I agree your findings may be true. Really depends on what you want the antenna's to do. On 20 meters I would have to say that you would have to have a very good dipole to match the G5RV since that is what a G5RV really is. I don't notice any directivity at all with my G5RV on 40 and 80 or 30 meters. I did with a dipole. Also at about the same height with the long wire I didn't think my home state had any hams. Now they do. May have something to do with the surroundings but doesn't seem to have directivity on any of the bands. The long wire I had 100 ft of wire and single wire counterpoise. Tried grasswire and varying heights. Checked against the G5RV at 10' and then 31'. The Dipole I didn't like and stayed with long wire was a Barker and Williamson. The last place I lived I couldn't have an antenna. I made a loop around my carport it worked pretty good. But can't compare it to anything. I was just posting a suggestion for someone in the same circumstances I have. Except on 20 meters full size monoband dipoles may be best but I know my neighbors and Wife wouldn't like all that wire in such a small place. I talk to the same people every week and can switch back and forth between antenna's or could I have since taken the long wire down. And no I don't sell antenna's as one person seemed to think. May have something to do with where I live also. Possible the radiation pattern of my antenna is good for 470' above sea level. Who really knows it's all theory and each situation is different. What works at one place may not work at yours. After all unless you live out in an open field and get your antenna above 50 ft will it really perform as the software says?
Ron D'Eau Claire <[EMAIL PROTECTED]> wrote: A simple ground stake or single wire counterpoise can be expected to produce antenna efficiencies of over 90% when used with an end fed *half wave* wire. The ground resistance is in series with the radiation resistance. A half wave shows several thousands of ohms at the end while even a crummy ground rod usually will show a few hundred ohms. So almost all the RF is dissipated in the radiation resistance of the antenna and only a small percentage is dissipated in the ground connection resistance. Where that scenario breaks down is when the antenna is shorter. At 1/4 wavelength it has a radiation resistance of about 35 ohms. Now more than 90% of the RF is lost in a 300+ ohm ground connection and less than 10% is radiated. At lengths less than 1/4 wavelength the situation worsens. It's not uncommon for a short whip and single wire ground counterpoise to have an efficiency of only 1 or 2 percent. The problem with 1/2 wave wires is that most antenna tuners, including the various tuners offered by Elecraft, can't match to them. The high impedance that makes them efficient is too high for the ATU to handle. So when using most ATU's a compromise length is needed that is as close to 1/2 wavelength, or a multiple of 1/2 wavelength, but still within range of the ATU. The efficiency will still be good. Ron AC7AC -----Original Message----- ) In a message dated 8/3/04 8:25:23 PM Eastern Daylight Time, [EMAIL PROTECTED] writes: > Mediocre? I'll match it against any trap dipole. If I didn't have > the > G5RV I would suggest a windom. Had a trap dipole once and long wire beat it G5 > RV beat the long wire. I have read varying reports on the G5RV some call it > compromise others love it. I would say it's the best antenna I have had. My results have been that a *good* trap dipole beats a G5RV - but not by much. Both beat an equivalent long wire *unless* the long wire has a good ground system (as in more than a few radials and a ground stake). YMMV The keys to trap dipoles are the trap construction and overall adjustment. Lossy, low Q traps will give mediocre results. Good high Q traps will do much better - typically less than 1 dB down from a full size dipole. 73 de Jim, N2EY _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
