio to hang the information for 5 seconds after I stop broadcasting. It will also show my distance and azimuth from his location (5.2 mi 102°). You can see how this simplifies everything. It does provide extra information, but it doesn’t have to be used. It is nice to have it and not need it than to not have it and need it.

Finishing Up

Digital voice isn’t for everyone. Nor do I expect everyone to jump onboard. Like with everything, it is another tool in your toolbox. The nice part is that is just works. There isn’t much fuss to get it setup. Okay, there is a little with DMR. Overall, it is a nice mode to use. I have enjoyed it. I saved the biggest positive for this part. You can find the people you want to talk to. I know ham radio is about making contacts, but sometimes, you just need information. When I first got into satellites, I didn’t know how to work linear satellites. I connect to the AMSAT node, and there were plenty of people to help me out. It was great having that available. As I’ve said in previous posts, it can be difficult to find information. It is almost expected that you find an elmer to mentor you. Depending on where you are, this can be tough. Having digital radio puts every elmer a PTT button away. This is invaluable, especially for a new operation like myself.

Thank You

Thank you for reading. It has been a few weeks since my last post, but this one took a bit. I’m currently writing about my fox hunt from last weekend. My wife and I were the fox, so this took a bit of preparation. It was fun, and I plan to post about it.

Follow on social media to stay up to date on everything. You can find me on YSF Node #11689 which is the US Amsat node. This is crosslinked to DMR talk group 98006. Thank you for reading. Stay safe.

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