Radio, Tech, Infosec, Politics, Travel and More
If you’re running noaacap to send severe weather alerts via APRS, there is a mandatory update available. The zone parsing code has been completely redone to address some issues discovered after the recent protocol update by NOAA.
The current version of noaacap is 1.4.0 and is available here.
In an effort to make it easier to install ampr-ripd on an OpenWRT system, I’ve revisited my packaging code and published it to github. Along with the OpenWRT SDK you ought to be able to generate an ampr-ripd package for any current OpenWRT platform.
ampr-ripd is a modified RIP listener written by YO2LOJ. It is used by licensed amateur radio operators who have received a Net44 allocation from ARDC.
The high-level workflow is:
Install the SDK for the target platform on the host of your choice.
Copy the contents of the repository to ./packages/ampr-ripd/.
make package/ampr-ripd/prepare
make package/ampr-ripd/{clean,compile
The resultant ampr-ripd_{your architecture}.ipk will be found in ./bin/packages/{your architecture}/base/.
73 de K2IE
The National Weather Service has updated their Common Alerting Protocol (CAP) to version 1.2. This broke our noaacap weather software and the related DAPnet NWS paging rubrics for a bit.
Thanks to an alert radio amateur who called this to my attention, both systems have been updated to process the new alerting format. What you see will not change. All the changes have been behind the scenes.
If you’re running aprx or Dire Wolf as your APRS software, be sure to take a look at noaacap and consider providing weather updates for your county. If you’re already running noaacap, please update to the latest release.
Next time you think about interrupting a digital voice QSO for a radio check, think again and connect to XLX020 Module S.
There, you’ll find our DV Bot. Key up on the module and try something like “This is <Insert Callsign>. May I have a radio check please?” No doubt, this will lead you down an amusing rabbit hole.
The DV Bot is a voice to text interface to ChatGPT, the much talked about artificial intelligence backend. Yes, AI does digital voice! Give it a try and let me know what you think in the comments.
73 de K2IE
Brandmeister is out there innovating again.
There’s a low latency VOIP solution based upon on an open source codec. The codec is called Speex and, as the name indicates, is optimized for speech. So bring on Mumble.
Mumble is a multiplatform VOIP client that makes use of Speex. It has been integrated into the Brandmeister backend and is currently being tested with a few select talkgroups…CNJHAM 31340 is one of them. You can also get on 3100 and some others.
So if you’re brave (and aren’t going to bug me or BM for support), give it a try. Your user ID is your CALLSIGN-DMRID (ex. N0CALL-1234567 and case matters) and your password is your BM hotspot security password. You’ll need to add mumbleeast.repeater.net as your server.
Remember, this is a test. This is only a test, so your mileage may vary.
73 de K2IE
The FCC recently authorized the use of frequency modulation in the Part 95 11 meter Citizens Band. This action was in response to a petition filed by Cobra Electronics. This change, a clear attempt to generate sales of radios for CB radio manufacturers, could well breathe new life into CB radio.
I think the FCC made a mistake, however, by mandating that new radios having FM capability also have AM capability. While this is intended to provide backward compatability, it would probably be better if the FCC had sunsetted use of AM a few years out. Then we’d be rid of the heterodynes and squeals caused by too many AM signals on the same frequency at the same time.
In the same Report and Order, the FCC authorized the use of position reporting systems on the CB band. Expect to see APRS-like reports using packet FM from GPS enabled portable and mobile radio.
I suggest that we watch for increased interest by the general public. There could be a revival of CB radio as it becomes more usable for local communications. No, we’ll never have a resurgence of the 1970s CB boom, but static free local communications at low cost is going to be attractive to a lot of folks.
73 de K2IE
A local group of hams has been talking on 2 meter FM simplex for as long as I can remember. In recent years, they’ve been using 146.4 MHz as their primary frequency. I recently ran into one member of the group on a local repeater trying to test something. I responded to him, in case he needed assistance. He he told me how the local repeater on 443.200 MHz was bleeding into conversations on 146.4. Trying to be helpful, and knowing who to get in touch with on the tech side of 443.200, I got involved.
The 443.200 repeater in my area is linked to 146.76 MHz. I surmised that 146.76 was the actual culprit. At my location, 10 miles from the repeater, I could not hear the interference. The hams that are being interfered with are much closer to the repeater site than me. They provided links to some recordings and I gave them a listen.
I noticed that in addition to hearing the audio from 146.76 I also heard mixing from 147.12. I reported that to some of the folks at the club responsible for 146.76 as well as to the owner of 147.12. I observed that 147.12 – 146.76 = 0.36 and that 146.76-146.4 also = 0.36. This seemed significant to me although I did not know what it represented. The club president chimed in with the determination that the 2 repeater output frequencies, when mixed, generate a third order intermodulation distortion product on approximately 146.4 MHz. Wow!
From my reading, a third order IMD product is created when two non-linear signals mix. To me, that indicates a problem at one or both of the repeater sites. Some local hams familiar with the situation voiced the opinion that there is no way to fix this for stations close to the 2 repeaters (which are also relatively close to one another). I was told that at least one of the repeater keepers was also heard expressing this position. Based upon my understanding, I initially disputed the “nothing can be done” position with the thought that if the cause is non-linearity, something can and should be done.
Today I tried an interesting experiment. I took 2 HTs which are probably fairly spectrally pure (a Kenwood D74A and a Yaesu VX7R). I set them both to one watt and put a receiver on 146.4 MHz. One radio transmitted on 146.76 and one on 147.12 MHz.
If I keyed up one radio without transmitting on the other, no signal was heard on 146.4 MHz.
However, when I transmitted on both frequencies simultaneously a perfect signal was heard on 146.4 MHz!
If this behavior can be so easily reproduced with two (supposedly) spectrally pure transceivers and provides the same result on multiple receivers — an RTL-SDR stick and a Kenwood TS-2000– there may just be something to the “nothing can be done” school of thought.
73 de K2IE
The best way to synchronize the time of your Windows based PC is not a third party add-on. It is to use the capabilities built into Windows 10.
I have read numerous threads in amateur radio forums about time synchronization for digital modes such as FT8 and FT4. These usually turn into long threads recommending this or that third party solution. None of them are needed.
Here is the solution that I use. It requires only Windows 10.
Open a Windows 10 command prompt as administrator and run the following commands. These stop time synchronization and resets the service to some defaults settings.
net stop w32time
w32tm /unregister
w32tm /registerNext, run regedit. Carefully make the following changes.
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\w32time\Config\MinPollInterval
Set to 10 decimal
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\w32time\Config\MaxPollInterval
Set to 15 decimal
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\w32time\Parameters\NtpServer
Set to time.windows.com,0x9
If you have a different server you want to use feel free to do so
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\w32time\TimeProviders\NtpClient\SpecialPollInterval
Set to 1800 decimal
This will update the time every 30 minutes
You may have to create this keyIf your computer is not attached to a domain (normally the case for non-workplace computers), make sure that time synchronization is automatically triggered when your computer is on the network.
sc triggerinfo w32time start/networkon stop/networkoff
Finally, restart time synchronization.
net start w32timeThis restarts the time synchronization process. Your time will be synchronized to the ntp server that you specify every 30 minutes.
You can check your work with the following command:
w32tm /query /peersThe output will show that you are synchronized and to what server. I run a local GPS time source. This is what my output looks like:
Peer: ntp.private,0x9
State: Active
Time Remaining: 0.0000000s
Mode: 3 (Client)
Stratum: 0 (unspecified)
PeerPoll Interval: 0 (unspecified)
HostPoll Interval: 10 (1024s)
Peer: ntp.private,0x9
State: Active
Time Remaining: 1784.6442139s
Mode: 3 (Client)
Stratum: 1 (primary reference - syncd by radio clock)
PeerPoll Interval: 17 (out of valid range)
HostPoll Interval: 10 (1024s)73 de K2IE
What most of us call an IP address, in the form 1.2.3.4, is really an IP Version 4 (IPv4) address. IPv4 has a serious limitation. The largest number that can be respresented in the 32 bit binary value of an IPv4 address is 2 ^ 32 (4,294,967,296). Believe it or not, these addresses are in short supply.
IPv6 was created as a solution almost 23 years ago. An important specification document was published in December 1998. IPv6 World Launch Day was 10 years ago! IPv6 is not new. IPv6 provides 2 ^ 128 (340 trillion trillion trillion) addresses. So why aren’t we all using IPv6 now?
Aside from a bounty of address space, there are other reasons to adopt IPv6. Large network providers have built new and optimized infrastructure with IPv6 in mind. Here’s an example of how this can work to your advantage.
The 020 Digital Multiprotocol system has bridge to the Brandmeister DMR (BM) system. Low network latency is of critical importance in delivering high quality voice connections. Any network latency created issues are amplified when voice transmissions are passed through multiple applications and protocol transcoding hops.
Using the IPv4 network, ping time between our end of the bridge and BM is about 8 ms. That is actually pretty good. IPv6 blows that away, with about 1.5 ms ping times. That reason was good enough for me to get my hands dirty and modify some Python code to be IPv6 capable.
IPv6 also helps with the problem of NAT and port forwarding on residential routers. Simply put, NAT can be thrown into the trash bin of computing history. Instead of just one address, the minimum network assignment under IPv6 is 64 bits. That is 2 ^ 64 addresses!
Several ham software authors and volunteers are working on updating their software to be IPv6 capable. My amateur radio wishlist for full IPv6 capability includes xlxd, DMRGateway and ircDDBGateway. HBlink will be there once my pull request is merged. That is the Python code I referred to that links the 020 world to Brandmeister.
N7TAE has a functional QnetGateway using IPv6. I could not get it to work with my DVAPs and will need to followup up with Tom, but he has provided a wide range of hardware support including MMDVM devices.
There are a lot of bits and pieces that will be involved with updating amateur radio software, much of it ancient, to IPv6. So let’s start now. This will take time. And, if you’re a ham working on some new software for the amateur radio world, please make sure that it supports IPv6 out of the box.
73 de K2IE
Since before the days of the commercial internet, amateur radio operators have had their own Class A block of IPv4 addresses. Net 44 or AMPRNet is a non-routeable amateur radio experimentation network and access is only available to licensed radio amateurs around the world.
While hams have been experimenting with Net 44 since the early days of packet radio, interconnecting RF and wired networks via AX.25, I’m a relative newcomer. A couple members of the 020 Team are up and running on the AMPRNet and looking at potential use cases.
My driving use case is the to get around the limitation of one ircddbgateway behind a single network address translation (NAT). This limitation prevented me from running an ircddbgateway to service my Pi-Star hotspots and to use Icom Terminal Mode on my IC-9700 at the same time. What is the limitation? UDP port 40000, used by the ircddb protocol, must be forwarded to the destination system. As the Highlander said, “There can be only one.”
By establishing a Net 44 subnet behind my firewall and assigning a Net 44 address to the Icom, I get around the single IP NAT limitation. There’s a bit more to this, but a Net 44 gateway can be run on a spare Raspberry Pi or your internet gateway router (or any Linux based host). This article is not, however, meant to be an implementation guide but more of a starting point for thought.
It is also an announcement that XLX020 is now available on the AMPRNet for use by those with Icom Terminal Mode radios. Our gateway address on the AMPRNet is 44.64.12.57 and you can connect to any module using a To Call of /XLX020m (replace m with your module of choice). If you’re on Net 44, feel free to connect.
73 de K2IE