Help understanding my antenna analyzer

[Magard]

Not necessarily. A 102 will usually show around 25 to 35 Ohms impedance. The Vswr will look good and long range will be easy. The 50 Ohm is a free space figure.
To be Honest the only 50 Ohm antenna I have ever seen was my old co-phased 102's on my old Dodge Carryall. The thing to worry about is just the Vswr. As long that is low you are in good shape. Don't too much about all the other readings. They are not of much use to you unless you are going into design and research.
some interesting reading about resonance and where the XL and XC come from in your analyzer.
https://www.electronics-notes.com/a...gation/antenna-theory/resonance-bandwidth.php

So low resistance isn’t a big deal if swr is under 2

 

[Tallman]

So low resistance isn’t a big deal if swr is under 2

 

[Magard]

So I figured these antennas out..... mirrors weren’t grounded to the doors. So now I got something that I can work with. So Swr is 1.08 potential. Ohms is 50 potential and resonance is 26.401
At the moment. What I’m asking is if everything is wanting to work. What should I be tuning for optimally. I am at 1.12 swr at my normal frequency of 27.335. 45 ohms.

 

[144inBama]

If I'm understanding this correct.... you're resonant @ Freq. 26.401? If so, that means you're resonant on the Super Low (band B) between channels 29-30....
*edit to add*
1.12 is a very good reading....a lot of people struggle for that good of a number.

 

[BJ radionut]

Magard: Usable the way it is...However the antennas are too long as rigged now.
Do these have adjustable whips on top?
If so, are they bottomed out or pulled up?
If you shorten them, you will move the resonate frequency up.
If they are bottomed out, you can "tweak" it a little more. I would start by cutting like 1/2 inch off each antenna Whip bottom push them all the way down...Measure again>

 

[BJ radionut]

If those adjustable whips DO NOT bottom out into the fitting...Just move them down about 1/2 inch on each side ...Measure Again
Mark where they are now with a Marker(so you can find that spot again)!
Don't cut them unless they bottom out in the fitting...SOME DON"T

 

[Magard]

Thanks guys. I understand tuning a antenna up or down the band. I’m really after understanding more than swr tuning. I would like to understand the graph part of this analyzer. R and x what does negative x mean

 

[BJ radionut]

Antennas and Radiation
https://www.sciencedirect.com/topics/computer-science/antenna-impedance

Scroll Down to:


Resonant Frequency and Bandwidth
"The input impedance Zin of the antenna is a function of the frequency of operation. Figure 6.5 shows the magnitude of the input impedance of an example antenna as a function of frequency. In this case, the antenna impedance looks like a parallel RLC resonant circuit. The frequency, fr, for which the impedance magnitude is maximum, or equivalently the reactance is zero, is often defined as the resonant frequency. It is desirable to operate the antenna at this resonant frequency so that it can be easily matched to an input transmission line with a real characteristic impedance. The frequency span Δfr, beyond which the impedance magnitude falls below half of the resonant value, may be defined as the impedance bandwidth of the antenna. The antenna may be usable in this frequency band. Outside the antenna's bandwidth, the input power to the antenna would be significantly reflected due to impedance mismatch, resulting in poor radiation."...

"In such cases, the resonant frequency is defined as the frequency of best performance and the bandwidth as the frequency span over which the performance can be tolerated, as dictated by the application. It is meaningful to call the resonant frequency and the bandwidth of an antenna with an appropriate parameter prefix, such as the impedance–resonant frequency, the impedance–bandwidth, gain–resonant frequency, the gain–bandwidth, ..."

More: X (=0) the reactance tells you when the antenna "resonate" in that specific frequency. That is what you usually need first, to make the antenna resonant at a specific frequency.
Then, when you got an antenna close to X=0, then you check R, the impedance, usually you need to go close to 50 Ohms. R=Z
Z is the total impedance, from R + X. If you get R=50 and X=0 then SWR will be 1.
Not all antennas are designed for 50 Ohms.

https://ham.stackexchange.com/questions/13157/rigexpert-aa-35-interpreting-the-information

 

[Magard]

So here is where I tuned it. These are dual 5 foot power sticks Quad Wire set up. Guys in the know I’m sure have a better name for them. I guess legendary top load antennas. I believe these are good numbers. Just a little encouragement for myself and others that taking the task upon yourself can result in good results. You can’t pay for someone to dual a system in like this. I choose this frequency because it’s what I talk on most of the day. Channel 19 is still really good.

 

[BJ radionut]

Magard: It just does not get much better than that!
Enjoy! Good Job
All the Best
Gary

 

[Magard]

I just talked 40 miles across a valley to another mobile. He was weak but said I was loud and clean. Finally got this radio like it should be.

 

[S&W357]

Great report

 

[Tokin]

I just talked 40 miles across a valley to another mobile. He was weak but said I was load and clean

Take the BATTERIES OUT of your analyzer and put it up in a clean dry place until your next antenna set up. DO NOT SELL IT. Some folks sell them because they just sit around and then wish they hadnt when they set up a base station or a new mobile rig.

 

[M0GVZ]

Yes, I did say I won't run anything higher than a 1.3 on my antenna systems. Are you trying to say I shouldn't bother tuning my antenna systems for max efficiency because "most hams" don't?

Contest winning contester here., SWR makes you stupid. I never bothered trying to reach 1:1.0 and in fact I ran SWRs 10,20,30 or more times that at the antenna feedpoint using wire antennas multiband. Modelling my inverted L antenna fed by a SGC230 that was 85:1 SWR at its highest on one band, it could hear a gnat fart on the other side of the world, didn't stop me working the world, being told I was the loudest station in Europe on 40m during a contest where I was running a frequency with just 100W.

As long as it was below 1.6:1 for transmitting, enough to keep the transistors in the PA happy (which is what the SGC matched it to), it was good to go and on valve gear I'd push it to 3;1. You'll notice no difference in receive or transmit by getting lower than that.

Right now thats over back to the analyser.

First point is you need to be connected to the antenna as near to the feedpoint as possible so that means using as short a length of coax as you can. If you can't do that you need to ideally be using an ELECTRICAL half wavelength of coax as the end of that will give you figures the same as the antenna end.

You want to be looking at TWO different sets of figures.

First you need to look at is what the feedpoint impedance (Ohms) is when Z=0 so scan around the results until you find where Z is the lowest or nearest to zero and read out the Ohms. That will tell you how efficient your ground plane is. A quarter wave over a perfect ground has a feedpoint impedance of 36.8 Ohms at resonance (where Z=0). The further away from that the more ground losses you have.

Second one is your SWR. The SWR dip will be in a different place to where the Z dip is. You want this to be below 1.6/1.7:1 on a CB and ideally you'd see 50 Ohms at that point but if you're using the coax that came with the mount you may see a reading different than that due to the effect of the coax..

 

[Eldorado828]

I'm currently in the job of getting the base antenna tuned with the use of my rig expert but after getting my brain all jammed up with the numbers I dug to find this. It made me realize that some of my understanding of the readings wasn't correct or I confused the hell out of myself.

The true impedance of a quarter wave antenna, normally falls between 35-40 ohms.
What your looking for on the analyzer is this
Z=R or very close
X=0
This is where the antenna is truly resonant = greatest efficiency.
This normally occurs at about 1.4:1...1.5:1
When you tune the antenna for the "magic 1:1...you will normally see that X has a value Greater than 0...This is called reactance. Reactance (X) causes wasted power.
The trick on the analyzer is where is this point reached.
You need to measure the antenna on several channels.
Channel 1...better/worse
Channel 20...better/worse
Channel 40... better/worse
Looking at not only VSWR but X
If VSWR and X is lower on Ch:1 then then the antenna should be to long
If this occurs on Ch:40 then the antenna is too short
If you run the test in sweep mode as 4string suggested, the analyzer will tell you the point of resonance.
Hope this helps
All the Best
Gary

@BJ radionut , thank you sir for your explanation.

Ok, same analyzer i have. Your user manual will show you how to operate your R, X chart and a lot more.
Hook your antenna up to to the analyzer.
Press 3/fq range
Set center frequency to 27205 and a sweep range of 17500kHz
Press OK
Arrow up to R, X chart, press ok
Press ok to start.
Resonance frequency is shown at the bottom of the chart.
SWR chart will show you where your lowest swr is.
X/cancel will take you to home screen
To check other channels/frequencies press 3/fq range and change the frequency.
My best advice is to get more familiar with the analyzer itself then work with the antenna. Thats what i did and im pretty green to the technical side of antennas. I had do the crawl, walk, trip and fall game hahaha. Still havent learned to run yet but i know a lot more now than i did. Google can help answer some questions also.
View attachment 40398 View attachment 40399 View attachment 40400
The user manual is easy to follow. Dont be afraid to play with all the different functions
Im on a dummy load so pay no attention to the readings.

@Tokin , thank you as well.

Great stuff in here! I might return if I need assistance.