topbuzzuk
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Full Wave 80m Loop Tips/info?
Hi i have the wire to build a 80m full wave horizontal loop and was wondering if anyone had any tips, do's or don'ts. i have been reading about a multi band loop fed with ladder line and a 4:1 balun but never tried this before as i haven't had the room, but i have now 
Last edited by topbuzzuk, 19/Feb/2013, 10:04 pm
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15/Feb/2013, 4:39 pm
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yamanx1
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Re: Full Wave 80m Loop Tips?
Paddy, Tony 26FB150 or John 26FB193 are your men for this.
John's not been heard of in a while, but Tony is about, he was on the cluster today. His username on here is tonymaloner, or similar spelling 
He has made some really excellent 80-86m wire loops, hidden ones on fences and all kinds
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15/Feb/2013, 6:44 pm
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topbuzzuk
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Re: Full Wave 80m Loop Tips?
hi dave, i sent tony a pm on here a while ago with my new address but haven't heard anything from him.
theres a lot of different information online about them, some say use a balun, some say not to use one. some say feed them with coax some say feed them with ladder line. It would be handy if i could use it on other bands too and they say that it should work 80m through to 10m. I have some ladder line off my doublet i can use to feed it but i'm just a bit stuck about wether to use a 4:1 balun or not, just something else to have to buy 
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15/Feb/2013, 10:09 pm
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topbuzzuk
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Re: Full Wave 80m Loop Tips?
righty ho,,, i got 276 ish foot of loop around the garden and i am feeding it with around 40 foot of ribbon/ladder line 300ohm i think. It tunes on 80m but when i check the SWR without the tuner it seems resonant on 2.8Mhz. I'm not sure but i think if i add the length of the ladder line(2x40')to the length of the loop i end up with the length of a antenna for 2.8Mhz ish. So i think the ladder line is acting as part of the antenna which is causing it to be resonant on 2.8Mhz. Lots of head scratching and Googling goin on here right now????
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18/Feb/2013, 9:19 am
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John193
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Re: Full Wave 80m Loop Tips?
Hi Paddy .
Wow you have got some room to play. A loop is not a world beating bradbander for a start but as your using ladder line its really a vertical with a top hat hence the resonance freq you got. The feed impedance of a loop is 108 ohms in free space getting lower as you aproach the ground. For 86m that works at about 50 ohms at around 20-30' high in an average senario. So raw coax feed here is a perfect match no other matching tech is required or needed. The lobe at design freq is very good but at all other harmonics its crap so thats why i said its not really broadbanding material, loops by there nature are not broadband. ladderline by its nature will become part of the antenna at all its multiples of 1/4 wavelength so unless you dont mind poor efficiency lots of use of a tuner i wouldnt go down the ladderline loop route.
You can place other loops inside the big one and connect them live to feed and they will become harmonic and radiate as you approach there design freq. Ive used four inside each other with good effect before now. Hope that helps mate Tony Simon or Dave have my number if you need a chat on it. cheers john193
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19/Feb/2013, 1:26 pm
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topbuzzuk
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Re: Full Wave 80m Loop Tips?
cheers john, i do have a big garden at the new qth i will rewire it with some coax and if i have to i will just have to use it for one band. i could hang a 45 meter dipole between two supports i have and that will be sorted for the low bands.
is it wise to use a choke/ugly balun at the feed point? on the loop?
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19/Feb/2013, 10:03 pm
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SuperNasty
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Re: Full Wave 80m Loop Tips/info?
Hi Paddy, I made a full size loop for 86m a few years ago, it was fed with open line which I prefer to use rather than a balun and coax (for multiband use), it worked, but was not as great as I imagined it was going to be. I made one of these (below in the image) also and had it in a horizontal fashion, again a lot of work with less than expected performance, in all fairness it was a bit of a squashed triangle loop and would of worked better more spread out. Eventually I went back to my 137ft doublet with open line to a balanced tuner.
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(Forum user name was previously - mikefox whiskey) - 68 FB750 - Pat
Kenwood TS870 - Centre fed balanced dipole - HPSD 2 element Moxon for 11m, vertical 'Ringo' for 11m.
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20/Feb/2013, 7:17 pm
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topbuzzuk
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Re: Full Wave 80m Loop Tips/info?
hi patrick, i did speak to cyril the other night on it and was getting out to him ok but theres not a lot of activity on 86m so havnt spoke to anyone else to get reports.
i tried the coax feed and the lowest SWR was on 3.2Mhz but it wasnt very low. also my yaesu fc102 tuner wont tune it on 3.470 any sense, its really hard work(not happening)to get swr down to a workable level. This tuner will usually tune a damp bit of string which has surprised me that it wont tune the loop with a coax feed on 3.5Mhz. I am thinking of scrapping the idea of a full wave loop for 80m until i can get my hands on a antenna analyzer
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23/Feb/2013, 2:00 pm
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SuperNasty
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Re: Full Wave 80m Loop Tips/info?
Yes mate, from my side there has been very little activity on 45 or 86m, i've been on 11m mostly this weather. Keep and ear tuned to this space!
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(Forum user name was previously - mikefox whiskey) - 68 FB750 - Pat
Kenwood TS870 - Centre fed balanced dipole - HPSD 2 element Moxon for 11m, vertical 'Ringo' for 11m.
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23/Feb/2013, 10:02 pm
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topbuzzuk
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Re: Full Wave 80m Loop Tips/info?
update on antenna... i spent the afternoon up and down the ladder and managed to get the loop resonant on 3.470Mhz. Its not very broadband so the swr is only any good without the tuner between 3.4 and 3.5. I ended up using 45 ish foot of 75 Ohm coax as a matching stub and a short patch lead of 50 Ohm to the tuner. Now just need some activity on 86m lol 
I must say thanks to Martin 19FB305 for the radio reports as he has been my only contact since doing the antenna.
Patrick have you stil got a antenna up for the low bands? and are you stil using the Moxon on 11m?
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25/Feb/2013, 7:33 pm
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