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
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
|
Questa e-mail è stata controllata per individuare virus con Avast antivirus.
www.avast.com
|