Hi Stefan,
I's too fast to deside H field antenna rather than E field antenna.
It is a phenomena that wet ground makes weak signal rather than dry
ground with a same two electrodes earth antenna. Does the antenna work
as E field antenna like pa0rdt-Mini-Whip ?
Try more.
73 Rick
On Tue, 2010-08-17 at 19:05 +0200, Stefan Schäfer wrote:
> Hi Tony,
>
> This is very fine! Probably you monitored DHO38 @ 23,4 kHz (TX in
> nothern Germany). So it is once again confirmed that the antenna behaves
> rather like a loop antenna. Additionaly the signal drop when
> disconnecting the far electrode (opening the loop) confirms that it is
> rather working as a H field antenna than a E field antenna. This agrees
> very much with my own experiments i did some weeks ago.
> I wrote my report here and in a published pdf but currently i don't know
> the link ;-)
>
> It would be very interesting if you would try to receive my signal in my
> next VLF experiment with that earth antenna!!!! ;-) The E/W antenna
> should be best. In some weeks i will transmit again on 8970 Hz :-)
>
> Best 73, Stefan/DK7FC
>
>
> Am 17.08.2010 17:11, schrieb Tony:
> > Hi Stefan
> >
> > I tried the antennae this afternoon on 23 KHz and the E/W wire is 12dB
> > up on the N/S wire.
> > I have no idea what I was receiving as I was using a FRG-7700 which
> > only displays to the nearest KHz.
> > When I disconnected the far end from the earth stake the signal
> > dropped by 18dB, the receiver is at the eastern end of the E/W wire
> > and the northern end of the N/S wire.
> >
> > I will try sub 10 KHz when I sort out where my local QRM is coming from.
> >
> > Tony, EI8JK.
> >
> >
> > On 16/08/2010 22:16, Stefan Schäfer wrote:
> >> Hello Tony,
> >>
> >> Thanks for that interesting work!
> >> Could you extend the measurements to the VLF band? It would be
> >> interesting what the levels and directivity would be there.
> >>
> >> 73 and pse a sked for your upcoming LF stn! :-)
> >>
> >> Stefan/DK7FC
> >>
> >> Am 16.08.2010 16:35, schrieb Tony:
> >>> Yesterday I spent some time playing with different antennae.
> >>> I started by laying out another wire 52m long orientated roughly
> >>> north/south and then I shortened my original wire also to be 52m and
> >>> this one is east/west, both terminated with an earth rod.
> >>> Results were not as expected however as although the two earth
> >>> electrode antennae show most definite directivity they were the
> >>> wrong direction.
> >>>
> >>> I monitored BBC R. Bristol on 1548 KHz which is about 500 Km due
> >>> east of me and on the inverted L (tuned VSWR 1.6:1) I could just
> >>> detect a carrier heterodyne, on the N/S earth electrode antenna it
> >>> was S1 but on the E/W earth electrode antenna it was S3.
> >>> RNE5 on 531 KHz about 960 Km due south of me was S3 on the E/W and
> >>> S8 on the N/S
> >>>
> >>> HGA22 (135 KHz) to my east was S4 on the E/W and S1 on N/S
> >>>
> >>> Readings were taken about 12:00 utc so most definitely ground wave.
> >>>
> >>> I was expecting the directivity to be broadside on the earth
> >>> electrode antennae, but they seem to behave like a Beverage in that
> >>> respect, but something that I think I will investigate further,
> >>> maybe see if there is any difference if I terminate them with a
> >>> resistor.
> >>> I'm sure Mal is correct though that they would be useless to TX
> >>> through but for RX they seem to have possibilities especially after
> >>> dark as they are a lot quieter.
> >>>
> >>> All good fun.
> >>> 73, Tony, EI8JK.
> >>
> >>
> >>
> >
>
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