LF: RE: questions about a tx square loop fpr 470KHz

[Rik Strobbe <Rik.Strobbe@fys.kuleuven.be>]

Hi Mauro,

 

with this dimensions the antenna impedance will be mainly determined by the loss resistance.

For a loop circumference of 20m and a 2 turn loop the copper resistance will be about 0.13 Ohm.

Putting 20 W into 0.13 Ohm will cause a current of 12.5A, no problem for a 6mm^2 wire.

But the location of the loop seems far from perfect, very close to a wall and even some metal objects inside the loop perimeter. This will increase the loss resistance significantly beyond the 0.13 Ohm copper loss.

 

73, Rik  ON7YD - OR7T

 

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Van: owner-rsgb_lf_group@blacksheep.org [owner-rsgb_lf_group@blacksheep.org] namens IK1WVQ Mauro [ik1wvq@stmb.it]
Verzonden: donderdag 30 april 2015 23:16
Aan: rsgb_lf_group@blacksheep.org; rsgb_lf_group@blacksheep.org
Onderwerp: LF: questions about a tx square loop fpr 470KHz

73 to all,

I would like to know your opinion about this:

I can made a square TX loop for 470KHz of 7 * 3 meters (see picture) in the terrace of the building where I live (6 floors).

the questions are:

- it is enough a 6mmq copper electric wire ??  (20W is the output power of my tx).
- single turn or two turns spaced 10cm max ?? (two turns =  less pF required to take the resonance).
- Is this a good idea to start to trasmit on 470KHz WSPR ??

thanks in advance for your attention.

73 de Mauro IK1WVQ

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