Delta Loop Help

[2RT307]

Hi guys, I have a delta loop on my roof due to HOA restrictions. I believe that each leg is about 30 feet long. Wasn't able to measure it while I was on the roof, and I fed it from a spool. So I'm estimating the entire loop is 90 feet. That should be resonant around 11 MHz, right? Not a representation of my house, but the triangle part is the same... I have it fed from the bottom right corner of the triangle, as shown in my primitive diagram:



I'm getting conflicting messages on which way it is polarized being fed in the corner. My ARRL book says it is vertically polarized, but in figure 10-11 of this publication, it says it is horizontal:
http://www.k4qky.com/files/ON4UN-Large Loops.pdf

This is obviously a compromise antenna, but I'm trying to figure out how to best make use of it. Receive is really good with it on 40-10 meters. And if anyone wanted to do an Eznec model of it, it would really be helpful. I don't have an antenna analyzer, so I don't really know where it is "good".

Adding on to this: I actually have the wire antenna connected directly to a 4:1 balun. It seems to work. My shack is only about 12-15 feet away. Should I run ladder line from the loop to the balun, and then run coax to the shack, or is it fine just like it is?

73,
Brett

 

[GnG8d]

I wouldn't look at the attachment point as much as the orientation. With it being laid back like that I'd guess it's just acting like a horizontal loop.

 

[RatsoW8]

How close is the lower leg and feed point to the gutter and are they plastic or metal? A metal gutter that close to a wire antenna and in parallel with it can cause some problems.

 

[W5LZ]

If that balun is at the feed point, and it's working, I think I'd leave it alone unless you just want to experiment.
As far as the vertical/horizontal thingy, I doubt if it will make a huge difference, do you?
- 'Doc

 

[Henry HPSD]

Not sure the angle it is in....
and of course not dealing with the house etc.
but....:

rt207 | CB Antennas
(click)



Roughly ; 2 resonant points.

And for you the see when it is vertical or horizontal.

Hope this is what you were looking for and if it is of use..

Kind regards,

H.

(ps i wont leave it on long...let me know if u have futher questions and/or have seen it.)

 

[2RT307]

How close is the lower leg and feed point to the gutter and are they plastic or metal? A metal gutter that close to a wire antenna and in parallel with it can cause some problems.

No gutters on *my* house on that side. Shoulda mentioned that!

73,
Brett

 

[2RT307]

If that balun is at the feed point, and it's working, I think I'd leave it alone unless you just want to experiment.
As far as the vertical/horizontal thingy, I doubt if it will make a huge difference, do you?
- 'Doc

'Doc, I don't know if it will make a huge difference or not. Right now, I do pick up some noises from what I think is the alarm or cable system. Nothing really bad, but I thought if it were horizontally polarized I might totally eliminate them. ARRL actually shows a loop similar to this in my antenna book, and they say it works really well. I've only had marginal results so far on 10 meters with it. Can't play anywhere else until I get General.

73,
Brett

 

[2RT307]

Not sure the angle it is in....
and of course not dealing with the house etc.
but....:

rt207 | CB Antennas
(click)



Roughly ; 2 resonant points.

And for you the see when it is vertical or horizontal.

Hope this is what you were looking for and if it is of use..

Kind regards,

H.

(ps i wont leave it on long...let me know if u have futher questions and/or have seen it.)

Thanks H. SWR plot sure is high, huh.

73,
Brett

 

[Henry HPSD]

Perhaps i should have said...

Dont look to much at the SWR...
SWR is of not that important (although many think otherwise hihi)
In this case it is set to look at 50 ohms...direct feed.
So...if you would direct feed the antenna with 50 ohms thats more or less what you would come up with.
If you "set" it at 200 ohms it would provide other results.

THe reason why SWR is not so important:
Its one of the few factors of a antenna you CAN change with rather limited effort.
(your balun for example)

Changing the az/el plots..thats a different story.

 

[2RT307]

Perhaps i should have said...

Dont look to much at the SWR...
SWR is of not that important (although many think otherwise hihi)
In this case it is set to look at 50 ohms...direct feed.
So...if you would direct feed the antenna with 50 ohms thats more or less what you would come up with.
If you "set" it at 200 ohms it would provide other results.

THe reason why SWR is not so important:
Its one of the few factors of a antenna you CAN change with rather limited effort.
(your balun for example)

Changing the az/el plots..thats a different story.

I see. I wasn't sure if you had calculated the 4:1 balun into it or now. I see 2.16 db gain on 28.500. I guess that's not TOO bad.

73,
Brett

 

[HomerBB]

It's good to see you figuring out how to overcome the HOA restrictions.
I still have the 11 meters rectangle loop in the attic. I also still have an EDZ dipole above the roof ridge about 3'. The loop is better than the EDZ. I don't know if that is a universal expectation, but the results are what they are. I'm thinking in my case the loop is not as sensitive to the nearness of the roof and whatever is within it as the loop.

I hope all is well.

 

[2RT307]

It's good to see you figuring out how to overcome the HOA restrictions.
I still have the 11 meters rectangle loop in the attic. I also still have an EDZ dipole above the roof ridge about 3'. The loop is better than the EDZ. I don't know if that is a universal expectation, but the results are what they are. I'm thinking in my case the loop is not as sensitive to the nearness of the roof and whatever is within it as the loop.

I hope all is well.

Hey Homer, all is well. Hope you and your family are too! I've been tossing the idea of an EDZ around, as it is an all band option for me, and the length looks do-able. Then I will have three wire antennas in the yard. An invisible antenna farm, if you will. The end fed 1/2 wave you made for me still works well, but I'm looking for a General class answer to multi-banding. I don't think I can hit 80-75 with my space, but the ARRL claims a extended double zepp will hit it (barely) with 70 feet of wire. Should be fun to try it.

I noticed R+L has the MFJ analyzer that you have for a little over 200 bucks now.
MFJ 2 MFJ-259B , MFJ MFJ259B R&L Electronics REALLY tempted to buy one, as I don't see myself fiddling around with experimental home-brew antennas much in the UHF end of the spectrum. So the 259B should be enough for me. Thanks for putting in your comments, they are always much appreciated. BTW, you really need to get your ticket. Just sayin'.

73,
Brett