Would anyone know what the feed Impedance is for the older TELREX 10 and 15M532 series of antennas? The described original ¼ wave 75 ohm balun gives the appearance of something like a 4 or 6 to 1. Also looking for a manual for a 20 metre 4 element Telrex beam that is on about a 35 foot boom. Thanks all Paul VE3SY