Digital Communications and Technology Net

The Digital Communications Net is an informal net that meets every Tuesday evening at 8:00pm on the SBARC Hub repeater network.

JT65 operating on 10m

JT65 operating on 10m

We discuss and operate all kinds of digital communications and special modes such as 2m/440 Yaesu System Fusion digital radios, mesh networking, as well as HF oriented modes like PSK31, JT65, FreeDV, SSTV, Olivia, DominoEx, the Winlink 2000 system and many others. We typically discuss and operate digital modes on HF but sometimes operate on VHF/UHF as well, so everyone gets a chance to participate regardless of your station equipment or license class.

Using a radio and your computer, you can send data, voice, pictures, documents, and even email over the air. We also discuss using the various digital mode software applications and explain how to install and use them.

Arduino and Raspberry Pi

Arduino and Raspberry Pi

We also discuss using microprocessors like the Arduino as well as small micro-computers like the Raspberry Pi. Both of these devices and similar development boards are fun to learn about, and are great for creating projects you can use with amateur radio.

If you are interested in digital communications or learning about working with microprocessors and micro-computers, we are happy to help you get set up and explain how things work.

The net is hosted by Brian – K6BPM and everyone is invited to check in. We hope to see you there!

You’ll find recordings of previous nets in the SBARC Audio Archives.

Please consider joining the SBARC Digital Modes and Digital Radio Discussion Group mailing list and participate in the group off the air! It’s easy to do. Just send a blank email to digital+subscribe@sbarc.org.

For quick access to the programs we use for digital communications and other helpful resources, visit the link below…

Digital Communications Downloads and Resources


Windows Audio Issue and *NEW* Permanent Fix

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This week a bug report rocked the digital modes ham world.  Apparently the Texas Instruments audio chip used in many popular devices had a conflict with many version of Windows and was ruining receive performance on all digital modes.  This was especially troubling since it affected many popular radios and audio interfaces including:

  • All Icoms with built in USB Audio
  • All Kenwoods with built in USB Audio
  • All Yaesus with built in USB Audio, as well as the SCU-17 Interface
  • All Signalink USB’s

For a few days after the discovery, there was a known workaround that fixed the issue temporarily.  Today, a permanent fix was discovered which solves the issue even after the computer is restarted.   This YouTube video details this new permanent fix but for those who want just the facts, here’s what you have to do to optimize Windows settings to fix the bug.  These instructions are from Tigertronics, the makers of SignaLink, however the steps should work with any of the affected devices or radios:

1 – Right-click the white colored speaker icon located in the
lower-right corner of your desktop and select “Recording Devices” from
the pop-up menu.

2 – In the new window that opens, click one time on the SignaLink’s
“Microphone – USB Audio Codec” sound card to select it and then click
the “Properties” button.

3 – In the Properties window that opens, click the “Levels” tab.

4 – Right-click the percentage display to the right of the Level slider
and then select “decibels”.

5 – Lower the Level slider to “0db” or as close as you can. This is
“-0.4db” in Windows 7. It might be slightly different in Vista, Windows
8 and 10, but in any case, the closet value to 0db will work just fine.
Note that you can use the left/right arrow keys to move the slider
once you’ve clicked on it. This might be easier than using your mouse.

6 – Click OK, then click OK on the Recording Devices window.

7 – That’s all there is to it!

Digital Mode Emergency Communications

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Last evening (May 5th) we were introduced to digital mode software that is used for emergency communications during the ATV Digital Modes Net . While digital emergency communications use essentially the same types of software and protocols as popular digital modes, additional software is used in emergencies when it is necessary to send specially formatted information and when accuracy is vitally important. The official name for this is NBEMS, or Narrow Band Emergency Communications Software. Many amateur radio operators involved in everyday digital HF communications are also proficient with NBEMS as well. It is a good skill to have, and it is not just limited to HF. Many times 6m, 2m and 440 FM are used for NBEMS as well.

ARRL RAdiogram

ARRL Radiogram

Last night we focused on the most familiar of these formats, the ARRL Radiogram. If you took your technician test in recent years, you were probably introduced to the radiogram and how it is used. If you don’t remember it, that’s okay, because hardly anyone actually knows how to send or receive one. You send it from one station to other stations monitoring the frequency. What they receive actually looks like a regular telegram! It can be printed and delivered, or the recipient can follow the instructions requested by the sender.

So how is a radiogram used? Let’s say there was a major earthquake and Santa Barbara was cut off from normal landline and cellular communications. How would you let friends or relatives know you were okay? Well, you could get on HF if you have that capability and try and contact another ham somewhere and ask him to relay the information to someone for you. Hopefully the other operator will get the information right the first time, because it entirely possible you won’t be able to contact that same operator again.  But what if you could send the equivalent of a telegram? Then you would be assured that phone numbers, addresses, whatever information you need to pass would be sent with 100% accuracy and the message relayed to your friends or family. This is the purpose of a radiogram.

Emergency communications are important. At least a few people in Santa Barbara should know how to send radiograms and use the other emergency message protocols. In an emergency there may be a need to send accurate data to a distant location and have confidence that it will arrive where it is intended. If this interests you, check out the ARRL website for more information, and tune in to future ATV Digital Modes Nets on Tuesday evenings at 8:00 pm and listen in on our discussion. Or better yet, check in and learn how to participate!

Digital Voice Modes Explained

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Below is a link to a YouTube video from Ham Radio Now dated March 3, 2015. This video features an interview with the inventor of FreeDV, a digital voice mode we often discuss and operate on the ATV Digital Modes Net.  The video runs about 70 minutes, but if you are at all interested in digital voice, it is extremely interesting. They discuss the current “state of the art”, new hardware products, and research into new VHF/UHF modes. The last 20 minutes or so are particularly interesting as they discuss a new implementation of TDMA in ham radio VHF/UHF communications that has the potential for completely redefining how repeaters work.

Digital Mode and ATV Net Time Change?

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Tonight on the Digital Mode and ATV Net we are going to request input from participants about the idea of changing the net times from 8:30 pm – 10 pm, to 8:00 pm to 9:30 pm. The original time was chosen back when there was another ATV net running in another county that ended at 8:30. After that net was over, some on those participants moved over to the SBARC ATV net. These days there is very little discussion (if any) about ATV, and much more about digital voice and special modes and the participants are mostly local club members. So there is no particular reason why we cannot start the net a little earlier and end a little earlier. It is the opinion of the net control that  we may be able to attract more participants, and more participants can stay longer, if we start and end at a more convenient times.

So what do you think? If you have any opinion on this please weigh in by leaving a comment below.

ATV Special Modes Net – February10, 2015

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We had a great turnout this week with 9 check-ins to the net. Several Club members have recently purchased new Yaesu digital VHF/UHF radios, so this net is becoming the place to come to learn about this exciting new twist on day to day FM voice communications. Everyone that has experienced using this special digital mode cannot stop raving about the clarity and total lack of noise. Often, when two or more members go off to another frequency to experiment with digital, it is difficult to get them to come back! As we continue to experiment and test we’ll devote a portion of this net to talking about digital FM each week.

During the past couple of nets we have also been talking about operating with JT65. To many, this low power, weak signal mode seems somewhat boring, so we talked about some of the finer points this week. Low power, weak signal operating can really become an art form if one takes the time to explore it deeper than face value. Once you learn basic operation, it is not unusual to hear about operators using incredibly small output wattages in the sub-1W range and making thousand mile contacts.

We also talked about using JTAlert, an add-in product for JT65 that adds a lot of additional functionality and convenience to the two major JT65 applications. JTAlert can be freely downloaded at http://hamapps.com/. If you are a JT65 user, this is a useful addition to your setup. It offers a full macro system, callsign lookups, log book interface, and even allows user to user real time chat.

ATV Special Modes Net – February 3, 2015

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Last nights net was very well attended with 8 checkins and at least half of us operating JT65 at the same time. KI6HGH Steve, also joined in on both Allstar and 40m JT65 from Yucca Valley. HGH and K6FLD Frank also carried on QSO’s with other hams on the band and we were all able to watch the action. Even the Shackmaster was able to find a little time in his busy Tuesday night schedule to follow along from the Club Station. This was a really great demonstration of how JT65 works and why it is becoming so popular.

We also took some time to discuss Yaesu’s new digital voice HT radios. In a week or two, we should have 5 members who have these powerful little radios and we’ll be able to add a new digital activity to our nets. These radios have a lot of interesting capabilities we’ll be exploring and learning about.

So tune in to the ATV Special Modes Net next Tuesday at 8:30pm and keep up with the latest and greatest in digital ham radio.

Digital Voice 2m Communications – First Impressions

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If you get QST Magazine, it is hard to miss Yaesu’s push for their 2m/440 digital/analog radio offerings. They have been taking out 2 page ads right after the cover for some several months now. Yaesu  digital radios use the C4FM modulation method. It is currently only compatible with other Yaesu radios.

FT1DRYaesu’s base HT radio, the FT1DR, has become very reasonably priced, with most outlets selling them for less than $300. First, they are full featured dual band analog HT radios with all the features you would expect from Yaesu. But there’s more. A lot more. This radio also has digital capabilities, GPS, and APRS.

Levi K6LCM and I decided to take the plunge and order a pair of these powerful little radios. They operate just like any other quality HT on VHF and UHF analog so they are great for every day communications. Levi and I tried our first experiment with digital using simplex between his home QTH on the far western end of the ocean side of the Mesa, and my QTH on the far eastern end of the Riviera. Between us there are two hills to overcome, so we hooked our radios to our rooftop antennas and used 5 watts of power.

Wow! The first thing I saw was Levi’s callsign come up on my radio. His voice was completely natural and absolutely clear. No static, no background noise, just an absolutely clear voice as if he was next door.

There are all kinds of other cool features we have yet to experiment with, like seeing the other person’s location and relative distance. For now the bottom line here is that digital communications is not a gimmick. It really works. We’ll continue to explore the capabilities of these little radios and post more in the future.

If you want to learn more about digital voice radio, tune into the ATV Special Modes Net on Tuesday at 8:30pm. We will be discussing this more there this week.