I am curious as to what happens to a symmetrical dipole center-fed with balanced feeder-line. Let's assume the dipole is arranged as a sloper - that means it's not parallel to ground (horizontal). Additionally there are several buildings, trees or other conductors or in short, the dipole might be mechanically symmetric but electrically it is unbalanced. The balanced feeder-line is made of 12cm spacers and travels along a path between two surrounding buildings (each 2m distance) until it reaches the symmetrical coupler (ATU). The setup is a crowded city so this scenario should show a bad condition.
According to theory and books there shouldn't be expected any issues related to imbalance and common-mode. But is that true in reality? Let's go further and assume our balanced feeder-line is mechanically not symmetric, for example one lead is 5 or 10cm shorter/longer than the other one. It is self-explanitory that a ham radio operator wouldn't do that intentionally. Is it earrated to use a choke as shown here? (see attachment)
http://www.wolfgang-wippermann.de/balun1zu1undefklein.pdf
This is a 21 winding Reisert balun scheme (it reverses the windingopposite for lower capacitive coupling). He says that placing this choke between a symmetrical feeder line and a coupler will prevent imbalance (common mode current) through the wires. It will not prevent imbalance occured through stray emmission. Makes sense for me but I would like to hear your comments. Will this choke placed right after the output of a symmetrical coupler prevent imbalance currents, that are caused by the example mentioned?
http://www.dg0sa.de/balunatuhl.pdf
73 Nick!