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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 full local RRD site index can be found here.

Daily meteor activity received by G7IZU

 
FIREBALL AND EVENT ARCHIVE
   
I'm uploading radio fireball and other "events" to a third party photo hosting site. 
 

The latest five events - click on them to view. More Radio Fireball Events from G7IZU

 

LIVE FFT Spectrum analysis
The main page updates every minute. I also have an archive page showing hourly captures from the past 24 hours. 

The main live page consists 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.
 

 
  
The latest 48.25/60.50 MHz FFT plot. Click here to open the live FFT page 

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

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Get a DESKTOP METEOR ACTIVITY indicator for your desktop! Under WinXP, click on the image below to open a new browser window, then copy the page url into your active desktop (right click on your desktop, click on "properties>desktop> customize desktop>web>new" to get there). Paste in the url and click OK. I've also found that this can be added as a Gadget under Vista, thanks to a third party who wrote some code for it without asking! Click here to visit the Google Gadget page. I don't know if it works as I don't have Vista. Resize and place the window on the desktop where you want it,  check the "lock desktop items" box, and click OK.

The Meteor Activity Email Alert Service Follow this link to start receiving email alerts. This service is not available from any other website (as far as I know!)   METEOR ACTIVITY INDICATOR KEY:  The trigger levels for these states are now adjusted hourly. "No data" = 0 (zero - usually occurs after I've rebooted or changed something - it may be there for up to an hour or so) "Low" "Active" "High"  "Very High" "Cannot count meteors!" Constant carriers detected! Note: the "trend" graph show the previous five hours' activity, with the latest hour on the right.  NOTE: I cannot guarantee that this indicator will be up to date and operational at all times. Sorry!

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Introduction

LIVE SPORADIC-E maps are available



This is a LIVE map of sporadic E clouds over Europe.
They are marked as yellow dots, which are the mid-points of
amateur radio contacts on 50 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 the maps of Europe and the western hemisphere. The Es map page is here.

[NB. The Es maps are now back online as of 26 April 2008]

Third receiver

I have a third receiver, sometimes tuned to the new French satellite radar frequency near 143 MHz. The geometry is bad for me so I don't receive a lot of meteors on this system. The higher frequency gives better detail to the reflections.

See the LIVE #2 page 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 a bit out of date, so do not expect things to work first time if you're trying it yourself!

Several European TV stations are present on these frequencies that cannot be received via 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 bonbarded 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 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)

December 2004
For a few hours each day I was automatically switching the receiver in the upper trace away from 59.257 MHz, to an HF broadcast station. I'd chosen Radio France International on 21580 kHz, as this appears to be one that's moderately close to me, and active for most of the day. Signal reflections from meteors on HF can last minutes longer than VHF reflections. In the FFT example above, you can see the RFI carrier at 960 Hz. This is constant due to me being within skip distance of the transmitter. Nevertheless, the meteor trail is clearly visible as a Doppler shift from the carrier. The same meteor left a very strong reflection from the Spanish 48.250 MHz transmitter (lower trace at 810 Hz), and a lesser hook-shaped one from the Swiss transmitter (at 690 Hz). 

Six other lines are visible which mimic the Spanish reflection (660, 710, 760, 810, 860, 910 and 960 Hz). These occur on strong reflections from any analogue European TV carrier, and are caused by the modulation of the TV carrier which is locked to mains frequency (50 Hz).
 
For daily update announcements about this site, click the weblog link on the live page.

Browser issues
This site is written using MS FrontPage 2000. Therefore, it's best viewed using IE5 or later - IE6 is recommended. Netscape 7.2 appears to give good results, as does Opera 7.5. There may be a problem with Mozilla Firefox. 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.

Andy.

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?]
 

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