SWR setting

[GoNavy]

I know SWR should be 1:1 or 1.5:1 for best results, but what if you get swr reading below 1:1. My SWR meter hardly moved, maybe a 1/4 : 1 . should I be actually adjusting the tip until I get a 1 : 1 reading. My old antenna died on me, the plastic at the base got chalky and cracked, and the wire broke off where it went in the base. Didn't even last six months, they were K40 too, suppose to be good antennas, I thought. Could the low SWR have cause this, burn it up or something. I have a Cobra 29 with the meter built in the unit. I just put on another antenna, a K40 plus, don't want to burn up another antenna if the low swr is a problem.

 

[jim202]

Could I be wrong in guessing that your understanding of SWR is a tad bit on the lacking side.

It sure wouldn't hurt to take SWR 101 next time they offer the course.

Yup, your going to have to watch all 4 of those watts coming out of your CB set that they don't
over heat the wire your antenna is made out of.

I know SWR should be 1:1 or 1.5:1 for best results, but what if you get swr reading below 1:1. My SWR meter hardly moved, maybe a 1/4 : 1 . should I be actually adjusting the tip until I get a 1 : 1 reading. My old antenna died on me, the plastic at the base got chalky and cracked, and the wire broke off where it went in the base. Could the low SWR have cause this, burn it up or something. I have a Cobra 29 with the meter built in the unit. I just put on another antenna, don't want to burn up another antenna.

 

[GoNavy]

And that answered my question how?

 

[mario_verasso]

I wish i could help you out with that. My dad was the radio guy in the family. He told me when i was younger that 1 to 1 is good but he always like to get it as low as possible. Could be your meter is off also. Check it with an SWR meter other than the radio.

 

[DX949]

I know SWR should be 1:1 or 1.5:1 for best results, but what if you get swr reading below 1:1. My SWR meter hardly moved, maybe a 1/4 : 1 . should I be actually adjusting the tip until I get a 1 : 1 reading. My old antenna died on me, the plastic at the base got chalky and cracked, and the wire broke off where it went in the base. Didn't even last six months, they were K40 too, suppose to be good antennas, I thought. Could the low SWR have cause this, burn it up or something. I have a Cobra 29 with the meter built in the unit. I just put on another antenna, a K40 plus, don't want to burn up another antenna if the low swr is a problem.

Yes adjust it so you get 1:1 to 1:5,lower than 1:1 will cause damage.

 

[kb2vxa]

SWR or "swors" are essential for proper operation acting like grease allowing the signal to slide through the coax and antenna with least resistance. It looks like somebody at the factory forgot to install SWR so when that happens a can of antenna grease comes in handy. Just ask the guy at your local truck stop peak and tune shop, they always have some for just such occasions. Remember, resistance causes heat and you don't want to burn out another antenna but be careful not to use too much grease, wipe the excess so signal doesn't leak out and there's nothing worse than getting signal stains on the car.

 

[kg6yll]

This link may help. SWR and TRANSMITTERS - What is SWR all about? Making Sense of SWR Readings

 

[gdsteele]

[FLAME ON]

You know, you guys can be such *******S sometimes. The guy asks a question, might or might not completely understand the theory behind it, and you start with the 'I know it all, you must be stupid' routine. Think about it, if you took the time to go to someone and ask a question and you got the response that you just entered, would you want to ask any more questions? Warren - this certainly is meant to call you out. Re-read some of the posts you have answered lately. Is this all you have to do is make others feel bad about asking questions? I see you have your tech license. Does this mean that you are too stupid to get your general or extra? Do you know what Thevenin's theorm is? Could you even tell anything about a circuit using Nodal analysis? Maybe you could use a can of antenna grease out yourself? Mayb yu wud be smurt two?


[Flame off]
Guys, think about what you write. If it doesn't help the poster, just keep it to yourself. Like GoNavy said: "This answered my question how?".

I'm done. Go ahead and start slamming me. I've got a thick skin. You want to do it over the phone, let me know and I'll be happy to post my number for all to see.

- bye

 

[N2JDS]

I'd consider finding somebody with an external SWR meter also, just in case your internal one isn't quite right. I also agree, there are a lot of guys on here with nothing better to do than slam peoples questions.

 

[GoNavy]

Thanks Gdsteel...I guess I am not going to get my questioned answered. I fell for the grease stuff and others like 100 foot of flight line and ball tab grease, mail buoys and the like when I was in the Navy, but I was 17 at the time, not quite as gullible now. I have read several article on SWR, but none answer my basic question, what happens when the swr is below 1 to 1.... like I had with my previous antennas. I get it, 5 watt cb is probably not enough to burn up an antenna, I get it, but it can burn up my cb. I am just not that knowledgeable about CB's and antennas, hence why I asked the question, from people I thought might know...you know we all have different training and knowledge, I spent 24 years in the Navy, I can navigate a war ship to any point in the worlds oceans, I can plot and launch nuke weapons and hit any point in the world...do you guys know how to do that...probably not, and I don't ridicule people who don't, because I know they haven't been trained to do that, I was....I can also adjust the Pulse repetition rate of an Air search radar and burn out every tv set within 50 miles, but that is not a CB and it has about 49,995 more watts. So I know wattage can burn stuff up, especially if it not adjusted right.

All I am asking is.. can it also burn up antennas if adjusted wrong and is swr below 1:1 a wrong adjustment, maybe add what could going on that would allow me to adjust swr below 1:1 if it is not possible. Something messed up my old antennas, they usually don't just fall apart after six months normally do they, the plastic cracked and fell off and the wire separated from the base, pretty drastic for just six months of use, don't you think...

 

[JamesPrine]

Hello GoNavy!

Built-in meters on CB rigs are notoriously unreliable; it might be a good idea to use a reliable external meter for a more accurate reading.

I've never heard of any low power transceiver burning out an antenna due to 'too low' a SWR, but some of the experts here might enlighten me on that matter.

Your K40 antenna might have had a problem with moisture leakage, or perhaps it was faulty...difficult to tell without a bit of forensic analyais <g>.

Good luck in any event, and I wish you well with your new antenna!

73 de KC5JLA

 

[GoNavy]

OK Jay sent me an email explaining swr of 1 to 1, just to explain if you look at the pic of my swr meter, I assumed the first space below the swr label to be 1 hence 1 to 1, I was to the left of that, thinking I was below 1 to 1, not unreasonable in my opinion. I don't build CB's or CB meters. It would have been nice if Cobra would have explained that meter and told me the space is 1.5 and all the way to left is 1. I get it now thanks everyone.

 

[kb2vxa]

"You know, you guys can be such *******S sometimes."
Sometimes?
"Warren - this certainly is meant to call you out."
OK, I'm out so what do you intend to do with me? I hate to disappoint you but I'm not that kind of girl. I just have to ask being all I see in your post is an angry bluff and bluster based on sheer ignorance and a total lack of humor.

"Is this all you have to do is make others feel bad about asking questions?"
No, obviously all YOU have to do is seek out the negative while ignoring all the help I have given and the thanks and compliments I have received for it. Man, you have more spin and bias than Fox and that surely makes a statement.

"I see you have your tech license."
Oh here we go again, another one of THOSE judging the license rather than the license holder. Only more proof of the simple fact you don't know one single thing about me yet you pass your narrow minded judgment out of sheer ignorance. The cure for ignorance is education and frankly you can get an education watching me sleep. Unfortunately like Ron White says "There just ain't no fixin' stupid." I'll reserve judgment of you pending further developments... IF I should take the time to read another of your adrenalin clouded rants.

"You want to do it over the phone, let me know and I'll be happy to post my number for all to see."
Nah, you may have outed me but you'll never get a date THAT way.

Onward Navy:
"...not quite as gullible now."
I can see that, you didn't fall for the jokes but rather saw them AS jokes being you have a sense of humor even if you may be just a bit puzzled. How do I know? You didn't come on stage jumping up and down like James Brown, you kept your cool and continued nonplussed. Now the fun and games are over let's get down to brass tacks.

Starting at the bottom line and working upward, when tuning an antenna all you do is adjust for the lowest reading of reflected power. That's right, the standing wave ratio is the ratio of forward to reflected power so the less that's reflected by the load back to the transmitter the better. That brings us around to the heat joke, the truth is reflected power is dissipated as heat in the final amplifier stage so actually the reverse is true, if the SWR is too HIGH you can burn out the transmitter and the antenna couldn't care less either way.

Now we're at the top of the "theory chain" with the math behind it all. SWR is an indication of impedance match, the closer the antenna is matching the transmitter and transmission line the more power is radiated and less returned to the transmitter. Living in the real world there is no such thing as a 1:1 ratio being nothing is 100% perfect making anything less quite impossible even in mathematical theorem. I don't know of any meter outside a laboratory that will show a minuscule amount of reflected power so if the meter shows 1:1 it's lying to you but it's doing the best it can do.

In the real world and from a practical standpoint pretty much anything below a 2:1 is acceptable, 1.5:1 is pretty darn good and being meters, any meters are most accurate at full scale making the bottom end pretty sloppy if you're reading is any lower your meter is lying to you.

"It would have been nice if Cobra would have explained that meter and told me the space is 1.5 and all the way to left is 1."
What would have been nicer is proper placement of the markings. Putting "SWR" on the far left over "SIG" would have left enough room for "1.5" over the scale mark. Eh, all the way to the left is nothing, I just told you 1 doesn't exist so maybe that's why...

One is the loneliest number that you'll ever do
Two can be as bad as one
It's the loneliest number since the number one

No is the saddest experience you'll ever know
Yes, it's the saddest experience you'll ever know
`Cause one is the loneliest number that you'll ever do
One is the loneliest number, worse than two

 

[DX949]

"You know, you guys can be such *******S sometimes."
Sometimes?
"Warren - this certainly is meant to call you out."
OK, I'm out so what do you intend to do with me? I hate to disappoint you but I'm not that kind of girl. I just have to ask being all I see in your post is an angry bluff and bluster based on sheer ignorance and a total lack of humor.

"Is this all you have to do is make others feel bad about asking questions?"
No, obviously all YOU have to do is seek out the negative while ignoring all the help I have given and the thanks and compliments I have received for it. Man, you have more spin and bias than Fox and that surely makes a statement.

"I see you have your tech license."
Oh here we go again, another one of THOSE judging the license rather than the license holder. Only more proof of the simple fact you don't know one single thing about me yet you pass your narrow minded judgment out of sheer ignorance. The cure for ignorance is education and frankly you can get an education watching me sleep. Unfortunately like Ron White says "There just ain't no fixin' stupid." I'll reserve judgment of you pending further developments... IF I should take the time to read another of your adrenalin clouded rants.

"You want to do it over the phone, let me know and I'll be happy to post my number for all to see."
Nah, you may have outed me but you'll never get a date THAT way.

Onward Navy:
"...not quite as gullible now."
I can see that, you didn't fall for the jokes but rather saw them AS jokes being you have a sense of humor even if you may be just a bit puzzled. How do I know? You didn't come on stage jumping up and down like James Brown, you kept your cool and continued nonplussed. Now the fun and games are over let's get down to brass tacks.

Starting at the bottom line and working upward, when tuning an antenna all you do is adjust for the lowest reading of reflected power. That's right, the standing wave ratio is the ratio of forward to reflected power so the less that's reflected by the load back to the transmitter the better. That brings us around to the heat joke, the truth is reflected power is dissipated as heat in the final amplifier stage so actually the reverse is true, if the SWR is too HIGH you can burn out the transmitter and the antenna couldn't care less either way.

Now we're at the top of the "theory chain" with the math behind it all. SWR is an indication of impedance match, the closer the antenna is matching the transmitter and transmission line the more power is radiated and less returned to the transmitter. Living in the real world there is no such thing as a 1:1 ratio being nothing is 100% perfect making anything less quite impossible even in mathematical theorem. I don't know of any meter outside a laboratory that will show a minuscule amount of reflected power so if the meter shows 1:1 it's lying to you but it's doing the best it can do.

In the real world and from a practical standpoint pretty much anything below a 2:1 is acceptable, 1.5:1 is pretty darn good and being meters, any meters are most accurate at full scale making the bottom end pretty sloppy if you're reading is any lower your meter is lying to you.

"It would have been nice if Cobra would have explained that meter and told me the space is 1.5 and all the way to left is 1."
What would have been nicer is proper placement of the markings. Putting "SWR" on the far left over "SIG" would have left enough room for "1.5" over the scale mark. Eh, all the way to the left is nothing, I just told you 1 doesn't exist so maybe that's why...

One is the loneliest number that you'll ever do
Two can be as bad as one
It's the loneliest number since the number one

No is the saddest experience you'll ever know
Yes, it's the saddest experience you'll ever know
`Cause one is the loneliest number that you'll ever do
One is the loneliest number, worse than two

Like Henry H. Goddard would say.............You sir are a Moron.

 

[GoNavy]

OK not a big deal, got my questions answered ...sorta. Now I got another problem, Put my new antennas on, now I have a red Ant warning light when I key. The swr reading are 1.5 on ch#1, 2.5 on ch#40 and in the middle around 1.8 or so on #20 tried to even it up with the movable tips, no matter what I do, they don't move swr stays the same...is this a ground problem maybe. Radio works fine, swr is not over 3, just keep getting the red light and can't make the swr change....I might add this is on a 2008 Freightliner dual mirror setup, I am using the oem ant mounts and coax if that makes a difference. New ants are three foot k40 plus tunable tips..


Addon: Think I may have solved the original ant problem, buddy of mine at work asked if I had been using the chrome bright at work on my mirrors, yes sir I do...lol...turns out the acid in chrome bright doesn't respond well with plastic, like on those antennas, may be why just the base of the antennas were affected, just took six months of eating away to get all the way through to the wire. My best guess, will just have to be careful with the new ones.

so now whats going on....lol

 

[bezking]

Cut the bickering. Now.

 

[drouse3]

OK not a big deal, got my questions answered ...sorta. Now I got another problem, Put my new antennas on, now I have a red Ant warning light when I key. The swr reading are 1.5 on ch#1, 2.5 on ch#40 and in the middle around 1.8 or so on #20 tried to even it up with the movable tips, no matter what I do, they don't move swr stays the same...is this a ground problem maybe. Radio works fine, swr is not over 3, just keep getting the red light and can't make the swr change....I might add this is on a 2008 Freightliner dual mirror setup, I am using the oem ant mounts and coax if that makes a difference. New ants are three foot k40 plus tunable tips..


Addon: Think I may have solved the original ant problem, buddy of mine at work asked if I had been using the chrome bright at work on my mirrors, yes sir I do...lol...turns out the acid in chrome bright doesn't respond well with plastic, like on those antennas, may be why just the base of the antennas were affected, just took six months of eating away to get all the way through to the wire. My best guess, will just have to be careful with the new ones.

so now whats going on....lol

Do you have a part number for these k40's or a picture.

 

[GoNavy]

Do you have a part number for these k40's or a picture.

lol...sorry I forgot K40 is a brand name. Got two of these from the pilot truck stop down the road...

K40 Electronics T300PLUSBK 3’ Top Loaded CB/10-Meter Whip - Black T300PLUSBK 045464232727

 

[kb2vxa]

You keep saying "antennas" plural which gives a clue to your problem, one too many antennas. Contrary to popular belief two are no better than one (I'm sure somebody will contradict me) and often leads to tuning problems like you are experiencing. Being they interact when you tune one the meter is still looking at the other one which would confuse the heck out of Einstein. (Theoretical physicists aren't communications techs.) Considering the fact that two driven elements make up a directional array with highly variable and unpredictable results under these conditions and you're having tuning difficulties you're better off with one.

Now if you insist on the pair there is a correct way to tune them, one at a time. Disconnect the "phasing harness" completely and tune one, then the other for the lowest SWR reading. If you had one antenna I'd say the whip is slightly too long and needs to be shortened a little at a time until the lowest reading falls on ch20 but with that mess of coax things can get tricky. Once you have the antennas properly tuned reconnect the harness and see what the SWR looks like, if it goes wacky again the problem is in the harness, get rid of it and remove the other antenna. No, don't believe them when they tell you there's a bad connector or something, odd lengths of coax fool the meter which is why when tuning it should be placed AT THE ANTENNA whenever possible.

Going back to basics isn't always a bad idea, the more you have the more can go wrong. Sooner or later you'll discover KISS isn't just a glam rock band, it's an acronym for a practical philosophy, keep it simple stupid.

"Like Henry H. Goddard would say.............You sir are a Moron."
LOL! Now mind your spelling and pay particular attention to the caption.

 

[drouse3]

A higher swr on 40 means you need to lower or shorten the ant. setting. If it is already at it's lowest setting the next thing would be to remove any washers between the mount and ant. Tried to get the same reading on channel 1 and 40.