I've been experimenting with a different antenna setup. It's a combination of a loop and vertical. In this case it's a large ferrite loop antenna and a balanced vertical wound on a length of PVC pipe. The two antennas are combined in a unit with two potentiometers and a 0 or 180 degree switch. There are two bifilar wound 1:1 transformers and a trifilar wound 1:1:1 transformer used as the combiner. All on ferrite toroids. No phasing components.
The loop and vertical are mounted within a few feet of each other. The vertical is fixed position while the loop is rotatable on a camera tripod. It really is a simple arrangement. To use it, the pot for the vertical is turned all the way down and the loop pot all the way up. The loop is rotated to make the best null of the undesired station. Then the vertical pot is turned up to lower the null. If the signal raises, then the 0/180 switch is flipped. Most times the vertical is less than 100%, though occasionally the loop is turned lower. This has made very deep nulls on stations that have been very hard to null in the past. For example, even using a good quality commercial phaser, it's been hard to null the local 550 station. This can knock it down to essentially inaudible. The nulls are fairly broadband as there is no tuned circuitry in it. All broadband. These are indoors and within a few feet of a computer, so it's somewhat noisy. The antennas can be configured to minimize the noise. Only a single DX Engineering preamp is used between the combiner and receiver. It brings the signal up to very good level. I'll be doing some further work with this. It has some potential. Craig Healy Providence, RI _______________________________________________ IRCA mailing list [email protected] http://montreal.kotalampi.com/mailman/listinfo/irca Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers For more information: http://www.ircaonline.org To Post a message: [email protected]
