SPLAT !
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K4EET
Chaplain
You are one busy beaver. SPLAT! is decent propagation analysis software for Windows and Linux. I use the Windows version. As a RF propagation engineer myself, originally trained in college and at Motorola, it makes using this software easier. You do need to input valid variables or the plots are not going to come out right.
To understand what to do with SPLAT!, you really need a good instruction manual but RF Propagation books are not cheap as seen by searching Amazon for "RF Propagation." One book caught my eye but I can't vouch for it because I've not used it. The book is titled:
Radio Frequency Propagation Made Easy (SpringerBriefs in Electrical and Computer Engineering) 2015th Edition
by Saleh Faruque (Author)
https://www.amazon.com/Frequency-Propagation-SpringerBriefs-Electrical-Engineering/dp/3319113933/
There may be some web sites on the Internet that discuss RF Propagation but I did not search for them. If I have time later, I might give it a go.
As you've found out, RF Propagation software can be quite cryptic to the uninitiated. I do want to ask, what exactly are you looking to plot? If point-to-point communications, SPLAT! may be a tad overkill.
73, Dave K4EET
Its just the way I learn things. I learn quickest when I start at the bottom with basics, then jump towards the middle, then back to the basics, then jump up to the middle again... Eventually that pattern moves higher up the scale to the advanced stuff. It makes the learning curve steeper, but decreases the time. Its what works for me.
I figured out SPLAT was overkill about a minute after I clicked the exe file, but I like overkill. Even if I don't learn it all, which I'm sure I won't even come close, it is still beneficial and a lot of fun trying.
The version I have is 1.1.2 (for windows).. and its not quite right. When it generates the PPM text for the command line, its using the wrong executable file. I have to edit the beginning of the command line of the [filename].ppm.txt file before using it in DOS.
Then it seems like it gets busy doing its thing and processing, until it gets to the city.dat and it just hangs. It goes through several processing steps which takes about 3 to 5 minutes on my Core i5, but when it says "processing city.dat", it just stalls.. I let it run there for an hour and nothing.
I figured out SPLAT was overkill about a minute after I clicked the exe file, but I like overkill. Even if I don't learn it all, which I'm sure I won't even come close, it is still beneficial and a lot of fun trying.
The version I have is 1.1.2 (for windows).. and its not quite right. When it generates the PPM text for the command line, its using the wrong executable file. I have to edit the beginning of the command line of the [filename].ppm.txt file before using it in DOS.
Then it seems like it gets busy doing its thing and processing, until it gets to the city.dat and it just hangs. It goes through several processing steps which takes about 3 to 5 minutes on my Core i5, but when it says "processing city.dat", it just stalls.. I let it run there for an hour and nothing.
As for what I'm trying to plot? Everything.. I want to know it all.. I'll probably end up knowing 20% if I'm lucky and motivated though.
K4EET
Chaplain
Are you sure you have all of the parameter inputs the correct value? If you just guessed at numbers to fill in the blanks, you might end up with a "divide by zero" situation that might cause the program to hang. Even I have to do a fair amount of research to come up with all of the parameters to get a "accurate" plot.
I too have Windows GUI Version 1.1.2
What type of analysis are you trying to plot?
73, Dave K4EET
I too have Windows GUI Version 1.1.2
What type of analysis are you trying to plot?
73, Dave K4EET
I'm trying to run the sample files that came with the software.. One is "Dresden Water Tower" or something. I have no idea where that is but its what came with the software as a sample.
You thought I was trying to use my own parameters? LOL.. Ya, I wish. From the looks of it, I'm going to be spending days learning to understand each parameter and what it means. Then probably more days experimenting and changing it to figure out how it affects the results.
ENTER "Earth Dielectric Constant" Huh? What the heck is that? Actually, that was a really easy one to comprehend, and figuring out what number I need to enter into that parameter was as simple as a google search.
Of more interest on the EDC, how would that number change, and how much, if one was in an area where they mine iron ore or copper near the surface? And how critical is this parameter? Is a guesstimate acceptable or is it an important value that will greatly affect the results?
For now, I'm just trying to get SPLAT to run with the sample files. All the files and parameters are preset.
K4EET
Chaplain
I never did try to run the sample files. I'll try that today. Cheers! Dave
Had some success! I finally got SPLAT to generate a KML file based on the Dresden Water Tower data and was then able to superimpose that data over a google earth view and see coverage results.
Then I tried it with my own parameters, copied most of the stuff from the Dresden file... SPLAT didn't do anything with it.
Got frustrated and going to give it a break for a while. Made some progress and learned a few things..
In the words of Arnold "I'll Be Back!"
Then I tried it with my own parameters, copied most of the stuff from the Dresden file... SPLAT didn't do anything with it.
Got frustrated and going to give it a break for a while. Made some progress and learned a few things..
In the words of Arnold "I'll Be Back!"
Ok, so I got my own parameters to work and am capable of importing to Google Earth. So now I need to model my antenna and I'm not sure where to go from here.
Assuming I have an N9TAX antenna connected to 50 feet of RG8 /U (.405 diameter) and feeding 50 watts at 145 Mhz. (lets just ignore SWR so my head doesn't explode)
From what I understand, the N9TAX has a 6db gain and has an angle of radiation of 10 degrees. Is that plus and minus 10 degrees or a total of 10 degrees?
So if I push 50 watts into a 6 db antenna at 144 Mhz, and my coax, connectors, etc, suffers -3db, then my ERP (effective radiated power) is 50 watts +3db which is 100 watts.
Do I have that correct?
Assuming I have an N9TAX antenna connected to 50 feet of RG8 /U (.405 diameter) and feeding 50 watts at 145 Mhz. (lets just ignore SWR so my head doesn't explode)
From what I understand, the N9TAX has a 6db gain and has an angle of radiation of 10 degrees. Is that plus and minus 10 degrees or a total of 10 degrees?
So if I push 50 watts into a 6 db antenna at 144 Mhz, and my coax, connectors, etc, suffers -3db, then my ERP (effective radiated power) is 50 watts +3db which is 100 watts.
Do I have that correct?
I'm having a problem understanding the SPLAT .az files and how they apply to a SlimJim N9TAX antenna.
I've looked at the Dresden Tower .az file and another one posted on the internet and not sure how much sense they're making.
Wouldn't the power radiated for an omni directional antenna be the same all the way around the azimuth?
The .az file is supposed to list each degree of azimuth from 0 to 360 and then a number from 0 to 1 representing (i think) some kind of power ratio.
I'm guessing that a large object near the antenna would cause those numbers to vary a bit.. Perhaps even the magnetic field lines of the Earth cause some variation as well??? But I would think the numbers should all be close yes?
What do those numbers actually represent?
I've looked at the Dresden Tower .az file and another one posted on the internet and not sure how much sense they're making.
Wouldn't the power radiated for an omni directional antenna be the same all the way around the azimuth?
The .az file is supposed to list each degree of azimuth from 0 to 360 and then a number from 0 to 1 representing (i think) some kind of power ratio.
I'm guessing that a large object near the antenna would cause those numbers to vary a bit.. Perhaps even the magnetic field lines of the Earth cause some variation as well??? But I would think the numbers should all be close yes?
What do those numbers actually represent?
K4EET
Chaplain
All depends on how the manufacturer speced the antenna. Also, the radiation pattern is probably not a perfect doughnut shape.
Yes, ERP = Transmitter Power Output x Line Loss x Antenna Gain = 100 x 0.5 x 2 = 100
Cheers! Dave K4EET
K4EET
Chaplain
The correlation between ERP and EIRP is:
ERP = EIRP/1.64 = 100/1.64 = 60.975 watts
In your previous post, that is technically right too based on the formula which actually assumes that you are talking about Equivalent (or Effective) Isotropically Radiated Power (EIRP). When you throw in the calculation to compare to an isotropic radiator, then you get this formula.
Cheers! Dave K4EET
K4EET
Chaplain
Theoretically, yes.
FROM: https://manned.org/splat/263a6da8
The first line of the .az file specifies the amount of azimuthal pattern rotation (measured clockwise in degrees from True North) to be applied by SPLAT! to the data contained in the .az file. This is followed by azimuth headings (0 to 360 degrees) and their associated normalized field patterns (0.000 to 1.000) separated by whitespace.
The Dresden Water Tower antenna pattern looks to be Cardioid with the null at 196.5 degrees from North.
Cheers! Dave K4EET
K4EET
Chaplain
With respect to the ERP versus EIRP question, this is a pretty good writeup:
https://en.wikipedia.org/wiki/Effective_radiated_power#Dipole_vs._isotropic_radiators
73, Dave K4EET
https://en.wikipedia.org/wiki/Effective_radiated_power#Dipole_vs._isotropic_radiators
73, Dave K4EET
Theoretically, yes.
FROM: https://manned.org/splat/263a6da8
The first line of the .az file specifies the amount of azimuthal pattern rotation (measured clockwise in degrees from True North) to be applied by SPLAT! to the data contained in the .az file. This is followed by azimuth headings (0 to 360 degrees) and their associated normalized field patterns (0.000 to 1.000) separated by whitespace.
The Dresden Water Tower antenna pattern looks to be Cardioid with the null at 196.5 degrees from North.
Cheers! Dave K4EET
So wouldn't an N9TAX slim jim antenna just be an even number all the way around for the most part on the horizontal axis? I realize there might be some variance but what number would I plug in from 0 to 1?
I figure the horizontal should be a no-brainer.. but the vertical numbers need to make it look like a doughnut or an inflated tire inner-tube right?
I created my az file by putting my numbers into an excel sheet first and labeling rows 0 to 359.. then I assigned each row the number 0.8 and sent the whole thing into a text file and labeled it Home.az. My top number is 360 to mean all 360 degrees but I wasn't sure if it should be zero or 359.
Like this
360
0 0.8
1 0.8
2 0.8
3 0.8
As it stands, SPLAT is showing me only smooth and even concentric circles and doesn't seem to be taking any topographical features into consideration. I'm doing the Longley Rice path loss thingy and if I didn't know better, I think the software thinks I'm in outer space because the rings are so perfectly round.
Come to think of it, the software might be right.. LOL.. This stuff is over my head.
K4EET
Chaplain
While J-Poles theoretically have a "decent" omnidirectional pattern, nowhere does N9TAX on this webpage specify what the horizontal plane radiation pattern is. N9TAX was criticized in this review for not providing that pattern.
Lacking any specific criteria, I would just use a normalized figure of 1 all the way around.
Theoretically, yes.
If you live in the middle of a flat dessert, a circle is what you will get. Don't drown in the details. LOL!
73, Dave K4EET
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