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  1. #1
    Quagmire's Avatar
    Quagmire Guest

    Default What radio frequencies to "hear" Perseids ?



    Tried to read the how to's but cannot find a single "ping" .... can you
    please suggest a frequency (s?) I could try ?
    Am in Nottingham UK.

    Thanks



  2. #2
    Mike Dworetsky's Avatar
    Mike Dworetsky Guest

    Default What radio frequencies to "hear" Perseids ?

    "Quagmire" <noaddress@nowhere.com> wrote in message
    newsDslk.55565$Lw1.1477@newsfe29.ams2...

    The trails (of ionized gas) briefly allow FM radio frequencies to reflect
    from distant stations that you cannot normally receive by line of sight
    transmission. You have to use a radio that locks in on a specific frequency
    rather than use one that hunts for the strongest local signal of , e.g.,
    Radio 3 ( some car radios do this unless you change the setting). An
    omnidirectional aerial is best. When you get a brief enhancement of
    intelligibility it is likely due to a meteor.

    You will need to look up radio station frequencies around the UK and get
    actual transmitter settings. E.g., London local radio station LBC is at
    97.3 MHz. Meteor trails between London and Nottingham will provice
    enhancements.

    You could also try stations in Ireland or The Netherlands. The further the
    better, but cross-talk between adjacent channels is a problem.

    It's a bit early to get many Perseids, they will peak around the 12th.

    --
    Mike Dworetsky

    (Remove pants sp*mbl*ck to reply)


  3. #3
    Peter Lynch's Avatar
    Peter Lynch Guest

    Default What radio frequencies to "hear" Perseids ?

    On Mon, 4 Aug 2008 02:07:49 +0100, Quagmire wrote:
    The radio amateurs use the term "meteorscatter" You could try googling
    for that. I don't know what equiment you're using, but the impression I
    have is that you'll need quite a sensitive receiver and a decent aerial.


    --
    .. Pete Lynch I have learned from my mistakes and
    .. Marlow ... I am sure I can repeat them exactly
    .. www.pete-lynch.com --- Peter Cooke.

  4. #4
    Hils's Avatar
    Hils Guest

    Default What radio frequencies to "hear" Perseids ?

    Quagmire wrote


    Most independent researchers seem to favour frequencies around 50MHz.
    There's an amateur radio allocation at 50MHz, and a number of European
    broadcast stations on nearby frequencies which can be monitored for
    propagation via meteor trails etc.

    Some radio amateurs have developed a digital mode tailored for
    communication via meteor trails: search for WJST for more details. (The
    software is free, open source and cross-platform.) If you want to
    transmit on the amateur band(s) you'll need a licence.

    Andy Smith has a particularly sophisticated automated radio reflection
    detection system described (including spot frequencies and links to
    related sites) at

    http://www.tvcomm.co.uk/radio/how-to.html

    (Some of the real-time data pages are enormous.)

    --
    Hil

  5. #5
    Hils's Avatar
    Hils Guest

    Default What radio frequencies to "hear" Perseids ?

    >Quagmire wrote

    If you mean "hear" radio reflections from meteor trails, read my
    previous post. If you mean "hear" the trails themselves, you could try
    taking a portable VLF receiver to an electrically quiet location (where
    the receiver won't be swamped by mains hum). You could even try going
    without a receiver to a sonically quiet location: it's now recognised
    that under the right conditions you can hear meteor trails with the
    naked ear.

    There are a number of VLF receiver designs on the internet; you can also
    get ready-built receivers from http://www.auroralchorus.com, and kits
    from http://image.gsfc.nasa.gov/poetry/inspire/.

    --
    Hil

  6. #6
    David Entwistle's Avatar
    David Entwistle Guest

    Default What radio frequencies to "hear" Perseids ?

    In message <sqjbtMRjx5lIFwEb@newearth.demon.co.uk>, Hils
    <hils@nospam.demon.co.uk> writes

    Good pointer Hils - Andy has an excellent site.

    Hi Quagmire,

    For the moment, I'd suggest trying one of the following:

    The vision carrier from one of the remaining West European analogue TV
    transmissions on the "E" channels...

    48.25 MHz, 49.75 MHz, 55.25 MHz, 62.25 MHz.

    Or the vision carrier from one of the East European analogue TV
    transmission on the "R" channels...

    49.75 MHz 59.25 MHz.

    The main broadcast TV sites all radiate at pretty high-power. The vision
    carrier is amplitude modulated by the video content, but has a
    constant-power component close to the frequencies quoted above. Use USB
    demodulation and tune your receiver to about 1000 Hz below the carrier
    frequency given above. All vision transmissions are offset slightly, in
    frequency, to reduce the visual impact of co-channel interference, so
    you may need to tune around slightly to get pings at the desired
    heterodyne frequency.

    There are a couple of other alternatives, which you could look at, if
    these cause a problem, or if you get serious. Unfortunately the analogue
    TV transmissions are gradually being phased out, so some may have
    already gone and the rest will not be available for much longer.

    If you need any further advice, you can contact me via the SPA web site
    - just look at the bottom of the page.

    <http://www.popastro.com/sections/meteor.htm>

    Good luck.

    --
    David Entwistle

  7. #7
    john's Avatar
    john Guest

    Default What radio frequencies to "hear" Perseids ?

    In message <oDslk.55565$Lw1.1477@newsfe29.ams2>, Quagmire
    <noaddress@nowhere.com> writes
    If a local library stocks "Practical Wireless" magazine, or if you know
    someone who has back copies, you may get some tips from the VHF pages.
    Many radio amateurs watch for Sporadic_E reception and also use their
    gear to pick up stations by means of meteor 'backscatter'.
    (I gather that this is a very tricky subject, to say the least!)
    --
    Good luck,
    John.

  8. #8
    Quagmire's Avatar
    Quagmire Guest

    Default What radio frequencies to "hear" Perseids ?

    Thanks for the info David, what should I be hearing ? On the odd frequency
    there's a sound like "data" I presume that's the modulated carrier ? And
    should I be hearing that at all without scatter ?
    Ive gleaned that I should be on USB, maybe tuned a little "low" ?

    At the moment I'm recieving on my wire HF antenna... would a beam prove more
    fruitfull ? (pointed at sky ?)
    So far Ive heard nothing like a "ping" despite listening for hours :-()

    Thanks for the advice guys, keep it coming.



  9. #9
    David Entwistle's Avatar
    David Entwistle Guest

    Default What radio frequencies to "hear" Perseids ?

    In message <GDLmk.230058$oo.138804@newsfe09.ams2>, Quagmire
    <noaddress@nowhere.com> writes

    To hear meteors you need to be listening on a channel where the
    transmitter is too distant to 'hear' by non-meteoric propagation modes -
    ground wave, tropo etc. At this time of year and at certain times of day
    that can be difficult to achieve as sporadic E propagation occurs
    frequently and you hear even quite distant transmitters by ionospheric
    propagation. If that's the case you may need to try at another time.
    Typically Es propagation isn't a problem in the morning, but builds to a
    peak in late afternoon.

    The first thing to check is that you are typically hearing just noise
    (hiss) and not any form of modulation, or carrier directly from the
    transmitter. If that is the case, then when as a meteor, with the right
    alignment, occurs you'll get to hear a burst of steady tone as the
    carrier reaches you and beats with the local oscillator of your
    receiver. Dependant on the circumstances you may also note some
    frequency shift in the tone resulting from the movement of the meteor
    head, or more generally from the movement of the trail in the upper
    atmosphere winds.

    THE American Meteor Society have some samples of typical radio meteor
    sounds here:

    <http://www.amsmeteors.org/audio/index.html>

    There's a recording of a unusually strong head-echo here:

    <http://www.radiometeor.plus.com/meteors/headecho/headecho.htm>

    Small meteoroids produce underdense trails and larger meteoroids produce
    overdense trails. 'Pings' from underdense trails will be brief. Those
    from overdense trails will last for several seconds, or in some cases
    tens of seconds.


    Yes, it depends on the distance to the transmitter, but a moderately
    direction antenna, specific to the band of interest, and pointed in the
    general direction of the mid point between the transmitter site and
    receiver site would be ideal.



    Away from the showers, the background meteor rate has a 'diurnal
    variation' with a peak of sporadic meteor activity at about 06:00 local;
    time and a minimum at 18:00 local time - it's due to the Earth's motion
    through space.

    If you listen in the early morning, or when a shower is active, your
    chances will be better. Fortunately, the Perseids will be becoming
    increasingly active over the next few days and are expected to peak some
    time on the 12th August.

    Activity predictions are on the following sites

    UK specific:
    <http://www.popastro.com/sections/meteor/meteor-aug2008.htm>

    More general:
    <http://www.imo.net/>


    Good luck. I hope you get to hear the Perseids and you can always try
    and see a few too.
    --
    David Entwistle

  10. #10
    David Entwistle's Avatar
    David Entwistle Guest

    Default What radio frequencies to "hear" Perseids ?

    In message <6qNDnlCdD9mIFwfv@radiometeor.plus.com>, David Entwistle
    <David@invalid.com> writes

    Having listened to the AMS recordings myself, these recordings perhaps
    aren't so typical - I don't think the receiver was set up in USB mode.

    You could have a look at the Sky at Night 'Meteor Mania' programme which
    included coverage of the 2007 Perseids.

    <http://www.bbc.co.uk/science/space/spaceguide/skyatnight/proginfo.shtml>
    --
    David Entwistle

 

 
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