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Re: off toppic -- multipath doppler??



All:

Thanks to everyone who replied about the doppler / multipath question and 
special thanks to I8CVS.

Having experienced 2 meter meteor scatter, this mode seems unlikely since 
there would need to be a high number of busts per hour, even for Leonids 
conditions. The time is off for peak activity as well -- late afternoon 
local time.

We live about 15 miles from the nearest airport and I'm leaning towards 
airplane scatter. But according to a friends calculations, the 100hz doppler 
shift we're seeing on 2m would come from an object moving 3200mph!

We'll have to QSO again this evening to find out more.

Thanks to everyone; I can always rely on amsat members for answers.

73 Tony KT2Q





----- Original Message ----- 
From: "i8cvs" <domenico.i8cvs@tin.it>
To: "KT2Q" <dxdx@optonline.net>; <farmer.aj@gmail.com>; <vk3jed@gmail.com>; 
"KC6UQH" <kc6uqh@cox.net>; "Edward R. Cole" <al7eb@acsalaska.net>
Sent: Thursday, November 17, 2005 4:25 AM
Subject: Re: [amsat-bb] off toppic -- multipath doppler??


> Hi All in the list
>
> Enjoy with the article "Aircraft scatter" by WA5VJB
>
> 73" de
>
> i8CVS Domenico
>
>
> ----- Original Message -----
> From: "KT2Q" <dxdx@optonline.net>
> To: <AMSAT-BB@amsat.org>
> Sent: Thursday, November 17, 2005 4:53 AM
> Subject: [amsat-bb] off toppic -- multipath doppler??
>
>
>> All:
>>
>> Sorry about the off topic question...
>>
>> While working a local station on two meter CW (about 12 miles away), we
>> noticed what seemes like multi-path with momentary "blips" of doppler
> shift
>> (about 100hz). This happens both ways.
>>
>> To the best of my knowledge, doppler is not associated with multi-path
>> unless the reflecting objects are in motion. The only things I can think
> of
>> is meteor or airplane scatter.
>>
>> Having worked meteor scatter on 2 meters before, the signal strength and
>> number of random meteors needed to match this situation seems unlikely.
>>
>> Airplane scatter seems possible, but it happens so often duing a QSO,
> there
>> would have to be a lot of them overhead, all the time :  ).
>>
>> So, is it possible for multi-path signals on 2 meters to show doppler
>> without being caused by something in motion? I have a recording of the
>> signal if anyone would like to hear it.
>>
>> Thanks,
>>
>> 73, Tony KT2Q
>> ----
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----
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