I see some similar Patterns between the Pattern View in the article and my Eznec, but this software program likely uses a lot more "smoothing" and details in their images.
Let me read the text again,
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Antenna height
- Thread starter edfiero
- Start date
Let me read the text again,
Sure Marconi, I just noted that the article premise is "0.25-1.25 lambda = bad, don't do that". Yet the model at 0.5 wavelength looks to emit more RF at a lower angle than the 2 images prior. In my test over the weekend I had feed point at approx 3.5 - 4m and it seems to work ok.
Blaster, I'm currently having my computer with my Eznec updated to Windows 8, so I can't compare a 1/4 wave GP with horizontal radials to the antenna modeled in the article above.
Just looking at the Antenna Patterns however, they are basically showing what I demonstrated at 36', 40', and 50' feet using my model of a SP500, 5/8 wave. At least the trends seem to be similar...with angle going down in raising the antenna, and the gain increasing as we raise the antenna up.
I also did a model at 1.25 wavelength to show those effects on this model, because Mike made a specific claim for a big difference in angle at 0.26wl and 1.25wl. There is a difference and I talked a little about that already,
Just looking at the Antenna Patterns however, they are basically showing what I demonstrated at 36', 40', and 50' feet using my model of a SP500, 5/8 wave. At least the trends seem to be similar...with angle going down in raising the antenna, and the gain increasing as we raise the antenna up.
I also did a model at 1.25 wavelength to show those effects on this model, because Mike made a specific claim for a big difference in angle at 0.26wl and 1.25wl. There is a difference and I talked a little about that already,
Yes I just noted the models imagery seem to tell a different story than the words in that particular article.
Again, I will comment when I get my Eznec back and am able to model that conventional 1/4 wave GP.
The text is in complete agreement with the polar elevation image presented. It is clear that the larger portion of the radiated power is present in the upper high angle lobe.
However, it would seem to me that what could "bring you up into DXCC highscore" would be increased levels of power in the lower of the two pattern lobes instead of wasting power at the higher angles, unless of course you're into multi-hop propagation.
However, it would seem to me that what could "bring you up into DXCC highscore" would be increased levels of power in the lower of the two pattern lobes instead of wasting power at the higher angles, unless of course you're into multi-hop propagation.
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Here is my model Blaster. I did the 1st model to show these would be similar using Eznec. I don't feel like doing all the work just to try an duplicate the work in the article. There is a small difference to be noted and that is likely error or some dimension.
Based on my reading, I think this report is much to do about nothing.
We do see what the author describe higher lobes...but I don't concentrate on the high angles, because as the antenna is raised, so is the gain at the maximum lowest angle.
Some times this lower lobe gets to be more narrow in beam width...so that might suggest a limiting in effective work at a distance at some angles.
I did not consider the 0.25wl idea, but the 1.25wl idea seemed to me to only add a new lobe up high. IMO, it is likely useless for good work...unless maybe you need a higher angle to get over a mountain for example.
Just my opinion and observations.
Can you please explain how does the "hat rim" going beyond that of the top of the hat represent "the larger portion of the radiated power is present in the upper high angle lobe." (on what must be the X axis in dB)
Peak gain looks very obviously to be at a lower angle. See the red below on attached image that is a lower angle not higher. This is my last post on this because it is so unbelievably obvious that I cannot waste further time of my life on it. if you cannot see it then so be it.
Thanks Marconi GPA looks like it should DX just fine at 0.25 wavelength, at least in the model.
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Modelling is all fine and dandy.
Problem is if you don't have the real estate to follow that modelling you have limited choices.
First you have to decide what you want to do with the antenna, local contacts? get it up as high as feasable and safe which gives you the furthest distance to the horizon and range.
DX? get it up as high and as safe possible, so you get good local contacts and dx as well.
Is it perfect? no, is my Imax 2000 perfect? no
Is my hight above ground ideal?, no at 11.5 meter it is not.
It however fills my needs since it works on 10/11/12/15/18 with decent swr, house + alutube is 11.5 meters above ground.
The imperfect antenna at imperfect hight for those bands worked from the Netherlands to New Zealand, Australia, Japan, in short the world round with good signals.
See, since i use it as multiband antenna there will always be an not ideal hight or radiation pattern, working as 5/8 to 1/2 wave antenna for 15/18.
It does work the world around, takes the 1000 watts from the Heathkit SB-1000 without problems, and the last one worked 18 years before the top broke off.
Cost only a fraction of what a HAM multiband antenna would have cost and i got this one for free.
In reality conditions will have much more to do what you work, most real dx is in 2 to 10 degrees above the horizon but multi hop propagation on higher angles will work just as fine.
It helps that under the antenna's here i have 3000 feet of radials for my 160 meter vertical, that radial field runs under all my antenna's horizontal/vertical.
Helped by good soil ( young rich sea clay) does the rest.
Mostly running 100 watts here, so that is that.
Running digital mode now on 15 with the Imax, Indonesia, Israel, Brazil, Kenya,Argentina, for starters, just in 15 minutes.
So you can model an antenna to death and then do some real life experiments like i do on the edge of the city here, within the restrictions you have from your real estate or possible antenna site.
Seems real life experiments work as well.
Problem is if you don't have the real estate to follow that modelling you have limited choices.
First you have to decide what you want to do with the antenna, local contacts? get it up as high as feasable and safe which gives you the furthest distance to the horizon and range.
DX? get it up as high and as safe possible, so you get good local contacts and dx as well.
Is it perfect? no, is my Imax 2000 perfect? no
Is my hight above ground ideal?, no at 11.5 meter it is not.
It however fills my needs since it works on 10/11/12/15/18 with decent swr, house + alutube is 11.5 meters above ground.
The imperfect antenna at imperfect hight for those bands worked from the Netherlands to New Zealand, Australia, Japan, in short the world round with good signals.
See, since i use it as multiband antenna there will always be an not ideal hight or radiation pattern, working as 5/8 to 1/2 wave antenna for 15/18.
It does work the world around, takes the 1000 watts from the Heathkit SB-1000 without problems, and the last one worked 18 years before the top broke off.
Cost only a fraction of what a HAM multiband antenna would have cost and i got this one for free.
In reality conditions will have much more to do what you work, most real dx is in 2 to 10 degrees above the horizon but multi hop propagation on higher angles will work just as fine.
It helps that under the antenna's here i have 3000 feet of radials for my 160 meter vertical, that radial field runs under all my antenna's horizontal/vertical.
Helped by good soil ( young rich sea clay) does the rest.
Mostly running 100 watts here, so that is that.
Running digital mode now on 15 with the Imax, Indonesia, Israel, Brazil, Kenya,Argentina, for starters, just in 15 minutes.
So you can model an antenna to death and then do some real life experiments like i do on the edge of the city here, within the restrictions you have from your real estate or possible antenna site.
Seems real life experiments work as well.
i encourage guys that experiment and work in the Real World with their radios. I spent a few years doing that after I retired in 1991. I did my 1st model in 2011.
At 82, I enjoy my modeling and that is about all I can do physically anymore.
So, I don't think I'll let you steal my joy today.
At 82, I enjoy my modeling and that is about all I can do physically anymore.
So, I don't think I'll let you steal my joy today.
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I don't have a problem with antenna modelling.
I have Karl Rothammels antenna book, RSGB, ARRL antenna books, UN4UN low band dx book, our bibles before antenna modelling became the new fad.
At 68 i still climb on the slanted tiled roof to change my antenna's or take down and re erect my 77 foot long vertical if need be.
Problem is with modelling you get a nice idea what an antenna will do in the model limitations and take some of that if it fits in your real estate as rule of thumb.
Problem is no real estate is the same, i live on the edge of the city good ground ( silty sea clay) and a row of 6 houses on a plot that is 100 x 23 feet in size, postage stamp dimensions.
On that tiny plot i got up an FD-4 lengthened with coil and 33 feet of wire to work from 160 - 6 meter, the Imax 2000, an vertical L of 77 feet high 3000 feet radials from my plot into the neighbours plots and street, and Diamond X 510N and Diamond discone.
Add homebrew active HF antenna as far from buildings as possible
So whatever modelling i would do, all antenna's will have influence on eachother, as will the radials in/on the ground have, as well the buildings will have, as well my far field ground influence have on my antenna's and radiation patterns.
The antenna books were our antenna modelling aids, i picked out of them what i could get away with including offering whipped cream cakes to neighbours to get permission to use their houses as hanging point for my wire antenna,s and guy wires for the vertical.
I would like to see the computer modelling program that can take all that stuff in and come up with real results.
So, for the time being i stick to hard work putting (experimental) antenna's up and see what they do in real life.
For me that is the fun in the hobby, put up an antenna even when you fail you will learn from it.
That is how i did it from the ripe age of 12 years young.
I have Karl Rothammels antenna book, RSGB, ARRL antenna books, UN4UN low band dx book, our bibles before antenna modelling became the new fad.
At 68 i still climb on the slanted tiled roof to change my antenna's or take down and re erect my 77 foot long vertical if need be.
Problem is with modelling you get a nice idea what an antenna will do in the model limitations and take some of that if it fits in your real estate as rule of thumb.
Problem is no real estate is the same, i live on the edge of the city good ground ( silty sea clay) and a row of 6 houses on a plot that is 100 x 23 feet in size, postage stamp dimensions.
On that tiny plot i got up an FD-4 lengthened with coil and 33 feet of wire to work from 160 - 6 meter, the Imax 2000, an vertical L of 77 feet high 3000 feet radials from my plot into the neighbours plots and street, and Diamond X 510N and Diamond discone.
Add homebrew active HF antenna as far from buildings as possible
So whatever modelling i would do, all antenna's will have influence on eachother, as will the radials in/on the ground have, as well the buildings will have, as well my far field ground influence have on my antenna's and radiation patterns.
The antenna books were our antenna modelling aids, i picked out of them what i could get away with including offering whipped cream cakes to neighbours to get permission to use their houses as hanging point for my wire antenna,s and guy wires for the vertical.
I would like to see the computer modelling program that can take all that stuff in and come up with real results.
So, for the time being i stick to hard work putting (experimental) antenna's up and see what they do in real life.
For me that is the fun in the hobby, put up an antenna even when you fail you will learn from it.
That is how i did it from the ripe age of 12 years young.
I agree conditions are the most important factor. However the antenna and its installation related performance can become the most important factor when the DX is weak. Then the antenna and installation can make the difference between RX hiss and call signs in the log book.
Like that 7dB null circa 30 degrees in those model overlays. I would not fancy one of those antennas for Sporadic E DXing... which was essentially the entire summers DX here, maybe 150-200 contacts May - September made (excepting a few F2's in the 3-6k miles distances come autumn after the E layer calmed down)
And what of the most interesting contacts ? S0 to S2's usually (as it has always been in weak skip) - interesting countries, islands and pedestrian ops. Not the same old same old.
You are right reality is using your antenna and being successful. Without reality of DX contacts (afterall what are you in it for?), models have no point to exist.
They have a place and I do enjoy looking at them. But the end result of contacts is what radio means to me. I have that part in the bag for 11m at least.
Like that 7dB null circa 30 degrees in those model overlays. I would not fancy one of those antennas for Sporadic E DXing... which was essentially the entire summers DX here, maybe 150-200 contacts May - September made (excepting a few F2's in the 3-6k miles distances come autumn after the E layer calmed down)
And what of the most interesting contacts ? S0 to S2's usually (as it has always been in weak skip) - interesting countries, islands and pedestrian ops. Not the same old same old.
You are right reality is using your antenna and being successful. Without reality of DX contacts (afterall what are you in it for?), models have no point to exist.
They have a place and I do enjoy looking at them. But the end result of contacts is what radio means to me. I have that part in the bag for 11m at least.
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I envy you young guys getting to work on your ideas for antennas.
Soon, I will be on the air after about 5 years hiatus from the hobby. I have children that can get the work I need done. So, it's Christmas time for old Grampa...at Marconi's house.
Texas Call 39zero.
Soon, I will be on the air after about 5 years hiatus from the hobby. I have children that can get the work I need done. So, it's Christmas time for old Grampa...at Marconi's house.
Texas Call 39zero.
Great you have the assistance ! I love putting antennas up.. one of the favourite parts of the hobby. and at the end of the day you can do much with little in this hobby, you don't have to be seeking the very best performance possible.
You don't have to climb anything to ground mount a good antenna with a bunch of performance enhancing radials, look up and be proud of your work. And a decent antenna can cost next to nothing as well.
There are many areas of interest and everyone has preferences for some areas of radio than others. You do the parts that you like to ! That is the beauty of it.
You don't have to climb anything to ground mount a good antenna with a bunch of performance enhancing radials, look up and be proud of your work. And a decent antenna can cost next to nothing as well.
There are many areas of interest and everyone has preferences for some areas of radio than others. You do the parts that you like to ! That is the beauty of it.
Hi, TB.
The text is a statement of quantity, not gain.
The hat brim shows more gain along a very thin slice over the overall 'quantity' of rf radiated. Above that thin hat brim there is a deep null.
Above that there is a big bulge (lobe) of radiation. That big lobe has the largest 'quantity' of rf.
Most of this hat is in the big lobe, not the brim, but the brim sticks out laterally more than the bulk of the hat material.