Re: Steve ugly-build LZ1AQ using MPS2222 sweeps uploaded to Photos
|
To Dan,
When the loop length is ?close to the wavelength there are standing waves ?- in your last data? from NEC (thanks for that) the ratio Imax/Imin is? 1.4 – the max. ?current ?being at the loop side and min. current at the load. I plotted ?the current vs. segment# and I can ?see a typical ?standing wave pattern. The current variation is not very large so with fixed current source measurement setup we can expect even at these frequencies to get a glimpse of the frequency response of the antenna factor . ??
?
About loop as transmission line
Yes, I think that the loop can be considered as a ?transmission line. ?But since the loop is so short compared to the wavelength ?we cannot observe standing wave patterns ?at low frequencies when loop is shorted or opened. ?For me closed and open loop are both standing wave cases. ?By the way if we terminate one side of the small loop with? characteristic impedance of this transmission line ??we will get something? like traveling wave antenna?? - ??Flag antenna ?is a typical example. Flag becomes unidirectional when load R = Zc of this ?tr. line. ?But I will stop here – my knowledge in antenna theory is very very limited, I am just a standard NEC user.
? Chavdar lz1aq
|
