MB7UIV is back

A little history
In January 2000 I started running the first licensed APRS Internet gateway in the UK originally with the callsign GB7UIV.  Within a week of experiments starting on the 26th January 2000, the gateway was on air and connected to the internet 24/7 except for periods when the connection dropped out and the modem (remember those?) had to redial.  The callsign changed to MB7UIV some time later.

The gateway was on 144.800MHz and was on the air until the 5th June 2010 when it was finally retired. At the time of closedown it was still running UI-View32, written by the late Roger Barker (G4IDE) and a very modest computer, a 1.5GHz P4 system with just 1Gb RAM and Windows 2000.
The RF side was a Kenwood TM-261E with 10 Watts ERP from a roof mounted co-linear and driven by a PacComm Tiny-2 Mk2 in KISS mode.  The packet driver used to control the TNC was the AGW packet engine, know as AGWPE.
The callsign of GB7UIV and then MB7UIV was chosen to reflect the very popular APRS software in use at the time: UI-View.

The return of MB7UIV
At 13:55z on Wednesday 8th February 2017, MB7UIV returned as an APRS receive only iGate using a Raspberry Pi Zero and an RTL-SDR dongle configured as per the method described in this blog.  All local APRS traffic received here on 144.800MHz is gated to the APRS Tier2 Server Network.

I’m very pleased to have MB7UIV active again and am happy to provide the service to any radio amateurs in the area who operate APRS in any way whatsoever.

Posted in Amateur radio, APRS, Data, FM, Raspberry Pi, VHF | Tagged , , , , , , | Leave a comment

Setting up an APRS RX only iGate using a Raspberry Pi, RTL-SDR dongle and a pre-built image

After my previous post, it was suggested that an easier way to set up a receive only APRS iGate would be to provide a pre-built image which only needs slight tweaking to go live.  That seemed like a good idea to me so I’ve prepared an image that just requires a handful of configuration changes which I will go through in detail below.

The entire process detailed here should take less than half an hour to complete.
You will only need to edit two or perhaps three files in total.

First, download my custom built Raspberry Pi image from here or preferably as a torrent from here.  This is a 1.6Gb file which will expand to approximately 4Gb when you decompress it.  Unzip it and write it to an SD card.  You don’t need a high capacity SD card, this image will fit on a 4Gb card and work perfectly.  This image is fully up to date as of 3rd February 2017.


There are two methods of downloading the Raspberry Pi image. The first is direct from SourceForge and the second is as a torrent.  If you use the torrent method, please seed the file for as long as possible because the more people who seed, the quicker the download will be for others.
Thank you.

MD5 of aprs-igate.zip is dde367dc0db9365b84850fcdc46519e4
MD5 of aprs-igate.img is 93060310c5a5c4a3a46822944dc0401f

Connect your RTL-SDR dongle and a network cable to your Raspberry Pi and boot it.  I thoroughly recommend you use a dongle with TCXO as it won’t drift in frequency and you shouldn’t need to do any frequency calibration.  I’m using an RTL-SDR R820T2 RTL2832U 1PPM TCXO SMA Software Defined Radio (Dongle Only) device which is the latest model, complete with TCXO.  Other dongles are available such as this NooElec version from Amazon which is a little cheaper and will arrive quicker or you can search eBay for similar dongles.

You will need to know what IP address your Raspberry Pi has on the network.  I do this by looking at my router and checking what devices have connected and then set up a DHCP reservation so each particular Raspberry Pi I own will always have the same address each time it reboots.

Open up a terminal/dos prompt or whatever client software you’re going to use to connect to the Raspberry Pi and log in.  In my case, the Raspberry Pi is on 192.168.1.144 so I use the command
ssh pi@192.168.1.144

You’ll be prompted for a password – It’s currently set to raspberry.
Use the following command to enter the Raspberry Pi config utility:

sudo raspi-config

Expand the filesystem by pressing enter on option 1 then select OK and you’ll be returned to the main screen.

Use the arrow keys to move down to the second option Change User Password and press enter.  Press enter again and you will be prompted to Enter new UNIX password.  Type a new password, press enter and re-type your new password again.  You will get a message telling you your password has been changed successfully.

Use the arrow keys again to move down to Localisation Options and press enter.  Use the arrow keys again to select Change Timezone and press enter.  First select your Geographical area and press enter and then select your Time zone and press enter.

You will now be returned to the main Raspberry Pi Software Configuration Tool main screen.  Use the tab key to select <Finish> and press enter.  You will be asked if you would like to reboot now.  Press enter to reboot.

You will need an APRS passcode so use the APRS Passcode Generator at Magicbug to generate one.

All the software has been pre installed, all you need to do is edit two (or possibly three) files.

cd ~
sudo nano sdr.conf

Scroll down to line eight and change the xxx to your callsign and required SSID.  I use -10 as my SSID so this line reads MYCALL G6NHU-10.  Please use your own callsign, mine is just shown as an example.

In the section below, edit the line starting with IGSERVER to be the correct one for your region.  I’m in Europe so my line reads IGSERVER euro.aprs2.net

Scroll further down and you’ll find a line that starts with IGLOGIN.  Change the xxx to be the same as the callsign you entered above (including SSID) and then change the numbers 123456 to the passcode you obtained from the APRS Passcode Generator.

At the bottom of that file there is one long line that starts with PBEACON.  Replace xx.xxxxxx with your latitude, yyy.yyyyyy with your longitude and zz with your callsign (including SSID).

Save the file by pressing ctrl-x, then hit the Y key and then press enter.

You can now perfom a test using the following command
(144.800 is the APRS frequency in the UK, change as required).

rtl_fm -f 144.80M - | direwolf -c sdr.conf -r 24000 -D 1 -

If all is well, you should see something like this.

Initial test of the Raspberry Pi and RTL-SDR Dongle APRS RX only iGate

Initial test of the Raspberry Pi and RTL-SDR Dongle APRS RX only iGate

Press ctrl-c to exit the test.


*** UPDATE – READ THIS IF YOU GET AN ERROR WHEN RUNNING THE TEST ***
I’ve had some feedback that on some older model Raspberry Pis, you may get an error when you try and run the initial test.  The error ends:
Signal caught, exiting!

User cancel, exiting…
Illegal instruction

If this happens, you need to redownload and compile Direwolf using these commands (copy and paste them one at a time exactly as written below:

cd ~
sudo cp sdr.conf sdr.old
git clone https://www.github.com/wb2osz/direwolf
cd ~/direwolf
make
sudo make install
make install-rpi
make install-conf
cd ~
sudo mv sdr.old sdr.conf

Now reboot your Raspberry Pi and run the test again.


If your local APRS frequency is NOT 144.800MHz then you will need to edit an additional file.
cd ~
sudo nano dw-start.sh

You’re looking for this line.


Change 144.80M to whatever your local APRS frequency is.
Save the file by pressing ctrl-x, then hit the Y key and then press enter.

The last thing to do is to configure the system so that the APRS iGate starts automatically whenever you reboot the Raspberry Pi.  Enter the following command:
crontab -e

Scroll down to the bottom and you will see the following line.
#* * * * * /home/pi/dw-start.sh >/dev/null 2>&1

Delete the # at the start of that line.
Save the file by pressing ctrl-x, then hit the Y key and then press enter.

Reboot your Raspberry Pi and once it’s restarted, it will automatically connect to the APRS network and operate as a receive only iGate. Nothing will be echoed to the display while it’s running like this so you can check your status on aprs.fi by searching for the callsign you entered (including SSID).  You don’t even need to log into the Raspberry Pi, the gateway will start automatically within ninety seconds of rebooting.

It’s been mentioned that you might like to calibrate the frequency of your RTL-SDR dongle.  I didn’t and I didn’t notice any performance issues but it’s likely that if you’re using an older or cheaper dongle then it might be a little off frequency.  If you’d like to do this, it’s very straightforward to do requiring that you edit just one file.  I’ve written some instructions which you can see by clicking here.

Please note – I am not claiming originality for this setup method, I’ve simply followed what’s already available out there on the internet and created an image based on those instructions for your convenience.  My two source documents were Raspberry Pi SDR IGate and Raspberry Pi Packet TNC.  I thoroughly recommend you familiarise yourself with both of them to see what’s been done here.  You can also read my previous blog article where I list each command I used to create this image.  It’s also worth downloading the full Dire Wolf user guide.

I hope this image is useful and as always, I’d appreciate any feedback, comments or thoughts below.

Posted in Amateur radio, APRS, Data, FM, Raspberry Pi, VHF | Tagged , , , , , , | 62 Comments

A guide to setting up an APRS receive only iGate using a Raspberry Pi and an RTL-SDR dongle

I originally bought a Raspberry Pi back in October 2012 but as I didn’t have a specific purpose in mind for it, I quickly sold it again.  A few months ago I decided to play around with a Pi again and bought the latest model. Since then I’ve found a few uses including an ADS-B aircraft tracker and an adblocker for my whole house. In fact I’ve become quite fond of these little devices and now have a small fleet of them!

I’ve been looking at other things I can do and I tried a NOAA weather satellite receiver which, although it worked wasn’t particularly great with the aerial I used and I really didn’t need to put another antenna up outside.  I also looked at a 137MHz ship tracker but the less said about that, the better.

One thing I thought might be interesting to try was a receive only APRS iGate using a Raspberry Pi and cheap RTL-SDR dongle so I’ve set one up and it’s working really well.

I found everything I needed in two guides which are both very well written although there’s more in them than you need so I’m going to reproduce exactly what I did here.
Please note – I am not claiming originality for these instructions, I’m simply following what’s already available out there on the internet.  My two source documents are Raspberry Pi SDR IGate and Raspberry Pi Packet TNC.  I thoroughly recommend you download them both as they go into a lot more detail than just listing the commands.  It’s also worth grabbing the full Dire Wolf user guide.

If you want a pre-built image for this setup which only requires you to edit a maximum of three files, see my more recent blog entry here.

You will need a Raspberry Pi and an SDR dongle.  I’ve been using an RTL-SDR R820T2 RTL2832U 1PPM TCXO SMA Software Defined Radio (Dongle Only) device which is the latest model, complete with TCXO.
I have this running successfully on the smallest and cheapest Raspberry Pi currently available – The Raspberry Pi Zero.  I bought my Zero from Pimoroni along with a three port USB/Ethernet interface which ironically costs more than double the price of the actual Raspberry Pi Zero.  Typically the CPU usage sits around 30-35% on the Zero.

First download install your operating system.  I used the full latest version of Raspbian Jessie from here and the installation guide from here.  Because we’re going to be doing this install entirely by command line, before you plug the card into your Raspberry Pi, you’ll need to create a file called ‘ssh’ on the card to enable remote access.  In my case, on my Mac I simply right clicked on the mounted SD card, selected Services/New Terminal at Folder and then at the prompt typed the command
sudo touch ssh
I was then asked for my password, this created the file and I moved the SD card into my Raspberry Pi.

You will need to know what IP address your Raspberry Pi has on the network.  I do this by looking at my router and checking what devices have connected and then set up a DHCP reservation so each particular Raspberry Pi I own will always have the same address each time it reboots.

The next thing to do is some basic housekeeping which I do on all new installations.  Open up a terminal/dos prompt or whatever client software you’re going to use to connect to the Raspberry Pi and log in.  In my case, the Raspberry Pi is on 192.168.1.144 so I use the command
ssh pi@192.168.1.144
The default password is raspberry, one of the first things to do is change that via the Raspberry Pi configuration utility which you run now using sudo raspi-config

This is what you see when you open the config utility.

The Raspberry Pi software configuration tool

The Raspberry Pi software configuration tool

Select option 1, select OK and you’ll be returned to the screen above.
Select option 2 and following the prompts, change your password.
Select option 3 and first choose Desktop / CLI and then Desktop Autologin.  This is important because without this, the iGate will not be able to start automatically when you reboot the Raspberry Pi.
Select option 4 and configure your Timezone and Wi-fi country.  I generally don’t bother with Locale and Keyboard Layout.
Select option 7 and then choose Hostname.  Give your Raspberry Pi a name other than the default.

Once all these changes are done, use the tab key to move down to <Finish> and hit enter.  You’ll be prompted to reboot the Raspberry Pi.

The next thing to do is to make sure the Raspberry Pi software is fully up to date.  Issue the following commands:
sudo apt-get update
sudo apt-get dist-upgrade

Depending on which model Raspberry Pi you have and how old the image is, this may take some time to complete.
Then remove the Wolfram engine using the following three commands:
sudo apt-get purge wolfram-engine
sudo apt-get clean
sudo apt-get autoremove

Once this is all complete, reboot the Raspberry Pi and you’re ready for to start the actual installation.
sudo reboot now

Remove pulseaudio and reboot.
sudo apt-get remove --purge pulseaudio
sudo apt-get autoremove
rm -rf /home/pi/.pulse
sudo reboot now

Log back in and install the sound library.
sudo apt-get install libasound2-dev

Download the Dire Wolf source code.
cd ~
git clone https://www.github.com/wb2osz/direwolf

Compile and install Dire Wolf.
cd ~/direwolf
make
sudo make install
make install-rpi
make install-conf

Test
direwolf

This will fail with the following error because you haven’t configured any audio devices.

Now it’s time to install the software for the RTL-SDR dongle.
sudo apt-get update
sudo apt-get install cmake build-essential libusb-1.0-0-dev
cd ~
git clone git://git.osmocom.org/rtl-sdr.git
cd rtl-sdr
mkdir build
cd build
cmake ../ -DINSTALL_UDEV_RULES=ON -DDETACH_KERNEL_DRIVER=ON
make
sudo make install
sudo ldconfig

Now you need to complete the final configuration.  Use the APRS Passcode Generator at Magicbug to get your own passcode.
cd ~
sudo nano sdr.conf

On line eight, change the xxx to your callsign and required SSID.  I use -10 as my SSID so this line reads MYCALL G6NHU-10
In the section below, edit the line starting with IGSERVER to be the correct one for your region.  I’m in Europe so my line reads IGSERVER euro.aprs2.net
Scroll further down and you’ll find a line that starts with IGLOGIN.  Change the xxx to be the same as the callsign you entered above (including SSID) and then change the numbers 123456 to the passcode you obtained from the APRS Passcode Generator.

You now need to add an extra line at the bottom of the file.
PBEACON sendto=IG delay=0:30 every=15:00 symbol="igate" overlay=R lat=xx.xxxxxx long=yyy.yyyyyy COMMENT="zz iGate | DireWolf 1.3 on RPi+RTL-SDR"

Note that although it’s spanned over two lines above, you should enter this as one continual line in your file. Replace xx.xxxxxx with your latitude, yyy.yyyyyy with your longitude and zz with your callsign (including SSID). Be aware that there is a space between the lat and long values.

Reboot.
sudo reboot now
If you don’t reboot, you’re going to get errors.
It’s now time to test this.
Enter the following command (144.800 is the APRS frequency in the UK, change as required).
rtl_fm -f 144.80M - | direwolf -c sdr.conf -r 24000 -D 1 -

If all is well, you should see something like this.

Initial test of the Raspberry Pi and RTL-SDR Dongle APRS RX only iGate

Initial test of the Raspberry Pi and RTL-SDR Dongle APRS RX only iGate

You can see that it’s started up successfully, connected to euro.aprs2.net and I’ve already received an APRS packet from M0SDJ-9 relayed through MB7UH.  The magenta text shows that my own beacon has been sent to the internet and I can check that by searching for G6NHU-10 on aprs.fi.

If you’re using a Mac and connecting to your Raspberry Pi via the terminal you may notice the screen flashes badly.  You can fix this easily and quickly by going into the terminal Preferences/Profiles and make sure the box “Allow blinking text” is not ticked.

The last thing to do is to set everything to start automatically when you restart the Raspberry Pi.  To do this, edit dw-start.sh
cd ~
sudo nano dw-start.sh

Scroll down and look for this line

Edit it to remove the hash at the start and change the frequency to whatever is appropriate in your area.  In the UK, APRS is on 144.800 MHz so my line looks like this

Save the file and then run the following command to make the script executable.
sudo chmod +x dw-start.sh

Finally, add a line to cron which will run once a minute to check whether Dire Wolf is running and if not, it will restart it.
crontab -e

If this is the first time you’ve edited the crontab, you’ll get a prompt asking which editor to use – Just hit enter to select nano as the default.

Scroll down to the bottom and paste the following line.
* * * * * /home/pi/dw-start.sh >/dev/null 2>&1

Reboot your Raspberry Pi and once it’s restarted, it will automatically connect to the APRS network and operate as a receive only iGate. Nothing will be echoed to the display while it’s running like this so you can check the status on aprs.fi.

I hope this guide is straightforward enough to follow – It looks more complicated than it actually is, it’s really quite simple just to follow all the steps through.

Posted in Amateur radio, APRS, Data, FM, Raspberry Pi, VHF | Tagged , , , , , , | 19 Comments

ADS-B setups – Comparing internal and external aerials

Following on from my last update, I’ve spent a fair bit of time experimenting with two very different ADS-B aerial configurations.  I have two Raspberry Pi3s, both running identical software and exactly the same receivers, the FlightAware Pro Stick Plus which is a version of the RTL-SDR dongle with a built in preamplifier and bandpass filter.  This may (or may not) be as good as the other dongle I own combined with the Uputronics preamplifier/filter but I wanted both setups to be identical.

My first station is using a commercial aerial, a Moonraker “Radar-110” 1090 MHz collinear base antenna mounted on the side of the house, 38ft above the ground and in the clear.  Between the aerial and the receiver is approximately 15m of ExoFlex 15 coaxial cable which I calculate will give about 1.4dB loss at 1090 MHz.  The receiver is connected directly to the bottom of the coax with the Raspberry Pi attached directly to the receiver.

Moonraker Radar-110 base antenna

Moonraker Radar-110 base antenna at 38′ AGL

The second station is a homebrew aerial, a two element J-Pole collinear which I made using an SO-239 socket and a length of enamelled copper wire.  This is connected via a PL-259 to SMA adapter and then directly into the FlightAware receiver so there’s no loss whatsoever between the aerial and the receiver.  It’s mounted in my loft and as you can see, it’s quite heavily blocked in a south-southwest direction.

Homebrew two element J-Pole collinear

Homebrew two element J-Pole collinear in the loft

I’ve been running these two installations simultaneously for a few weeks and the results are interesting. Here you can see the figures reported for the total number of aircraft received daily and the total number of position reports received daily.  Here are the figures from the last two weeks.

ADS-B statistics - Averages at bottom

ADS-B statistics – Averages at bottom

The first surprise may be the actual numbers.  Yes, I really am seeing an average of nearly three thousand aircraft per day.  That’s a lot!

Perhaps more surprisingly, I’m seeing more aircraft on the internal aerial than the external aerial although the receiver attached to the external aerial is receiving more position reports per day.  I know this isn’t down to either system being swamped by signals as I’ve run gain optimisation on each setup and they’re adjusted appropriately.

Another thing to look at is the variation in distances.

Breakdown of distances received using the Moonraker aerial

Breakdown of distances received using the Moonraker aerial

Breakdown of distances received using the homebrew J-pole

Breakdown of distances received using the homebrew J-pole

Again, I think it’s surprising to note that I’m receiving a lot more signals from 150nm out using the internal aerial as compared to the external aerial.

Finally, it’s worth looking at the heat map for each setup.  This shows the maximum range received in each direction.

Heat map of aircraft received using the external Moonraker aerial

Heat map of aircraft received using the external Moonraker aerial

Heat map of aircraft received using the internal homebrew J-pole

Heat map of aircraft received using the internal homebrew J-pole

This is what I would expect to see.  The external aerial is in the clear and has a good view to the horizon with no obstructions whereas the internal aerial doesn’t have such a good takeoff and is clearly blocked in a couple of directions.

My conclusion to all this is that you don’t need a big external aerial, mounted really high in order to be able to see a lot of aircraft traffic.  Because all the aircraft traffic is up in the air that means that everything you’re receiving is direct line-of-sight and apart from local obstructions, there’s nothing in the way.  Of course, location is important and although I’m only 72′ above the sea, I happen to be in a prime location for spotting air traffic over the UK and north-west Europe.

Finally – If you’re interested, you can actually connect to my system here.  I have both receivers feeding a piece of software called Virtual Radar Server which combines the two inputs and plots them on a map.  It’s live aircraft data showing exactly what I’m receiving.  To access it click here.

Posted in ADS-B, Construction, Data, Raspberry Pi | Tagged , , , | Leave a comment

Building an ADS-B receiver setup

I realised recently that I’ve barely touched this blog for most of 2016 and I suppose that’s because I’ve not done a massive amount of radio this year.  My low powered QRSS/WSPR transmitter continues to run mostly 24/7 on various bands (on 30m at time of writing) and my radio high point of the year was being involved with the organisation and operation of the GB5RC special event station back in August.

My Hexbeam is currently down following a rotator failure and although I have a replacement rotator, I’ve not had the time or manpower available to get it back up again.

But I digress from the subject of this entry.

A few weeks ago I bought a Raspberry Pi3 to use for my own personal DX Cluster to replace the old computer I have running Windows XP.  I spent a while playing around with it, getting it working and then decided to look for other things to use it for.

I re-discovered aircraft tracking using the ADS-B system.  I had an old RTL-SDR dongle and so I bought myself a second Raspberry Pi3 and started experimenting.  I went through a few different builds and finally ended up using the instructions on the ADS-B Receiver Project site.  There are more detailed instructions on the Flightradar24 site showing how to set things up to ‘feed’ what you see to the internet.

I started off by connecting a 6m/2m/70cms collinear to the receiver and I was receiving just a few aircraft out to 50 miles or so but I wasn’t overly happy with that so I built a quarter wave groundplane aerial out of some copper wire and an SO239 socket.   By hanging that in my window, I was instantly receiving aircraft from over 150 miles away.  Absolutely incredible.

Quarter wave groundplane aerial for 1090MHz ADS-B reception

Quarter wave groundplane aerial for 1090MHz ADS-B reception

This wasn’t enough for me.  I did some research and ordered myself a combined pre-amp and bandpass filter by Uputronics which arrived a day later and my reception range increased out to over 200 miles.  I could have just set this up in the loft and forgotten about it, it would be a good setup.

Uputronics preamp and bandpass filter for 1090MHz ADS-B reception

Uputronics preamp and bandpass filter for 1090MHz ADS-B reception

But of course, anyone who knows me will be aware that I don’t like to compromise and an internal aerial is a compromise.  I could do better.  I was spotting over 1,000 aircraft/day using that internal aerial so what could I do with an outside aerial?  Two years ago, my 10m vertical broke in a storm and the pole it used to be mounted on was sitting outside.  I sourced an external aerial, fitted it on the pole using my old run of RG213 and switched it on.

Disaster.

Although I was receiving many more aircraft, they were all within 50 miles.  A quick calculation of the cable I was using suggested well over 4dB of loss, so over 60% of the signal was being lost in the cable.  It occurred to me that I had a run of EcoFlex 15 coiled up in the loft from my old VHF aerial installation so I fed that outside and ran it up the mast to the aerial.

Success (well, sort of).

I’m now receiving more aircraft from further away.  I’m still not 100% it’s working as it should be so I’ve ordered some test gear and once I’ve got that I can do some more checking.

Over 250 aircraft being tracked in the skies above G6NHU

Over 250 aircraft being tracked in the skies above G6NHU

A basic setup for ADS-B reception can be done cheaply with a small home made aerial, a Raspberry Pi and an RTL-SDR dongle.  I’ve gone a little further but this is a simple project which can be completed in an evening.

Posted in ADS-B, Construction, Data, Raspberry Pi | Tagged , , , , | Leave a comment

Video of the ten minute multi QRPp mode transmission

After my entry a few days ago, I’ve made a video of my Hans Summers Ultimate 3S transmitter going through all four modes in a single ten minute frame.  It’s annotated with comments along the way describing what’s happening at every stage.

Posted in Amateur radio, Construction, CW, Data, HF, QRSS, WSPR | Tagged , , , , | Leave a comment

Running four QRPp modes in a ten minute frame

Over the last month or so I’ve been doing some experimenting using a newly built Hans Summers Ultimate 3S transmitter fitted with the new oven controlled crystal oscillator and I’m now running four different modes in a single ten minute frame with space at the end for a calibration cycle.

You should note that to be able to run this setup, you need the v3.09 or later firmware.  There is a bug with the CW timing in all versions prior to v3.09 which means that once you go above 12wpm, the CW becomes progressively harder to decode and the RBN will struggle to receive it.  If you have v3.08 you may be able to do this by setting your CW speed to 12 and decreasing your calibrate time but in any versions prior to v3.08 you can’t have separate timings for the different modes and can’t configure multiple messages so this configuration isn’t possible.

Also, I would expect you to be locked to a GPS for calibration for this entire procedure.  It may work if you have a nice stable transmitter, all manually calibrated without a GPS but I’ve not tried it that way so I can’t guarantee it’ll work.  You do need your clock to be absolutely spot on for the WSPR cycle to start on time.

The four modes are WSPR, FSKCW, CW and slow Hell.

In order to do this, I’ve set up four transmission slots for the four modes as follows:

Slot Mode Power Frequency
0 WSPR 23 07.040.060
1 FSKCW 00 07.039.890
2 CW 01 07.027.300
3 Slow Hell 02 07.039.888

The numbers used in the power column are linked to the messages – For WSPR I’m running 200mW as indicated by the 23 but for the other three modes, the numbers call the messages as described below.
For slow Hell, I’ve selected a frequency a couple of Hz directly below my FSKCW so as just to centre it a little bit more with that mode.

My messages are configured as follows:
” #CS” | “CQ #CS #CS TEST” | “#CS”
The | is the delimiter character (this is a solid block on the U3S screen) and the ” are just for show – You don’t enter them. Please note that there’s a space in the first message before the #.
I’ve used the short messages here to save entering my callsign multiple times. When the U3 goes into transmit, the messages transmitted are as follows:

Message number Used by which mode Message text
0 FSKCW [space]G6NHU
1 CW CQ G6NHU G6NHU TEST
2 slow Hell G6NHU

Speed settings are:

CW dit Hel
24 006 17

So that’s 24wpm on CW, six second dits on FSKCW and each character takes 17 seconds to send via slow Hell.

Calibration timings are set to 01 040 which means that the calibration cycle will run for 40 seconds and there’s just enough time for this to complete before the next frame starts. Depending on your callsign length, you may need to shorten the second parameter a little bit to allow the cycle to complete.  Start with 40 seconds, watch the frame complete and then keep an eye on the timing.  If the calibration routine doesn’t finish before the next frame starts, simply reduce the time.  If you find that you simply don’t have enough time in the ten minutes to complete the transmission cycle, never mind the calibration then you can try reducing your dit setting from 6 to 5 in the Speed menu page which will help.

Frame start settings are 10 08 which means that the frame will start at 08, 18, 28, 38, 48 and 58 minutes past the hour and run for ten minutes. I’ve chosen this start time because many grabbers will stack received images and this keeps the FSKCW/slow Hell within a single stack.

This configuration means that you can be spotted by a number of different systems. You’ll get the instant gratification of being reported on the WSPR network and also your CW will be picked up by the Reverse Beacon network but be aware that you won’t get as many CW spots on the RBN as you do via WSPR. You will also be spotted by any QRSS grabbers which happen to be on the same band.

I’m sure that many of the Hans Summers kits have been sold and are only working on WSPR, simply because the owners don’t know anything about the other modes.  If this article has raised your interest in the other modes that you can run from your transmitter, or even if you already know about them, I thoroughly suggest you take a look around the active grabbers to find a clear frequency before you just pick one and start transmitting.  In particular, 30m is already very busy.  For an up to date list of current WSPR/QRSS allocations, take a look at this page.

Here’s a frame from my own grabber on 40m showing WSPR, FSKCW and slow Hell.  You can’t see the CW because it was on a totally different frequency to the grabber and anyway, at 24wpm, it would be a mere blur.

WSPR, FSKCW and slow Hell in the same frame

WSPR, FSKCW and slow Hell in the same frame

To demonstrate the difference in signal between FSKCW and slow Hell, here is a single frame captured at the Pensacola Snapper grabber run by Bill, W4HBK.  You can see the FSKCW is much stronger than the slow Hell.  Bill is around 4,500 miles (7,300 kilometres) away from me.

G6NHU single frame at W4HBK

G6NHU single frame at W4HBK

To emphasise this even more, here’s a frame made up from three stacked images at the grabber operated by Pete, ZL2IK in New Zealand.  You can see the slow Hell is barely readable compared to the FSKCW.  Pete is located over 13,600 miles (21,900 kilometres) away by long path, which is the route this would have taken.

G6NHU on a stack of three frames at ZL2IK

G6NHU on a stack of three frames at ZL2IK

Finally the best image of the lot is another one made by Bill, W4HBK who stacked around sixty ten minute frames to produce this composite image.  It really is a testament to the stability of both the transmitter and the receiver that such a good image can be produced over such a long time.

G6NHU stacked at W4HBK

G6NHU stacked at W4HBK

Posted in Amateur radio, Construction, CW, Data, HF, QRSS, WSPR | Tagged , , , , | Leave a comment