A note on folded back antennae. I have a 3 element SteppIR with the 30/40 kit. The antenna is mounted at about 67 feet above the ground. I have compared the folded antenna at 67 feet to a full sized inverted V at 40 feet and find it noticeably stronger. Even though it is only a dipole which is a little more than half length it is noticeably bi-directive with deep nulls off the element ends. It is quite effective as a DX antenna and I believe the SteppIR claim that it is only one or two dB down from a full sized rotatable dipole. Of course, its improved performance over the inverted V is mostly because of the elevation difference, but I would not hesitate to fold the ends of a dipole if restricted by lot size or other physical restraints. Willis 'Cookie' Cooke K5EWJ & Trustee N5BPS, USS Cavalla, USS Stewart
----- Original Message ----- From: Don Wilhelm <[email protected]> To: Niel Skousen <[email protected]> Cc: Elecraft Reflector <[email protected]>; [email protected] Sent: Monday, June 18, 2012 6:18 AM Subject: Re: [Elecraft] Antenna Question Neil, When you see an antenna element folded back on itself like that, think "linear loading" (look it up in the ARRL Handbook or similar). There is no "magic", but it is one way of shortening an antenna. It is not as efficient as a full length antenna, but is more efficient than using loading coils. Everything is relative. If you have the space to put up full size half wave dipole antennas, that is the way to go. If you need shortened antennas for the lower bands, linear loading is one way to achieve resonance with shortened length. 73, Don W3FPR On 6/17/2012 11:26 PM, Niel Skousen wrote: > I'm pretty sure I've seen this antenna on the net, but don't recall the name > nor have I been able to find a link to a description / design data. > > The county ERC has a 'shortened fan dipole' with three parallel elements, > spaced about 18-24" apart on each side. the longest element folds back > around the mid-length element toward the shortest element. The antenna end > insulator / guy rope is attached to the long element, where it folds back. > There appears (from the ground) to be a 6~8" insulator / gap between the end > of the shortest element, and the longest element where its been folded back. > no traps, loading coils, or loading resistors that I can see. > > I'm assuming three or four band coverage (80, 40, 20, and 15 ??) with a 75m > dipole, a 40m dipole (with 15m as a freebie), and a 20 m dipole. but would > be interested in more technical details if anyone can decipher my text > description above… > > Thanks > Niel > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
