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From: John Rabson <john.rabson@numeo.fr>
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Date: Tue, 8 Feb 2011 09:41:48 +0100
Message-Id: <74525E07-772E-4308-AE0B-7188983FD13B@numeo.fr>
References: <252130CB355C48E4BC32BA23475FEF68@White> <F9A791BEE5F643208B491CD3BFBC05EF@JimPC> <001101cbc71f$b57f3f00$0401a8c0@xphd97xgq27nyf>
To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: Re: Re: OE5ODL over different paths
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Mall,

I agree with you. Ideally one should have a fixed antenna for transmit. In=
 practice this is not always possible and, even when it is, one cannot alw=
ays choose the ideal site.

In many ways, amateur radio is like observational astronomy. You cannot co=
ntrol the motions of the astronomical objects you are interested in, so yo=
u just have to cope with an imperfect situation.  For example, you cannot=
 control when meteors appear in the sky, yet people have done useful work=
 on meteor scatter.

You seem to have identified three major variables in Ossi's experiments:=
 propagation effects, the antenna current and the inclination of the anten=
na.  They may or may not be connected.

Jim's graph shows a periodicity of about 1.4 cycles per hour*. Would it be=
 possible with suitable mathematical techniques (FFT, deconvolution etc)=
  to analyse his raw data with a view to separating the three effects?

Data on antenna current and inclination would also help the analysis.

73
John F5VLF
*I do not think it would be helpful to quote that in uHz

On 8 Feb 2011, at 00:35CET, mal hamilton wrote:

> Jim
> The variations in signal you observed was due to the Balloon being buffe=
ted
> about due to wind, thermal dynamics, and up drafts and not a valid
> propagation study. I was in touch with Ossi and he described to me that=
 the
> baloon was almost horizontal at times, therefore the wire antenna attach=
ed
> would vary from vertical, slant, horizontal.
> He also said that the antenna current was well down at times, so many
> variables effecting the transmitted signal. All the facts have to be
> gathered before a valid observation is made otherwise its all Guesswork=
 and
> supposition.
> To do a meaningful propagation study the transmitted signal needs to be
> launched from a FIXED antenna.
> The same criteria applies to Kite borne antennas.
> mal/g3kev