Message-ID: <4C6AC14C.9010809@iup.uni-heidelberg.de>
Date: Tue, 17 Aug 2010 19:05:16 +0200
From: =?ISO-8859-1?Q?Stefan_Sch=E4fer?= <schaefer@iup.uni-heidelberg.de>
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Subject: Re: LF: Earth electrode antenna tests
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Hi Tony,

This is very fine! Probably you monitored DHO38 @ 23,4 kHz (TX in=20
nothern Germany). So it is once again confirmed that the antenna behaves=
=20
rather like a loop antenna. Additionaly the signal drop when=20
disconnecting the far electrode (opening the loop) confirms that it is=20
rather working as a H field antenna than a E field antenna. This agrees=20
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=
=20
the link ;-)

It would be very interesting if you would try to receive my signal in my=
=20
next VLF experiment with that earth antenna!!!! ;-) The E/W antenna=20
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=
=20
> up on the N/S wire.
> I have no idea what I was receiving as I was using a FRG-7700 which=20
> only displays to the nearest KHz.
> When I disconnected the far end from the earth stake the signal=20
> dropped by 18dB, the receiver is at the eastern end of the E/W wire=20
> 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 Sch=E4fer wrote:
>> Hello Tony,
>>
>> Thanks for that interesting work!
>> Could you extend the measurements to the VLF band? It would be=20
>> 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=20
>>> north/south and then I shortened my original wire also to be 52m and=
=20
>>> this one is east/west, both terminated with an earth rod.
>>> Results were not as expected however as although the two earth=20
>>> electrode antennae show most definite directivity they were the=20
>>> wrong direction.
>>>
>>> I monitored BBC R. Bristol on 1548 KHz which is about 500 Km due=20
>>> east of me and on the inverted L (tuned VSWR 1.6:1) I could just=20
>>> detect a carrier heterodyne, on the N/S earth electrode antenna it=20
>>> 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=20
>>> 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=20
>>> electrode antennae, but they seem to behave like a Beverage in that=20
>>> respect, but something that I think I will investigate further,=20
>>> maybe see if there is any difference if I terminate them with a=20
>>> resistor.
>>> I'm sure Mal is correct though that they would be useless to TX=20
>>> through but for RX they seem to have possibilities especially after=20
>>> dark as they are a lot quieter.
>>>
>>> All good fun.
>>> 73, Tony, EI8JK.
>>
>>
>>
>