simplest antenna
Posted: Sat Aug 19, 2023 3:33 pm
do you have some length of old coax sitting in a corner ? Do you need a "cheap and dirty" antenna to use at whatever location ... even to transmit ?
Well, read on
Pick your coax, be it RG58, RG59, RG6 or whatever. as long as you know its characteristic impedance, say 50.or 75 Ohm, now .. pick a coax plug, say an SO-239 one, solder the braid to the center pin and the center conductor to the ground connection (not kidding !) then, at the other end of the coax, shunt braid and center using a resistor (or some parallel/series ones) having the same value as the coax impedance (say 50 or 75 OHm), if you are going to use the antenna to transmit, ensure that the resistor,(s) will dissipate at least 70% of the TX power (so 70W for a 100W TX) and that the coax length is at least 10m (33ft)
Hang that coax as you like (vertical, horizontal, sloper, inverted V, ...) and as bigh as possible, cinnect it to your rig and start operating on whatever frequency you want
Sure, it isn't a super antenna, but try it the next time you'll look at that coil of old, lossy coax you have around
Well, read on
Pick your coax, be it RG58, RG59, RG6 or whatever. as long as you know its characteristic impedance, say 50.or 75 Ohm, now .. pick a coax plug, say an SO-239 one, solder the braid to the center pin and the center conductor to the ground connection (not kidding !) then, at the other end of the coax, shunt braid and center using a resistor (or some parallel/series ones) having the same value as the coax impedance (say 50 or 75 OHm), if you are going to use the antenna to transmit, ensure that the resistor,(s) will dissipate at least 70% of the TX power (so 70W for a 100W TX) and that the coax length is at least 10m (33ft)
Hang that coax as you like (vertical, horizontal, sloper, inverted V, ...) and as bigh as possible, cinnect it to your rig and start operating on whatever frequency you want
Sure, it isn't a super antenna, but try it the next time you'll look at that coil of old, lossy coax you have around