(meteorobs) Fwd: Re: Negative HF radio meteor reception

[Jean-L. RAULT]

Hi George

I did NOT receive a signature that can be correlated to a HF ( 17 or 21 MHz ) emission from a meteor

Jean-Louis




Le 03/03/2012 15:20, drobnock a écrit :
> Hi
> Please clarify, did you or did you not receive a signature that can be
> correlated to a HF ( 20-30 mhz ) emission from a meteor?
>>> Tom,
> I tried some times to look at short waves signals radiated by meteors,
> but with no results until now<<
>
> George John Drobnock
>
> "Jean-L. RAULT" wrote:
>
>>
>>
>>
>>
>>
>>
>> Sam, James
>>
>> The lowest frequencies I used  when observing meteors in forward or
>> backscatter mode were 21 and 17 MHz. And it works.
>>
>> This mailing list does not accept attached documents, so I'm forwarding
>> you directly two examples of meteor echoes I recorded in 2006 from a 17
>> MHz and from a 21 MHz broadcast transmitter.
>>
>> Tom,
>>
>> I tried some times to look at short waves signals radiated by meteors,
>> but with no results until now
>>
>> Regards
>>
>> Jean-Louis F6AGR
>>
>>
>>
>>
>>
>> Le 02/03/2012 18:48, Sam Barricklow a �crit :
>>> Thomas,
>>>
>>> Due to the lower frequency, the doppler shift is considerably less at
>>> HF frequencies than at VHF.  Also, to hear a meteor radio echo that is
>>> not "polluted" by either ground wave or sky wave, your receiver must
>>> be within the "skip zone" and beyond ground wave distance.  The skip
>>> zone is where the skywave is passing above your location on its way to
>>> or from the refraction zone in the ionosphere, and before the signal
>>> returns to the Earth's surface.
>>>
>>> The ideal signal source for HF meteor radio echo work would be a
>>> shortwave broadcast station that is located over the horizon, too far
>>> away for you to hear groundwave and too close for ionospheric
>>> propagation to occur.
>>>
>>> Here's a link to a YouTube video on the subject:
>>>
>>> http://www.youtube.com/watch?v=xgrxQdRrCRE
>>>
>>> A limited amount of information is available at the following website:
>>>
>>> http://sci2.esa.int/leonids/leonids99/leolisten.html
>>>
>>> WWV in Fort Collins might be useful for you when the MUF (maximum
>>> usable frequency) is lower than or near the receive frequency,
>>> especially for the 15 and 20 MHz frequencies.  WWV transmits at 2.5,
>>> 5, 10, 15 and 20 MHz.
>>>
>>> Other propagation modes might produce "interference" even when no
>>> direct ionospheric or groundwave propagation exists, such as
>>> backscatter or even forward scatter, both of which are mostly produced
>>> by the ionosphere.  Backscatter from distant mountains or ocean waves
>>> may also provide signal reflection / refraction at times.
>>> Tropospheric ducting might occasionally allow propagation, but it is
>>> more common at VHF and above.
>>>
>>> Note that refraction produced by meteor trail ionization will normally
>>> last longer on HF than on VHF.
>>>
>>> Sam Barricklow
>>>
>>> On Mar 2, 2012, at 11:54 AM, Thomas Ashcraft wrote:
>>>
>>>> I am not aware of any HF radio ( high frequency or decametric  ) direct
>>>> emission monitoring of meteors or papers on the subject.
>>>
>>>
>>>
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>>
>>
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