Radio Meteor detection and imaging

 

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For many years I used to monitor a Band 1 VHF TV station analogue carrier on 48.250 MHz CW (locator IN70 1582 km) to test my MS receiving capabilities, with a 250 kW CW transmitter in Spain, IN70 locator square, being particularly useful before it closed down and was replaced with UHF TV transmitters in 2010. It was possible to hear the 'pings' of the reflected carrier from the many meteors often less than 0.5 of a second long, but sometimes for over a minute. This detection method is utilising many of the characteristics of what we know as RADAR.

 

 

 

 

 

In 2011 there remained a few Band 1 TV transmitters in Europe that could be used to monitor Meteor Scatter activity. The TV station in Prague, JN79 locator square, on a carrier frequency of 49.740 MHz CW (locator JN79 1341 km) being very useful, sadly also now closed down.

 

 

 

 

 

 

All analogue TV stations in the Czech Republic closes down on 30th June 2012. Portugal too ceased on 26th April 2012. For a list of analogue TV closures by Country please follow this link for Digital Television Transitions 

 

 

It appears that time is rapidly running out for European Band 1 TV video carriers audible via Meteor Scatter reflections here in Northern England and few options remain. The ideal distance for such transmitters is not less than 300 km and not further than 1500 km away from the receiving station, although a maximum working distance can extend as far as 2,300 km but with much weaker reflected signal strengths.

 

 

Radio Meteor Scatter detection sources for Northern England
Carrier Frequency CW (MHz) or USB if shown	Power	Location	Distance from IO84	Remarks	Results
32.550	12 kW	JP89 Norway	1842 km	SkiYMET, Andenes Meteor Radar, Institute Atmospheric Physics, over ideal 1500 km distance & good power. At solar maximum frequencies between 30-35 MHz can be negatively impacted for MS working.  N.B. Operating in pulsed mode, not CW carrier so unlikely to be of use for radio detection(Thanks Toralf DJ8MS for info)	Tested May 2012, nil heard
32.550	12 kW	JO64 Germany	1017 km	Juliusruh Meteor Radar, Institute Atmospheric Physics, good distance & power. At solar maximum frequencies between 30-35 MHz can be negatively impacted for MS working.  N.B. Operating in pulsed mode, not CW carrier so unlikely to be of use for radio detection (Thanks Toralf DJ8MS for info) .	Tested May 2012, nil heard
36.200	12 kW?	JO61 Germany	1110 km	Collm Meteor Radar, near Leipzig, good distance & power.   N.B. Operating in pulsed mode, not CW carrier so unlikely to be of use for radio detection (Thanks Toralf DJ8MS for info) .
39.025-39.175	100 W	UK Locations unknown	? km	UK Meteor Burst Communications (MBC) 7 x 25 kHz channels. Full locations unknown, one company operates master station at Newbury, Berkshire. May be Mobile Meteor Burst Stations (MMBS) and only transmit once per hour. See reference document. European harmonised Meteor burst frequency allocation is 39-39.2 MHz.
46.400	500 W	UK IO92ot Leicestershire	246 km	UK Meteor Burst Communications (MBC) All are being phased out as legacy systems, some are already closed down in 2024, this system remains on until contract ends. Below recommended minimum 300km distance .	Tested September 2012, nil heard
46.500	8-160 kW	IO72XK Wales	263 km	NERC MST Weather Radar Facility. Below recommended minimum 300km distance. N.B. Operating in pulsed mode, not CW carrier so unlikely to be of use for radio detection .	Tested May & September 2012, nil heard. Closed down in 2024
46.950	100 W	?	? km	UK Meteor Burst Communications (MBC) Return frequency for main 46.975 Transmitter .	Tested September 2012, two extremely weak pings and missed Fireball over UK on 21.09.2012 completely!
46.975	500 W	UK Bacton, Norfolk JO02RU	345 km	UK Meteor Burst Communications (MBC) .	Tested September 2012, nil heard
48.250	250 kW	IN70 Spain	1583 km	TV carrier Spain, closed down in 2010. This had been the strongest Band 1 TV signal observed here from Europe	Closed down in 2010
49.739.49	40 kW	KN29 Ukraine	1970 km	TV Carrier Lviv R1, over ideal 1500 km distance	Tested March 2012, nil heard. Closed by 2018
49.739.66	150 kW	JO70 Czech Republic	1285 km	TV Carrier Prague R1, until June 2012, good distance and power	Closed down June 2012
49.749.83	17 kW	KN68 Ukraine	2536 km	TV Carrier Krivy Rig R1, over maximum workable 2,300 km distance	Not workable too far away. Closed by 2018
49.74920	149 kW	KP50 Russia	2090 km	TV Carrier St.Petersburg, Russia R1, over ideal 1500 km distance	Testing in September 2012 & May 2015 has found some Meteor pings.
49.749980	25 kW	K033 Belarus	1934 km	TV Carrier Minsk, Belarus R1, over ideal 1500 km distance	Signal on this frequency heard via Es on 30.04.2012. Testing in September 2012 has found some Meteor pings.
49.757615	? kW	K046 Ukraine	1999 km	TV Carrier Glubokoye, Ukraine, over ideal 1500 km distance (slight warble)	Closed by 2018
49.757800	? kW	K056 Ukraine	2120 km	TV Carrier Novosokolniki, Ukraine, over ideal 1500 km distance	Closed by 2018
49.760.4	100 kW	JN99 Czech Republic	1590 km	TV Carrier Ostrava R1, just over 1500 km distance, good power	Closed down early in November 2011. Thanks Martin G4FUI for the update
49.96917 USB	150 W	JO20 Belgium	702 km	BRAMS Meteor Beacon, Balise Dourbes, Belgium dedicated MS beacon, but low power, very good distance	Very few weak pings detected so far
49.98918 USB	50 W	JO10 Belgium	607 km	VVS OT1KZG Meteor Beacon, Ypres, Belgium dedicated MS beacon, but low power, very good distance	Some frequent weak pings detected. Stronger and more frequent than Balise Dourbes
50.40720 USB	75 W	IO93 England	205 km	GB3MBA Meteor Beacon https://www.meteornews.net/2022/10/26/uk-radio-meteor-beacon-project/	Rather too close for me
53.500	12 kW	JO64 Germany	1017 km	Juliusruh Meteor Radar, Institute Atmospheric Physics, good distance & power.  N.B. Operating in pulsed mode, not CW carrier so unlikely to be of use for radio detection (Thanks Toralf DJ8MS for info)	Tested May 2012, nil heard
53.500	4.5-90 kW	JO54 Germany	889 km	OSWIN VHF Radar, good distance and power varies.  N.B. Has not been operating in Meteor Scatter mode since 2009 (Thanks Toralf DJ8MS for info)
53.500	2.4-60 kW	JQ78 Svalbard	2717 km	SOUSY SSR VHF Radar, over maximum workable 2,400 km distance	Not workable too far away
53.500	1.8-36 kW	JP88 Norway	1842 km	ALWIN VHF Wind Radar, good distance and power varies.  N.B. Operating in pulsed mode, not CW carrier so unlikely to be of use for radio detection Can sometimes be used to measure Meteor activity when the site operator wishes, but not main priority.	Tested May 2012, nil heard
55.250.071	90 kW	HP85 Iceland	1628 km	RUV TV Carrier E3 Stykkisholmur until 2013, over ideal 1500 km distance, excellent power, not known if 24H or closes down at midnight.	Closed down 2015
55.250	60 kW	IN50 Portugal	1640 km	TV Carrier E3 Lousa, over ideal 1500 km distance, excellent power. Due to shutdown permanently on 26th April 2012, followed by a final week in TV test card mode. My last detected Meteor ping was at 0920z on Friday 4th May 2012.	Closed down 4th May 2012
59.256.5	7 kW	KN18 Ukraine	1897 km	TV Carrier Uzghorrod, over ideal 1500 km distance, power less than most TV stations	Closed by 2018
59.297.8	150 kW	JN78 Czech Republic	1341 km	TV Carrier Ceske R2, until June 2012, good distance and power	Closed down
62.251313	300 kW	HP94GF Iceland	1488 km	RUV TV Carrier E4 Skalafell mountain, Iceland until 2014, good distance, excellent power N.B. These two Icelandic TV stations frequencies are shown inverted depending on which source you view, so they could be either way round	Closed 2015
62.251737	80 kW	IP25VE Iceland	1327 km	RUV TV Carrier E4 Gagnheidhi mountain, Iceland until 2014, good distance, good power N.B. These two Icelandic TV stations frequencies are shown inverted depending on which source you view, so they could be either way round	Closed 2015
87.600 WFM	100 kW	Germany	800 km	Several BC FM Radio stations in Germany at ideal distance and high ERP	TBC 2023
143.050 CW 143.04920 USB	<767 kW	JN27SI France	(1000 km) 1250 km	GRAVES Military Space Radar system, believed excellent power, fairly good distance, but high frequency with far fewer reflections detectable compared to 50 MHz. Note distance is not to transmitter site itself but to area of Southern France 250 km further South where Ionosphere is illuminated by the Radar at 100 km altitude and reflections detected. However, in theory this is detection via Backscatter and ideally Forward scatter is much preferred for MS work.	Possible few weak reflections detected

 

 

N.B. If monitoring any of the above CW carrier frequencies using SpectrumLab or similar software, you will most likely need to be in USB mode and therefore around 800 Hz lower in displayed frequency than quoted i.e. 55.250.0 MHz CW carrier = 55.249.2 MHz in USB on your radio display, then look for the signal at around the 800-1000 Hz point on the software screen.

 

 

 

I was using in 2015

49.74920 MHz USB St.Petersburg TV carrier, KP50, Russia

as my primary Meteor Spectrogram reception frequency, however results were poorer than before when I could use the 55.250 MHz signal from the TV transmitter in Portugal, due to lower ERP and greater distance away.

My alternative frequency in 2015 was

49.98918 MHz USB OT1KZG Meteor Beacon, JO10, Belgium

 

I cannot understand why the Skalafell TV transmitter on 62 MHz in Iceland was not the very strongest signal here in Europe in 2012 as it is closer to me than the strongest closed down TV stations in Spain or Portugal were and has higher output power of 300 kW. The only thing I can think of is that the 48 MHz and 55 MHz frequencies the other TV stations used respectively are lower and better frequencies for MS and the amateur radios used have better receiver design characteristics for those frequencies too.

 

2015

Looks like the Iceland TV transmitters may have closed down since I last looked in 2013, which only leaves Eastern European TV transmitters in or near Russia left now in 2015 as shown on the map below

 

 

 

 

2020

 

It appears all Band 1 analogue TV transmitters suitable for Radio Meteor Observation in Europe have closed down leaving a few other choices now. for me the following transmitters appear to be the possible solution and are both in regular use by other stations monitoring meteor reflections.

 

49.98918 MHz USB OT1KZG Meteor Beacon, JO10, Belgium

 

143.04920 MHz USB GRAVES Military Space Radar, JN27, France

 

 

 

 

GRAVES an alternative high power transmitter exists, but is much more difficult to use, shown below.

 

 

143.050 MHz CW 

This is the carrier frequency of the French GRAVES space surveillance radar system and will provide pings from both meteors as well as satellites! Maidenhead Locator Square JN27SI near the City of Dijon and the border with Switzerland. (Red dot on map indicates transmitter location on former airfield)

 

There are 4 Phased Array antennas on 143.050 MHz CW situated on a disused Airfield. The four transmitted beam lobes are designed to overlap and cover a 180 degree arc of Sky, at an elevation of 25 degrees, in a Southerly direction towards the Mediterranean Sea.

 

GRAVES Space Radar beam geometry

Preliminary experimental results using only an indoor 144MHz 1/2 wave colinear on 143.050 MHz CW have produced what I think may be Meteor Scatter reflections or the ping could could be from a satellite! In the screen grab below there is a distinct vertical ping shown in a bright yellow colour just before 0625 UTC on 24th March 2012.

 

I was also experimenting in 2012 to see if some of the dedicated Institute for Atmospheric Physics (IAP) high power VHF transmitters for Meteor Scatter detection are audible here in the North of the UK. There are stations located in Andenes, Norway on 32.550 MHz  running 12 kW and another station in Juliusruh in Northern Germany on 32.550 and 53.5 MHz at 12kW. However all my attempts to use these sources have failed and I have been advised that as they are 'pulsed' signals and not CW they may not be at all suitable.

 

 

 

 

Here below are my first attempts at automatically uploading my latest captured Radio detected Meteor Scatter images. Inspiration mostly drawn from Andy G7IZU and his excellent web guide on how to do this. I am using DL4YHF SpectrumLab software to capture the images and AutoFTP Pro to send them to this website automatically every 10 minutes whilst the system is active. Technically I suppose this is Radio Astronomy. If there are no meteors then this image will be mostly blank.

                                                                   

 

Meteor Pings captured in the above image (if detected) should also show up on the live Plotter image below, where they exceed -50 dB signal level as high green coloured peaks and should correspond with the 3D image below that.

 

 

 

 

 

 

And if there is something 'special' to see then, in theory, an Alert image should be shown below! This is still very much in test mode and is currently set to activate if a Meteor ping is stronger than -50dB..

 

 

Observations of many Radio Meteor Spectrograms by myself, and others, suggest that the captured Spectrogram images appear to fall into one of approximately 15 categories, which are described and explained below. For consistency, all example captured images are at the highest FFT resolution my system will allow and are edited into a cropped size of 156 x 156 pixels (unless that will not allow the full trail to be seen).

 

Surprisingly few aircraft traces seen when I listened on 55.250 MHz to the now closed down Portugal TV carrier.

 

 

 

I have only been experimenting with Radio Astronomy using SpectrumLab software since around 29th March 2012, all the example Doppler Spectrogram images above have been acquired by me since then, using my primary frequency of 55.250 MHz CW and simple aerials, no beams. The FFT settings for SpectrumLab have been experimented with to try to obtain the highest resolution imagery I can get. I try to leave my system on to automatically capture the images, which I review for content later.

My settings shown as screen captures:

 

 

The most difficult task has been setting up the 'Conditional Actions' script for SpectrumLab to identify Meteor pings correctly and record the numbers, grab images every 10 minutes, record 'Special' events, measure background noise and signal levels, etc.

I owe a debt of gratitude to the British Columbia Meteor Network who provided on their website a script that worked for my setup with minimal alteration required and other direct assistance.

This is still a work in progress to perfect, but my current settings are shown below, for a single receiver, so that they may help others with this daunting task.

 

In the script above some of the numbers require explanation, as they may differ for your station. In line 2 after 'noise' are shown '300,1000' these refer to listening to the noise level between 300-1000 Hz and that noise level measured in dB will become value 'A'. The numbers could just as easily have been 0,2700 for a typical SSB signal width of 0-2700Hz or anything in between. 'D' is duration and 'E' the count of pings.

Also on line 2 after 'peak_a' is shown '880,920' this is asking the software to measure the peak signal between 880-920 Hz in dB which will become value 'B'. These numbers were chosen by me because when I tune to 55.249.2 MHz USB to monitor in SSB the actual TV carrier on 55.250 MHz CW the signal falls on my SpectrumLab display at 900 Hz exactly centre of the frequency range 880-920 Hz I chose. I only want to measure the signal strength of the detected TV carrier, heard via Meteor Scatter, so limited this range deliberately to avoid picking up anything else.

In line 3 if the measured meteor sound level B, is noise level A 15dB then that is a 'ping' for counting purposes. This '15' dB level above the measured background noise level was initially set at 20 dB, but I found some weaker signals were not counted; when set at 10 dB too much noise from night-time lighting was being counted, so for my setup 15 dB works. Also shown is the timer) duration set at 5 seconds so that ionization trails which ma have short breaks after the meteor are not counted as new meteors.

In Line 4 if the meteor ping (B) signal level is greater than -50dB then timer9 starts and 90 seconds later a screenshot is taken for an 'alert' image. I set 90 seconds to let the SpectrumLab screen scroll away from the edge so as to hopefully capture a better picture.

In lines 7 & 9 'F:/Local disk/Spectrum/...../' is most likely to be different for you as this is the computer path here for my external HDD and you should replace the path to reflect your own computer files, possibly something like C:/Spectrum/......

Now my equipment for detecting Radio Astronomy Meteor Scatter reflections is undergoing a review as at 2nd April 2012. Initially in March 2012 I used my Kenwood TS-2000 transceiver with a Sandpiper MV3+6 Vertical antenna, however the Meteor Scatter reflections at 100 km altitude are most likely to be at high angles of elevation back to Earth, so I switched to my horizontal Racal Military tactical dipole aerial to assess if this  improved the signal strengths.

 

Also my Kenwood TS-2000 is limited to a maximum frequency of 60 MHz and with Band 1 TV closing down in Europe totally in the very near future I will need to explore what Band 2 VHF FM radio stations in the frequency range starting from 87.5 MHz can offer. I also have interest in frequencies between 60-87 MHz and want to leave my Meteor Scatter receiving system running 24H. I need my Kenwood TS-2000 for other amateur radio activity. 

 

I've tried using my SDR FlexRadio 3000 but it doesn't appear sensitive enough on 55.250 MHz compared to my Kenwood TS-2000, results so far haven't been encouraging.

I have decided to experiment using a FUNcube Dongle Pro, which in theory can be used from 51.5 MHz - 1700 MHz (Rated from 64 MHz - 1700 MHz) all mode including SSB to turn my laptop PC into a dedicated radio receiver. I will use with SDR-Radio.com software for frequency control and SpectrumLab to analyse Meteor Scatter results. This will also permit me to experiment with the GRAVES Space Radar on 143.050 MHz too.

 

First impression of the FUNcube Dongler Pro was that it requires both extensive Radio and computer knowledge to setup properly. Took a little while to find the information online how to update the latest firmware (required for all features and software compatibility) and set it up for proper use. Tried SDR-Radio.com software as my preferred front end, as it is so very comprehensive, however I ran into a common problem of listening to a local Band II FM Broadcast Radio station on 92.5 MHz FM and the audio being very distorted.

Several hours later, by trial and error, I have tried the alternative HDSDR software front end and have little to no audio distortion when using96000 Hz in and 96000 Hz out audio settings via the soundcard. Will try again with SDR-Radio.com software on frequencies other than Broadcast FM which shouldn't cause overloading or exceed the audio bandwidth specification of the dongle.

I have in the Summer of 2012 abandoned using the FunCube Dongle and returned to my traditional analogue radio the Kenwood TS-2000.

 

 

2015

I now also have an Icom-7100 Transceiver which I have begun experimenting with for Radio Astronomy. Due to a PC HDD failure I lost all my SpectrumLab settings and realised that my setup instructions above are a bit lacking, so please find shown below some screen shots of my new configuration settings in case it helps others get setup too.

I am using Java FTP Scheduler Pro 2.1.4 to upload my captured images every 5 minutes