Despite any impending discussion whether or not there is any interference from each other
another approach to using two antennas feeding one receiver is to make use of one single length of
1/4wave(or odd multiple of) series transformer right after the T-Connector to the receiver.
Thus you can use your favorite Coax as avbl or used before.
Using two equal lengths of 50 Ohm Coax from each antenna to the T-Position,
then followed by said 75 Ohm length. Since 1/4th is difficult to determine with connectors so close use a practicable length of odd multiples and then connect to your rundown length of 50 Ohm again.
1 using 50 Ohm in the first place is to keep mismatch between antenna and cable small,
Cable nominal 50 Ohm - Antenna nominal 50 Ohm (who really knows ?) are matching.
2 since both feeders are T-connected thus in parallel the resulting output will have 25 Ohm
Impedance and this has to be raised with a.m. length of 75 Ohm cable.
Its output will have an odd result of 43.3 Ohm, which is close enough to the nominal 50 Ohm Line.
Whatever 75 Ohm coax you get your hand on, carefully check its Velocityfactor and apply
to your calculated choosen transformer length.Slight Mismatch here 50 : 43.3 less than 1.2,
which may be neglected for receiving purposes.
One word of warning though, those who are inclined to use this method for their Discones or LPDAs
the description 1/4wave series transformation points out this method is frequency dependent
and ideal for a defined single freq only.
Klaus
