Yes, I've done this before with the Radio Plus Quantum Phaser and my current Wellbrook phased array. Some of my MW DX friends have done extensive work in this area by modifying the MFJ phaser, or building Misek-based units such as the phasers Dallas Lankford designs. Mark Connelly in particular is leading the pack with phasing approaches. His Web site is a wealth of information: http://www.qsl.net/wa1ion/
Part of the difficulty in phasing semi-locals from my usual DXpedition locations at the WA coast is the combination of groundwave and skywave during the prime sunrise/sunset DX windows. Arrival angles of the foreign DX varies a lot at sunrise, too, and makes it very tough to impossible to achieve a steady null. Guy KE7MAV -----Original Message----- From: Jim Dunstan [mailto:[EMAIL PROTECTED] Sent: Wednesday, July 11, 2007 9:47 AM To: [EMAIL PROTECTED]; flexradio@flex-radio.biz Subject: Re: [Flexradio] Manual notch filter? <SNIP> Hi, Have you tried RF phasing to reduce local MF interference? For example you would be receiving A3Z on your phased array or Beverage and you can be receiving KOMO on a small loop antenna. Combine the signals and adjust the loop so its phase cancels KOMO on your DX antenna. You could also use a small whip for KOMO and use a separate combiner/phase shift circuit to do the same thing. MFJ used to market such a device ... designed for HF ... however I have heard of dxers modifying it for MF. Personally I have used this kind of 'RF phasing' for qrm rejection with my interest in Crystal Radio DXing. It takes a little getting used to but it works. I bring the antenna into the shack into a kind of 2 stage antenna tuner (2 high Q circuits in series) carefully adjust both circuits to maximize the DX and minimize the QRM. In my experience it is easier to deal with the interference of weak signals before detection. Jim VE3CI _______________________________________________ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Knowledge Base: http://kb.flex-radio.com/ FlexRadio Homepage: http://www.flex-radio.com/
