Meteor activity for July / August 2023

Below is a carpet plot produced in Microsoft Excel that shows the hourly meteor counts recorded during July / August 2023 from the Raspberry Pi 3-based receiver at Brough Astronomy's Observatory (BLAS).  These were post-processed on my development system at home.  This shows the "overdense" meteor reflections received from the GRAVES radar in France and probably correspond with those that were probably visible with the naked eye, albeit over the Mediterranean! 

During July and August there is a procession of meteor showers, as predicted by the tables published in "The Radio Sky" Lashley.

I'm looking at setting up a second receiver and computer to decode amateur radio meteor scatter activity using MSK-144 for the next meteor shower and have installed WSJT-X on my desktop Raspberry Pi that I'm using to develop my radio telescope.

New APRS Digipeater and Gateway - on 144.9375 MHz

I now have the Notice of Variation to run an APRS Gateway MB3UNN from my home QTH in North Newbald, East Yorkshire.  This gateway will provide the connectivity for the proposed digipeater that will be co-sited with the GB3NY UHF repeater at High Hunsley - The reason for the oddball frequency is due to both my QTH and the proposed digipeater being close to the restriction of 50 km from TA 012869, Irton in Scarborough, specified in Schedule 2 of the Amateur Radio Licence.

It's currently running receive-only for test purposes, using a Raspberry Pi 3B with an RTL-SDR, piping the RTL_FM audio into Direwolf, it will be upgraded to full operation using a single band 2m radio following further test and evaluation.

Python Script for Icom PCR-1000 Receiver

Work in progress: creating Python code for the Raspberry Pi at Brough Astronomy so that I can add a second radio receiver to provide the much needed audio for a true "multimedia" experience watching meteor showers.

 If anyone is interested the instructions are here

More WSPR on 40 metres

A short break from work gave me some time for more experiments using WSPR over the Easter holidays from my WFH desk with a Raspberry Pi and Yaesu FT-817.

I first tried using a Clansman E-VHF sleeve dipole which happens to work rather badly on 30m and 17m and then with a Maldol 40m mobile whip operating at ground level in the garden.

Despite the simple setup, I managed to be heard in Australia, New Zealand the Falkland Islands.  I've also learned the trick (from a DL) of calling CQ on CW on the same dial frequency which makes you audible at +700Hz whilst remaining outside of the WSPR audio pass-band at +1.5kHz.

Radar Meteor Observations

The meteor radar detection system at Brough Astronomy is based on a Raspberry Pi and low cost USB Software-Defined Radio dongle.  Despite it's small size, it is able to receive signals and distinguish between meteor echoes and the erroneous signals from satellites such as Elon Musk's "Starlink" constellation.

Over-dense echoes, caused by meteors with a mass that is greater than 1 mg, result in an ionised trail that persists over several seconds and occur in a daily peak associated with the earth passing through the meteor stream. 

Whilst the rapidly decaying under-dense echoes, caused by the background of meteors with a mass less that 1 mg, appear to follow a sinusoidal pattern that is caused by the Earth's rotation into the meteor stream.

These graphs explains why meteor showers are best observed in the early morning before sunrise when the population is greatest - for more information see the presentation that was given to group's monthly meeting. 

Yaesu FT-8900 Setup for Raynet Comms Test.

 My Yeasu FT-8900R configured for a North Humber Raynet communications test on both 6m (with CTCSS set for compatibility with the Clansman military radios) and for the UHF Raynet repeater located at Weedley Farm in the Yorkshire Wolds.

Update - we actually managed to cross-band using my radio at my usual mobile location near home from Sandtoft with an RT-350 on 6m to Withernsea via the repeater.

Amateur Radio Astronomy Lecture

Joint online lecture on Amateur Radio Astronomy given to the Blackburn Leisure Astronomy Society (BLAS) and the Pretoria Centre of the Astronomy Society of South Africa via Microsoft Teams.

Itty Bitty Radio Telescope and AO100 downlink

How to make a "Itty Bitty Radio Telescope" from a satellite dish and LNB using SV1AFN's AD8313 power detector module to measure the signal in dBm and convert it into a voltage that can be digitised using an Adafruit ADC for the Raspberry Pi - using the design from F5VLB.

Nothing goes to waste as we can use the same dish and LNB to receive amateur radio signals from the Qatar-OSCAR 100 Narrow band transponder onboard the Es'hail-2 geostationary satellite with an RTL-SDR dongle, alternatively we could use the RTL Dongle as part of our Itty Bitty Radio Telescope and measure the power using a GNU Radio block on the Raspberry Pi.

See my post from 15th March!

Australia on 2 Watts

Extremely happy - Running WSPR on a Raspberry Pi 4 driving an FT-817 with Yaesu  SCU-17 sound card interface, I have been heard in Australia! (Anyone else getting spurious decodes with a similar setup ?)

The  antenna is a MALDOL 40 metre band mobile whip mounted on a clothes dryer spike and a "Clansman" PRC counterpoise...

Although I reported 5 Watts (37 dBm) in the transmission, the AGC was backed off and I have since measured the output power with an RMS meter at just under 2 Watts.  I think it's time to build the QRP Labs Ultimate WSPR/QRSS kit or even a Raspberry Pi transmitter!

FT-8 using Clansman EVHF antenna on 17m

With the good conditions on HF, I tried using FT-8 on 17 metres using a Clansman EVHF sleeve dipole.  Despite several attempts to contact stations in the Caribbean, no contacts so far, some experimentation with the FT-817 and WSJT-X settings is required to get some RF out of the antenna...

The olive-green antenna is almost invisible as our neighbour had walked past it several times over the week and not noticed it!  The combination of the lockdown heatwave and guinea pigs hasn't been good to the lawn...

Using the Dwingeloo WebSDR for GRAVES Meteor Scatter

If you are thinking of setting up a meteor scatter receiver using the GRAVES radar, did you know you can use thc Dwingeloo WebSDR in The Netherlands?

Visit http://websdr.camras.nl:8901/ and then select the GRAVES option!

Es'Hail QO 100 WebSDR for the Raspberry Pi

Not bad for a morning's work, setting up a WebSDR for the Es'Hail QO-100 transponder on a Raspberry Pi 3.  Just need a dish, LNB and bias tee.

The software can be downloaded from https://github.com/dj0abr/QO-100_SSB-WebSDR_DATV-WebSpectrum following the YouTube video from DJ0ABR https://www.youtube.com/watch?v=nyf5-YOdivU

Perseids Metoer Observations

Presentation to Blackburn Leisure Astronomy Society (BLAS) about the Radar Observations of the Perseids Meteor Shower made on the 12th August using the French GRAVES (Grand Réseau Adapté à la Veille Spatiale) Radar. We set off looking for meteors but ended up capturing lunar echoes on the Waterfall display !

BBC Radio Humberside Interview for Perseids Meteor Shower

Caroline Brocklebank from BBC Radio Humberside visited the Blackburn Leisure Astronomy Society to find out about how to observe the Perseids meteor shower with your eyes and our plans to use an amateur radio receiver and Yagi antenna to detect reflections from the French GRAVES (Grand Réseau Adapté à la Veille Spatiale) space surveillance radar.

How Britain Won the Space Race

Look out for the “Timeshift” documentary on BBC iPlayer that charts how Sir Bernard Lovell’s radio telescope was used by both the Americans and Russians during the Space Race.



The programme starts with the experiments using wartime surplus radar equipment to detect the reflections from the ionised trail that is formed as meteors penetrate the Earth’s upper atmosphere.  The radio observations were correlated against the visual observations made by volunteers lying on their backs in the open field.  From here, things became larger with a fixed dish made up from wire catenaries supported wartime surplus Army antenna masts, with what can only be described as a garden shed on stilts containing the receiving antennae at the focus – I’m not going to paraphrase the whole programme, but the 250ft diameter dish that was built was used to chart the early launches during the cold war when both sides were eager to demonstrate their ability to launch Intercontinental Ballistic Missiles, with everything coming to a head during the Cuban Missile Crisis as one of the first Ballistic Missile Early Warning Systems (BMEWS) to be used by the British in the cold war.

The first part of exploring radio astronomy will probably follow the route of detecting the signals reflected by meteors, making use of the GRAVES radar in France – GRAVES is short for the Grand Réseau Adapté à la Veille Spatiale, which translates to Large Network Adapted to Space Watch.  What makes this radar ideal for amateur observations is that it transmits a continuous beam of signals from one site, whilst simultaneously receiving signals from a second geographically separated site elsewhere in France. Secondly, it transmits with sufficient power that it is possible to detect its reflections from the surface of the moon, and finally, it transmits on 143.050MHz, which lies just below the popular 2-metre amateur radio band, and hence I already have most of the equipment needed already to get started, so watch this space...

Repeat of WSPR Experiment from Barmby Tidal Barrier

To provide a comparison with the previous experiment, the WSPRLite was again setup from the Goole Radio and Electronics Society's portable location at Barmby Tidal Barrier.  Apart from changing the callsign back to G0VRM, the setup was identical.  This time, there was some grayline DX to the Canaries at approximately 8PM, otherwise the results were virtually identical.

WSPR from a Diamond HF-30HX Mobile Whip

Whilst on holiday in Trawsgoed, near Aberystwyth, Wales I setup my WSPRLite using a Diamond HF-30FX 10 MHz mobile whip.  The WSPRLite was configured using the WSPRLite Explorer App using Samsung Galaxy S7, setting the callsign and locations from the phone's GPS, and was left powered from the phone and left running overnight in the car.

Whilst the phone's battery was completely discharged in the morning, the transmitter worked from 8PM until approximately 4AM, and despite the "compromise antenna", contacts into most of Europe were logged.

Arduino Class Libraries for WSPR and SiLabs Si5351 Clock Generator IC

My first attempt at writing an Arduino sketch that transmitted a WSPR message using an AD9850 DDS Signal Generator module, whilst successful required the WSPR message to be generated using the WSPRcode.EXE and then manually edited into the Arduino Sketch before compiling the code.  Ideally, I'd like to be able to read the position and time from the NMEA string from a GPS, encode the message and then transmit it automatically - OK there are niceties such as a User Interface and LCD to contend with! 

Looking back at the Etherkits website, they appear to have a module available which has an SiLabs Si5351 Clock Generator mounted into a breakout, as do Adafruit, however they also supply an easily integrated Class Library.  Until a recent C# online course at work, I didn't really understand what C++ classes did and how to use them, so it's  time to experiment as I've got the example code to compile without error.

I've also got some building to do as I've got some QRP Labs low-pass filter modules to build for 5 and 10 MHz together with a Kanga / M0XPD Si5351 Shield for the Arduino. 

Raspberry Pi WSPR Transmitter

Sometimes several things come together that make a really easy project...

Having read several copies of the Official Raspberry Pi Magazine, I was intrigued that one of the issues this magazine actually gave away a Raspberry Pi Zero on the front cover in the same way that computer magazines in the 90's used to have CD-Roms and floppies on the front!

The current incarnation of the Raspberry Pi Zero W has onboard WiFi and Bluetooth networking and with the addition of a Raspberry Pi Stem becomes a complete OTG (On the Go) USB stick - ideal for working away in Lancashire without the need to cart a mouse/keyboard/monitor up to your hotel room!  You can even get a 3D printed case online for a few pounds...

Then I found WsprryPi - a WSPR transmitter that uses the Raspberry Pi's onboard frequency generator to transmit WSPR and uses NTP (Network Time Protocol) to discipline the oscillator frequency - all that is needed is an external Low-Pass Filter and you have a little transmitter.

Enter Language Spy with a neat little filter module.  I managed to get one for 17m (another one of my favourite bands) before the stock ran out.  

The Raspberry Pi output pin is a square-wave switched from 0V to 3.3V and therefore is approximately 1.65V RMS, there are obviously losses in the low-pass filter as the higher harmonics that make up the square wave are lost, however I measured the output at approximately 0.9V(RMS) into a 50Ω load

This works out to approximately 10 mW (or 10 dBm) so QQRP.

Unfortunately a recent upgrade to Windows 10 appears to have broken the raspberrypi.local shortcut, so whilst the board still works, the OTG capability doesn't and a mouse and keyboard are needed once more.  

Further Adventures in QRSS...

Having decided to buy the Yaesu SCU-17 USB Sound Card Interface for the FT-817, which  provides a dedicated USB sound card, serial port and PTT switching etc.,  I tuned my receiver to 10.13870 MHz and shortly afterwards received an off-air signal from IK2CMN over several minutes (as shown in the WSJT waterfall display below).

Setting my own callsign was a doddle and shortly afterwards I managed to get the OpenBeacon to transmit "G0VRM IO93QT" in QRSS into the dummy load, however it's not quite as clean as the off-air signal.  Following the instructions, I uploaded a WSPR string and it worked first time!

Notice that there are two entries for G0VRM, however one is 35 dB down and is probably some oddity of the radio being so close to the transmitter, although it appears to be very stable!  Looking promising, however connecting the beacon to an external antenna via a Z-match proved to be unsucessful.