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Technical Puzzle #28 - It's one 'L' of an antenna!
Technical Puzzle #28 - It's one 'L' of an antenna!
M0MGF
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Joined: Thu May 28, 2009 8:27 pm Posts: 450 Location: East Yorkshire, 'Gods Country'
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Re: Technical Puzzle #28 - It's one 'L' of an antenna!
Hi Steve, Downloaded and installed. I had a quick look at some of the pre-offered designs that come with the program. Then I decided to download the offered manual - there are not many pictures in there Is there much difference between the free version, and the more expensive versions? Regards Jase
_________________ Jason M0MGF RSGB Member RNARS 4842
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Sun Feb 28, 2010 6:33 pm |
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Technical Puzzle #28 - It's one 'L' of an antenna!
G3TXQ
Silent Key
Joined: Fri May 22, 2009 1:23 pm Posts: 5637 Location: Northampton IO92ME
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Re: Technical Puzzle #28 - It's one 'L' of an antenna!
M0MGF wrote: Is there much difference between the free version, and the more expensive versions? The key difference is that the free version constrains you to a small number of segments; that means you can't model more complex antennas. I'll discuss "segmentation" in a tutorial. If it's OK with you I'll assume very little knowledge about EZNEC and start with basics. I'll place the EZNEC model files onto my web site so that you can download them - that way we'll know we are working with the same model. Give me a couple of days to work something up and I'll start a new series of threads. Anyone else interested? 73, Steve G3TXQ
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Sun Feb 28, 2010 7:40 pm |
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Technical Puzzle #28 - It's one 'L' of an antenna!
MW3LSD
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Re: Technical Puzzle #28 - It's one 'L' of an antenna!
Certainly, that would be great.
I've been having a play with EZNEC today, had a fiddle with the "test drive" dipole tutorial. I've got my head around that, sort of, but it would be a great help to model slightly more complex antennae, such as the fan dipole I'm thinking of, or even my rather shoddily hung 5RV as being able to play with parameters and get a rough idea of what'll happen if I raise this element/shorted this bit/raise that part without going outside in this weather and getting soaked/called a nutter by the missus would be a great help.
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Sun Feb 28, 2010 8:30 pm |
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Technical Puzzle #28 - It's one 'L' of an antenna!
G0BXU
Moderator
Joined: Sun Aug 31, 2008 4:39 pm Posts: 6016 Location: Sleaford, Lincolnshire (Bomber County) IO93TA WAB-TF04
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Re: Technical Puzzle #28 - It's one 'L' of an antenna!
I too have downloaded the EZNEC demo programme, so will try and join in with your tutorials Steve. Always willing to learn something new about antenna construction. This is an area where the true amateur spirit can still be put into use - so I await your efforts to educate us 'mere mortals'. Just hope my brain can stand the strain By all means start with the very basics and of course assume no prior EZNEC knowledge - at least as far as I'm concerned. Alan
_________________ 73 de Alan.
Today I broke my personal record for the most consecutive days alive, despite Covid 19 - I hope to better it again tomorrow.
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Sun Feb 28, 2010 8:57 pm |
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Technical Puzzle #28 - It's one 'L' of an antenna!
M0BPQ
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Joined: Tue Jan 26, 2010 7:29 pm Posts: 115 Location: London
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Re: Technical Puzzle #28 - It's one 'L' of an antenna!
I have a registered version of EZNEC and will be very interested in a tutorial, Steve. I have got models running, but feel like I am still facing the steep part of the learning curve.... Steve
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Sun Feb 28, 2010 9:49 pm |
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Technical Puzzle #28 - It's one 'L' of an antenna!
gw8asd
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Joined: Fri Jul 20, 2007 1:02 pm Posts: 15916 Location: IO83lb, Wrexham
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Re: Technical Puzzle #28 - It's one 'L' of an antenna!
Looks as if this is going to be very popular Steve. I'll have to free up some time and give it a go. Particularly interested in the effects of differing heights on Yagis. Above 50MHz of course. Cheers Tont
_________________ 50MHz and above from IO83lb
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Sun Feb 28, 2010 10:28 pm |
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Technical Puzzle #28 - It's one 'L' of an antenna!
M0MGF
Contributor 2024
Joined: Thu May 28, 2009 8:27 pm Posts: 450 Location: East Yorkshire, 'Gods Country'
Feedback: 11 (100%)
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Re: Technical Puzzle #28 - It's one 'L' of an antenna!
Steve, It looks like you will be coming out of retirement at this rate Jase
_________________ Jason M0MGF RSGB Member RNARS 4842
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Mon Mar 01, 2010 12:13 pm |
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Technical Puzzle #28 - It's one 'L' of an antenna!
Zen Navigator
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Joined: Tue May 22, 2007 7:08 pm Posts: 330 Location: Manchester
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Re: Technical Puzzle #28 - It's one 'L' of an antenna!
Hi, I for one would be interested in 'playing around' with EZNEC. My prev. exp as been with cellular and microwave stuff can't recall the tool, as it was a fair few years ago. So any assistance in understanding HAM related stuff, for my part would be gratefully received. Dave G3TXQ wrote: G7VQE wrote: Actually Steve,do you have a link to the free EZNEC download and would it be worth a technically challengeed noob trying to use ? Dave, I'm a great "fan" of antenna modelling software - you can learn lots just by "playing around" with it. It takes a bit of time to get to grips with initially, but the effort is well worth while. The free demo version of EZNEC is available here: http://www.eznec.com/demoinfo.htmIf there was any interest, I'd be happy to run a few simple "tutorials" to help folk get started with it. 73, Steve G3TXQ
_________________ email: mzerogsm@googlemail.com
skype: dave.hall424
twitter: http://twitter.com/M0GSM
Last edited by Zen Navigator on Mon Mar 01, 2010 1:58 pm, edited 2 times in total.
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Mon Mar 01, 2010 1:09 pm |
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Technical Puzzle #28 - It's one 'L' of an antenna!
Zen Navigator
Advanced Member
Joined: Tue May 22, 2007 7:08 pm Posts: 330 Location: Manchester
Feedback: 18 (100%)
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Re: Technical Puzzle #28 - It's one 'L' of an antenna!
I can assure there was no Spring Sunshine where I was! Snow, sleet, and lots of rain. Anyway that'll teach me to camping in February Missed this one, but another super teaser and a bit more info stuff into the grey matter G3TXQ wrote: Everyone must be out enjoying the Spring sunshine - only one Pollster so far! I'll post an answer this evening.
73, Steve G3TXQ
_________________ email: mzerogsm@googlemail.com
skype: dave.hall424
twitter: http://twitter.com/M0GSM
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Mon Mar 01, 2010 1:15 pm |
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Technical Puzzle #28 - It's one 'L' of an antenna!
MM0GPZ
Novice Member
Joined: Sat Apr 21, 2012 3:43 pm Posts: 14 Location: Blantyre
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Re: Technical Puzzle #28 - It's one 'L' of an antenna!
Hi Steve. I hope you will see this post as the last message was Feb 2010. I have built antenna's for 80 and 160 to fit my smallish garden rather than for outright performance ha ha. I have a 40 feet tall fibreglass pole to support 2 wire wire inverted L's for 80/160. 160 uses full height and terminates on on a support from my tennamast on the house 50 feet away. Therefore, I have about 90 feet available space. As the antenna would be too small for 160, I simply wound enough of the insulated wire onto a 5" former and that is placed about 25 feet up the fibreglass pole, so that the wire just nearly reaches the mast at the house. With some adjustments, SWR is minimum of about 1.8:1 which my tuner deals with of course. I also then have a full size 80m inverted L hanging off wooden standoffs (about 60cm's) attached to the same fibreglass pole. It also has a minimum SWR of about 2:1. What I am not sure about is whether I should feed them with separate coax or just a single feed. It seems to tune similarly either way or what I could do to improve the antenna at all? I find having close to full length lets me use most of 80m at least and all of the DX portion of top band.
I also have a 1/4 wave vertical for 40m about 8 feet further back from the 80/160 pole.
I am mainly interested in DX contacts and contesting so it is important to me to be able to transmit on all bands. I am absolutely certain there are lots of unwanted interactions but what can I do?
Thanks Steve
BTW, I replaced my Hex with an Optibeam OBW 10-5 which is a wire beam for the 5 bands. I find it much more touchy SWR wise than the Hex was and not a better performer.
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