Hi John and Stefan,
I know that the electrodes can be improved, the ones I used are 1 m
long galvanized rods, driven 2/3 or so in the ground. But at this
stage, I wanted to keep all but one parameters the same, so I can get
an idea how each parameter affects performance. The other reason for
the short galvanized rods is that they come out of the ground very
easily :-)
Once I have a good idea on what's happening, I will probably commit to
a permanent installation. I still have a few aces up my sleeve, for
example, there is a dam in my block which is full of water (I
calculate about 1 megalitre) and of course there will be plenty of
water in the soil so, sticking an electrode or two in the dam, will
probably work much better. I also want to purchase some copper plated
rods, like the ones used for house electrical ground. They are longer
and will probably provide a better path to the ground.
There is a lot of work that needs to be done, stay tuned!
73, Dimitris VK1SV
2011/10/16 Stefan Schäfer <[email protected]>:
> Hi John,
>
> Yes, the more the better.
> If it is just one rod and the overall losses would be 450 Ohm, i expect a
> high ground conductivity which would be worse for an earth antenna... Maybe
> the elevated wire in the forest is the best (and long lasting) antenna
> system for /p. Then it must be a closed loop (and Scott and others use) or a
> looong earth antenna or just a full size dipole, lossy but full size :-)
> Some dry old and tall trees would be excellent, even as an insulator ;-)
>
> 73, Stefan
>
> Am 15.10.2011 18:43, schrieb John Rabson:
>>
>> On 15 Oct 2011, at 14:14CEST, Stefan Schäfer wrote:
>>
>>
>>>
>>> Hello Dimitris,
>>>
>>> I think the 450 Ohm you get is mostly caused by the earth electrode
>>> resistance. So if you spend e.g. 2 instead of one earth rod, maybe you can
>>> get a 3 dB improvement?
>>>
>>
>> The more the better up to 6 or 7 rods.
>> > From cave radio tests we find that the earth rods need to be spaced by 2
>> > or more times their depth.
>>
>> John F5VLF
>>
>>
>>
>>
>
>
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