A antenna issue that has me stumped

Is the top picture the original antenna or the new antenna setup numbers? Those numbers are very impressive.

Edit: Oh wait when you said bottom picture, I thought you meant the bottom picture showing the antenna.

 

I understand what you are saying, I just don't think it would be that noticeable performance wise. But I could be wrong. Here is an article about return loss which is basically the reflection of light in an RF signal. This article is referring to fibre optics, but the same principle applies to coax. Hope it helps.


What is Return Loss?
The measurement of the amount of light reflected back toward the source is called return loss, and it is expressed in decibels (dB). This measurement parameter is always a positive number, and a high return loss is a favorable measurement parameter that generally correlates to a low insertion loss. Similarly, reflectance, which is also a measurement parameter that expresses reflection in decibels, is a negative number, and if it is excessive, it is not a favorable measurement parameter.

Return loss is the loss of signal power due to signal reflection or return by a discontinuity in a fiber-optic link or transmission line. This impedance mismatch can be with a device inserted in the line or with the terminating load. Moreover, return loss is the relationship between both the reflection coefficient (Γ) and the standing wave ratio (SWR). Incidentally, if you increase the return loss, it will correlate to a lower SWR.

Return loss is a measurement parameter that expresses how well a device or line matches. A high return loss is advantageous as it will result in a lower insertion loss.

 

Your welcome, I really don't get too hung up on the theory about the return loss. I don't even know what the magical number is to look for, such as 20, 30 or maybe 40 something decibels. I just try to get the RL number as high as I can like you've mentioned before. I forgot to mention that 10 inch riser is very nice looking. The machine shop did a great job making that for you.

I did notice that the antenna looked kind of weak with it leaning so far forward. My goofy thoughts were that you need to stand it straight up, and tie some fishing string from the top of the antenna to the front grill of the truck.. Ha.

 

So you are using it from the coax into the truck.

just a thought, maybe I’m not reading this right but you need to see what the antenna is doing at the stud, not at the coax inside the truck, you are trying to determine what is wrong with a low frequency resonance.

check the mount and take the reading right at the antenna.

 

You can’t compensate for a bad feedline, it is a process of elimination.

you may also have common mode current issues.