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I thought it did a great job.....until I put up a rotatable 30 meter dipole about 15' above it. The difference was incredible. I don't know whether rotating the antenna reduced noise or increased the signal but it made a hell of a difference. I have never used a 40 meter rotatable dipole. My 30 rotating dipole was NOT a F12. I should point out that there is a F12 C3E on the same stack though. :)))))) Steve, N4JQQ John Petrich wrote: > > Jack, Hank and all, > > Read Hank's posting and wanted to add my 2 cents worth. My experience > on 80 and 40 meters agrees 100% with Hank's observations. Living in the > PNW, I am blessed with any number of really tall Douglas Fir antenna masts > for my antenna projects. Over the last few years, I have been conducting on > the air A vs. B comparisons of horizontal dipoles and some inverted V's in > various orientations on both bands for DX. My observations are that a > horizontal dipole does show a definite null off the end of the wire, and > that the inverted V shows relatively little but not "no" directivity. > > I have come to the same conclusion, "higher is better" for DX, and that > a high wire in the tops of a trees is more effective than a rotatable dipole > on a less high tower. A single good and high inverted V is a match for DX > compared to a rotatable dipole at typical tower heights, e.g. 60', on the > low bands. The only exception could be if the tower installation is better > sited and away from buildings or power lines. In that case, other near > field factors could come into play and tip the balance in favor of the tower > mounted rotated dipole. Some reduction in local noise pickup on reception is > possible with a rotatable dipole. Rotatable dipoles on a typical single > tower installation adds the possibility of interference with the other > antennas, especially a 15 meter yagi, and does add additional wind load and > a measurable reduction in the safety of the entire installation. > > Rotatable dipoles do have the advantage of "bragging rights" and are > impressive to look at. > > Best regards, > > John Petrich, W7FU > > ----- Original Message ----- > From: "Hank Phillips" <aa4hp@titustek.com> > To: <hafner_ko6ic@yahoo.com>; <Force12Talk@qth.com> > Sent: Sunday, October 06, 2002 9:33 AM > Subject: [Force 12 Talk] 40 Meter Dipoles and DXing > > > Jack, > > > > Just a quick observation on 40 meter DXing. I am using an inverted vee at > > about 60 feet and it doesn't display any really detectable > > directionality. For a while I had a second vee at 45 feet, oriented 90 > > degrees to the taller one, but I recut it for 30 meters after testing > > didn't reveal any benefit from the second antenna. I doubt that even at > 60 > > feet the vee has much of a low angle component to it, but it may not > > matter. If you will concentrate on the sunrise and sunset periods to > chase > > low band DX, the arriving wave angles are rather high. Running a KW into > > this antenna system snagged 200 countries on CW in just in the last two > > winter seasons alone. This may get easier as we come down off of this > > sunspot peak, and more DX gets chased down to the lower frequencies. > > > > I think before I put up a rotable dipole for 40 at a low height, > > particularly if it is something like a shorty forty, I would use a full > > sized wire antenna. Depending on your local tree type and count, you > might > > be able to get it up a bit higher than something with a rotator under it. > > > > No matter what you decide, have fun with it. > > > > Very 73, > > > > Hank > > AA4HP > > > > > > > > > > -------------------------------------------- > > 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 -------------------------------------------- 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 |
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