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Design for DX' by Paul Rockwell W3AFM). I have them on ARRL CD-ROM and refer to them now and then. (I also have the original QST's :) There is a lot of good info there but the series would serve as a good model for a review and update or a new series. There seems to be more info available for contest stations than for DX-chasers and the ground rules for station design are rather different. 73 Joe K4AW -----Original Message----- From: bjk@ihug.co.nz [mailto:bjk@ihug.co.nz] Sent: Sunday, October 13, 2002 11:51 PM To: Force12Talk@qth.com Subject: [Force 12 Talk] PS Was Force 12 Verticals Value engineering can be a useful approach to decisions about developing an hf amateur radio station. The classic reference is ?Rockwell "Station Design for DX. ca 1960. ARRL should stir itself and commission and up to date version. Another source I found useful was a series on HF DX by the RSGB around 1995 where they surveyed leading UK DX operators. Rockwell took the approach of looking at DX dB per dollar. In the matter of antennas for 14-30 mHz the finding was that around 40-45 feet gave the best cost vs benefit. Below this radiation angles are too high, above this costs escalate. Antenna mdelling programs will show the truth of this. The UK top ops had 40ft with a trap tribander as the most common set up. If using a light compact beam (such as the F12 C family) then inexpensive pipe masts can get up 40-45 feet, cheap. In the old Ham Radio magazine K6? did field studies comparing quads and yagis 14- 30mHz against a reference two element trap dipole at the same site at the samer site. Gain figures for the trap dipoles across any band were a bit sad, indeed the two element job compared very favourably with the big ones. Of course the tribanders gave directivity on receive and so improved overall station capability, but did not compare well with a dipole on most frequencies. The F12 propaganda is true, folks! Given a C family antenna at 40-45 feet and a reasonable transceiver and amp at the bottom one really has an effective radio station by any standard, where operator nous and skill will give more advantages than a heap more money spent on hardware, assuming a reasonable location. Do not be hypnotised by the super stations. Add a F12 rotary dipole to the above and fire up the mast against ground radials for 80 and one has a seriously effective station, able to work almost anything it can hear even in the presence of competition. (A dedicated receive antenna for 80 can be a good secret weapon). 73 Barry ZL1DD -------------------------------------------- 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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