by Gene DellaSala » 22 Jan 2007, 15:54
The answer to your antenna question depends on several factors. A Wellbrook 1530 loop is a good solution where there isn't space or suitable supports for a 50 to 100 foot wire antenna and there will be no need to transmit, because it can't be used for transmitting. A 50 to 100 foot wire 30 or more feet above ground generally will out-perform a Wellbrook loop, and if suitable supports such as trees, buildings, etc. already exist, is considerably less expensive.
Wellbrook loops do have one advantage in addition to their small size in that they have two sharp directional nulls and they sometimes can be rotated to reduce pickup from a local noise source (or two local noise sources if they happen to be in opposite directions). Of course, that sharp directivity can be a disadvantage where someone wants to be able to receive signals from those two directions.
Wellbrook loops use an untuned, broadband amplifier to increase the strengths of received signals. That amplifier can be over-driven by strong signals on any frequency throughout the frequency range of the loops. The result is cross-modulation splatter and reduced sensitivity throughout most of the receivable spectrum. Because of that, they are not a good alternative where high-power transmitters such broadcast transmitters or ham radio transmitters are not more than several miles away.
Another issue may be shipping cost. They are manufactured in the U.K. Wellbrook may have a U.S. distributor now, but a few years ago when I considered buying one they had to be shipped from the U.K. and there was significant shipping cost in addition to the purchase price.
Gene