Message-ID: <000d01ccb42e$c25f69f0$0401a8c0@xphd97xgq27nyf>
From: "mal hamilton" <g3kevmal@talktalk.net>
To: <rsgb_lf_group@blacksheep.org>
References: <4EDD515F.6060800@iup.uni-heidelberg.de> <009801ccb3b1$a6b20690$4001a8c0@lark> <4EDD6968.1030002@iup.uni-heidelberg.de> <003601ccb411$95635320$4001a8c0@lark>
Date: Tue, 6 Dec 2011 15:50:20 -0000
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Subject: Re: LF: Re: TA 137 kHz
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Alan es Co
Grabbers are useful as a rough guide to propagation but I also have
reservations when it comes to signal measurements. ie Grababer locations and
environmental noise, Type of antenna at site. For instance I  often display
a more intense trace on the 4X1 grabber than the YO grabber at the same time
frame, although YO is much closer to me. Although for convenience small
antennas are normally used at grabbers ie Mini Probes, small Loops they do
not yield the same results as stations using large verticals, large loops
and arrays of long wires.
I have tried small antennas, including one commercial small loop and the
signals from the smaller antennas are as much as 20 dB down in strength,
therefore weak signals would not even be detected on the small antennas.
I understand the argument that in noisy environments large antennas do not
work, but in quiet locations they are excellent performers, they do pick up
some noise but the signal over noise is still away above the others.
There is no substitute for Rhombics, V - Beams, High verticals,  and inv L
antennas if you have the space, these antennas erected as high as possible
also contribute to low angle of radiation, hence better for long haul DX
even on LF both for TX es RX

de mal/g3kev


----- Original Message -----
From: "Alan Melia" <alan.melia@btinternet.com>
To: <rsgb_lf_group@blacksheep.org>
Sent: Tuesday, December 06, 2011 11:35 AM
Subject: Re: LF: Re: TA 137 kHz


> Hi Stefan yes it looks like that was the case. As to the Iceland grabber
it
> is only one hop from you I guess so it always receives a good night-time
> signal. One must remember that the display of grabbers is very non-linear
> there is only about a 3dB change in signal strength to go from T to O and
> then little obvious change until it "dog-bones", so they are not ideal for
> seeing the detail of fading on a signal which it at least O, except when
it
> drops right out. You are also seeing not a real signal strength but more a
> S/N display which depends very much on local noise conditions.
>
> Great work keep it up!
>
> Best Wishes
> Alan G3NYK
>
> ----- Original Message -----
> From: "Stefan Schäfer" <Stefan.Schaefer@iup.uni-heidelberg.de>
> To: <rsgb_lf_group@blacksheep.org>
> Sent: Tuesday, December 06, 2011 1:01 AM
> Subject: Re: LF: Re: TA 137 kHz
>
>
> Hi Alan,
>
> Yes, ther is strong QSB at W1VD. I was watching his grabber in the last
> hour but my signal was lost then. Anyway i saved the cpature i saw when
> i first saw my signal. Now the capture is here too:
> http://dl.dropbox.com/u/19882028/LF/grabupload1.jpg
> QRSS-10 is relatively fast and it would be interesting to have a beacon
> running in that speed. Will first have a look on the TX system since
> there have been strong winds here.
> I hope for better propagation soon.
> TF3HZ seems not to care about propagation ;-) His grabber always shows
> very good signals.
>
> 73, nw gn, Stefan/DK7FC
>
> Am 06.12.2011 01:54, schrieb Alan Melia:
> > Hi Stefan
> > Interesting not a lot has changed in the last couple of days though the
> Dst
> > did recover from -30nT on the 4th to about -15nT today but that should
not
> > have dramatic effects. There was a small flare C5 just before midnight
but
> > that would only affect paths in daylight. Maybe you got favourable
fading
> > conditions tonight.
> >
> > Alan
> > G3NYK
> >
> > ----- Original Message -----
> > From: "Stefan Schäfer"<Stefan.Schaefer@iup.uni-heidelberg.de>
> > To:<rsgb_lf_group@blacksheep.org>
> > Sent: Monday, December 05, 2011 11:18 PM
> > Subject: LF: TA 137 kHz
> >
> >
> >
> >> Jay, LF,
> >>
> >> Propagation seems to be back ;-)
> >> http://www.w1vd.com/grabber.html
> >>
> >> Many thanks for looking Jay. Never expected to see my signal in QRSS-10
> >> on your grabber :-)
> >>
> >> 73, Stefan/DK7FC
> >>
> >>
> >
>
>