Hi Tony,
Thanks for the confirmation on directivity of the two electrodes earth
antenna.
The JA5FP's group said as follows:
(1)Same directivity exists in a short distance.
(2)Dried earth is good for transmittion. Wet ground does not work as a
good antenna. an imaginal loop may be shortened in a half.
Try the above phenomenons.
7L1RLL Rick
On Mon, 2010-08-16 at 15:35 +0100, Tony wrote:
> 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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