Re: [Elecraft] 80 Meter loop question
If you're not using Dan's (AC6LA) AutoEZ program as a front end to Eznec, you don't know what you're missing. On 4/2/2016 12:20 PM, Mel Farrer via Elecraft wrote: I agree, I use ver 5 also. Easier to move stuff around. Once you try modelling you will find it consumes an incredible amount of your time, but FUN. Mel, K6KBE From: Jim Brown To: elecraft@mailman.qth.net Sent: Saturday, April 2, 2016 10:44 AM Subject: Re: [Elecraft] 80 Meter loop question On Sat,4/2/2016 6:45 AM, Clay Autery wrote: Does anyone have any information or a link to information data on an 80 meter loop's complex impedance and VSWR values across the HF bands? It's pretty easy to model with NEC, which yields this data in the form a plot of VSWR vs frequency with data points as closely spaced as you choose. Move the cursor to each data point and you'll see complex Z. I've learned a lot from using NEC, not only to design antennas but also to learn from the results of the model, changing variables, etc. 4NEC2 is free and quite powerful. I use EZNEC 5.0 because I find the UI easier to relate to, but it costs money. :) 73, Jim K9YC 73, Jim K9YC __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] 80 Meter loop question
Thank you Richard! My thoughts exactly! Just pitch your loop up in the air and USE IT instead of trying to complicate it! My 75m loops is skewed all over the place, one side is lower than the other, one side sags, oh and one more thing, I've worked 289 countries with it!! W5sum Sent from Ronnie's IPhone > On Apr 2, 2016, at 20:18, Richard Collier wrote: > > In my opinion, conditions such as soil conductivity , slope, orientation, > height, obstacles, metal structures, length of feed line etc. vary so much it > is almost worth just putting it up without getting too deep into modeling. I > definitely would model it, I modeled mine and then just threw it up thinking > it may not work a few bands. But, after trimming it to 3.515 (my magic > number, at my location), the K3 tuner can tune it everywhere except 160 > meters. Mine is a irregular triangle of sorts with the point at 90 to 95 > feet in a pine tree and the bottom horizontal wire at about 50 feet.It is > somewhere between horizontal and vertical (the other two tree tie-offs are at > about 50 feet) and fed about 15' up one side. I run 120 feet or so (I > trimmed it a couple of times) of 450 ohm ladder line into a high power 1 to 1 > current balun outside of my shack and a 3' piece of high quality coax to my > tuner. This loop beats my 3 element Cushcraft triband at 45' on the high > bands ab out 80% of the time and has exceeded my expectations on 40 and 80. Keep in mind it does not have the back or side rejection of the triband beam on the high bands. > > FWIW, I did try to orientate it so the the modeled lobes pointed in > desirable directions on the low bands. For example, one of the lobes on 40 > meters should be pointed to Europe. It does work well to Europe from the > West Coast. > > Richard > Does anyone have any information or a link to information data on an 80 meter loop's complex impedance and VSWR values across the HF bands? > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to w5...@comcast.net __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] 80 Meter loop question
In my opinion, conditions such as soil conductivity , slope, orientation, height, obstacles, metal structures, length of feed line etc. vary so much it is almost worth just putting it up without getting too deep into modeling. I definitely would model it, I modeled mine and then just threw it up thinking it may not work a few bands. But, after trimming it to 3.515 (my magic number, at my location), the K3 tuner can tune it everywhere except 160 meters. Mine is a irregular triangle of sorts with the point at 90 to 95 feet in a pine tree and the bottom horizontal wire at about 50 feet.It is somewhere between horizontal and vertical (the other two tree tie-offs are at about 50 feet) and fed about 15' up one side. I run 120 feet or so (I trimmed it a couple of times) of 450 ohm ladder line into a high power 1 to 1 current balun outside of my shack and a 3' piece of high quality coax to my tuner. This loop beats my 3 element Cushcraft triband at 45' on the high bands about 80% of the time and has exceeded my expectations on 40 and 80. Keep in mind it does not have the back or side rejection of the triband beam on the high bands. FWIW, I did try to orientate it so the the modeled lobes pointed in desirable directions on the low bands. For example, one of the lobes on 40 meters should be pointed to Europe. It does work well to Europe from the West Coast. Richard Does anyone have any information or a link to information data on an 80 meter loop's complex impedance and VSWR values across the HF bands? __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] 80 Meter loop question
Thanks Jim... I've got 4NEC2, but haven't had the time to jump on that particular learning curve. I plan to invest in the pay version, may be EZNEC 5.0, I don't remember. But I'm drinking from several fire hoses at the moment. Soon, I hope... __ Clay Autery, KG5LKV MONTAC Enterprises (318) 518-1389 On 4/2/2016 12:44 PM, Jim Brown wrote: > On Sat,4/2/2016 6:45 AM, Clay Autery wrote: >> Does anyone have any information or a link to information data on an >> 80 meter loop's complex impedance and VSWR values across the HF bands? > > It's pretty easy to model with NEC, which yields this data in the form > a plot of VSWR vs frequency with data points as closely spaced as you > choose. Move the cursor to each data point and you'll see complex Z. > > I've learned a lot from using NEC, not only to design antennas but > also to learn from the results of the model, changing variables, etc. > > 4NEC2 is free and quite powerful. I use EZNEC 5.0 because I find the > UI easier to relate to, but it costs money. :) > > 73, Jim K9YC > > 73, Jim K9YC > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to caut...@montac.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] 80 Meter loop question
I've been using an 80 m horizontal loop for as long as I have had my license, about 15 years. It's a bit irregular with two supports on my house and three in trees, height is 7-12 meters. I feed it with open wire feeder to an indoor Elecraft 4:1 balun and then use the tuner of the K2 or K3 to match it to the transceiver. I've done 8-bands CW/digital DXCC, 80 - 10 m, with the loop as the work horse. My decision at the time I put it up was very much based on the simulations that L. B. Cebik, W4RNL published. His articles are kind of hard to find on the internet now, but his best ones that I have on my hard disk are: Horizontally Oriented, Horizontally Polarized Large Wire Loop Antennas My Top Five Backyard Multi-Band Wire HF Antennas Notes on All-Band Use of Horizontal-Plane Loops Horizontal Wire Loops How Big? How High? What Shape? These articles answer most questions on directional performance as well as impedance and SWR. 73 - Sverre, LA3ZA K2 #2198, K3 #3391, LA3ZA Blog: http://la3za.blogspot.com, LA3ZA Unofficial Guide to K2 modifications: http://la3za.blogspot.com/p/la3za-unofficial-guide-to-elecraft-k2.html -- View this message in context: http://elecraft.365791.n2.nabble.com/80-Meter-loop-question-tp7615830p7615857.html Sent from the Elecraft mailing list archive at Nabble.com. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] 80 Meter loop question
On Sat,4/2/2016 2:20 PM, Chuck - AE4CW wrote: Properly sized and fed, they offer well under 2:1 SWR within all the HF bands with the exception of 60M and 30M and perhaps 80M depending on the installed height. BUT -- remember that SWR is NOT a measure of antenna PERFORMANCE -- that is, how strong is the signal that it radiates, and the DESIRED angles, both vertical and horizontal. MANY antennas that have low SWR are lousy antennas! 73, Jim K9YC __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] 80 Meter loop question
Clay, I see you've received offers for data on the feed point impedance and VSWR of an 80M loop. If you feel you need more just let me know. I have modeled, built and used a number of 80M loops very successfully. Properly sized and fed, they offer well under 2:1 SWR within all the HF bands with the exception of 60M and 30M and perhaps 80M depending on the installed height. 300 ohm window line (more nearly 265 ohm) with a 4:1 balun can work very well. If you feed a square loop 80M at 1/3 the distance from any corner, the feed point impedance at resonance will be in the 200-300 ohm range...a good match for 300 (265) ohm window line and a usable match for a 4:1 balun. Modeling is a wonderful way to experiment with the design. You can play with loop circumference and the window line and coax lengths to optimize the SWR across the bands. We use these regularly at field day and only need a tuner on 80M. --- Chuck, AE4CW - --- Chuck, AE4CW -- View this message in context: http://elecraft.365791.n2.nabble.com/80-Meter-loop-question-tp7615830p7615851.html Sent from the Elecraft mailing list archive at Nabble.com. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] 80 Meter loop question
Modeling is also very educational. You may learn that a proposed antenna is inferior to a simple dipole. I agree that EZNEC is easy to use and reasonably accurate. John KK9A [Elecraft] 80 Meter loop question Mel Farrer farrerfolks at yahoo.com Sat Apr 2 15:20:09 EDT 2016 I agree, I use ver 5 also. Easier to move stuff around. Once you try modelling you will find it consumes an incredible amount of your time, but FUN. Mel, K6KBE From: Jim Brown To: elecraft at mailman.qth.net Sent: Saturday, April 2, 2016 10:44 AM Subject: Re: [Elecraft] 80 Meter loop question On Sat,4/2/2016 6:45 AM, Clay Autery wrote: > Does anyone have any information or a link to information data on an 80 meter loop's complex impedance and VSWR values across the HF bands? It's pretty easy to model with NEC, which yields this data in the form a plot of VSWR vs frequency with data points as closely spaced as you choose. Move the cursor to each data point and you'll see complex Z. I've learned a lot from using NEC, not only to design antennas but also to learn from the results of the model, changing variables, etc. 4NEC2 is free and quite powerful. I use EZNEC 5.0 because I find the UI easier to relate to, but it costs money. :) 73, Jim K9YC __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] 80 Meter loop question
I agree, I use ver 5 also. Easier to move stuff around. Once you try modelling you will find it consumes an incredible amount of your time, but FUN. Mel, K6KBE From: Jim Brown To: elecraft@mailman.qth.net Sent: Saturday, April 2, 2016 10:44 AM Subject: Re: [Elecraft] 80 Meter loop question On Sat,4/2/2016 6:45 AM, Clay Autery wrote: > Does anyone have any information or a link to information data on an 80 meter > loop's complex impedance and VSWR values across the HF bands? It's pretty easy to model with NEC, which yields this data in the form a plot of VSWR vs frequency with data points as closely spaced as you choose. Move the cursor to each data point and you'll see complex Z. I've learned a lot from using NEC, not only to design antennas but also to learn from the results of the model, changing variables, etc. 4NEC2 is free and quite powerful. I use EZNEC 5.0 because I find the UI easier to relate to, but it costs money. :) 73, Jim K9YC 73, Jim K9YC __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to farrerfo...@yahoo.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] 80 Meter loop question
On Sat,4/2/2016 6:45 AM, Clay Autery wrote: Does anyone have any information or a link to information data on an 80 meter loop's complex impedance and VSWR values across the HF bands? It's pretty easy to model with NEC, which yields this data in the form a plot of VSWR vs frequency with data points as closely spaced as you choose. Move the cursor to each data point and you'll see complex Z. I've learned a lot from using NEC, not only to design antennas but also to learn from the results of the model, changing variables, etc. 4NEC2 is free and quite powerful. I use EZNEC 5.0 because I find the UI easier to relate to, but it costs money. :) 73, Jim K9YC 73, Jim K9YC __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] 80 Meter loop question
Clay, I can run an EZNEC model for you if you give me some more info about the loop. You said about 45 feet high and assume square. Did you want to feed it in the middle of one side or at the corner? I will model above average ground conductivity just to keep all my analyses consistent. I can then put the results in SimSmith and spit out all the data you'll need, complete with any transmission line and length and complex impedance including efficiency across the whole HF frequency band. Myron WVØH Printed on Recycled Data > On Apr 2, 2016, at 7:45 AM, Clay Autery wrote: > > Does anyone have any information or a link to information data on an 80 > meter loop's complex impedance and VSWR values across the HF bands? > > R, X, VSWR from say 3.5-30MHz or better 1.0-54 MHz, measurements taken > at the loop ends with a short jumper, not a long feed-line. Preferably > with loop elevated above 45 feet or so. > > -- > __ > Clay Autery, KG5LKV > MONTAC Enterprises > (318) 518-1389 > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to thelas...@gmail.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
