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Re: [HCDX] [dxld] 125ms echoes
Wolfy, So what is the cause of this? You don`t mention long-path/short path.
Let us take 10 megameters as the rough distance between Europe and East Asia, i.e. one quarter around the world. Therefore a long-path signal will travel 30 megameters, three times as far, and 30 minus 10 = 20 megameters difference. The speed of radio is 300 megameters per second, so 20/300 = 0.067 second, roughly half the delay reported.
In the same way, an LP signal of negligible short-path distance would travel 40 Mm further, which would take .133 second. This is close, and the SP/LP echoes I sometimes hear from WEWN or WWCR which are only 1 Mm away from me, and thus travel 38 Mm further, would be 0.127 second delayed.
Are you saying ISS and BIB also had these echoes, as included in your list? Surely the delay affecting ISS and BIB signals would be quite different in the same way compared to the echoes on E Asian signals, so if they are all 125 ms, there must be some other explanation.
Single-hop satellite feed delays are quite a different matter, and of course would not affect a single frequency.
73, Glenn Hauser
--- On Fri, 2/19/10, Wolfgang Bueschel <BueschelW@xxxxxx> wrote:
> This morning monitored typical
> springtime echoes again - of 125 ms delay
> visible on Perseus screen - usually reported by Nils DK8OK
> in Austrian
> newsgroup.
>
> 0945 to 1015 UT report, echoes from East Asia. Kunming
> South China /
> Udorntani Thailand and Singapore too.
>
> 17560XIA 17670KUN 17690JIN 17875ISS
>
> 15130BIB 15135KUN 15190URU 15210KUN
> 15300ISS 15340SNG
> 15440KUN 15500BEI 15515UDO
>
> 13590BEI 13650Jammer 13765UDO
>
> wb - stuttgart germany
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