In early December 2022, I replaced my 110 m perimeter horizontal loop with
two antennas. This 54 m longwire (shown in yellow) was one of them.
An inverted V doublet (shown in red and white) was the other.
This unbalanced antenna is 54 m in length, and about 7 m high. It is matched
to 50 ohms using a home made Pi network matching unit.
Initial results (when tuned against a poor RF ground) indicate that the
longwire is one to two S points down relative to the doublet on 80m. On 160,
there appears to be no significant difference between the performance of the
longwire and the doublet. On both 160 and 80, the received local noise (SMPS
noise, etc.) is significantly stronger on the longwire relative to the
doublet. On 40m, the longwire is often significantly better than the doublet
when working UK and other European stations.