Hi Stefan,
A photo of the coil can be seen here:
http://people.physics.anu.edu.au/~dxt103/500/
The operating position is inside a little metal garden shed. I have a
wooden bench and it sits on that. There is maybe 0.5 m of space or
more between the inductor and the shed walls.
Ground losses are estimated to be a bit less than 20 ohm. This varies
a bit with the WX, currently after a bit of rain think it is probably
around 17 or 18 ohm. There is clay under the soil, which I think is
good news when it comes to conductivity :-)
Going from 27 ohm to say (Q=1000) about 20 ohm antenna impedance,
would result in a small but very welcome antenna current increase...
73, Dimitris
2013/2/15 Stefan Schäfer <[email protected]>:
> Hi Dimitris,
>
> Do you have a photo showing the coil in its position?
>
> What are the ground losses, about? R coil = 9 Ohm with that Q and XL....
> Litz wire helps of course, if you have enough...
>
> 73, Stefan/DK7FC
>
>
> Am 15.02.2013 01:31, schrieb Dimitrios Tsifakis:
>
>> Hello group,
>>
>> I would like to increase the Q of my loading coil for 475 kHz. . It
>> consists currently of a 20-litre plastic bucket with standard house
>> 240V electrical wire (with PVC jacket). I measured the Q and found it
>> to be about 220 (XL is about 2 kohm). I do have some Litz wire I can
>> use. I also have a piece of large diameter (25 cm) storm water pipe,
>> which I think is made of PVC. Would you recommend using a PVC former
>> or should I look for a more exotic material (glass/porcelain)? Would
>> you think the inter-turn capacitance is very detrimental and some
>> exotic winding technique would yield better results?
>>
>> I understand that ground losses are bigger in my case than the
>> inductor losses, but I would like to address the inductor first.
>>
>> 73, Dimitris VK1SV
>>
>
>
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