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EXCITEMENT IS IN THE AIR!
THIS SITE HAS BEEN UPDATED AND HAS CHANGED LOCATION.
PLEASE GO TO tvcomm.co.uk/g7izu for the new site.
Remember to update your bookmarks!
What is "G-7-I-Z-U"? It's my amateur radio callsign...
Please do not abuse these pages by embedding
images on websites without permission!
My copyright notice can be read here.
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 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.
The Sky at Night
Andy Smith and David Entwistle appeared on the BBC's "The Sky at Night" meteor special
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
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.
PARTIAL G7IZU RRD SYSTEM DIAGRAM (UNTIL
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.
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.
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.
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
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.
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
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 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.
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
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.
posted by "Gotdelot "to www.ukcultivator.org.
Gee, thanks! Why stop at Sweden?]
G7IZU local site index
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
Lab - (Wolf Büscher
The software that powers this website! Literally!
- (Freeware and shareware utility programs)
software from G7RAU)
- (AVPSoft) -
Automated FTP upload and backup utility - freeware
4 - (Thinkman) - system
SyncBack - (2BrightSparks) Automated FTP upload and backup utility -
2. Solar/auroral/propogation live data
Make More Miles on VHF -
An excellent, extensive site covering many propagation subjects (based in
sun image (SpaceW)
Space Weather Now (Noaa)
Current Solar Data
GOES Solar X-Ray
3. Live FFT and VHF Radio Observation and Radar sites
Live FFT (on this site) Andy Smith G7IZU,
Live FFT (Richard,
GI4DOH, Northern Ireland) - four channels of data with archives
Observatory Online (Live global data using colorgrammes and Pierre
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.
4. Meteors etc.
International Meteor Organization
- All you ever needed to know about meteors!
shower list - local link
Meteor Shower Activity Outlook - Alastair McBeath's
meteor diary - good
RMOB - Radio Meteor Observations
Meteor Observatory - Dave Swan
Ass'n of Lunar
and Planetary Observers - (ALPO)
- Study into meteor Doppler shifts (2001 Leonids)
Distance vs. Zenith Angle - American Meteor
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
Sporadic E - A Review - Mike Hawk (12.11.2001 - pdf document). Recommended reading.
Radio Propagation Studies - DF5AI. Also recommended.
Ionosphere - Wikipedia
6. Mailing lists
mail list homepage (for visual observations of man-made objects)
list homepage (for observation of meteors and meteorites etc)
7. Amateur Radio/TV+radio DX and frequency lists
- Lists of all European FM Stations 66-108 MHz
- The TV DXers bible!
Download PDF Documents
(For North America)
TV-DXing in South
- ZS6BTE - Netscape browsers only, but links work OK in
IE. Very interesting DX articles.
TV-ID and Fine Frequency Page
- more worldwide offsets - good
- TV ID and fine frequency page (Italy)
UKDX.org.uk - Dedicated to
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
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.
Association - "The Voice of Amateur Astronomy in the UK"
UKARANet - UK
Amateur Radio Astronomy Network
French pages - Radio Propagation, but different to:
Isle of Man
Astronomical Society - IOM Astronomical Society homepage
Teleskopy.net - Polish
The DX Zone
- Amateur Radio Resources Guide
10. Online mapping
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"
Contact me: See below.
The internal links for this site can be found here.
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