This is getting more and more interesting! Thank you Gary and Bill for the recent cliffside DXing results, and Nick for sleuthing out the limited technical papers on this topic.
Some years ago during an annual family vacation to Yachats, Oregon, I was parked at that exact spot of Gary's wonderful receptions, wondering if that might be a good place to DX-- if only an antenna could be devised. I was still in the mindset of large passive antennas like a Beverage or a lengthy active loop array being the only way to seriously DX. One look over the guard rail, down that steep cliff to the crashing surf below convinced not to try anything crazy like an impromptu vertical antenna! Gary's boldness to blaze the trail by DXing with an FSL between cliff and traffic dangers at this beautiful, coastal Oregon location has gotten me interested in figuring out a way to try a different way to DX from this wide spot in the road. I'm looking forward to giving it a try in early September. My goal is to be able to make broadband Perseus SDR recordings from the relative safety of a vehicle at this DX-friendly cliff QTH on Oregon's Highway 101. My wife doesn't know it, but her SUV is about to become a PRV... (Perseus Recording Vehicle :^) Guy Atkins Puyallup, WA > Date: Wed, 8 Aug 2012 01:30:47 -0400 (EDT) > From: [email protected] > To: [email protected] > Subject: Re: [IRCA] [NRC-AM] Recent DXpedition to Grayland, WA & > Florence, OR > Message-ID: <[email protected]> > Content-Type: text/plain; charset="us-ascii"; format=flowed > > Hi Nick, > > <<< But > there is an empirical gem in the second paper on page 917 concerning > cliff-side signals: "...mesurements of the magnetic-field strength > due to Rome, 845kHz, at the top of Beachy Head (a vertical cliff in > southern England 160m high), gave results 2.3dB higher than values > measured on a beach well away from the cliff. This enhanced filed > strength is believe to be a purely local effect, associated with the > sharpness of the cliff edge; 200m from the edge, the measured > increase was only 0.4dB. These figures are consistent with the > theoretical increases in the magnetic and electric fields which occur > near the apex of a rectangular wedge illuminated by a plane > wave..." Interestingly he goes on to say, similar to Bill's point > about Gary's "extreme DXing" prowess: "....severe practical > difficulties would attend the siting of an aerial so close to a cliff > edge." (hi) >>> > > > Thanks very much for that "empirical gem" from the Beachy Head study! > > It seems that by accidentally setting up on the side of the Cape > Perpetua sheer ocean side cliff with one of the small footprint FSL > antennas, I was stumbling across this theoretical 2.3dB gain boost that > the scientists had considered impractical to exploit. Some of the DU > signals observed during the Cape Perpetua DXpedition seemed to border > on science fiction, with even 765-Radio Kahungunu (2.5 kW) pegging the > PL-380's S/N reading at 25. Apparently the development of the new FSL > antenna will finally will allow DXers to tap into this ocean cliff > propagation advantage (assuming that they don't first use up all their > vacation $$$ by purchasing so many ferrite rods). > > 73, Gary DeBock (in Puyallup, WA, USA) > > > _______________________________________________ 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]
