| Index | Thread | Archive | Apr-2003 | Archive | Send |
 |
  |
 |
   |
|
  |
|
In reality, the feedlines will significantly queer the results unless there is a LOT of common mode suppression in place at the feedpoints of BOTH antennas. 30 db cross polarization separation is possible, but unattainable unless alignment is maintained, and NOT defeated by common mode feedline near the antennas or RF ground loops problems in the shack. If that separation is achieved, the null depth will fluctuate in the wind as flexing moves the cross orientation away from 90 degrees. In practice both geographical separation AND cross orientation achieve better results with less complexity, to the point that overall separation becomes entirely controlled by factors in the shack. 73, Guy. > > From: "Barry Kirkwood" <bjk@ihug.co.nz> > Date: 2003/04/07 Mon PM 11:31:02 EDT > To: "Jim Smith" <jimsmith@shaw.ca>, <force12talk@qth.com> > Subject: Re: [Force 12 Talk] R5 mounted above C4SXL - good idea or bad? > > Makes sense to me Jim. > Would not expect much interaction from a vertical element above the beam. > An approximation would be to model using 1/4 wave vertical monopoles above > the beam on each band. > 73 > Barry > > end > Barry Kirkwood PhD ZL1DD > Signal Hill Homestay > 66 Cory Road > Palm Beach > Waiheke Island 1240 > NEW ZEALAND > ph/fax 64-9-372-5161 > www.waiheke.co.nz/signal.htm > ----- Original Message ----- > From: "Jim Smith" <jimsmith@shaw.ca> > To: <force12talk@qth.com> > Sent: Tuesday, April 08, 2003 12:35 PM > Subject: Re: [Force 12 Talk] R5 mounted above C4SXL - good idea or bad? > > > > Hi, and thanks for the responses. > > > > I guess I wasn't very clear as to why I want the vertical. > > > > 1. When not at the rig I want to run BeaconSee for hours at a time, > > plotting the strength of the various NCDXF beacons around the world on > > the computer monitor and saving periodically for analysis. Can't do > > this with a beam. Need omni-directionality. > > > > 2. While DXing, would like to be able to monitor one DX station on a > > separate receiver (has he got to the sevens yet?) while chasing other > ones. > > > > 3. The Biggie. While contesting I want to be able to hunt for mults on > > the 2nd receiver (my old 75A4) while CQing on the MkV. I expect this > > capability would enable me to increase my scores by a good 20%. (I'm > > hoping for another 20% from the C4.) > > > > 4. When someone weak calls me off the side of the beam he'll probably > > be a lot louder on the vertical. Work him on the vert and don't waste > > time swinging the beam. > > > > So, you see, I really, really, really do want to have a vertical > > available. I did once have a mobile whip mounted as described over my > > present TH3 tribander. It was perfectly possible to listen to sigs on > > one band while transmitting on another. It would still be there but it > > didn't work worth a damn as a vertical. > > > > So, any advice as to things to watch out for or shareable models > available? > > > > 73 de Jim Smith VE7FO > > > > > > > > -------------------------------------------- > > Force12Talk mailing list provided as a service by Force 12 Antennas, Inc. > > Force12 Web Site: http://www.force12inc.com > > > > To Submit Message to the List: Force12Talk@qth.com > > To unsubscribe and view the Message Archive: see > http://qth.com/force12/list > > For problems with the list: contact n4zr@qth.com > > > > > > > > > > > -------------------------------------------- > Force12Talk mailing list provided as a service by Force 12 Antennas, Inc. > Force12 Web Site: http://www.force12inc.com > > To Submit Message to the List: Force12Talk@qth.com > To unsubscribe and view the Message Archive: see http://qth.com/force12/list > For problems with the list: contact n4zr@qth.com > > 73, Guy K2AV -------------------------------------------- Force12Talk mailing list provided as a service by Force 12 Antennas, Inc. Force12 Web Site: http://www.force12inc.com To Submit Message to the List: Force12Talk@qth.com To unsubscribe and view the Message Archive: see http://qth.com/force12/list For problems with the list: contact n4zr@qth.com |