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On Jul 14, 3:10 am, derek wrote:
On Jul 14, 8:16 am, Art Unwin wrote Hi Art The details for the variometer would be of help if you could oblige thank you. Derek If he hasn't got a variometer he can use his tuner as a substitute. The SWR meter he is using is referenced to 50 ohms so his readings are false. When using twisted wire the impedance will go very much higher than untwisted wire at least one hundred times . The impedance of his antenna is probably around the 300 ohm mark so he should add a 6 or 9 to one transformer. As a furthur adjustment he can put the up and down wires in parallell such that the 1100 feet of wire which is two wavelengths of the top band when wound in series is now 1 wavelength and the impedance will change accoringly. So there are options available which the ham can chose as well as changing connections from series to parallel as well as the diferent places he can add his tuner in the circuit. If he stands the wire tube antenna upright say as a lamp shade so it appears unobstrusive the radiation will be omni radial or partialy direcftional if he tilts it and if it is low power DX that is his hobby then the lower lobe is at least half of that of a yagi which in his circumstances it should be ideal.Since the wire is close wound I am not sure of the power limitations but with it being Hi Temp magnet wire with circuitry of a wavelength I really don't see a guy in a nursing home having a problem One thing I am not sure of is the nearnes of the point radiation antenna with respect to personal health so he may well want to place it outside say as a frost protector for a rose bush or the like Regards Art |
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