Hello Guy, You have raised an interesting question ref. using dual channel SDR for phasing. These may in future afford an alternative to some expensive commercial phasers. Also the SDR has the option of offering a fixed phase over a very wide bandwidth. This could be useful for phasing two orthogonal loops to provide omni-direction or with a loop + a resistance loaded longwire for a wideband cardioid pattern.
However, like most other phasing schemes the SDR cannot provide a null over a wide bandwidth when used say with similar antenna pairs. This can only be done with a special Phased array controller when the two endfire antennas are run in anti-phase with a delay-line. This phasing also requires a design that has zero interaction on the antenna inputs verses phasing/amplitude adjustments. One interesting phaser that may have been overlooked was designed by the Late Graham Maynard in the late 1980s. He used a variable delayline to provide a 90 degree phase shift with a fixed 180 degree phase reversal transformer switched in 4 quadrants to provide 0-360 degree phasing. The advantage of this scheme was a wider null bandwidth as it could be used for an endfire array too. 73 Andrew Ikin _______________________________________________ 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]
