>A tuned loop on a Battleship could be tricky with all
the metal about.
Agreed.
OTOH I know from a retired Marconi antenna engineer that tuned loops
(first shielded
later unshielded) in general have been used by the marine for
DF.
From experience I also know that a Wellbrook *untuned* broadband
receiving loop like the ALA1530
(diameter 1m) has a hard time when it is compared to a tuned dipole of only
2x15m on 160m
or 80m.
On 500kHz according to CCIR curves external noise is around 13dB
stronger than on 1,6Mhz,
i.e. about 63dB *at extremely quiet locations*, on 137kHz it's somewhere
between 75dB and 80dB.
So a receiving antenna could 'afford' an efficiency of say 70dB less than a
fullsize dipole/monopole
without degrading the SNR on a decent MW/LW receiver having a
reasonable noise figure.
Therefore it's obvious that a well made *tuned loop* with
reasonable dimensions would compare
favourably against any fullsize or near fullsize antenna (not talking of
arrays).
Don't forget that the Wellbrook loop version you've tested against your
wire antennas was a broadband
untuned design *and* not optimized for MW/LF.
73
Clemens
DL4RAJ
