I noticed when I went looking for soundmodem that its homepage had disappeared off the face of the ‘net, and with it, its source code.
Thankfully, there were some traces of it still around. The Wayback Machine had all bar the source code, and Debian had the rest of what I was looking for.
So you can find a mirror of the old soundmodem site, along with the software at the following address.
This last week the local repeaters here in Brisbane have been rather quiet.
One repeater I used to use a lot has been acting up, and so rather than potentially try to exacerbate a possibly worsening issue, I figured I’d leave it well alone until it was fixed.
Another I lurk on, has been working fine, but many of the people I’d talk to, are away on holidays.
So, I figured I’d dust off my trusty HF whip and give the lower frequencies another crack. This time last week I was getting nowhere on 15m. Maybe wrong place at the wrong time (Aside: is there ever a right time to be in the wrong place?) and so didn’t get anywhere.
40m I knew worked on this particular antenna, so I’ve been lurking there… calling in on the Coral Coast net on 7060kHz in the mornings, and tuning up and down the band on the way home. I make note of my listening frequency via APRS-IS, see my tracker or look for VK4MSL-10 on aprs.fi.
I knew the antenna worked there, not perfect, but it did work. It works particularly well when the other station is equipped to pick up weak stations. Earlier this evening, I set out from my workplace listening on 7060kHz where I was this morning. I noticed it was chock-a-bloc full of stations north of us. Indonesia and surrounds by the sounds of things.
Couldn’t make a head or tail of what they were saying, so I moved up the band, stumbled across a couple of “local” stations chatting around 7175kHz. Turns out one was portable in Barcaldine, didn’t catch the name, but the callsign was VK2DQC, I think. (I didn’t write it down.) We chatted for a short while, but apparently my signal was up and down like a yo-yo.
No surprise, I started the QSO walking up Greer Street, Bardon, continued my next over riding down The Drive, Cecil Road and Bowman Parade then up through Sunset Park. Anyone who knows that stretch knows it goes up then down then up again then down. I finished the chat as I came down Monoplane Street, Ashgrove.
Tuning around, I found another pair talking on 7158kHz. Bob VK6KJ and Bruce VK2??. As they were talking a third station, Joe, W5?? called in from Florida USA. To say I was impressed would be an understatement, all three were coming in Q5, and signal strengths in excess of S6 in most cases. Bob was peaking S9.
Joe mentioned is misfortune of having some equipment destroyed in a storm, and this necessitating the replacement of a computer along with its OS. Apparently he’s not a fan of “Window 8” (as we call it at work). I did try to call Joe but must’ve doubled and wasn’t heard.
I did though, manage to make contact with Bob. He was located in Albany, about 400km south-southeast of Perth, and running 400W into a two-element beam pointed at the US. With my measly 100W and stubby home-made antenna, I apparently was registering a Q5S5 signal with the odd drop-out.
Clearly Bob’s end was doing all the work, but impressive nonetheless. Seeing as the evenings can be particularly quiet, I think I’ve found a new past-time to while away the hour-long trip home, stirring up HF on the deadly-treadly-mobile!
Well, this year’s International Rally of Queensland didn’t go the way everyone expected. We were there with Brisbane Area WICEN, providing the backup communications for the event. Our primary role was to relay the scores given to us by the post chief in the timekeeper’s tent. They looked after scheduling the cars, getting times, and sending the cars through. We just passed on scores (start/finish times) and other traffic.
Saturday went well. My father and I were set up at Kandanga North running the WICEN checkpoint for stages 6 and 12 of the rally. After some early hiccups getting the packet radio network going, we had the scores being sent out on time and everything running smoothly. Apart from some cows holding up traffic, there were no delays.
Sunday however… just about everyone would have heard about the fatality. My father and I ran the WICEN checkpoint at the start of the fateful Michell Creek Special Stage 14.
Having now seen the ABC website footage, looking at the competitor lists and my own logs, I can say with 90% certainty which car (and therefore 45% certainty who the deceased is) the unfortunate car was and when they left the stage.
My condolences go out to both driver and co driver at this difficult time.
Update: The names have been released.
Over the last year or so, I’ve done a number of improvements to the bicycle mobile station. I’ve kept meaning to document what’s happened, as a number of people have asked about the station, and not everyone gets to see it up close.
A big move was when the FT-290RII 25W PA died, I was using the FT-897D a lot, and that thing is a heavy lump of a radio to lug around. So I bought its smaller sister, the FT-857D with its remote head kit.
A second move was from the heavy 40Ah battery pack to a much lighter 10Ah pack. Then, in July last year, I bought myself a new pair of wheels. The ’09 model Boulder pictured earlier still gets regular use and is good on the road, but longer trips and on hills, it’s a drag, and the tyres are not good on dirt.
Thus I bought a Talon 29 ER 0… in contrast to the Boulder, this bike is designed with mountain-biking sports in mind, so a little heavier duty, better gearing and suspension. Sadly not dual-suspension … they don’t seem to make one that will take a pannier rack on the back like I require. Nonetheless, this one has been going well.
VK4MSL/BM Mk3: New and improved
Rather than buying an open basket like I did on the other, I went one step further, I bought a motorcycle hard top-box and mounted that on the back. Thus the FT-857D could live in there, sheltered from the weather. I later also bought pannier bags: my battery, some tools, spare tubes, visors for the helmet, etc, live in one bag, my clothes live in the other.
The station is otherwise, not much different to how it was in concept. The antennas now mount on opposite sides of the top box with right-angle aluminium. I still have to work on grounding for the HF side but even then, the station still delivers respectable performance on 40m.
On my way to BARCfest this year, I was being heard S9+40dB in Newcastle with 60W PEP. I’d have ran 100W, but due to the earthing problems, I found I was getting a bit too much RF feedback.
The 2m antenna is similar to previous ventures, just a 51cm length of RG-213 with the jacket and braid stripped off and a PL-259 plug soldered onto one end. It’s a simple design that’s easy to make, easy to fix, cheap and can be constructed from readily available parts. If you can make your own patch leads, you can make one of these.
VK4MSL/BM: 2m antenna. Just some RG-213 and a PL-259 connector is all you need
70cm remains a work in progress. In theory, a ¼λ antenna resonant at 144MHz should also resonate at 432MHz, as this is the ¾λ frequency. In practice, this has been a pain to tune. I basically just stick to 2m and leave it at that.
As for coupling the radio to the head unit… I could use the leads that Yaesu supplied. One distinct disadvantage with this is that it ties me into using only compatible equipment. The other is that the connectors are just not designed for constant plugging/unplugging, and the 6P6C and 8P8C connectors become unreliable very quickly if you do this. A solution was to make up a patch lead to go onto each end, and to use some standard cable in the middle.
Initially I did this with a 25-pin printer cable, but found the RF problems were terrible! Three lengths of CAT5e however, did the job nicely. Yes, I sacrifice one pin, right in the middle. 24 pins is more than enough. I allocate six pins on one end for the head unit cable; choosing the wires so that the connections are consistent at each end.
The other end, I have a standard convention for microphone/control cabling. The balanced nature of the CAT5e works well for microphone cabling on a radio like the FT-857D which was designed with dynamic microphones in mind.
The only other connectors I need then are for power, and for lights. Power I just use Anderson PowerPole type connectors, the 30A variety… and for lighting, I use ruggedised 6-pin automotive connectors.
VK4MSL/BM Mk3: Rear connections onto top box
At the handlebars, things have been refined a little… the switches and push buttons are in plastic boxes now. Here I still have to work on the front basket mount, this compromise of a former broomstick handle hose-clamped to the handlebars is a workaround for the basket bracket’s inability to clamp around the rather thick handlebars. This arrangement is fine until one of the hose clamps slips (which happens from time to time).
For now I put up with it. The controls from the radio are now mostly on the left side… Since the rear gear shift and front brake are on the right-hand side, I do far more with my right hand than with my left. Thus doing this, I free up my right hand to actually operate the bike and use my less-busy left hand to operate the radio.
VK4MSL/BM: Front handlebar controls
I mentioned earlier about HF… the HF antenna should look familiar. It’s actually the same one I’ve been using for a while now. Most distant contact so far has been into the Cook Islands on 20m. I’ve had successful contacts on 80m, 40m, 20m and 15m with this antenna. 10m and 6m are the two that elude me just now.
VK4MSL/BM Mk3: With the HF antenna
It is a little difficult to see the entire antenna. I did try to pick the angle to show it best… but if you look above the tree, you’ll see the tip of it immediately above the top box. Below is a close-up shot to give you an idea where to look.
VK4MSL/BM Mk3: Base of HF antenna
One big advantage of the new set up, is that night-time visibility is much better than before. On the front I have a LED strip which lights up the path maybe 2m ahead of the front wheel. Not a strong light, but ticks a box… my main headlight is on the helmet — people frequently assume they’re being filmed by it. On the rear however, is a different story:
VK4MSL/BM Mk3: All lit up
It doesn’t look like much in the day time, but it is quite bright at night. The back uses two LED strips mounted in behind the red plastic on the top box, and one can easily read a book in the light produced. Looking in the rear vision mirrors at night, the red glow can be seen reflecting off objects for a good 100m or so.
On my TO-DO list, is to mount switches to operate the brake light (just above the callsign). Options include reed switches, hydraulic switches in the brake lines, or strategic placement of micro-switches. I’ll have to experiment. The other electronics is in place.
As to the other bike? It’s still around, in fact if you look at the photo of the VHF antenna, you can see it in the background… along side the trailer I use when I do my grocery shopping.
I’ve done away with the basket on it, and gotten a second mounting plate, so the same top box fits on the back of the other bike, along with the same pannier bags, and same front basket. It has done about 2800km since I bought the Talon (mid July, 2012), the Talon itself has done 2617km.
Thus I’d estimate the Boulder is well and truly past the 10000km mark, probably closer to 11000km now. It’s still the primary means of getting around, averaging close to 100km a week and with a heavy load. Not bad for a bike that’s designed for a little recreational riding.
Recently I purchased a second hand Kantronics KPC-3 packet TNC. Brisbane Area WICEN make heavy use of packet at one particular event, the International Rally of Queensland, where they use the 1200-baud network to report the scores of rally cars as they progress through each stage.
Now, I’m a newcomer to radio compared to most on the band. I got my license in 2008, and I’ve only had contact with packet for the last two years, and even then, mostly only at a distance. I had a hand-held that did APRS, and I’ve also done some APRS using soundmodem and Xastir. Full-blooded AX.25 has taken me some time, and I’m slowly coming to grips with some of it.
One thing I wanted to try and figure out, is how to re-lay traffic from a host connected to the RF world, to a host on a local network. I knew there was some protocol that did it, but didn’t know what, or how it worked. Turns out the protocol I was thinking of was AXIP, which basically overlays AX.25 frames directly atop IP. There’s also a version that encapsulates them in UDP datagrams; AXUDP.
The following are my notes on how I managed to get some routing to happen.
So, my set-up. I have my FT-897D set up on 145.175MHz FM, the APRS frequency in Australia. (I did go hunting for BBSes the other night but came up blank, but since APRS uses AX.25 messaging, it’ll be a start.)
To its data port, I have the KPC-3, which connects to my trusty old P4 laptop via good ol’e RS-232 (the real stuff, not pretend USB-RS232, yes the laptop is that old). This laptop is on my local LAN, with an IP address of 192.168.64.141.
In front of me, is my main workhorse, a MacBook at the address of 192.168.64.140. Both laptops are booted into Linux, and my target is Xastir.
First thing I had to do was compile the AX.25 kernel modules, and the ax25-tools, ax25-apps. The userspace tools needed for this are: ax25ipd and kissnetd.
This is the P4 in my case, the one with the TNC. First step is to get the TNC into KISS mode. In the case of Kantronics TNCs, the way to do this is to fire up your terminal emulator and run int kiss followed by reset.
Important note: to get it back, shut down everything using the serial port then run echo -e '\0300\0377\0300' > /dev/ttyS0. This sends the three-byte exit-kiss-mode sequence (0xc0 0xff 0xc0).
Configure /etc/ax25/ax25ipd.conf. Three things you’ll need to set up:
In my case, my ax25ipd.conf on the P4 laptop looks like this:
socket ip mode tnc device /dev/ttyS0 speed 9600 loglevel 2 broadcast QST-0 NODES-0 # This points to my MacBook; d means default route route 0 192.168.64.140 d
Once done, we start the ax25ipd service as root, it should fork into the background, and checking with netstat should show it as listening on a raw socket.
Here, we also run a AXIP server, but this time to catch the packets that get flung our way by the other system. We want Xastir to pick up the traffic as it comes in. Two ways of doing this.
One is to configure kissattach to give us a PTY device which we then pass onto ax25ipd, then run Xastir as root and tell it to use the AX.25 stack directly. Gentoo’s Xastir ebuild ships with this feature disabled, so not an option here (unless I hack the ebuild like I did last time).
The AX.25 tools also come with kissnetd: this basically generates several PTYs and links them all together so they all see eachother’s KISS traffic. So ax25ipd will receive packets, pass them to its PTY, which will then get forwarded by kissnetd to the other PTY attached to Xastir.
There is one catch. Unlike in kernels of yore, kernel 2.6 and above (3.x is no exception) do not have statically configured PTY devices. So all the AX.25 docs that say to use /dev/ptyq0 for one end and /dev/ttyqf for the other? Make that /dev/ptmx for one end, and the tool will tell you, what the other end is called. And yes, it’ll change.
Run kissnetd -p 2; the parameter tells it to create two PTYs. The tool will run in the foreground so make a note of what they’re called, then hit CTRL-Z followed by bg to bring it into the background.
vk4msl-mb stuartl # kissnetd -p 2 kissnetd V 1.5 by Frederic RIBLE F1OAT - ATEPRA FPAC/Linux Project Awaiting client connects on: /dev/pts/1 /dev/pts/4 ^Z [1]+ Stopped kissnetd -p 2 vk4msl-mb stuartl # bg 1
Now, in this example, PTYs 1 and 4 are allocated. I can allocate either one of them to Xastir or ax25ipd, here I’ll use /dev/pts/4 for ax25ipd and the other for Xastir. It is possibly best if you make symlinks to these, and just refer to the symlinks in your software.
# ln -s /dev/pts/4 /dev/kiss-ax25ipd # ln -s /dev/pts/1 /dev/kiss-xastir
Whilst you’re at it, change the ownership of the one you give to Xastir to your user/group so Xastir doesn’t need to run as root.
Set up /etc/ax25/ax25ipd.conf on the client. Here, I’ve given it a route for all WIDE* traffic to the other host. It might be possible to just use 0 as I did before, I wasn’t sure if that’d create a loop or not.
socket ip mode tnc device /dev/kiss-ax25ipd speed 9600 loglevel 2 broadcast QST-0 NODES-0 # This points to my P4, attached to the TNC; d means default route route WIDE* 192.168.64.141 d
Now start up ax25ipd and Xastir, you should be able to bring up the interface and see APRS traffic, more over, you should be able to hit Transmit and see the TNC broadcast your packets.
Some stations visible direct via RF (click to enlarge)
Just recently, I managed to kill yet another hand-held. Not deliberately, just a combination of conditions and not adapting my behaviour to suit.
I have a Yaesu VX8-DR, which I mainly use on the bicycle for APRS. It isn’t bad, the GPS could be faster, and the Bluetooth is more of a gimmick (in that it only works with some Bluetooth headsets and is intermittent at best), but my biggest nit with it, is that you can’t charge the thing while it’s turned on.
This leads me to the bad habit of just leaving a DC power lead semi-permanently plugged into the side, with the other end plugged into the 12V supply on the bicycle. You guessed it… one bad day of rain, some water got in via the DC jack and basically destroyed it. I’m pretty sure warranty doesn’t cover that kind of abuse.
I’m not in a hurry to buy another one. In fact, I probably won’t. I’m too clumsy to look after an expensive one, so better just to keep the two Chinese cheapies going (Wouxun KG-UVD1P’s). This lead me to thinking about what I specifically like in a hand-held, and what features I’d look for.
Looking around, it seems the vast majority of sets out there are evolutionary. An extra handful of memory channels, higher power, bigger battery, ohh look Bluetooth, and this one has {insert some semi-proprietary-digital-mode here}. Yawn!
Most of them have tiny screens which can’t show a decent amount of information at a glance. Digital voice is a long way being usable, with about 3 or 4 proprietary or semi-proprietary competing standards. What about D-Star you say? Well, what about it. Nice mode, pity about the codec. How about P25? Same deal.
If a digital mode is going to succeed in Amateur radio, it’ll be necessary for a home base to be able to implement it with nothing more than a desktop or laptop computer loaded with appropriate Free Software and a sound card interface. Not a silly proprietary “DV-Dongle” or some closed-source blob that speaks gibberish no other software can understand.
As for portable use; it should be possible for a hand-microphone that implements the mode on a DSP be plugged into an existing hand-held (like the Wouxun or Yaesu sets I mentioned earlier) to make it interoperable — open standards will help keep costs down here.
Until such a mode comes along (and they’re working on it — already making excellent progress on HF, keep it up guys!) there’s no point in pouring money into a digital mode that will be a white elephant in a few years.
By far the most popular mode on VHF and UHF is plain old FM. The mode Armstrong made. It’s everywhere, from your cheap $100 Chinese firecracker set to the most expensive SDR, they all offer it. Repeaters abound, and it’s available to pretty much all amateur license classes. And it works good enough for most.
The big problem with FM, is interfacing with repeaters. In particular, the big use case with hand-helds and repeaters, is being able to recall the settings for a repeater where ever you happen to be. Now you can carry around a booklet with the settings written in, and punch them into your radio each time.
This works better for some than others. On the KG-UVD1P with its horrid UI, it is a tiresome affair. The Yaesu VX-8DR and Kenwood TH-F7E aren’t bad, once you get used to them. It’s still fiddly and time consuming, definitely not an option while mobile. This is where memory channels come in.
Now I realise that sets which stored more channels than you could count on one digit-challenged hand were considered a revolution about 10 years ago. Back then the idea that you could basically control a digital counter, which would supply an address to an EEPROM that would spit out the settings to drive a PLL synthesizer and other control circuitry was truly remarkable.
Today, the EEPROM and counter have been replaced by a MCU that reads the keypad matrix and outputs to a LCD panel, but we’re still basically incrementing a counter that’s acting as an address offset into non-volatile memory. The only change has been the number of channels. The Kenwood set I had gave you 400. The VX-8, gives you 1000 — which can be optionally grouped into 24 banks (by far the best system I’ve seen to date). The Wouxun gives you a poultry 128.
The hardest thing about this is finding a given repeater in a list. 128 is more than enough if you don’t travel, or if you pre-programme the set with the appropriate channels in some logical ordering before you leave. In there hints another factor; “logical ordering”, since there’s no way to sort the memory channels by anything other than channel number.
In this day and age, 1000 channels, linearly indexed, is a joke. I can buy a 2GB MicroSD card from the supermarket for $10. How much repeater data could you store on one of those? FAT file system drivers are readily implementable in modern MCUs and a simple CSV file is not that big a deal for a MCU to parse.
It wouldn’t be difficult to build up a few indexes of byte locations to store in NVRAM, and have the CSV store frequency, call sign, a Maidenhead locator and other settings of all the repeaters in the country, then allow the user to choose one searching by frequency, by call-sign, or if the user gives their current grid square (or it derives it from a GPS), by proximity. That would be a revolution. The same card could also store a list of Echolink and IRLP nodes, and make a note of such nodes via RF so it can automatically suggest the nearest IRLP node, take you there, then dial whatever node for you after you announce yourself on the frequency.
I’ve seen more elaborate software written for 8-bit micros like the Apple II, the Commodore 64 and the Sinclair ZX Spectrum back in the day, so clearly not beyond today’s equally powerful AVR, PIC, MSP430 and ARM chips. A STM32F103RE packs 64KB RAM, 512KB flash and a SDIO interface in a nice small TQFP64 package and costs less than $8. Even for a Wouxun, that’ll maybe add no more than 20% still keeping it rather competitive with the opposition.
As for user interface? We don’t need Android on there, although that could be nice. A decent size resistive touch-screen with a reflective dot-matrix LCD would more than suffice. This technology, thanks to mobile phones, is cheap enough to implement in this application. The MCUs needed to drive them have also come down in cost greatly.
Even without the touch-screen — a LCD bigger than a matchbox would allow for text that is easily readable, menus that aren’t constrained in their presentation, and a generally nicer user experience.
SDR hand-helds will likely be the next big revolution, if they are affordable, but I feel that’ll be a way off, and for rag chew on a local repeater, I doubt SDR will be that much superior. It certainly will push the price up though.
I suppose a start will be to try and come up with a suitable front-end device that can be bolted onto existing transceiver hardware, maybe something that drives the computer control port of a mobile rig such as the FT-857 or IC-706.
From there, it just takes one brave manufacturer to package such a device up with a suitable transceiver in a hand-held form factor to put something to market. If they did so in a way that could keep this UI module open-source, even better. Bonus points if there’s a bit of an interface that can take a DSP for digital modes.
Want D-Star, P25, FreeDV, Wongi? You got it, just slot in the right module, load on the firmware into the UI module, and away you go. Want to do something special? Break out the text editor and compiler and start hacking. The RF side of things can still be as it was before, so shouldn’t pose any more of a problem for regulators than a transceiver with a digital modes jack and computer control interface.
I’m not sure if anyone has worked on such a front-end. Another option would be a cradle that takes a modern smart-phone or tablet, interfaces via USB to the set, and uses the smart-phone as the UI, also extending the phone’s battery at the same time by supplying the 5V it needs to charge. Bonus points if it can feed the audio signal to/from the phone for digital modes and/or interfacing with BlueTooth. A pocket APRS I-Gate and Echolink node, perhaps? Whatever takes your fancy.
I guess the real answer here will be to come up with something and see if there’s any interest — the “throw it against the wall and see what sticks” approach.
Some may recall my old set up I used to record the AWNOI net. A bit fiddly, but it worked, and worked well. However the machine I used was short-lived. Basically, I wanted to stream in both directions between a sound device connected to a HF radio transceiver, and a USB wireless headset, with a feed being recorded to disk.
The problem with newer sound devices is the rather limited sync range possible with the modern audio CODECs. Many will not do sample rates that aren’t a multiple of 44.1kHz or 48kHz, and I have a headset that won’t record any other sample rate other than 16kHz. ALSA’s plug: doesn’t play nice with JACK, and I shelved the whole project for later.
Well, tonight I did some tinkering with gstreamer to see if it could do the routing I needed. Certainly all the building blocks were there, I just had to get the pipeline right. A bit of jiggling of parameters, and I managed to get audio going in both directions, and to a RIFF wave file to boot. I’ve put it in a shell script for readability/maintainability:
#!/bin/sh
# GStreamer bi-directional full-duplex audio routing script
# Stuart Longland VK4MSL
CAPT_BUFTIME=50000
CAPT_LATTIME=25000
PLAY_BUFTIME=20000
PLAY_LATTIME=1000
STREAM_FMT=audio/x-raw-int,channels=1,width=16,depth=16,rate=16000
OUTPUT_FMT=audio/x-raw-int,channels=2,width=16,depth=16,rate=16000
OUTPUT="${1:-out.wav}"
HEADSET_DEV=hw:Headset
HEADSET_CAPT_FMT=audio/x-raw-int,channels=1,width=16,depth=16,rate=16000
HEADSET_CAPT_BUFTIME=${CAPT_BUFTIME}
HEADSET_CAPT_LATTIME=${CAPT_LATTIME}
HEADSET_PLAY_FMT=audio/x-raw-int,channels=2,width=16,depth=16,rate=48000
HEADSET_PLAY_BUFTIME=${PLAY_BUFTIME}
HEADSET_PLAY_LATTIME=${PLAY_LATTIME}
SNDCARD_DEV=hw:NVidia
SNDCARD_CAPT_FMT=audio/x-raw-int,channels=2,width=16,depth=16,rate=48000
SNDCARD_CAPT_BUFTIME=${CAPT_BUFTIME}
SNDCARD_CAPT_LATTIME=${CAPT_LATTIME}
SNDCARD_PLAY_FMT=audio/x-raw-int,channels=2,width=16,depth=16,rate=48000
SNDCARD_PLAY_BUFTIME=${PLAY_BUFTIME}
SNDCARD_PLAY_LATTIME=${PLAY_LATTIME}
exec gst-launch-0.10 \
alsasrc device=${HEADSET_DEV} \
name=headset-capt \
slave-method=resample \
buffer-time=${HEADSET_CAPT_BUFTIME} \
latency-time=${HEADSET_CAPT_LATTIME} \
! ${HEADSET_CAPT_FMT} \
! audioresample \
! audioconvert \
! ${STREAM_FMT} \
! queue \
! tee name=headset \
! audioresample \
! audioconvert \
! ${SNDCARD_PLAY_FMT} \
! alsasink device=${SNDCARD_DEV} \
name=sndcard-play \
buffer-time=${SNDCARD_PLAY_BUFTIME} \
latency-time=${SNDCARD_PLAY_LATTIME} \
alsasrc device=${SNDCARD_DEV} \
name=sndcard-capt \
slave-method=resample \
buffer-time=${SNDCARD_CAPT_BUFTIME} \
latency-time=${SNDCARD_CAPT_LATTIME} \
! ${SNDCARD_CAPT_FMT} \
! audioresample \
! audioconvert \
! ${STREAM_FMT} \
! queue \
! tee name=soundcard \
! audioresample \
! audioconvert \
! ${HEADSET_PLAY_FMT} \
! alsasink device=${HEADSET_DEV} \
name=headset-play \
buffer-time=${HEADSET_PLAY_BUFTIME} \
latency-time=${HEADSET_PLAY_LATTIME} \
interleave name=recorder-in \
! audioconvert \
! audioresample \
! ${OUTPUT_FMT} \
! wavenc \
! filesink location="${OUTPUT}" \
headset. \
! queue \
! recorder-in.sink1 \
soundcard. \
! queue \
! recorder-in.sink0
Now the fun begins ironing out the kinks in my data cable for the FT-897. At present, it works for receive, and seems to work for transmit. I use VOX on the radio itself and keep the headset’s microphone on mute when I don’t want to transmit.
At present, I was getting a bit of distorted audio coming back through the headset when I transmitted, almost certainly RF-pickup in the cable and line-in circuitry of the computer’s sound card. I’ll have to see if I can filter it out, but the real test will be seeing if such distortion is present on the outgoing signal — or rather, if it’s significantly audible to be a problem.
Well, it’s been a while since I touched this tablet. I basically chucked it in a corner in disgust after it shat itself rather unceremoniously on the trip before we even got to the NSW/Victorian border. By “shat” itself, I mean corrupting files on the internal microSD card, intermittent device resets, display flickers, all the hallmarks of a dry joint.
The seller on eBay that sold me the device have been completely unresponsive as to the problems, so looks like I kissed about $250 goodbye. Ahh well, such is life. They are still being sold on eBay, but buyer beware, they are cheap, and it’s pot luck whether yours is cheerful, or nasty like mine. If you want something reliable, look elsewhere.
Having made this mistake, well, I’m looking to make lemonade from the lemon. First step, was to figure out what on earth I had. So out with the screwdriver.
You’ll notice on the top and bottom of the unit, there are four small plugs concealing screws. These hold the LCD screen assembly in place. Undo these, then you need to carefully work your way around and release the clips that hold the LCD screen assembly. Do not try to detach the LCD touch panel from the LCD! I initially couldn’t get it to budge, so I tried doing exactly this in the hunt for possible hidden screws (there were none). This was the end result:
Why one should not try to detach the touch panel.
Never mind I say… the unit was just about destined for the bin as it was. External USB HID devices work for what I’m after, but it’ll mean any touch-related fun is out unless I can pick up a replacement 4-wire panel. Element14 and RS have them at >$80, to which I say, bugger it, I’ll do without.
Having pulled the unit apart, the main PCB is held to the back shell by a few screws, one thing is immediately apparent. The whole device is based on what looks to be a fairly generic System-on-Module based around the Vimicro VC0882BCXA System-on-Chip, and the Vimicro VC7822EL companion chip.
Flytouch III PCB
Top left is a Wifi module based on the Realtek RTL8111, and to the right, the GPS module (which hooks to one of the serial ports from what I recall). Down the bottom of the image are the USB ports. Near the HDMI socket is a Silicon Image SiI9022ACNU HDMI transmitter.
The system on module looks interesting, and I’m curious to find out more about it, as for hobby projects, the pins are not too small to deal with using a soldering iron. The OS and boot loader exist on the microSD card. I tried putting a 16GB card in, but evidently I wasn’t getting the partition table right as it wouldn’t boot. I haven’t tried hooking up a serial port as yet, so it’s hard to know what is wrong. Some research indicates that ttyS0 lurks on this board just near the aforementioned microSD socket:
The system on module within the Flytouch III
I haven’t spotted the bad joints that were giving me grief. In fact, having gotten it out of the case, I find the top USB port (flakey from day one) seems to be behaving, and I’ve had no issues with it running with the case apart. Otherwise I’d be running a soldering iron over a few joints just to make sure everything was right.
Next step? Well for now, I’ll put it back together (minus touchscreen) and put it aside. I’ll have a look at tacking a connector onto those serial pins, with a level shifter so I can interact with the serial console.
Having gotten bootloader access, I should be able to debug the SD card cloning issue, then I can have a close gander at what the current u-boot and kernel are doing to tickle the hardware. End game? Well, Android isn’t much use without a touch screen, so I’ll be probably hacking together a Gentoo-based environment with some amateur radio related software. We shall see.
Prior to my road trip to LCA 2012 Ballarat, I bought a new toy, namely a Yaesu VX8-DR handheld.
At that point it turned up only just before I was due to leave, so I wasn’t able to get the accessories I wanted. I cobbled together my own 12V charger lead by snipping the original power supply and soldering on a cigarette lighter socket, but otherwise I used the handheld in its out-of-the-box configuration.
Having gotten back, I have purchased the FGPS-2 GPS module, CT-136 GPS adaptor and the BU-1 Bluetooth module.
The set works quite well. The antenna is pretty deaf and useless on 6m, maybe I can get a better after-market tri-bander whip, but on 2m and 70cm it works reasonably well. I’ve heard APRS traffic over distances of 100km, and even been heard on APRS by a digipeater some 90km away.
Audio quality is good, both transmit and receive. Plug in a pair of stereo headphones, and the wideband FM receiver sounds excellent; in stereo to boot.
Probably my biggest nit, is you can’t simultaneously charge and externally power the set. To charge, you must either detach the battery and drop it into a separate charger cradle (an optional extra) or turn off the set.
When I purchased the VX-8DR, it was a real toss up between it and the VX-8GR. The reason I went the VX-8DR was because it had 6m, and Bluetooth. Having gotten the GPS, I’ve run into the problem a lot have reported; the GPS module is deaf as a post.
The VX8-GR doesn’t improve on this either. However, the good news, is that because my module is external, I can (1) mount it in a better spot, or (2) replace it with a better compatible module. For VX8-GR owners, this is the end of the road, they can do nothing but moan to Yaesu. I at least have options.
The module is mounted vertically inside the FGPS-2 casing. Usually with GPS modules such as these, they embed a small patch antenna, whose radiation pattern is perpendicular to the plane of the antenna surface. Being vertical, this means when you hold the radio vertically (as you normally would), GPS reception is poor because the radiation pattern is directly in front of the radio.
The radio seems to perform a lot better, if the radio is held with the screen facing upwards towards the sky. It’ll even work inside my house if I do this. It seems this is a screw-up on par with the iPhone 4. Another alternative is to replace the module, the FGPS-2 apparently uses 9600 baud serial with NMEA format strings. However, it seems the parser in the VX-8 is rather crude. I have a module that does NMEA at 4800 baud, so I’ll either need to coax it up to 9600, or use a microcontroller to buffer and convert rates, and perhaps do some tweaking of the sentence format to make up for the VX-8’s shortcomings.
My hunch; if I make an alternative bracket to the CT-136 adaptor, I can nail this, and another problem, the inability to plug in the GPS and a headset. I have the CT-M11 cable, and thus I plan to make a bracket to connect the FGPS-2 to the end of this cable; allowing me to also plug in a wired headset.
I bought the Bluetooth as an insurance policy to give me another means of interfacing a headset. Then began the fun of getting it to work with my headsets. I have a couple; a Bullant earmuff-headset, a lightweight mono Digitech headset, and a “MyTalker” headset.
The first was one set I bought some years ago, back when the Bluez was far less stable than it is today, and also long before I was into Amateur Radio or possessed a Bluetooth-capable phone. I tried pairing using a USB Bluetooth dongle, but had little luck, so they got put on one side. Also despite advertising being able to stream music, it only supports HFP and HSP profiles, so you get to listen to your tunes in 8kHz 8-bit mono. They are sold at some hardware stores, such as Mitre 10 The Gap (where I bought my set).
The handheld did pair with this set, but I couldn’t get PTT to work, and the headset itself also had a few faults; namely it was always noisy, and the broadcast receiver stopped working, so I’ve taken them apart for now to see if I can fix these issues. I can key the radio up using the radio’s PTT, but then both internal and headset microphones go live.
The second set is sold by Jaycar, catalog number AA2080. This would be my preferred set to use with the radio as it can pair with two devices simultaneously. It supports the same profiles as the earmuffs, but it’s at least more lightweight.
The BU-1 takes one look at this set, and turns its nose up at it, with the VX-8 giving up and displaying “PAIRING ERROR”.
I also bought the MyTalker set from Jaycar, catalog number XC4894. This set is much like the earmuffs. It embeds its own microphone, but the unit itself provides a 3.5mm socket for you to plug in your own headphones, or use the supplied earphones (which are awful and uncomfortable, don’t use them). At the other end of the unit, is a lead terminated with a 3.5mm plug to plug into a music player. I’ve modded this set to be able to use an external microphone, switchable between a transceiver and the Bluetooth set, allowing a headset connected to a radio to also connect to a phone. I’m still working on this bit.
The VX-8 treats this set with much the same contempt as the mono headset before.
Today, I poppsed in and bought a more expensive set; this time I looked for A2DP functionality, Jaycar have one, catalog number AA2082. Like the AA2080 it can talk to two devices, unlike the AA2080 it supports AVRCP and A2DP. Also, not advertised, is it can function as an analogue headset; supplied in the box is a dual 3.5mm to mini-USB cable that can plug into the headset and allow you to use it with a non-Bluetooth capable device.
I plugged it into the bicycle’s battery to charge on the way home. When I got home, I read the instructions (which are in awful Chinglish). Basically, the English translation of the pairing instructions go like this:
So, the steps I followed:
Having got this working, I notice a few things:
I’m tossing up whether I get one of these motorcycle Bluetooth headsets. I ride on the bicycle quite a lot, and at the moment I use headsets embedded in the helmet that are home-built from old computer headsets. The longevity of the microphone seems to be the biggest problem I also am on the look-out for an earmuff headset for things like the Imbill car rally, ideally one that can do A2DP. The Bullant ones I know can’t do this. I see some earmuffs in the $400+ price bracket that offer Bluetooth, but no idea if that includes A2DP, and frankly, I shudder at that price.
The motorcycle ones are designed to fit a wide range of helmets, and they look as if they’ll fit a set of cheap regular earmuffs quite well. They typically sell for about $200, support A2DP, multiple devices, and intercom. Add in $30 for a set of earmuffs, and it makes this a much more attractive option.
More experimentation will be needed I think, but this is looking promising. I’ll probably post up more details as I come across them.
It’d be nice if Yaesu had been a bit more up-front on what the BU-1 supports: the AA2080 supports both HFP and HSP, yet the BU-1 won’t touch it, the Bullant set supports the same profiles yet the BU-1 works fine with it. The reasoning for this is not clear, but it does seem that it’ll reliably talk to A2DP capable headsets, so maybe that is a starting point for others.
Likewise with the CT-136, I’ll see if I can fabricate a bracket using the CT-M11 cable, and see where that gets me.
This post may also be read here.
Well, today I did some more work on the 2m linear. Earlier this week I ordered some SMA connectors and some 1N5711 diodes for the project.
Two 1N5711 diodes will be used to make a voltage peak detector, to detect when the amplifier is subjected to power above 60mW. The SMA connectors will be the interconnects between the modules. This afternoon’s effort was spent soldering the SMA connectors onto two of the boards, and mounting the 2m amplifier module onto the heatsink.
The EME157B2 preamplifier kit was originally intended to be mounted in a masthead box, with BNC connectors soldered to the PCB, and stuck up a pole near the antenna. In my application, I wanted it to be in the same enclosure (with suitable shielding) as the power amp, so that I could use its RF detection to automatically switch the power amplifier on. I will also be using different relays, mounted on a separate board.
Instead of mounting the SPDT relays for the kit on the EME157B2 board, I’ve instead left these off. I also omitted the 2N7000 MOSFET which turns on the relays, and L4, an RF-blocking choke which permits the preamp to run from a 12V source supplied up the coax. I instead will power the preamp directly.
Since the relays will be on a separate board, the plan is to run wires from the gate and source connections where the 2N7000 belongs, and run those out to a controller board. With the relays gone, the RF detection and the preamp are essentially two distinct circuits. So 3 SMA connectors will be needed. Here is the completed board with the SMA connectors fitted, and suitable jumpers installed, ready for tuning.
Completed 2m preamplifier. Connectors going left-to-right: Antenna input, Amplifier output, RF detector input.
Next, I finished off the power amplifier board, mounting it to the heatsink. I have left one EMC filter disconnected for now, as the instructions say to power it up first with it disconnected to set the trim pot for 4.5V bias. Rather than mounting the board flat on the heatsink, I have instead opted to mount the PCB at 90? to the module. I had to make the supplied eyelets a fraction longer to accommodate this. I also mounted SMA connectors on this board.
Completed 2m power amplifier. RF input is on the left.
The plan is, I’ll route RG195 coax on the left side to a small module which will contain the overload detection circuit and two SMAs for an external attenuator module. On the right, a low-pass filter will be connected. I also had a stab at tapping holes into the sides of the heatsink for mounting a bracket. This bracket would hold the fans on top, and would bolt onto the main enclosure. In doing this, I managed to bugger up two of the 8 holes, and thus what I’ll probably do, is buy a M4 tap tomorrow, drill them all out to 3mm and tap them to 4mm. These are structural holes, so bigger is probably better anyway.
Much of today though was spent designing the controller. I’m still finalising the design, but a rough schematic is below.
2m amplfier controller
So, not yet going, but big parts are built now.
Updated every 5 minutes.
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