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Date: Sun, 21 May 2000 16:28:15 +0000
From: "g3kev" <g3kev@netscapeonline.co.uk>
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To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: Puckeridge test 3
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Dick Rollema wrote:

> >From PA0SE
>
> Dave, G3YXM wrote:
>
> > Dick and all.
> >
> > Very puzzling!
> > I worked Jim straight after you and found exactly the opposite..... 4dB
> > better on the "small" antenna. We tried the test twice and I continued to
> > listen, each time it was the same.
> > Directional?
> > Which side of the big mast was the little antenna I wonder?
> >
> > 73. Dave G3YXM.
>
> Dave and All,
>
> There is a simple explanation.
> I was very busy doing the measurements, changing the receiver input from
> aerial to signal generator and back, reading levels etc.
> I therefore did not listen carefully to what Jim was sending (experienced
> telegraphists can do a job and copy CW at the same time but I am far
> removed from that category)

You certainly FOOLED us all but you are not the only one that cannot copy cw on
LF

> . So I assumed that the bigger signal came from
> the bigger aerial. Rather foolish of course and I apologize for that.
>
> So the S8 (-79dBm) signal I reported must have been from the small aerial
> and the 4dB
> weaker signal (-83dBm) from the Decca aerial.
>
> That is 30dB less than the signal from G3WSC/P operating from Puckeridge on
> April 16 at 1000 UTC.  G3WSC/P at that time reported an aerial current of
> 9A.
> In his e-mail of May 18, 15.54, Jim announced he was going to run an aerial
> current of 0.34A into the Decca aerial. That is a difference of
> 20log(9/0.34) = 28.5dB; within 1.5dB of my measured values. That confirms I
> got the two aerials mixed up.
>
> Assuming that at the distance of 317km between our locations the inverse
> distance law is still applicable my measured field strength of  8.6猩/m
> yields a radiated power by the small aerial of 83mW, close to the 80mW Jim
> was aiming at.
> For the Decca aerial  I find 33mW.
>
> Up to now (0951 UTC I have heard no signal from Jim on 73kHz.
>
> 73, Dick, PA0SE
>
> This was my earlier report:
>
> > To All from PA0SE
> >
> > At 0955 today I worked Jim, M0BMU/P at the Puckeridge station.
> > On the Decca antenna his signal was exactly S8; corresponding to a field
> > strength of 8.6 microvolt/metre.
> > On the "amateur antenna" the signal was 4dB weaker.
> >
> > I reported the signal exhibited a fast fluctuation in strength with a
> > frequency of a few hertz. But I later found out it was my signal generator
> > interfering with Jim's signal. even with the output turned down to zero.
> >It shows that even a HP606B is not perfectly screened!
> >
> > 73, Dick, PA0SE