Friday, September 28, 2018

Listening to D-Star on the Rasperry Pi3 with op25 and a SDR

A while back I blogged about how to listen to DMR using a SDR.  I tried to do the same with D-Star, but was having problems.  I ended up reaching out to the author.  He just released a fix, so if you download / install from now on, you shouldn't run into the head banging that I was.





I am not going to lie, it doesn't sound the best.  There was no information for coder's to work off of, so what we have is rather crude, but intelligible.

If you are looking to help improve it, start here.  This is from the folks from the community that brought us what we have today.


There was also this tip from user "groovy"

If anybody wants to continue the research / work, I suggest you look at the osmocom GMR code that Sylvain Munaut worked on. Those phones use a similar codec - I believe with longer frames for the satellite latency. Initially he used the mbelib code, enhanced it for things like tone support, but he later rewrote the synthesis code completely. See OsmocomGMR for his presentations and source code.

Unless other developers take this on, DVSI releases specs, or you switch to a hardware-based decoder like the thumbDV, I don't see the dstar voice quality improving in the short term.


I'd love to see further work on OP25. More so on the transmit part (hooked to analog radio, perhaps using the MMDVM hardware/Arduino.   Anyone care to join forces with Max?

Perhaps an update to Johnathan Naylor's (2009) GUI Linux client that would decode and generate GMSK using a soundcard and interface to a radio with a 9600 Baud packet connector. ..

Wouldn't mind a way to hook op25 to Allstar either  :-)


Monday, September 24, 2018

The Next 100 Years of Ham Radio

A few years back I shared a video about ham radio in the future.  It's was from a 2012 webinar, where Chris Imlay W3KD and Ed Hare W1RFI predict and speculate what ham radio will be like in 25 years.

As the focus of my blog has been more of a modern ham radio theme, it seems appropriate also share an excerpt from Mike & Key Amateur Radio Club (Seattle) Newsletter (K7LED Relay) by Peter N. Glaskowsky K4PNG.

October 2014

The Next 100 Years of Ham Radio

By Peter N. Glaskowsky K4PNG, Activities Manager

The video we saw at last month’s meeting, ARRL at 100 — A Century of Ham Radio, helped me to better understand the history of our hobby. It also got me to thinking about how amateur radio might continue to advance over the next 100 years.

I believe the key elements of ham radio’s future will be developed from recent history’s three biggest technologies: the personal computer, the Internet, and the cellphone. Each of these fields has much to offer us. I'd like to explain some of these opportunities and describe one possible vision of what we can achieve.

The evolution of the PC has shown us that microprocessor-based digital electronic devices are faster to develop and more flexible than those using fixed-function digital or analog circuitry. While most modern ham radios have some digital logic in them to manage buttons and displays, most of the RF and audio processing in these radios is still done by analog circuitry.

Even most of the so-called software-defined radio (SDR) products on the market are still predominantly analog inside, with digital processing only in the audio stages. While features such as noise reduction, voice processing, and simple digital modes are valuable enough, the full potential of SDR is achieved only in direct-conversion designs that digitize one or more bands with minimal analog processing.

Although there are several direct-conversion radios on the market, including commercial and hobbyist designs, it’s still early days for this product category. Many valuable features remain to be integrated, including features that will come from those other two fields: the Internet and the smartphone.

The Internet teaches us the advantages of packetized data. Packets let us route our transmissions through complex networks, share a single channel among multiple users and messages, and confirm error-free reception where desired.

The latest smartphones deliver high-fidelity voice quality similar to that of landline phones—but over radios, a far more demanding environment. They also feature full-duplex operation, which is more convenient for users and opens the door to techniques such as collision detection, transmit power minimization, and real-time band coordination. Whereas cellphone networks are controlled by one central authority, amateur radio operators work together to follow the guidelines of band plans they develop themselves, like those of the ARRL and the Western Washington Amateur Repeater Association (WWARA).

It may seem as though many of these technologies could use more of our limited spectrum for the same amount of traffic. After all, packets and control channels add considerable overhead, extra error-correction bits do no good for clear, strong signals, and it’s wasteful to retransmit a whole message when only a word or two isn’t heard.

But in truth, today’s amateur radio is terribly inefficient. How many times, on average, do you send (or say) “CQ” for each QSO you complete? How many calls do you hear, but not understand? And when nobody is transmitting, the frequency is still occupied. Our modulation schemes are far less efficient than digital methods. CW, which is one of our more efficient modes, uses about 100 Hz of bandwidth to carry 35 words per minute (roughly 30 bits per second) of information. With a digital modulation scheme such as 64-symbol quadrature amplitude modulation (64-QAM), the same amount of data would fit into as little as 5 Hz of spectrum... and 64-QAM is far from the most efficient modulation scheme known. Digital radios are also better at sharing one channel among multiple users, delivering the benefit known as statistical multiplexing.

There are dozens of other techniques used to improve the throughput and reliability of communications channels, more than I could possible describe here, known by terms such as 8B/10B, CDMA, DSSS, MIMO, NPML, PRML, RLL, Turbo, and Viterbi. Some of these methods are already used in radios, and some were developed for wired networks or even disk drives, but they’re all worth studying to see how they might apply to the unique requirements of amateur radio.

A common objection to the rapid adoption of advanced technologies is that they interfere with what 47 CFR 97.1 describes as “the amateur's proven ability to contribute to the advancement of the radio art.” It’s a rare amateur who can understand everything going on inside modern analog radios, never mind digital ones. It may seem as though adding more layers of technology will make it more difficult for amateurs to contribute meaningful innovations—but digital radios are simpler inside, and it’s easier to add new features with software than hardware.

Amateur operators used to lead the development of radio technology. It may take many years for amateur radio to regain technical parity with commercial interests, but I believe we can and will get there.

Opening up our hobby to technologies that were developed for computer networks and cellphones creates the potential for hams to attract interest and assistance from the companies that developed them. Intel, Qualcomm, and Samsung (to mention just three of the largest) employ armies of RF and communications system engineers, but few if any of these professionals work on ham-related projects because their employers see no significant profit potential there.

These leaders of the cellphone industry are aware, however, that they aren’t taking full advantage of the potential synergies available in large networks of smartphones. In a technology known as cognitive radio, smart radios cooperatively adapt to changing conditions and requirements. With the flexibility to try experimental new technologies and the pressing need to deal with the changing conditions of the HF bands, amateurs may already be making more rapid progress toward cognitive radio than commercial firms.

Similarly, while there is much talk of “cloud computing” today, rigidly hierarchical computer networks aren’t very cloud-like. Mesh networking technology, which is under active development here in the Pacific Northwest, is a great solution for amateur radio and may also be a better solution than the networks from which the public Internet is built. As amateur mesh networks become more sophisticated, their underlying technologies may transfer back into the commercial world.

Unlocking the full potential of amateur radio will require more than technology. The language of the law will have to change, too. The current legal framework dates back to the days of crystal-controlled radios, and creates unnecessary obstacles to improving spectrum utilization with smart, agile SDRs. The current prohibitions on commercial and encrypted content preclude using amateur frequencies for Internet access; reversing that stance would surely create tremendous new demand for ham licenses and radios. Such prohibitions still make sense in the crowded HF and VHF bands, but with tens of megahertz of amateur spectrum available in UHF, and over a gigahertz in the SHF band—where line-of- sight propagation means the bandwidth in a geographical area is practically unlimited—more accommodating policies could spur more rapid progress.

I’d like to show how all of these advancements could apply to amateur radio by sketching out a hypothetical future DX contest—using only technology we could deploy today.

As the contest opens, participants introduce themselves by broadcasting just one digital CQ call. Since everyone has a software-defined radio that simultaneously receives and decodes every transmission on every band, each station knows the call signs and locations of every other station within minutes. The stations spontaneously construct a distributed control system that calculates the ideal combination of long-range and short- range connections to maximize the number of QSOs on the network.

The best stations get the most points for completing their own QSOs and for relaying the QSOs of others. Instead of a hundred contacts per hour, each operator could make thousands.

True, some of the skills needed for this kind of contest aren’t the traditional ones, but they are unquestionably more relevant to the real- world needs for amateur radio. There would be very little difference, for example, between a contest and a disaster-response operation, except for the content of the messages. And bear in mind that digitally programmed and enforced band plans will keep digital radios from interfering with CW, SSB, and RTTY operations. The spectrum of the future will have plenty of room for tradition and progress.

Wednesday, May 16, 2018

20 years ago...

After being in the hobby only a few years and having been running a 9600 baud packet station I was looking to go faster.  At the time there was an ongoing TAPR project to create a 128 Kbps frequency hopping spread spectrum 1 watt, 900 MHz radio.  I was interested, the problem was it had been stalled for a while.  And to make matters worse; the only real price clue was that it would be under $500, and it would be dual marketed, to hams and for unlicensed use.

Barry, VE3JF had a webpage dedicated to higher speed options using wireless LAN modems.  At this point consumer networking products where switching from 900 MHz to 2.4 GHz.  And the price had dropped to the $100 range.  I started to make a ruckus on the TAPR spread spectrum list, why weren't hams embracing this technology?

There were a lot of naysayers.  Some said the 1 Watt automatic power control rule made Part 97 operation less desirable than Part 15.   Later this rule was done away with.

This was the start of what later became HSMM.  It was clear to me that direct sequence was going to win over frequency hopping for the newly emerging 802.11 (now legacy standard) circa 1997 or so.  This was good and bad, but sure made shifting the operations totally withing the ham radio overlap easy.  It was clear to me, that 802.11 was going to be common placed in the average home in a few short years.  And it seemed since this stuff was already operating on ham radio frequencies, we might as well at least draw some attention to it, and see what we could do with it to use it for slightly longer distances.  Heck, I just snagged a bunch of partial screen parabolic antennas for the band that were being removed from service from a rural "wireless cable TV" provider that went under.

I know I as well as others wrote letters to the ARRL at the time.

Fortunately the ARRL president at the time (Jim Haynie, W5JBP) had open ears, and formed a working committee that reported to the Technology Task Force.  It was actually Paul Rinaldo (chief technical officer), W4RI's recommendation to the ARRL board that the group be formed.  A survey conducted by the ARRL Technology Task Force, of League members and other amateurs revealed that the number one interest in new technologies was in high-speed digital networks.  Amateur radio, particularly EmComm (this was just after 911), needed some means of data transmission significantly faster than conventional packet radio.   The group was chartered to find out what it would take to do high speed data and other modes on frequencies above HF.

Now about this time in my life, I had just been transition from high school to college and started working, bought a house.  So at the time I actually didn't know Jim had appointed this group.  I didn't end up catching up with what was going on till about 2005 or so.

I learned that John Champa, K8OCL became the chairman of the working group.  The group had made several recommendations that ultimately all went no where.  Some were a matter of policy; like the regulation by bandwidth proposal that hams weren't ready for yet.  Another was trying to get TAPR to help develop 2.4 to 3.3-3.5-GHz transverters, a 70 cm OFDM modem, etc.

But the groups publicity, drew people out of the wood work to try things.  And the enthusiasm continued past the official working groups dissolution in 2006.  I felt this was good.  I had actually hoped there would be other working groups formed.  Like SDR, etc.

Anyway, the work continued without the ARRL.  By the Fall of 2008, a group of amateurs from the Texas area announced development of their own custom firmware for the WRT-54G to enable HSMM-Mesh networking.

In my opinion, this was a major thing, and this is when hams really paid attention to what others were doing.

Summary:
Sadly ham radio really doesn't have enough enthusiasm and/or skilled folks to build our own stuff to do things that we are able to do now a days with commercial networks.  The market is simply not there either.

The model of the TNC, where it started by hams, initially as a kit, and then something that small manufacturers started to sell to amateurs and to a commercial market is a very unlikely thing to see again. 

VHF and above ham radio has always pretty much adapted things from the commercial market.  Now a days that market is pretty slim.  The heyday of two way radio has come and gone.  What is left is the public safety market.   Heck we had to adapt 802.11. 

That is basically the best you can realistically hope to for.  It's important to keep eyes and the mind open to things abroad.  Things that might have a commercial market in other (perhaps less developed) countries that could be imported and used in ham radio.

The rules should be relaxed as much as possible so that if future things from the commercial market can be adapted to use in ham radio, that there won't be a need for any drawn out future requests to have that emission type permitted etc.

The present generation of hams should ban together to religiously petition that the rules be relaxed as much as possible to prevent anyone in the future from being denied from trying to do anything. Experimentation is the key to new ideas.  And lastly if you hear someone saying "you can't do that", kick them in the nuts and don't listen to a word they say.


Monday, March 12, 2018

Yaesu System Fusion (YSF)

It seems that Yaesu has learned from the ARRL.  Their youtube channel has comments turned off, and their yahoo group is moderated.

I tried to make some comments on their firmware updateable radios.  This is a concept I wrote about a long time ago.  Obviously if it was something open to 3rd party development like how the WRT-54 series router hardware turned out to be, then it would be truly awesome.  But that isn't realistic I suppose.  So short of buying one to give to Travis Goodspeed who has hacked the MD380, that likely won't be happening any time soon.

I was envisioning Yaesu later adding features like the ability to listen to ATSC TV audio.  I miss the days of when things were a bit dull on the ham bands, tuning over to the TV audio channels while at work with my VX-5.

It is truly a shame that they haven't/won't at least add D-Star receive support at the very least.  I have to say I had hope for them early on.  Maybe it was because I realized they are now solely an amateur company and unlike the others do not have a commercial line to supplement their bottom line.  At that time some of us where hoping when there were not saying a whole lot about their introduction to the ham digital market, that C4FM meant there might be a chance of whatever they unveiled would be backwards compatible with P25 or DMR.  Instead they further contributed to the digital fragmentation problem, but unveiling yet another format that is totally incompatible with anything else.  And that stubborn / bullheadedness unfortunately continues but not embracing and adding support for other modes like DMR or D-Star, in addition to their moderated/censored comment approach.

I'd sure like to see someone do it... And they'd seem like a good candidate, as they are solely ham, with no commercial line anymore... You cant tell me that it wouldn't sell and boost their name.

I can't say their digital mode or any of the other really interest me a whole lot till we have someone willing to embrace these interoperability concepts.  So the only things that I think are worth my time and money are things like MMDVM, OP25, and XLX cross connect reflectors.

Till then its old school thinking that continuing their segregation approach to digital somehow helps their bottom line. When in fact I tend to think if they would add support for another digital mode, they would have a hot selling radio.  


Saturday, January 13, 2018

Listening to DMR on the Rasperry Pi3 with op25 and a SDR

This past summer I blogged on how to listen to a simulcast APCO-25 trunked public safety system. Since that time was looking for a way to listen to a DMR system.  Last winter I gave the Raspberry Pi2 a try using DSD.  That didn't go so well.  I suspect because DSD was written a long time ago, and is a single threaded application that can't take advantage of the Pi's multiple cores.

Last April Transmit support was added to op25 for; DMR/YSF/P25 and D-STAR.  Just after Christmas this year, Receive support was announced.  So I had to try this!

I just heard DMR audio on a Pi3.. And it sounded good!

Linux op25 4.9.28-v7+ #998 SMP Mon May 15 16:55:39 BST 2017 arm71 GNU/Linux (Raspbian Jessie)

ppm set to 3 for me (see json file below) 
using my NooElec SDR




Note: DMR audio for the second time slot is sent on the specified port number plus two.  In example 'udp://127.0.0.1/56122', audio for the first slot would use56122; and 56124 for the second.

You can setup a mix of the various digital channels in the json file... It works like a scanner.. And if you want you can define SDR dongles to channels... In case you want certain channels banded to a certain hardware... for RF/antenna reasons for example.


Graham and Max have been hard at work improving op25.  And thanks to that hard work its child's play to install:

sudo apt-get update
sudo apt-get build-dep gnuradio

cd ~
git clone https://github.com/boatbod/op25
cd op25
./install.sh

If you are wondering what your tuning offset is, the best thing is to enable the datascope plot, and adjust the ppm value by one click at a time to center the eye plot.



Wednesday, January 10, 2018

myARRLvoice


Before the latest ARRL shit storm erupted, I had written in November 2017 my section manager (KA1RB).  Pay attention to my 6th paragraph where I commented to KA1RB that I never see any division directors or section mangers make public FCC comment, thus I have no idea if they represent my interests.

You may have noticed I wrote to my section manger instead of Kermit, W9XA, my division director.  I haven't been impressed with Kermit, W9XA since he replaced W9GIG.  Not that I thought Dick Isely was that great anyway.  At least Pat, KA9RB responds enthusiastically, and comes off as having an open ear.  An impression I wasn't left with when I'd communicate with Dick or Kermit.

Patrick,
That was me who shyed away from your table at the fest when you brought up renewing.  I figured I can articulate my issues via email here better.  As a side note, that was probably the best Appleton fest I have seen in recent years.

I am considering not renewing this year.  I have been a member off and on, and more steadily the last few years.  Honestly I think the ARRL does a piss poor job of steering amateur radio. Maybe they don't want to, but ultimately someone should in my opinion. The don't even attempt to create enthusiasm about anything new.  I always admired Wayne Green despite some flaws, in that he inspired a more hand-on approach and promoted new ideas.  (I ended up being the somewhat silent curator to collect scans of his magazine, that he later signed off for release into the public domain, if you weren't aware)

I have brought up in past communications that I saw good things come from the HSMM working group around 2001 that was created under the direction of Jim Haynie, W5JBP. I had hoped other working groups would be formed, SDR and so forth as there seemed to be good ideas, enthusiasm, and promotion stemming from the HSMM WG.  I haven’t really heard much about the Technology Task Force since Brennan N4QX took over for Paul Rinaldo, W4RI, which is disappointing.

Anyway the ~$50 that someone might send the ARRL, in my opinion is better donated to an open source ham radio software project in my opinion.  I think folks like Jonathan Naylor, G4KLX are some of the unsung heros of ham radio.  Might just have to bring this up at a local meeting.

There was a recent entry license survey which I am sure you are aware of.  And since I got into the hobby in my high school days in the mid 90's I recall two big license changes.  I wasn’t paying attention at the time of those, but I would be interested in learning how those came about.   I assume they were ARRL endorsed/initiated to some degree.  Of course I am referring to the first was around 2000, where 5 WPM became the highest code test, and they consolidated the license classes, eliminating novice and advanced classes.  Then around 2006, when the code test went away all together.

So why the ARRL doesn't endorse some major rule changes bugs me. Seems like the bottom line to them is just to have a good number of folks entering the hobby.  And while I feel that is important, there are other important things like undoing some of these decades old rules to there is at least a chance of things moving forward on their merits. The bottom line is I don't know where they stand on things, let alone even where my division director feels personally.

Someone with the league really ought to write on what you can and can't expect ARRL to do and why.  Maybe that will help me.  Some years back I had similar confusion/frustrations with TAPR.
Thanks, any feedback will be used in making my renewal decision. Though I think the biggest thing that will help me make my decision will be this “vision of the future” that needs to be conveyed it to our current membership.  That is the shimmer of hope I have with the League right now.
Steve, KB9MWR

I am still waiting with money in hand for this vision, and some sort of action from the ARRL higher powers to indicate a willingness to move into 2018 with more transparency and a more democratic voice for it's membership.