Recent content by tj50

Ok, thanks again tech99

Thanks tech99, that should help me check my recent dipole antenna work.

Great, that's cleared things up, thanks jtbell.

@ sophiecentaur & tech99: Thanks both, that was very helpful & informative.

How can the electric field decreases of an em wave in free space be calculated? For example calculating what e new electric field 5m from a transmitter or the initial electric field is?

Thanks tech99, at 100Hz the skin depth for aluminium is around 8.2mm. Does this tell us that at approx. 8.2mm the E.field will drop by 1/e, and then after a further 8.2mm the field once again drops by 1/e and so on?

So with a high enough voltage you can get EM waves through every metal at any frequency so what use is a skin depth no.?

If I use 10mm (thickness) of a metal for the sides of a Faraday cage, with a 5mm skin depth at the frequency to be shielded, & increase the v/m of the EM wave to be blocked gradually, will there be a stage where the skin depth will increase to 6mm, or is 5mm the maximum limit?

Ok, thanks jtbell

Further to the messages above: To berkeman, Yes, if by terminal drive voltage you mean the modulated AC current running from the transmitter to the antenna via the primary element. To sophiecentaur & berkeman, Its a hypothetical question at the moment concerning all frequencies. After some...

To sophiecentaur, yes I'll look to Google the above to help answer this problem. To berkeman, I'll need a little research time so apologies if there's no quick reply to your questions, & thanks for the EZNEC link, I'll also look into the antenna design program you've suggested. Thanks both for...

Given the following: A directional radio wave transmitting antenna which creates a beam (diameter in mm), a current in volts, and a frequency (Hz), is it possible to calculate the em wave voltage (v/m or w/m2) immediately next to the antenna? and then at a distance of 10meters? What...