which is better to tune an antenna.... radio's SWR meter or separate?

Cornelius sorry it took so long to get back to this...

Yes you should recalibrate your meter for each channel you check it on.

Properly grounding covers a lot of discussion, there is rf grounding, dc grounding and depending on how you define it, ground-plane.

The ground that the antenna sees may be adequate in one instance (barefoot radio) and not as good in another (running power). The sheet-metal on a door typically is not enough ground for running power through your antenna but it should be adequate for a barefoot radio - the proof is in the pudding on that, big rigs run them all day long and are able to use their radios without issue.

Because of the angle to the antenna the door also provides a very poor reflective surface. In a best case scenario you will have significant reflective surface right under the antenna... But we work with what we got. Off-raoders have similar issues.

One of the problems you may be experiencing right now is, how much ground is the mount actually seeing? If the mirror bolt sees paint on one side and a protected galvanized surface on the other, it may not be making enough contact with enough metal to count. Actually in looking at that picture again... it looks like the front side is only seeing the plastic case of the mirror. That could be a big part of the problem. Right now the back side is a mystery; if this sheet metal was dipped or sprayed with any kind of corrosion protection you could have another barrier to ground.

The change in swr from moving it could be any number of things; it could be a difference in the way the mount is making contact, it could be a result of proximity to reflective surfaces (mirror, door)...

How to know if your antenna needs to be longer or shorter... When you change the length of your antenna it changes the capacitive values of the antenna. This changes the electrical length of the antenna and makes is "fit" into your range of frequencies better.

Tuning your antenna... If your SWR is higher on Ch-1 than you need to lengthen your tip. If it's higher on 40, shorten it. Keep in mind where you tune your antenna matters; you want it parked somewhere where nothing else is around. No building, no other vehicles, no trees, light-poles etc. I was working on my suburban in a a vacant lot, and was seeing a perfect match on my analyzer - which is impossible. I spent 20 minutes trying to figure out what was wrong with the setup before it dawned on me that the antenna was seeing the chain link fence 20ft away. As soon as I backed away from it everything came back to normal levels.

 

Hi there, is any body can help to me to give your opinions or suggestions.
I am just a bigger for CB Radio and search a lot of time in youtube to solve my problem.
Q1. My Channel 1 is high at 2.5 using Cobra 29 Classic with meter and also using stand alone workman SWR meter for comparison. Note... I did all the adjustment antenna up and down for 1/4 inch to fix the problem but nothing happen.
Q2. My Channel 40 is high at 3.6 using Cobra 29 Classic with meter and also using stand alone workman SWR meter for comparison. Note... same above.
Q3. I don't really understand why my SWR meter on Cobra radio is different result from my workman SWR meter.
Individual test:
> Cobra Radio SWR on channel 1 is 3.5 and workman SWR is 3.8 is too high
> Workman SWR on channel 1 is 3.6 and workman SWR is 3.8 is too high.
> Almost the same result.
Now, I did 10 times adjusting my magnetic cheap antenna for $20 on the roof top of my 4 runner at the center.
Thanks for your help.

 

[QUOTE"corneileous, post: 1479320, member: 35455"]Thats what Im kinda wondering. Why arent the built-in meters trustworthy?[/QUOTE]
There Is an adjustment inside radio to calibrate the SWR meter and those things are rarely accurate

 

I say the antenna is your problem. I don't even like to use a 4ft antenna. Longer is better, So if you have one of those little short, cheap magnetic antennas, that is where I'd start.

 

roma01, as noted, more information about your antenna would be helpful.

Generally, the longer it is, the better it is. However, sometimes a short antenna is needed for practical usage, but it should be only as short as needed.

In my case, I have a from-factory-35-inch K30 antenna that I had to shorten (cut) to about 32 inches to get the SWRs acceptable. At the shortened length, I'm getting 1.25 on ch 1, 1.50 on ch 19 and 3.0 on ch 40. I could cut it more to get the ch 40 lower, but since the antenna is already really short I left it as it is since I only use the radio on ch 19 for road conditions communication anyway.

I get much better SWRs with my 60-inch Wilson 1000 on my truck, but that antenna doesn't fit too well on my sedan in my garage.

 

First off the meter in the radio is a general purpose indicator. Rabbi mentioned that they can be adjusted but calibrated, no. They are not made to be calibrated, the strip line used is not what you would call accurate so it is just another selling point.

Second get a good meter and compare it to an antenna analyser which has been calibrated. However as I've warned people before this is just as good as you are going to get because ....

Third swr is only part of the equation to good antenna performance and is not the key to everything.

 

Cornieleous, I have heard the ticking sounds on 2 meter fm, CB's AM/FM radios and TV's just figured it was something in the circuitry. Sudden increases in the hash noise while moving can be related to dirty RF coming from lighting on signs and canopies at various businesses, For what ever reason those that up grade to LED lighting seem to be worse, non scientific observation. Had an older freightliner someone had converted to all led lighting, backing in across a parking lot every time his lights flashed it would break the squelch. Poor grounding or poor connections on power company power lines also can result in noisy conditions. I friend of mine was experiencing high noise levels, he complained to the power company, they sent someone out, said there was no problem. It continued he called FCC power company came out, said no problem, called local Congressman, Problem fixed in a few days, bad connection on pole a couple of blocks from his house