Loop Antenna Plan

HomerBB said:

When the zip file opens it shows the .maa in it. I have nothing that opens that extension.

Click to expand...

Link is in my post to the free modeling software mmana-gal, tiny program , easy to use, works very well.

Marconi said:

xm49,I did not try and unzip your file above that you posted as "mgmg my best loop.zip".

Not sure, but I think those files should open automatically with a file extension xxxxx.maa

Should we unzip the fill.

I entered this previous model from the images you posted. With the feed point set to horizontal the match was very good, right out of the box, using 75 ohm coax.

The vertical side was resonant but the resistance was 172.8 ohms with 50 ohm coax and was 2.305 ohms with 75 ohm coax and I made no attempt to match it. As you will see, the vertical side pattern showed 5.83 dbi gain at 11* degrees regardless of the mismatch. I also did not run these models in Free Space so as to check the Average Gain Results for model accuracy.

The pattern was similar to your image on post #1, but in your modeling details it showed it was horizontal. I think I see the feed point location at the 9:00 o'clock position, right?

Below are my two Eznec models in a PFD files. Just click on the "Open With" button in the pop-up window.

Homer, were you able to open xm49north7 zip file?

Click to expand...

Thank You Marconi for the modeling work, Good to have confirmation of my numbers , very close for sure, These are good numbers, feel free to tweak and see if you can get more out of here, I did get some higher numbers by dividing it up the middle with another wire, a smaller loop and a u shape, but it was nt worth the effort for building for another theoretical db. This general shape has worked well for me in the past I found it just by hand tuning in the air, so now that I can model in software I wanted to see if I was on the right track, and it seems that I am, I am still puzzled by why it would not have higher db with straight sides, I have run loops both straight sided, like this one, and some that were out of kilter a little, they all worked well, I do find for some reason that I seem to get a little better results with the feed more towards the bottom, and the software validates this, but in pure antenna theory, it should be dead center. Bt software and real work prefer it towrds the bottom 1-3, not the half way point. I have one up and fed for horizontal, but have no locals horizontal to try it with, a buddy is in the process of building a flat side 3 el beam, so I will know more in the spring when we get his flatsider up.

BJ radionut said:

It may be a cheap program and easy to use...but it has a major flaw!!!
Sorry but NO WAY a single loop antenna has 9.5+ DBI gain which would be 7+dB gain over a Dipole!
Can't happen! That's the gains of a 3 element yagi or if everything is done correctly, better than a 2 element Quad.
A single loop antenna if done correctly with impedance matching correct is at BEST 3dB over a dipole...period!
If this were as your program states correct, every manufacture for the last 75 years would have been building them, plus broadcast would be using them.
I am sorry North 47 but true!
I commend you for building and using your own antennas, however that program has some major design issues.
Well maybe that's what MACO, Gizmochee, Antron, and Solorcon use to model their antennas
All the Best
Gary

Click to expand...

not sure where you read over nine dbi, my model reads 6.15 dbi, which is around 4 dbd, which is well stated in most articles on quad loops, about double your standard vertical dipole, which really is what a loop is. Two dipoles in phase. I can attest to the effectiveness of loops, and concur that this seems to be the case in use. I do not have any trouble with these gain numbers. . Loops perform very well. I am surprised more people do not try them. Bi-directional with better pattern than a dipole, some gain , great receive. Loops sit in a sweet spot for me of having a bit of everything, I have had most every kind of antenna up. Loops have been very effective for me.

I have them around one full wave length, 36 feet to the feed point, higher is always better, up to about 1.5 wave lengths. 54 feet. After that you trade some dx for better local. I think any antenna for cb radio does very well at 36 feet to the feed. Loops will work at any height on a vertical feed, have even got out well with bottom wire 8 feet off the ground. I really do like a loop, have had 5/8th, dipoles, j-poles, 2 el beam, 4 el beam, a moxon, the loop has been my favorite to date.

Redbeard U812 said:

Current antenna at 37'. Have some play in build of new tower pending stability.

Just hope that when I get it all working there's propagation.

Click to expand...

Here in eastern ontario, skip starts around april 15 runs to about sept. 15, Get the odd contact in the winter , but few and far between.

Redbeard U812 said:

Few weeks ago had sporadic skip, made two contacts up yonder to Canada awl the way down here in TX.

Click to expand...

That is a good trip for sure, I have not had a contact in Texas yet, Have made most of the East coast as far as Florida On my 12 watt bearcat 980, on the full wave loop, last summer was great, got out many times every day.