Re: [Elecraft] 125' EFHWA (was: long wire balan)
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: Elecraft@mailman.qth.net 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
RE: [Elecraft] 125' EFHWA (was: long wire balan)
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: Elecraft@mailman.qth.net 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
RE: [Elecraft] 125' EFHWA (was: long wire balan)
Absolutely, for QRP levels! With the high impedances come very high RF voltages - voltages in the hundreds, even thousands of volts. That's why compact ATU's like the Elecraft ATU's can't handle those impedances - even if they could affect a match the voltages would destroy the caps, relays and other components at any power above a few watts. There's a reason why the antenna tuners shown in the old textbooks have huge capacitors and big coils wound on ceramic forms or air-wound and everything mounted on big ceramic stand-off insulators! That's what is needed when running more than a couple of watts into a really high-impedance load. Even at 50 watts I've seen a transmitting variable capacitor with 1/4-inch (6mm) plate spacing arc over when coupling to a really high-impedance load. Ron AC7AC -Original Message- Or. an intermediate simple ATU such as http://www.qrpproject.de/UK/fuchs_ant_.htm This should work? 73, Deni F5VJC GM3SKN ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
Re: [Elecraft] 125' EFHWA (was: long wire balan)
Well, it *is* an ETLA (extended three-letter acrynym), which is something I had to deal with a lot at Intel -- they love TLAs and ETLAs like only aerospace folks would understand. oo72 de Trent - N7GMT - Original Message - From: Dean Mertz [EMAIL PROTECTED] To: Elecraft@mailman.qth.net Sent: Tuesday, August 03, 2004 15:58 Subject: RE: [Elecraft] 125' EFHWA (was: long wire balan) At least it's not another TLA (Three-letter Acronym) :-) I work in aerospace, a field rife with with TLA's. 73, Dean K0MKT K2 #4359 (finishing alignments tonite, then on-the-air!) -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Trev - K6ESE Sent: Tuesday, August 03, 2004 2:49 PM To: Jim Brown; Elecraft List Subject: Re: [Elecraft] 125' EFHWA (was: long wire balan) These abbreviations drive me nuts! Me too sometimes ;-) EFHWA - End Fed Half Wave Antenna - Some examples found on the web: ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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: Elecraft@mailman.qth.net 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
RE: [Elecraft] 125' EFHWA (was: long wire balan)
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: Elecraft@mailman.qth.net 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: Elecraft@mailman.qth.net 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
Re: [Elecraft] 125' EFHWA (was: long wire balan)
On Mon, 02 Aug 2004 20:46:17 -0500, John Rader wrote: 125' EFHWA strung between. These abbreviations drive me nuts! What the hell is an EFHWA? Jim K9YC ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
Re: [Elecraft] 125' EFHWA (was: long wire balan)
Thats easy Jim, its in Slobodian and means a dipole. Or you can make up your own definition. The last three could be Horizontal Wire Antenna. You fill in the gaps yourself for E and F. Likewise the sentiments on strange abreviations. Bob, G3VVT ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
Re: [Elecraft] 125' EFHWA (was: long wire balan)
These abbreviations drive me nuts! Me too sometimes ;-) EFHWA - End Fed Half Wave Antenna - Some examples found on the web: http://www.qsl.net/aa5tb/efha.html http://www.qsl.net/aa5tb/halfwave.html http://www.g3ycc.karoo.net/endfed2.html http://www.qsl.net/aa5tb/coupler.html http://www.g3ycc.karoo.net/endfed.htm This is my choice for portable work where I have 1 support...performs quite well... 73's Trev - K6ESE http://www.qsl.net/k6ese dit dididit dit dit dit ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
Re: [Elecraft] 125' EFHWA (was: long wire balan)
A commercial version, very nicely made, in my opinion, is made by Par Electronics and sold by Universal Radio. It's got a sealed coupling network with a SO239 and the actual antenna wire is replaceable. 73, doug From: Trev - K6ESE [EMAIL PROTECTED] Date: Tue, 3 Aug 2004 13:49:28 -0700 These abbreviations drive me nuts! Me too sometimes ;-) EFHWA - End Fed Half Wave Antenna - Some examples found on the web: http://www.qsl.net/aa5tb/efha.html http://www.qsl.net/aa5tb/halfwave.html http://www.g3ycc.karoo.net/endfed2.html http://www.qsl.net/aa5tb/coupler.html http://www.g3ycc.karoo.net/endfed.htm This is my choice for portable work where I have 1 support...performs quite well... 73's Trev - K6ESE http://www.qsl.net/k6ese dit dididit dit dit dit ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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: Elecraft@mailman.qth.net 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
RE: [Elecraft] 125' EFHWA (was: long wire balan)
At least it's not another TLA (Three-letter Acronym) :-) I work in aerospace, a field rife with with TLA's. 73, Dean K0MKT K2 #4359 (finishing alignments tonite, then on-the-air!) -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Trev - K6ESE Sent: Tuesday, August 03, 2004 2:49 PM To: Jim Brown; Elecraft List Subject: Re: [Elecraft] 125' EFHWA (was: long wire balan) These abbreviations drive me nuts! Me too sometimes ;-) EFHWA - End Fed Half Wave Antenna - Some examples found on the web: ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
Re: [Elecraft] 125' EFHWA (was: long wire balan)
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. Unless you have alot of real estate and money. And can put up Rhombics and huge beams up 50 ft or more. I guess since the G5RV works on all bands except 160m unless you have a good ground or double the length mine must be a mistake. So many different antenna's for a small lot. Jay KC9EUH FP 750 FISTS 5344 Jim Brown [EMAIL PROTECTED] wrote: Perfect lot for a G5RV. But a mediocre antenna. Assuming 80, 40, 30, 20, 15, and 10 are your most important bands, I suggest an 80/40 trap dipole using loading coil traps made by Barry at HyPower Antenna Co (or buy the entire dipole pre-made). Add a DX Engineering balun, and it will work very well on 80, 40, and 30. I've got two of his antennas up now, and just bought three more sets of 160 m loading coil traps for my vacation QTH. Add a parallel wire 20 meter element and you've got that band covered. Spacers can be easily built using UV-resistant 1/2 PVC conduit. Barry also sells an antenna like that pre-made. For the higher bands, build a parallel wire dipole using the same parts -- a DX Engineering balun, #12 or #14 THHN wire from Home Depot, and the spacers. That shorter antenna will be much easier to find a home for, and doesn't need to be as high. I've become a big fan of parallel wire (fan) dipoles after having built some for my vacation QTH, Field Day, and now for the home QTH. Easy to build and no traps. That means higher efficiency and greater bandwidth. I use the traps only when I don't have the space for a full size dipole. Jim Brown K9YC ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
Re: [Elecraft] 125' EFHWA (was: long wire balan)
Perfect lot for a G5RV. My lot is about the same with tree's in the front and back. Mine is hung between a front tree and a back tree. Power lines are in the front only a few feet from the end of my G5RV No problem with it. It's up 30 ft and works great in all directions tunes all bands with the K-2 tuner. Seems to work both long and short distance. It's 102 ft long. Easy to make but mine is from antennasmore. Has survived multiple wind storms 60 MPH winds. Jay KC9EUH FP 750 FISTS 5344 John Rader [EMAIL PROTECTED] wrote: I have recieved an overwhelming amount of info on antennas that may take few days to read through. There is some work to be done on my ground system as well. A little progress was made by adding one radial, which made my TT 253 happy on 20m. The K2 and TT tuner are indicating consistent forward power 10m - 80m and low SWR. I would like to maximize the efficiency of this antenna for multi band use. I am on a 60 x 160 lot, in Dallas, with the shack located in the back corner with a large tree in the front and back that are 100' apart with the 125' EFHWA strung between. Our antenna height is restricted to 35'. Utility lines are locted in the alley along the back. I have a 17m moxon mounted to the roof of the house which is in the middle of the lot. I can change the length, grounding, or add radials along the property edge, but the height is restricted. Thanks, John K5XTX _ Express yourself instantly with MSN Messenger! Download today - it's FREE! http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/ ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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: Elecraft@mailman.qth.net 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
