Actually : Two earths joined with insulated wires are not very safe in
the vicinity of a ground strike , as are insulated 'long' radials ....
with a typical rise of 250KAmps / micro-sec , 'strange' things happen to
all connected at a time round T + 100 mS +/- a bit ...
Might be worth reviewing the dc path from this aspect ?
G..
--------------------------------------------------
From: "Alan Melia" <[email protected]>
Sent: Monday, August 16, 2010 4:51 PM
To: <[email protected]>
Subject: LF: Re: Earth electrode antenna tests
Hi Tony, why do you think the directivity is wrong? It looks as though
they
are operating like loops with the majority of the loop area in the ground.
This is a fairly common appreciation of ground "aerials" though Dave
Gibson
doesnt seem to agree
:-))
Alan
G3NYK
----- Original Message -----
From: "Tony" <[email protected]>
To: <[email protected]>
Sent: Monday, August 16, 2010 3:35 PM
Subject: LF: Earth electrode antenna tests
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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