Outdoor Loop

[HomerBB]

I did talk to Homer on .385/LSB when he was running his loop the other day. Seemed to work quite nice and gave him that report. Had him the red here in CA - BTW - which isn't the typical signal report given him before from his using the V4. He did a comparison with his attic loop and hiss external loop; the external loop seemed to work better, as it was higher up than the attic loop.

Thanks for the report, Robb.
I had expected it to outdo the attic loop. Today, it seemed to be better at your QTH than the vertical S4, too.

 

[Henry HPSD]

at what heigth will both be placed homer ?

PLease ingnore...i just read again the thread 41 feet...tnx

 

[HomerBB]

Hello Needle bender,

The angles straigth up produced by the antenna are not "handy" for sproadic e.
Though sproadic E requires a "higher" toa then the one we want for true DX, straight up is far beyond usefull.

The different heigths above ground are mentioned in each plot.
for example the first plot is "@5 meters heigth".
(roughly multiply that number by 3 to get feet.)

Kind regards,

Henry 19SD348
All about antennas

Henry, I am going to study your plots, etc more. Please continue to add whatever you believe to be useful to the discussion of loops mounted in the way this one is. I appreciate it.

 

[BOOTY MONSTER]

your mast on the tilting rig is also close to a wavelength isn't it ? so it would have potential issues above and below it . would the different polarization help minimize what ever effects they might cause each other ? i guess there could also be some possible benefits to each other too .... ??

 

[Needle Bender]

Hello Needle bender,

The angles straigth up produced by the antenna are not "handy" for sproadic e.
Though sproadic E requires a "higher" toa then the one we want for true DX, straight up is far beyond usefull.

The different heigths above ground are mentioned in each plot.
for example the first plot is "@5 meters heigth".
(roughly multiply that number by 3 to get feet.)

Kind regards,

Henry 19SD348
All about antennas

henry i thought the angles on the 11 meter high loop would be good for sporadic e dx since they look like about 35-40 degrees.
i saw the different heights but what i wondered was if the ground gain was already factored in not the simple free space gain that it looks like it shows. but i know its the height above ground causing the different pattern angles.
like a yagi beam has both simple free space gain you see in the models, then you add the horizontle ground gain of about 6db
so do these patterns just show simple free space gain even though there a certain amount above ground to get the pattern shape or is the 6db horiz ground gain already added?
the reason i ask is because some of those patterns show less than 6db gain even though its horiz polarity and seems like if the 6db horizontle ground gain was added it couldnt be less then 6db could it? are some heights actualy giving negative free space gain compared to a dipole and before the horiz ground gain is added?

 

[Henry HPSD]

Hello,

Ill get back to you needle bender probarbly tomorrow...its already past 21.00 and still work to do...spending way to much time behind the forum lol..

@ Homer BB,

Attached you can find a elevation plot of three different antennas at appoximently 41 feet.
The vector 4000 the Cobwebb and the horizontal quad loop.

The advantege of the "ground gain" with the horizontal polarisation combined with the rigth angle makes the smallest antenna the winner for real dx

You asked any other thing that came up...just to speak out...
Well you migth do a search on perhaps "phased single loop" (or somthing similair).
I recall a horizontal loop (thougth from a german) who had two feed points (fed as a w8jk) with the bennefit that the angles were brougth down to make it attractive for DX again.
Cant remember who it was though.. I do think i will remember perhaps after a good nigth sleep it migth get back to me...

Kind regards,

Henry HPSD
19sd348
All about antennas

 

[Needle Bender]

or if you just want to cut to the chase and get true omnidirectional low toa horiz with gain you could try 2 1/2 wave egg-shaped loops with the small end of the egg at the feed point and the big end open.
put one loop 22 1/2 feet above the other but phaze them with 3/4 wave x vf 75ohm like hams do with 2 meter halos.
you will also need a shorted matching stub on each one for 50ohm.
you can also reverse the phaze and flip one over to use one length of 1/4 wave long and one 3/4 wave long 75ohm :blink:

 

[Needle Bender]

here ya go homer 10m HALO PROJECT - i1wqrlinkradio.com
just add about 8.8% for 11 meters(ch20)
if you egg shape it then it will be closer to a true omni or else the feed end seems to have about 3db more gain then the sides and about 1 1/2 db more then the other (open) end.

 

[HomerBB]

Thank you, NB

 

[Needle Bender]

Thank you, NB

have fun. thats just one version. i prefer a shorted stub match but that will work good to.
and it was good to talk to you on L38 a couple months back

 

[Marconi]

Homer, here are three models, one is a quad physically mounted horizontally like your current antenna, the other is the same quad physically mounted vertically, and a single element horizontally polarized dipole. All are at 36' feet to the feed point. The first image is an overlay of all three patterns, with the *Primary being the horizontal dipole.

View attachment Homer's quad and dipole project.pdf

I have not yet compared my model of your horizontal quad at various heights like Henry did, but I have attached my model at 13 meters and it shows to be similar to his model at 13 meters.

View attachment Homer's horizontal quad at 13 meters.pdf

I would not have assumed that your quad mounted horizontally would show NVIS trendinesses, so I was surprised to see that in Henry's variations at different heights the vertical lobe showed up as it did. I've said it before that the positive affects of height is not linear, so maybe this proves again that higher is not always better. I only came to that understanding after learning to model a little bit, and now Henry's 11 meter model here helps confirm that I was right and not just some stupid mistake that I had made with the model. Your outdoor quad may just be mounted at a lucky height. My model showed it to be pretty responsive with some nice gain at a low angle, but it was not as good as I expected so I modeled the other two to see how it might compare and maybe help explain what you were seeing compared to your Vector.

Maybe if you raise the quad a couple of feet or more you'll see what Henry's models show...the NVIS lobe take over and the low angle gain go away.

 

[HomerBB]

Looks like raising it would be the worse thing to do for DX.

Your three overlays show a slight advantage to a dipole as I saw it, but not much. It seems the value of a loop is either vertically mounted, or as a quad.

Do me a favor if you can. Model the loop vertical with a second loop on the same vertical axis x-ways to the other so that looking straight down on them you'd see a +

Both of them fed in phase to create a single antenna pattern.

Like this:

 

[BOOTY MONSTER]

Looks like raising it would be the worse thing to do for DX.

Your three overlays show a slight advantage to a dipole as I saw it, but not much. It seems the value of a loop is either vertically mounted, or as a quad.

Do me a favor if you can. Model the loop vertical with a second loop on the same vertical axis x-ways to the other so that looking straight down on them you'd see a +

Both of them fed in phase to create a single antenna pattern.

Like this:

homer has left the box

 

[Needle Bender]

Homer, here are three models /

I would not have assumed that your quad mounted horizontally would show NVIS trendinesses, so I was surprised to see that in Henry's variations at different heights the vertical lobe showed up as it did...

i just gotta pat myself on the back and remind all my admirers that i saw that back in post #16
im so proud of myself

Do me a favor if you can. Model the loop vertical with a second loop on the same vertical axis x-ways to the other so that looking straight down on them you'd see a +

Both of them fed in phase to create a single antenna pattern.

Like this:

i think you will see an octapuss pattern.
will your modeling program let you input the same 90 degree cross but with one below the other a 1/4 wave?

 

[Robb]

I would turn Homer's horizontal loop to vertical and mount a reflector element behind it.

Instant PDL II!