speadsheet test ........

[GnG8d]

I haven't figured out how to save as a jpeg yet, so I am still printing/scanning. But with all of this antenna testing going on, and with me getting ready to build one, I thought I'd come up with a spreadsheet to show tuning results.

I used my mobile for a reference since all of my base stuff is on the ground. I took direct SWR readings, but altered the resistance and reactance to keep everything relative on the graph .....

resistance = R-50*.1
reactance = X*.01

see what you think, useful, useless?

 

[GnG8d]

Okay, well, I pulled my stinger out a bit and added some reference lines. I'm going to call it good. It aint professional or anything, but it'll work for me. If anybody wants to use it as a template, just PM your email for a copy.

 

[Marconi]

Pretty clever. I capture the data in my analyzer scans, but I don't do anything with it. You're factoring the values to control their relative placement on the graph is a great idea and probably the way is should be done.

I've tried plotting my R, X, SWR, but without my factoring the data like you did...the graph gets pretty big and unruly. Very nice work, and again a picture is worth a 1000 words...and certainly can tend to help understanding the wavering nature of these factors.

What device do you use to make your plots, that is slick also?

 

[GnG8d]

What device do you use to make your plots, that is slick also?

Not so slick actually, lol, I just sweep the freqs with my 259b and write the data down at the control points. Then I take that data and put into the spreadsheet.

 

[W5LZ]

It's a nice chart but what's the significance of it?
- 'Doc

 

[GnG8d]

Okay, I've wasted enough of my day and enough forum space on this now. I decided that reactance needed more weight and redid it, I'm done.

R-50*.1
X*.1

 

[GnG8d]

It's a nice chart but what's the significance of it?
- 'Doc

Significance of what?

 

[Marconi]

Significance of what?

I believe your idea is right 359, reactance is almost totally ignored by most that are interested in matching and the Z of a match point.

Doc' is right to question however, considering he probably uses a divining stick found in the garden...in order to find his feed point match.

 

[W5LZ]

I'm wondering what the purpose of this chart is, it's significance. It does show the relationship of reactance, resistance and SWR, and frequency, nothing wrong with that. But it only gives a quantitive value for SWR and frequency, no interpretive means of determining resistance. So, it does illustrate the behavior of Z/R/F/SWR. But that relationship isn't realistic because of that 'shape factoring', it doesn't keep the relationships of those quantities in factual perspective.
Instead of 'factoring' the measured values, how about 'factoring' the scale(s), make the scale(s) logarithmic instead of arithmetic?
- 'Doc

(That 'factoring' introduces distortion.)

 

[GnG8d]

But that relationship isn't realistic because of that 'shape factoring', it doesn't keep the relationships of those quantities in factual perspective.

(That 'factoring' introduces distortion.)

It changes the scale and keeps everything on a piece of 8x11 paper instead of a piece of poster board. And since I am looking for a resistance of 50 ohms subtracting 50 makes it relative to 0 like the other two varibales.

In my mind, this is not an analyzer or calculator, but a visual aid while tuning a large beam, or any antenna really. The shape of the graph won't change with scaling, there is no distortion in the shape because it's scaled.

When I start on this quad, it will take just a few seconds to put the variables into my laptop after every change that I make, giving me a visual map of what these changes are doing to the antenna, and that's all I'm looking for. A visual aid, not a calculator.

 

[Marconi]

Great idea for those interested in what may be going on when they try to tune their antenna. It's sure better than trying to remember what happened several minutes or days ago.

 

[GnG8d]

For me anyway, the graphical representation is easier to see quickly than this ....

Frequency SWR R X
26.525 2.6 56 52
26.635 2.3 54 44
26.745 2 54 36
26.855 1.8 52 3
26.965 1.6 51 24
27.075 1.4 51 18
27.185 1.2 52 13
27.295 1.1 54 6
27.405 1.1 57 0
27.515 1.2 60 0
27.625 1.3 63 9
27.735 1.5 66 16
27.845 1.6 69 22

 

[W5LZ]

359,
You answered my question. I think I'd take another look at your qoute at the end though, "check your premises".

Marconi,
It's okay, I know you're just jealous of my 'divining rod'... oops, I mean stick!
- 'Doc