During cloud-to-ground flashes, the most powerful emissions occur in the VLF range (3 kHz to 30 kHz)
Antenna - Two orthogonal crossed VLF loop antennas, 8 turns, diagonal size 1 m connected to Amplifier at feedpoint.
To measure the time of arrival of a lightning discharge, we need a wide-band receiving system, and not a tuned system.
The resonance frequency of this antenna is approximately at 1000 kHz (= 1 MHz).
Use a filter to reduce frequencies of 1000 kHz by -72 dB (=4000 times).
At least 4 sites not on a line are needed to define always a unique intersection point
We will consider briefly the TOA technique assuming that all three stations
have either precisely synchronised clocks or accurate absolute timing (GPS timing).
There will be a constant difference in the time of arrival of a signal
at Stations A and C from lightning striking anywhere on the blue curve (a hyperbola).
Similarly a hyperbola of constant TOA difference for Sensors B & C can
be drawn. The two curves intersect at two points.
You could resolve the location ambiguity using magnetic bearing angles
from the 3 sensors.Or you could draw another hyperbola - the curve of constant TOA
difference for sensors A & B.
Or you could use all of the available location data.
The Blitzortung comes with a unique station number and serial number.
The Bayside District Amateur Radio Society's Station Number is: 2201 and
can be accessed with this URL:
http://www.lightningmaps.org/station/2201
the Device-ID or Processor Serial Number is: 3400-4B00-1651-3631-3136-3335
Blitzortung is a network for the detection of lightning and thunderstorms in real time.
For an introductary description of the kit construction and system administration consult the "Cover Your Area" pages at:
http://en.blitzortung.org/cover_your_area.php
This is the app running on my Samsung and it shows the current location of the 2201 station with a cross symbol.
Construction and System Admin Documentation
Kit Construction and System Admin Documentation
The documentation for Blitzortung can only be described as shambolic.
There is a lot of details with no structure or version numbers. You simply have to dig for information.
There are several version of the same or similaid="kit-construct">Construction of the Mainboard Ver 19.4 Controller - Components, Construction, Boot, Programming and Debugging documents all with different names on different sites.
There does not appear to be any attempt at version control and many are not even published dates.
My recommendation is to read the ninety five page version of the 2014 system Red and Green manual first,
even though it is superceeded, there is a lot of information that is not covered in the sixteen page Blue Document.
HTTP://en.Blitzortung.org/Compendium/Documentations/Documentation_W_Red_PCB_10.4_PCB_12.3_PCB_13.1_PCB_14.1.PDF,
even though it applies to superseded models, as it contains more information than the fifteen page 2016 manual
HTTP://en.Blitzortung.org/Compendium/Documentations/Documentation_W_Blue_PCB_20_1.PDF.
The mainboard kit arrives partly assembled with the surface mount devices mounted and the firmware installed.
The kit with it's delivered components ready for assembly:
Front panel of enclosure:
Rear panel of enclosure:
Board revision level:
David VF4ZF did an excellant job of assembling the circuit boards with little documentation.
After the build was complete a pair of 8 pin Linear Technologs Corp 15697 which are Linear Phase,
DC Accurate, Tunable, 10th Order Lowpass Filters IC's were left over.
Component: Datasheet for the 15697 Low Pass Filters (pdf)
Note about Digital Filters:
From the June 9, 2016 documentation, page 9 Section 1.6:
The complete digital filter option consists of 4 digital filter ICs (LTC1569-7)
In general, it is not necessary to install the digital filter ICs. The system also operates without
them. However, if you want to experiment, or if you have extremely strong interferences at
frequencies above 20kHz, you can try to get better signals with the digital low pass filter ICs.
Since the digital filter ICs are relatively expensive, you should test one filter IC at one channel,
preferably at the E-Field channel. If the desired effect is achieved, the other channels can be
upgraded.
Notes about the Ethernet Controller:
Although the ARM Cortex M4 based STM32F4 micro-controllers already have an internal Ethernet
controller, they do not include an Ethernet Physical Layer Transceiver (PHY). For experimental reasons,
we additionally have placed the Ethernet controller ENC28J60 on the board of Controller 10.x.
The ENC28J60 is a very widely used "all-in-one" ethernet controller, but it can only handle 10Mbit/s
ethernet connections. With around 150mA current drawn, it has a relatively high power consumption.
The ENC28J60 is connected to the processor via SPI. In a forthcoming version, we intend to remove
the ENC28J60 and to replace it by an Ethernet Physical Layer Transceiver on the controller board.
Then we will use the internal Ethernet controller of the processor, which uses DMA and can also
handle 100MBit/s connections.
The VK4BAR Lightning Detector's Main Controller
This is the story of how we bought the BDARS Blitzorting kit, Node 2201, to life. Bob VK4YA, and I VK4PK received the beautifully soldered and constructed controller and two antenna modules. We applied the 5 volt power supply to the USB port and waited expectantly for the LEDS to light. Nothing! Oh no!! Have we hooked it up reverse polarity and "cooked it"? After a second check the polarity looks correct. Next, we attacked the enclosure with a screw driver eager to see what damage we had done but everything looked good. That horrible smell of failure was not present. After further inspection, with baited breath, we found it. A power jumper left open and the power switch with no connections! After a search in the parts box we found the correct jumpers and had it powered up, Red LED on, with no sign of smoke!
Okay, are we are good to go? No! Disappointment once again. No matter what we did, we could get no more than the power LED on. Determined not to give up we conected up the network port to the routed. DHCP should give us an IP address so we searched the address range with "nmap" but no address was found. We checked the router to see if it had allocated some strange address, but no luck there as well. The Network port's green and yellow LED lights were on and flashing, maybe there was some data we could read. Next, Bob called for an extra network card, and once found proceeded to rip apart my workstation. In went the network card, and in no time Bob had tcpdump running against the interface connected to the Blitzortung. Disappointment once again. Plenty of packets were been send to the Blitzortung, which accounted for the flashing data LED on the network port, but not one packet out.
The next idea in our quest to succeed was to use the USB port, so we disconnected the USB cable from the power pack and connected it to the computer's USB port. The Blitzortung came back to life, with the power red LED on, but there was no "ding-dong" sound from the computer to indicate it had found a new device. An inspection of the loaded devices confirmed that the USB port was also inactive! More disappointment.
We decided to call it a day.
Now I was on my own with Bob and Pauls support by email and Hangouts. After reading the various manuals for the umteenth time,I decided to hook up the five pin serial port on the Blitzortung via a PL2303 serial to USB interface. What were the pinouts and what wee the voltage levels? I read in one article that Blitzortun will not release the schematics, however, after more searching I struck gold. An FTP site with all the schematics. Here is the Schematic Circuit Diagram for the Society's 19.4 mainboard. I now had the pinouts with confidence. I hooked it up, ran "minicom" and conneced to the port. It is a wounderfull feeling to see data spewing forth each time I hit the reset button. It realy is alive! I have not destroyed the board! Now, after days of reading and testing, I now had something to to go on.
The Prolific PL2303 serial to USB interface connect to the mainboard Controller
During this time I was receiving generous support and encouragement from Bob VK4YA and Paul VK4PLY. I sent them a copy of the ascii dump from the serial port. This is copy:
Paul was quick to respond. The wrong Firmware had been loaded onto the board in Germany! It was "Firmware Rev. 8.3 RED" on a BLUE board!
Next, I had to figure out how to get the correct System Blue firmware on to the crippled main board. The convention method is to use Single Wire Debug (SWD) with the ST Link adapter and the associated Single Wire Debug (SWD) software utility. I immediatly ordered one from China and decided to do some more research while I waited for it's arrival. The St-Link procedure is described in Section 1.7.2 "Single Wire Debug (SWD)" of the Documentation_2016-05-04_Blue_PCB_20_1.pdf.
Then I read about loading the firmware via the USB port. However, I thought that is not going to work because the USB port, like the network port, is "dead". Then I discovered there is a jumper on the rear of the board that enables the USB port to be more than a power supply.
The jumper on the rear of the mainboard enables the USB port
But how do I load the firmware? Well there is yet another version of the System Blue Documentation that tells you how.
It is a google docs site:
Search for Section 2.4.3, "Device Firmware STMicroelectronics Extension (DfuSe)". As it instructs, I downloaded the DfuSe utility and the correct System BLUE dfu version of the latest firmware, which is, as at writing is Ver 8.4b, from
https://tracker.blitzortung.org/firmware/dfu/.
This is actually an ftp site. With the jumper closed, I connected the mainboard to the computers USB port. It was recognised immediatly.
The firmware load without a hitch. I rebooted the Blitzortung and it came to life with all LED flasting as expected.
A few minutes later the GPS handed over to the mainboard and the blue GPS LED became active. The Web Interface strang to life. Success! All system nominal! There was nothing else left to do but install the two antennas and later fine tune the paramater settings, and watch the data roll in.
The E-Antenna was installed with a 25 meter RG6 quad shielded 75 ohm feedline on the peak of the roof.
The E-Antenna was installed with a 25 meter RG6 quad shielded 75 ohm feedline on the peak of the roofThe E-Antenna with the lid off showing the amplifier circuit boardThe E-Antenna install as high as practically possibleThe E-Antenna was installed with reasonable height in the hope of obtaining an adequate signalThe H-Antenna does not require the height to function, so it was installed in houseThe H-Antenna with the lid off showing the three channel amplifierThe H-Antenna was installed on the top bookshelf above the Controller
The Local Web Interface to the Controller
The Web interface is intalled in the firmware of the mainboard controller and is accessed by typing a local IP address eg "192.168.1.90" into the browser. This PDF shows the Web Interface of the Society's Blitzortung controller:
The Web Interface (pdf)
The "Signal" Tab on the Web Interface displays a live graph for four signalsAnother capture of the live signal graph
Package building resources for the ToA Lightning Detection Tracker Program for OpenWrt.
OpenWrt, https://openwrt.org/ is an open source project
for embedded operating system based on Linux,
primarily used on embedded devices to route network traffic. The main components
are Linux, util-linux, musl, and BusyBox.
