HAM RADIO: Loop Antenna 80 metres to 10 metres
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- čas přidán 1. 08. 2024
- Thanks again to Rick, DJ0IP for publishing details of this antenna which he says provides great gain at higher angles for 80 and 40 metres as well as very good gain 20 metres through 10 metres. Let’s use MMANA-gal modelling to see if this agrees.
Check out Rick’s website here: www.dj0ip.de/my-favorite-ante...
Connect with my channel by subscribing and commenting. - Věda a technologie
I have been using this antenna for 35 years. works great.
I have used an 80m loop as my primary HF antenna for about 10 years now using trees as supports, and I agree with everything presented here. I originally started using a loop because of a noise issue originating with an AM broadcast station antenna array on 1300 KHz only 900' away. The 3rd harmonic was broad and nasty until I changed over to the loop. Having a balanced antenna also solved the problem of getting a good RF ground on the 2nd floor of a house. It was no longer required! I moved away from the 1300 KHz station several years ago and now feed it with about 100' of LMR400 coax. While not ideal, the loss is not terrible. I had aesthetic issues with the XYL using 450 ohm. My noise level at the new location is S1 or less. The loop is only 6 t0 10 meters off the ground yet I can still work 40 meters into Canada from Oklahoma with a hundred watts no problem. 30 to 10 meter band performance is superb as well.
They are truly very good and adaptable antennas!
How well does it work on the higher bands 10-30m?
In my experience it works very well. Even the nulls are useable. But the real beauty of a loop is how quiet it is. You can reduce your noise by 5 or 6 S units or more over a dipole. I think you would have to use a rotatable beam at 50' off the ground to do better, but I don't have measurements I can show you to back it up. I suggest just trying it out. The materials are relatively inexpensive. Take advantage of the next door neighbor's trees lapping into your yard for antenna supports. @@tzm1843
Thanks for the great Video! For many years I have installed a 165 meters long wire antenna on my property and across my neighbour’s house.. It is also known as a skyloop antenna and the feed line is an old tv antenna twin lead about ten meters long onto a 4:1 home made Balun in the shack.. Then it is connected by a short coax to an mfj tuner.. Works reasonably well on all the band including 160 meters for CW n FT-8 including the WARC bands.. 73 de YB0NSI..
Nice work!
It's a good design, but keep in mind loops can be just about any shape, so don't think a square or delta is all one has to choose from. Whatever shape fits in the yard or attic will work.
Well done (again), Tim. For clarification on the name: there are two kinds of loops, vertical and horizontal. Because this horizontal loop is laying down, I call it a "Lazy Loop".
Due to changes in my employment, I moved around a lot. I introduced this loop to three different clubs. Each club was using a tri-band beam or quad, plus dipoles for 80 and 40 at Field Day.
There are 4 major lobes and by proper orientation (here in Germany), with the strongest lobe pointed at stateside (NW), the SW lobe was pointing long path to VK, the NE was pointing to JA, the SW to the Middle East.
Besides blowing the dipoles out of the water on 40 and 80m, the loop held its own against the beam (or quad) on the high bands, at least in its 4 main direction. As a result, all 3 clubs ceased bringing a tower and beam to field day and just used the Lazy Loop on all bands. This gave us more time for Bratwurst and Beer.
73, de Rick, DJ0IP
Brilliant information Rick! It looks a very nice antenna. Love a beer and bratwurst too. 73 and much appreciate you stopping by.
I had an 80 meter full wave loop which I used for years. Best wire antenna I’ve ever built. Was at about 40 feet high, fed with 450 ohm ladder line with a 4:1 balun near my operating position. Internal tuner of my FTdx1200 handled the rest. I had to do some ladder line trimming to get it operating on all bands. Great DX results. I fed it in the middle of one leg (just a convenient spot).
Sounds a superb antenna
thank you so much for this excellent video tim. Whilst I wont do this in the QTH, I will go back to this video for my next field day with my local amateur radio society (G4PRS). Whilst 80m is always awesome, seeing the gain on 17M I was roaring with joy ! Out in the field with an IC705 and this setup for QRP but with the space and setup requirements, this is a lovely project to do on a field day. I cannot wait ! 73 2E0FWE
Thanks Al, good luck with the antenna
I had a 160m horizontal loop back in ZS, fed with homebrewed 450 Ohm feedline from a 4:1 balun and a short length of RG213 to the shack. My experience with that version convinced me to build an 80m version for my new QTH in CT7......best wire antenna I ever had. I will be supporting it with four 12m Spiderbeam heavy duty telescopic masts and a longer feedline to feed the Northeast corner, hopefully allowing me to contact my mates in ZS with my 100W on a good day. Thanks for the MMANA analysis of this antenna, I have been wanting to see such an analysis. Thanks for the video and for the time and effort to make, edit and upload. Much appreciated. 73 CT7/ZR1XZ.
My pleasure and I’m glad you can confirm the excellent results from this antenna 73
Thanks for the video Tim. To use the loop on 160m just add some *inductance... I'm using an 80m oblong loop connected directly to a 4:1 current balun and MFJ926B remote auto-tuner mounted directly below the ridge of my roof - so in practice there's no feeder at all. I use a relay to switch in a 235 microhenry coil on 160m to tune out the capacitive reactance. The coil is wound on an old ferrite rod former and I've slid in a small piece of ferrite rod to peak the signal level on 1940kHz. The auto-tuner is then able to match the loop across most of Top Band but to get a match in the CW section I have to climb into my loft and push the ferrite rod a bit further in.
*UPDATE - I've since replaced the inductor with a balanced L network to effect a better impedance transformation prior to the auto-tuner. The relay now places a 93 microhenry inductor across the loop and a 91pF capacitor in each leg between the loop terminals and the 4:1 current balun. With the auto-tuner bypassed (unpowered) sliding the ferrite rod will achieve an SWR of 1.7:1 which is then reduced to almost 1:1 when the tuner is powered on.
Great video, cheers from the other side of the pond
Thanks Joe 73
I had one of these in the 1980s, but it was only about 4m high. It worked great on 80 to most of Australia (I'm in VK5). With our Novice licence I only had 2 other bands 15m & 10m and I made lots of DX contacts.
I’d love to have the space
Interesting Tim, thanks for that 👍
Cheers Ray 👍
This is what I have been using for 25 years. Has never required maintenance Feed it with 800 watts and has a four clover leaf pattern on 20 of which I use the most.
Excellent
well done Tim, very interesting.
Thanks Brian 👍
Here's a way you may be able to get around the high SWR losses on 160 m. Open up the corner opposite the feed corner. Then (a) put a relay there to reconnect the two wires when desired. You'll want it open for 160 m and closed for higher frequencies. On 160 m with the relay open you've got a badly bent up half-wave dipole which should have a very low input impedance. Alternatively (b) at that far corner instead of a relay, connect to an additional length of ladder line 1/4 wave long at about 1750 kHz, shorted at its far end. That will present an open circuit to that corner outside the low end of 160 m at 1750 kHz, and inside the band will put a capacitive reactance across the open end of the loop detuning things to an even lower resonant frequency, but it still should work. On 80 m, 40 m, 20 m, 15 m, and 10 m the shorted ladder line stub will be an integer multiple of 1/2 wave long and will present a short to the corner of the loop causing the loop to behave pretty much the same as the original design on those bands. All bets are off on the non-harmonically related WARC bands with the stub, but with the relay they'll be like they are in your original design.
Now to get this to work correctly you're going to have to set the resonance point of the stub at the low end, 1750 kHz or thereabouts and everything should be fine for CW. Shorten the stub a bit to get it to work nicely on 75 m for 'phone operators and the harmonic resonances are all going to be way off, so good-bye 40 m and higher. Thus this trick is only going to be useful for us CW operators.
David VE7EZM and AF7BZ
Ok interesting
so the feed splits into to halves making it a dipole but are they connectected or a gap willl it short or be ok? a diagram for these would be useful to show.,
Nice video! I have been pondering putting up a 80m loop, I hear they’re quieter then open end antenna. Thanks for the modeling pattern of each band patterns very similiar to my 80m EFHW at 40ft.
My pleasure and enjoy the loop
2.5:1 balun is what I've used in the past, with great success 👍
Interesting
That's what I use also and works great.
Valuable information sir
Thank you!
I had a coax fed, through a Balun one of these up for a while, it only just fit in the garden and I was not happy with the position of some of the supports near the road. It seemed to work fairly well, a chap in Ireland had it off me and I think he was able to put it much higher, I was only at around 20 feet. The chap in Ireland was very pleased with it.
The extra height really helps
If I had space I'd have another Tim. My old one was coax fed and was great on all harmonic bands but 80m swr was sky high over 3.7mhz. If I had 🪜 line it would have been no issue. It was a great dx antenna on 40m working VK regularly on SSB.
Very nice antenna 👍👏👏
Sure is Mark. Just need euro millions jackpot to buy the real estate
I discussed this with Callum from DX Commander a little while back, he had a better solution:
"You build 2 x wavelengths for 40m and get it tuning.. Then near the tail of one end of the loops, build a loop of wire about 12 feet long (4m) and droop it from the feedpoint and connect it to the loop in a long arc (almost half a circle) then when 80m comes long, it'll try and use that too, forcing the resonant frequency lower (and should wide-band it slightly..)"
Its an option for sure
Don't you usually present from a shed? Anyway that's not why I called, are you saying it antenna works on all frequencies? If so is it compromised in any way?
Greetings from kyrgyzstan 🇰🇬
I think this is what I'll put up on the building I live
4 6m masts will put it 27m above ground
Building is 24m x 24m
Very noisy here in city
Hopefully a loop will lower qrm qrn
Also will use it for mw dxing as well
Love Building and listening to crystal radios
Thanks for video
No problem good luck!
Interesting video Tim, I have a book somewhere (25 simple Ham band antennas) and it is also referred to as a rhombic antenna and it suggested 100 feet per side fed by 600 ohm open feeder and supported by telegraph poles! A beast of an antenna I can only dream of. I look forward to your next video.
Sounds a wonderful antenna! Thanks for stopping by and commenting 73
I've heard that there's a chap somewhere with a lot of land, who had a whole circle of switchable rhombics so he could use them like a beam in which direction he wanted.
Rhombic has a terminating resistor at the opposite end to the feed line.
@@paulsengupta971 that would be just perfect.
rhombics are different again.
I've watched this video three times. I'm convinced I need to build a loop. I'm curious how a sloper loop might work. 10 meters high on one side and 3 meters high on the other. Hmmmm.
Modelling this with MMNANA is nice but everything is pure theory. Everything depends on the surroundings like buildings, trees etc.. I've had this antenna for years built around my garden. I've worked much DX on 80m. It is useless on 160m. It is also useless on 10m (and 12m) if you compare it to a 1/2 wave vertical or a simple 2 element beam (those will do much better). But it is a great antenna from 80-15m especially around the greyline when DX signals can be on high angles as well. Of course it is a excellent NVIS antenna. I had a lot of fun with it for years. Changed it now to a 2x20m doublet since my XYL didn't want the loop around the garden anymore. Personally I think the doublet is doing just as good as the loop. 73, Bas PE4BAS
I build the same Antenna but for 40M not 80M. It works very well on all frequencies which are multiples of 7.1 MHz , I feed it with coax cable terminated by a remote MFJ993 BRT antenna tuner and a 1:4 balun. I bypass the remote tuner on 15, 10 and 6m where the 1:4 balun is sufficient to match the Antenna. On 40 and 20 m and even 80m, the swr after tuning with the remote antenna tuner is perfect. On 160m, 60m, 30m, 17m and 12m , swr after tuning is between 2 and 3 and I use a second tuner in the shack to bring it down to less than 1.5. The loop is installed on the flat roof of my building at a height of 25m above the ground. I worked the whole world on FT8 on 60M and all above bands, a little bit harder on ssb but I am still happy of the performance, on 6m it is really spectacular when there is propagation, works decently on 80m but only for Europe no DX. On 160m it is warming the Sky, so no exotic DX FT8 stations are heard, in fact I hear almost nothing. Overall this is an excellent multiband Antenna, it could be also used too on 4m , 2m and even 70cm band as it resonates on these bands (but then only with a proper wideband 1:4 balun and it would also require to bypass completely - with transfer relays - the HF remote Antenna tuner).
now try switching to stainless wire instead of copper and watch yoru SWR drop a full point ;)
Nice job!
I have that loop in a triangle configuration about 9M high. Fed from the corner
If you but a resistor on the opposite corner of feed, it really point the gain in one direction.
that's a rhombic.
i hope you now the differens db and dbd over a dipol
For 160 meters, how about putting a relay in and open one end of the loop and run it against ground - or even a chain link fence?
Interesting
greetings Tim, ive got a question.
im limited on space in my qth, but i have managed to fit an shortened end fed 80 - 10 m antenna which i got from uk antennas. its about 5 meters from the ground, and ive managed to get in centre europe, with my set up.
but i want to do better on 40meters , do you have any suggestions?
i was thinking of putting up a dedicated 40meter dipole, on a pole, or should i be looking at something else. funds are tight, and cant spend loads, im in the middle of an housing area, but i can hide most of my antenna in a tree in my garden.
or should i be thinking along a different line, magnetic loop? multi band vertical antenna? dipole? or stay with my end fed?
Many options.. what size space do you have?
@@timg5tm941 i have a shortened 80 to 10 end fed running corner to corner in the garden, the antenna is 22.5m its about 7m off the ground. fed with rg213, and an unun choke approx 24 inches from the rig. works ok, but its noisy,
I built mine 85 meter loop as a pyramid with one 17 meter mast in the center 450 ohm line feed in the top of the mast works very well and no rf problem. 73 de sm6usu Svante
Sounds good!
I’ve been contemplating trying this antenna at my field using around 9m tall masts…….probably next year for one of the 80m contests or maybe CQWW.
Might try it with 3 mast as a triangle to make it cheaper & easier to build (as it would be a temporary setup).
You said that you were jealous of Tom having this antenna to play with. I know my field is a bit of a track from where you live but if I do try building it I’d be happy for you to come & join the fun so that you get a chance to try if.
Unfortunately that won’t happen until next year though.
James I’ll let you know that is a very kind offer.
triangular loops are fine, they are just a lot more directional than squares.
@@OllieVK In which direction? Kindly explain?
@@tzm1843 should probably clarify, if the feed point is in one corner, imagine a bow and arrow, the feed point is the back of the arrow, the opposite flat side is the bow, that's your gain direction. From memory it's broader if the feed point is in the middle of one flat side.
Hi, I am trying to make a good mag loop antenna and have a truly dumb question, I know, I may be asking the wrong person because you build large obvious loops but here is the question: In order o try to remain as stealthy as possible I would lke to paint my loop the same as the vehicle. Will a coat of paint effect my loop and is there a type of paint that would have the least influence on operation of the loop??? Sorry about being off topic but if you or one of your followers has an answer I sure would appreciate it. Shiny metal is not the least bit stealthy. Besides my trips off road I also live in a condo with restrictions. lol
No problem, I think paint shouldn’t hurt but someone might chip in with more info here …
Maybe for 160 the feedline can be connected together, make a vertical out of it, and use the loop as a capacitance hat? I heard this idea in an article somewhere.
It would look like 42m electrical wavelength excluding the feedline, too long for a 160m top loaded vertical
Hi just came across your channel . Very interesting. I was looking at a square aerial design for my QTH here in the North of Scotland. At the moment I have a doublet cut for a 1/2 wave on 160m . (on 3 masts) fed with 450 ohm ladder via a KW107 matcher. I was wondering what a top band square would look like modeled.? A have space for another mast . Im not to good on modeling software . May try it this summer . Like your videos 73 GM8NYV
Thank you! Depends on height. A FULL wave 160m loop at double the height of the antenna I show here would basically behave on 160m like this one does on 80. Then 80m would be like this one is on 40m and so on.
Hi Tim
I´ve been contemplating one of these as an option for my home QTH. I live on the 4th floor of an 8 story apartment block and wondered how a loop would perform mounted on the building roof. I´ve certainly got the room up there for an 80 mtr loop but I would need to feed it with coax. Anybody got an opinion on such an installation? I work 100% CW and am mainly interested in contesting. Currently, because of local Rx noise levels I tend to work portable but this restricts me to day time ops only.
The height sounds promising. Coax fed loops can work well. Or you could do ladderline to a remote atu up there and then coax to your operating position?
If mounted on the roof, it sounds like you should have plenty of height.
If you must use coax then I would suggest putting a remote tuner up on the roof.
Barring any unforeseen oddities such as undesirable interactions with any metal structure in or on the building, sounds like it should work well.
Your biggest problem is likely to be a high noise floor if you are in an apartment building (which is true for most hams these days).
@@AmateurRadioUK Thanks for the reply, good info indeed, and yes I currently suffer from a high noise floor, is it possible that a loop mounted on the roof could 'quench' that noise somewhat? Currently, when working from the apartment my antenna setup is a random wire (11mtrs) mounted to a horizontal 7mtr mast out of the window of my 4th floor shack in an upside down inverted L format. fed via a 9 to 1 unun into a Palstar AT2K tuner.
@@timg5tm941 Thanks for the reply Tim, that´s worth some thought indeed.
@@garyhill8333 Loops are generally considered quiet antennas, so I would expect a loop to be quieter than a random wire.
I guess that the only way to find out for certain is to try it!
Tim,
I plan on making this 4x the size, yes 1000ft, what would this look like 160m-6m
Fed with the same feedline
Monster James!
On the higher bands may it work like a rhombic.
it seems like very good NVIS antenna. 10 m and 12 m heights are about same
Indeed!
What would happen if the poles are 30 ft off the ground, got 25 Acers? Also can/should one build one with a relay (High Voltage Amps, Contacts 600v 450A) that would swap the feed lines connections at the top of the pole. I have a 12v DC relay contact rated at 600v 450A from an old power supply that was used in a Computer when they took a floor of a building for the computer room (could be used as boat anchors for as battleship) with false floors (DEC PDP-10 KI. One last question looking at a variety call sigh (W or K) if it was K I would like to KA10 KL10, but if I cant do the 4 letters. after the K or W would like - KA10, KI10, KL10 and PDP10 or PDP11. Had a general 35 years ago then got out of the military went homeless, Going to college living in my car. Sold my gear and did not renew my license. Work for DEC Digital Equipment Corporation, Repairing DEC PDP-10 (KA, KI, KL) KA10 Transister no IC, KI-10 built on 74XX logic IC's. going for my Tech and General in December. The last question can your Ham and GMRS license be the same call sigh.
That I am unsure about
I built a 40m delta loop and using 450 ladder line changed it to 300 ohm ladder line I and found it changed the resonant frequency had to make it shorter I suspect the capacitance of the 330 ohm line capacitence being greater increased the electrical length of the delta loop. Just a theory.
Presented an amended range of impedances probably?
Thanks for this Tim and Rick, I'm wondering If I can use something similar. I have a narrow plot just over 12 metres (40ft) wide but over 90 metres (350ft) in length. So, would this work as a rectangle of the same wire length rather than a square, please?
It’ll work .. would be interesting to see the radiation pattern
@@timg5tm941 Thanks for thinking about my problem and your reply Tim. I presume "interesting" means it will work but probably not well.
I’m not certain at all. I might try and model this to see. Are you looking for the full 40x350 ft?
@@timg5tm941 Thanks for the reply, what I thought at first was to use the same length of wire as you did for 80m but instead of square, make up the distance going rectangular.
The garden is actually 40ftx460ft but 350ft is away from the building line and RF noise, so I can use as much or little as works best. Thanks for thinking about this.
On 80 and 40m you will pretty much see the same performance as the square loop. On the high bands, the gain is going to be about the same but not off of the corners. It has nothing to do with corners, but rather the point at which the multiple current-maximums occur. This will be at the feedpoint and multiples of a quarter wavelength away from the feedpoint.
I have never tried a rectangle, but I have had several OM write me over the years and tell me they were quite pleased with its performance. Not very scientific, but at least encouraging.
For those of you with less space, try a half size (40m full wavelength). It won't work, at least not very well, on 80m but it's a killer for NVIS on 40m, works OK on 20 and shines on higher bands. 73 - de DJ0IP
How is Rx performance upper band? 10 and 15 m band?
The gain shown on those bands relates to RX too 73
What happens when it is 20m - 30m above the ground?
Some more lobes and nulls on higher bands but it’ll kick butt on 20/40 especially
What if you were to put a break in the antenna at the far corner for 160m?
Hmmm .. by break you mean??
@@timg5tm941 Cut the wire and put a spacer in (maybe with a relay....) to form a sort of dipole folded in on itself. Or put a terminating resistor in the gap. Worth modeling?
Have a look for terminated loop.
If you open the far corner, what you end up with is a folded half-wave dipole. This is basically the same as the cobweb. In theory it will have 12.5 Ohms impedance, lending itself to use with a 4:1 Guanella balun - backwards. However, that is only the theory and is certainly "close" when the loop is 100+ ft. in the air. How will work when close to ground? I have no idea.
However, you would have to close the loop (with a relay, or . . . ) when working higher bands.
73 - de DJ0IP.
do you have to use ladder line
No you can use a 4:1 Balun and use on harmonic bands
Looks awesome, shame I don’t have the space to have one though lol
Me too!
Short it and put it on 160 as an endfed wire?
Good idea
i do SWL and CB. i'm thinkin of building one for the shits and giggles since i got the space
Go for it!
A gent I talk with all the time on 40 has one up at 100' he booms coast to coast on it with 400W. If I had the space for one I would do it.
Sounds superb and yes so would I!
hi guys.... isn't this a mini rhombic?
It's a close cousin at least
So it's a Rhombic, right? That's what they use at shortwave station WTWW, and it sure works pretty good for them! I wonder if you could ALSO work in a 40 metre "4 square" from the supports themselves? After all, the vertical supports are already right there to use, that would give you the low angle and directionality for 40 m DX with a bit of phasing line and some switches... And maybe BREAKING the far end of the loop, opposite side of the feed gives you an 80 Metre Cobweb, some directionality there, sans the decreased noise of a completely closed loop? I also see with some switches, a couple of half-squares there... Alas, much like Relationships, Antennas are ALWAYS a compromise, eh? 73 DE W8LV
Totally right!
@@timg5tm941 no it's not. Loops and rhombics are similar but slightly different. Rhombics are intentionally diamond-shaped, with the feed point in one corner and a resistor on the opposite.
@@OllieVK You're right... I forgot about the diamond shape as opposed to the square. 73 DE W8LV BILL
Liked the review, but didn't think much of the antenna design. Very large antenna just to warm clouds, and suffer deaf spots all over the compass.
If only Tom had a decent tuner to use 😝
Ha!!!!!!
Blimey my gardens not even half that size :(
Same!
Αccording to the measures you give in the design, the antenna is wrong ... 4x21? the frequency that will have the least returns will be 3,350 MHz..with 4x20 meters it tunes exactly 3,500 MHz..and do not invoke programs (Μmana gal) if you do not know how to configure the parameters ...... with stupid theories, antennas are not made .... loop antennas require knowledge of the object ... to get the performance of the antenna, it takes a lot of searching ... unless you put the antenna and the connections directly in antenna tuner ... and know that what the antenna sees you do not see, because what you see in the drawings the antenna does not see ... ....lookin QRZ how are 2 loop antennas 160 m and 80 Mes (parallel butterflies) 160 - 10 m with both for 20 years ego.73 ` SV1BNC
The antenna has been built and used many times by the original designer. Modelling was used to test his assertions and has supported these through their outcomes. 73
My favorite HF multiband antenna. Works great on MW broadcast band as well. Aloha es Russ (KH6JRM).