LIVE PROP MAPS: Europe Es / Avg MUF | USA Es / Tropo
Trans-Atlantic ALL | FarEast&Oceania ALL | Aurora


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What is "G-7-I-Z-U"? It's my amateur radio callsign...

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My copyright notice can be read here.



Geminds 2010

In the past I've collected many interesting observations of meteor activity.
Some graphs of my observations of the Geminids shower in 2010 can be seen here.

Stargazing Live

The 2012 BBC Stargazing Live event took place between Jan 16th and 18th.

I'm very proud to say that I was a part of the show.
I was the BBC Engineering Manager at the Dulverton Outside Broadcast.

The main BBC show was hosted at Jodrell Bank.
Coincidentally, the Jodrell Bank meteor-detection system was inspired by my work,
having been put into action by Megan Argo with some advice from myself.

Daily meteor activity received by G7IZU

The Radio Meteor Detection Hobby

The casual hobby of radio meteor detection using the powerful signal source of analogue TV transmitters is now at  an end. Under European directives, most analogue TV transmitters will have now shut down.

The hunt is now on to find alternative signal sources before doom and despondency descends heavily upon the hobby. In western Europe there are a couple of alternatives, but they are not the whole solution. ONERA in France has helpfully provided an extremely powerful carrier wave satellite radar in the VHF band. As well as spotting satellites, it's also very good at spotting meteor trails. This radar is useful to observers in Western Europe as far north as the southern UK. Another alternative is a pair of 50W meteor transmitters set up by a Belgian group on frequencies close to 50 MHz. The useful range of these is only a couple of hundred kilometres.

There are now also other proposals coming forward, involving a possible UK network of linked meteor "radar" transmitters and observers, run in conjunction with various astronomical facilities. Amateur radio beacons
may also useful, although their low power will be limiting.

Unfortunately, as noted above, my own hunt for a suitable signal source has been fruitless.

Andy, 18.08.2013


The Sky at Night

Andy Smith and David Entwistle appeared on the BBC's "The Sky at Night" meteor special "Meteor Mania" on BBC 4 TV on November 25th, 2007. If you missed it, it can be downloaded in Windows Media format from here:

meteormania.wmv (Dur 29m29s, 192MB).

It may also be viewed in Real Player format at the BBC's "The Sky at Night" homepage. The regular monthly editions of the programme may be viewed in Real Player format on the site.

"The Sky at Night" co-presenter and co-author of "Bang! The Complete History of the Universe",
Chris Lintott, FRAS, held a live radio-meteor/astronomy demonstration on the fourth plinth in
Trafalgar Square for one hour, as part of artist Antony Gormley's "One & Other" project
on August 14th 2009.

The full local RRD site index can be found here.




A 24 hour FFT plot of the Quadrantids shower Jan 2004


LIVE FFT Spectrum analysis
(Note that the meteor detection system is now inactive)
The main page updates every minute. I also have an archive page showing hourly captures from the past 24 hours

The main live page consisted of an FFT screen, showing the audio pass bands from two ssb radio receivers, which are tuned to two European VHF TV channels. To the top left is a meteor activity indicator. Below the FFT is a panel showing various solar, auroral and ionospheric warning indicators. Below that is a graph which shows a four-day history of the meteor activity rate, along with a record of echo durations. If echo durations are high, this indicates that constant carriers may be present in the form of sporadic E or aurora. Meteors entering the atmosphere within the reflection range of distant transmitters cause signal reflections to show on the FFT display in various ways, dependant on their size, direction of travel, and the ability of the ionized trail left by the meteor to reflect the signal. More information about this can be found further down the page. The Spectrum Lab program, which creates the FFT and graph charts, counts the meteor "pings" and generates the information required for the activity indicators and alert email system.

Read on to find out more about what this stuff is all about, but beware that some pages are quite graphics-heavy
A broadband connection is recommended, along with a screen size of 1024x768.

Please consider making a donation towards the running of this website. 
Considerable time, effort and investment has gone into creating it.
It's quite expensive in electricity running the equipment, and 
I've also just had to invest in commercial webspace.
If the site is to continue and expand, it needs money. Please donate, however little.
Donations are made instantly through Paypals' secure server using the button above.
Thankyou! Andy.


Links to external sites of interest are at the bottom of this page.

Overview of the system until April 2012

The radio detection of aurora and meteors were made possible at my QTH in Tavistock, Devon, UK by listening to the carriers of distant  Band 1 TV stations. 

I use DL4YHF's excellent and dead cool Spectrum Laboratory v2.7, fed from the audio output of two Icom PCR-1000s in USB mode, which were tuned to frequencies of 48.250 and 55.250 MHz (the receivers' local oscillators are not exactly precise, so these frequencies may not match yours by 10s or 100s of hertz). The antenna was a 50 MHz 1/2 wave vertical.  
If you want to try it, any other frequencies that give good returns at your location will do just as well. Transmitters within a range of 400-1000 km should be ok. Too close and you'll see aircraft trails! I've found about 800-1200km to be best. See the links section below for various TV  frequency lists. Many VHF analogue TV stations are closing in Europe, so signal sources are becoming a rare thing!

LIVE SPORADIC-E maps are available

This is a LIVE map of sporadic E clouds over Europe. If they are around, they're marked as yellow dots, which are the mid-points of amateur radio contacts on 50 or 144 MHz via Es mode, during the last 30 minutes. These are sourced from an application called "LiveMUF" which monitors the amateur DX Cluster network for Es contacts, then plots them on maps of Europe and the world. The Es map page is here.
Further details about my radio observation station can be found here: [How-to setup a Radio Meteor Obs. Station]. Please note that some of the information there is now very out of date, so do not expect things to work first time if you're trying it yourself!

European TV stations present on these frequencies cannot be received via direct ground wave propagation. Any other mode of propagation that bounces the signal in my direction is detectable, such as sporadic E, meteor reflection, auroral reflection, reflections from high-flying aircraft or even re-entering spacecraft and debris. Coronal Mass Ejections from the sun become visible as the ionosphere is bombarded by protons from the sun. Doppler shifts of a few tens of hertz can be observed, caused by the ionized trails of meteors or debris drifting in the winds of the upper atmosphere, sometimes for several minutes on end. Sometimes the head of the meteor itself is large enough to register a swift Doppler shift of a few kHz over fractions of a second. A meteor shower, such as the Quadrantids (above) can keep the FFT display constantly active. In contrast, sporadic E events, during late spring to early autumn, can wipe out the display with strong carriers for hours and days at a time. Radio auroras can appear almost as wonderful as their visual counterparts, which, of course, would be visible outside if it wasn't cloudy/daytime/you live in a city etc. etc.

Radio Aurora

The image above is a very good example of an auroral signal. It was recorded on 31st Oct 2003 between 0010 and 0110 GMT, during the second night of big auroras over the UK. Visible in the sky over Plymouth were various red glows and an arc of white stretching overhead. The signal is spread out due to the rapid Doppler shift caused by the charged particles in the auroral curtain rapidly moving. Several TV carriers, which are a few hundred hertz apart, are being reflected simultaneously, making the Doppler effect appear bigger than it really is. 

Above is shown a typical busy meteor period. The upper part of the trace is monitoring the Eastern European channel R2, on 59.258 MHz. The spots are caused by "underdense" meteors. The lower part of the trace has a few "underdense" meteors, but also one quite heafty "overdense" trail lasting a few minutes. This might have been classed as a "fireball" had it been visually sighted.

This is an example of how a Sporadic E (Es) opening looks. Signal levels can be extremely high, and the receivers' AGC levels are often compressed. Here, two carriers only 6 Hz apart are visible on Channel R2. Also visible in the lower trace are the typical 50Hz harmonic lines from the analogue TV transmitter in Sweden. 

Another Sporadic E opening, showing how the signals can stop coming from one direction or location, and turn to another. Here TVE Spain gives way to RTP Portugal. The wobbling Portugese signal is caused by the transmitter frequency drifting in a 10 minute cycle, due to poor TX frequency control or local mains frequency instabilities at the TX site.

Above: Strong meteor echoes.

Above is what I believe to be a sign of a coronal mass ejection from the sun causing the ionosphere to become charged. The effect is similar to an aurora, with noise-like Doppler. See the Doppler shift in the lower trace go from negative to positive? I'm looking for an explanation of this. (See also the CME page)

For daily update announcements about this site, click the blog link at the top of every page.

Browser issues
This site is written using MS FrontPage 2002. Therefore, it's best viewed using  IE6 or later. Netscape 7.2 appears to give good results, as does Opera 7.5. Google Chrome woks well. There may be a slight problem with Mozilla Firefox and some other browsers. Some table cells are incorrectly sized and take their measurements from the background image within, rather than from the specified cell sizes, and make some pages look messy. If you spot any other problems please let me know. I will always attempt to resolve problems.


About this site and the author, a reviewer said recently (copied here as published):

G7i7u Radio Reflection Detection Site

This guy if i understand correctly is an extroardinary amatuer, and judging by the amount of info on this page,probably has a brain the size of sweden, but its worth a visit every now and then if your bored or planning something
Dont worry i haven't got one giant eye like galileo, or sir patrick moore, i dont understand harf of it myself but its interesting all the same, i find inhaling sharply on a blend of your choice, then exhailing slowly through the nose usually does the page no harm at all
[As posted by "Gotdelot "to www.ukcultivator.org. Gee, thanks! Why stop at Sweden?]

G7IZU local site index

[Introduction/Site Index]
 [ LIVE Meteor Detection ] [LIVE Radio Propagation Maps] [NLO LIVE]
[Geminids 2010] [Aurigids 2007 Report] [Guide] [Latest Event] [Alerts via Email]
[Aurora Gallery] [Sporadic E Gallery] [CME Gallery] [Meteor Gallery] [Meteor Shower Calendar]
[Links List] [How-to set up a Radio Meteor Obs Station] [G7IZU RRD Blog]

Follow me @g7izu

This website is Copyright 2004-2013 Andy Smith G7IZU.
Re-use of original graphics, data and alert systems on other websites is expressly forbidden,
unless prior authorization has been obtained from myself.
Email: g7izu (at) television.f9.co.uk
Twitter: @g7izu

External software, solar, geophysical, meteor and dx-ing links
(checked Jan 2011)  
All external links are opened in a new browser window. Please report any broken links you find to me.
Note: I am not responsible for the content of any external website you may reach through these links.

1. Free Software
Spectrum Lab - (Wolf Bscher - DL4YHF. The software that powers this website! Literally!
Outertech Technologies - (Freeware and shareware utility programs)
Live MUF - (Propagation/DX software from G7RAU)
Save2FTP - (AVPSoft) - Automated FTP upload and backup utility - freeware
Dimension 4 - (Thinkman) - system clock auto-correction
SyncBack - (2BrightSparks) Automated FTP upload and backup utility - freeware, excellent!
2. Solar/auroral/propogation live data
Make More Miles on VHF - An excellent, extensive site covering many propagation subjects (based in Germany, multi-lingual)
SpaceW.com (index)
Current sun image (SpaceW)
Space Weather Now (Noaa)
Space Weather.com
Current Solar Data
SOHO Online 
GOES Solar X-Ray Imager 

3. Live FFT and VHF Radio Observation and Radar sites
Live FFT (on this site) Andy Smith G7IZU, Plymouth, UK
Live FFT (Richard, GI4DOH, Northern Ireland) - four channels of data with archives
Radio Meteor Observatory Online (Live global data using colorgrammes and Pierre Terrier's RMOB format)
Radio Meteor Observatory Japan HROFFT format - global live observations (Hiroshi Okawa)
A Squint at the World of LF (W3EEE - Live plots and discussion of signals in the LF and MF world. Excellent!) 
4. Meteors etc.
International Meteor Organization - All you ever needed to know about meteors!
Meteor shower list - local link
UK Meteor Shower Activity Outlook - Alastair McBeath's meteor diary - good
- Radio Meteor Observations
Radio Meteor Observatory - Dave Swan
Ass'n of Lunar and Planetary Observers - (ALPO)
ESA - Study into meteor Doppler shifts (2001 Leonids)
Meteor Distance vs. Zenith Angle - American Meteor Society
IMCCE - Meteor Shower Ephemerides Server -
by J. Vaubaillon (IMCCE/CALTECH), in collaboration with P. Jenniskens (SETI Institute, NASA/AMES)

5. Sporadic E and Ionospheric Studies
Mid-Latitude Sporadic E - A Review - Mike Hawk (12.11.2001 - pdf document). Recommended reading. 
Amateur Radio Propagation Studies - DF5AI. Also recommended.
The Ionosphere - Wikipedia

6. Mailing lists
SeeSat mail list homepage (for visual observations of man-made objects)
Meteorobs mail list homepage (for observation of meteors and meteorites etc)

7. Amateur Radio/TV+radio DX and frequency lists
FM-LIST - Lists of all European FM Stations 66-108 MHz
TV-LIST - The TV DXers bible! Download PDF Documents
DX-Links (For North America)
TV-DXing in South Africa  - ZS6BTE - Netscape browsers only, but links work OK in IE. Very interesting DX articles.
IQ9OBK TV-ID and Fine Frequency Page
KC6WSF - more worldwide offsets - good
IT9OBK - TV ID and fine frequency page (Italy)
UKDX.org.uk - Dedicated to TVDXing

8. Zero to 25kHz (ULF to VLF). Links to interesting articles
Using a PC with Soundcard as a VLF Receiver - using Spectrum Lab (DL4YHF)
Radio Waves Below 22kHz - Exploring ULF-ELF and VLF Radio (IK1QFK)
Techlib.com - VLF Receiver Projects
London Guildhall Fine Arts Society Lecture 22/10/1998 - A very interesting VLF article by Joe Banks, written in 1998 (Text)
9. Other interesting sites dedicated to radio, astronomy, propagation, satellite reentry etc.
British Astronomical Association - "The Voice of Amateur Astronomy in the UK"
UKARANet - UK Amateur Radio Astronomy Network
F6CRP  French pages  - Radio Propagation, but different to:
Isle of Man Astronomical Society - IOM Astronomical Society homepage 
Teleskopy.net - Polish astronomy site

The DX Zone - Amateur Radio Resources Guide 

10. Online mapping
GPS Visualiser 
Google Earth 

11. Analogue transmitter shutdown information
Local summary with links to information - (some information may now be out of date)

12. Links to "Graves" satellite radar news and information
A Graves Source Book - A compilation of current information (PDF Document)
French say "Non" to US Disclosure of Secret Satellites - Space.com article

13. Other subjects!
"Diane Smith Fabric" Ebay shop.

Contact me: See below.

The internal links for this site can be found here.


Any comments please to: g7izu(at)television.f9.co.uk

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