help with CB antenna tuning

BradandJanee · 12-01-2006, 01:18 AM

I'm just not satisfied with my Cobra CB radio. I doesn't seem like I'm getting very much range. I should be able to talk to someone who is five mile-markers ahead of me. Perhaps it's the antenna. It has those rings at the base of the which are for tuning but I don't know how to use them. Do I have to buy a SWR meter and hook it into the antenna cable? Then I guess I press the transmit button on the mike and screw those rings up and down until I get the highest signal strength reading. Do that on channel one and on channel 40 and I have the best signal for that system. Am I getting that right? Sure could use your advice; its new to me.

BradandJanee · 12-01-2006, 01:18 AM

I'm just not satisfied with my Cobra CB radio. I doesn't seem like I'm getting very much range. I should be able to talk to someone who is five mile-markers ahead of me. Perhaps it's the antenna. It has those rings at the base of the which are for tuning but I don't know how to use them. Do I have to buy a SWR meter and hook it into the antenna cable? Then I guess I press the transmit button on the mike and screw those rings up and down until I get the highest signal strength reading. Do that on channel one and on channel 40 and I have the best signal for that system. Am I getting that right? Sure could use your advice; its new to me.

John_Canfield · 12-01-2006, 03:37 AM

Yeah - that's basically the scenario. I would just tune it up for lowest SWR on channel 19 and not worry about the band edges. If you can get around 1.5:1 (or close to that) you're in good shape.

On the antenna, one ring is for tuning, the other is a lock ring.

If you don't want to buy an SWR meter and mess with the tuning, maybe you could find a CB shop and let the pro do it.

depchief · 12-01-2006, 03:43 AM

Some radios have a SWR meter built into the set, this will save buying one. Check and make sure you have a proper ground on the radio. If the bracket is mounted to plastic you should run a ground wire from the bracket to ground. Look for the lowest SWR reading on both channel 1 and channel 40, then check on channel 19. Since your roof is fiberglass you do not have an antenna ground. If you see the same reading on 1 and 40 the ground should help with the adjustment.

Finally got mine working after checking antenna sites and found the ground notations.

Good Luck

troth · 12-01-2006, 04:01 AM

Also consider this:

Tuning CB antenna

TXiceman · 12-01-2006, 04:51 AM

If you are not familiar with radios, you will probably be better off taking the rig to a CB shop and let him check and tune the antenna. It is not hard to do with an SWR meter, but you also need to be sure the radio and antenna are properly grounded.

Also, a cheap antenna will not perform as well as a good antenna. You may need to have a better antenna installed.

As for range, remember that the radio only has 5 watts of output and is basically a line of sight communication device. If you are in a wooded area on hilly area, these will greatly effect you range. You may only be able to get a mile or two out of the radio.

Ken

FLYTYER · 12-01-2006, 07:04 AM

What type of antenna do you have and where is it mounted?

Points of interest...

Antennas on motorhomes actually need to be up as high as possible in order to have a low angle of radiation ( antenna theory says the lower the angle the greater the talk distance).

However we have to be careful with overall height and obstructions as we travel. So we mount antennas in a lower position and that affects the way an antenna will load and radiate you signal. Even with good SWR adjustments on an antenna mounted on a mirror or at the edge of the window or even a bumper, the radiation pattern will be altered by the location of the antenna.

In the ham radio world we have a saying..."If you cannot hear him, you cannot work him." Many times this is because of the other guy's antenna pattern and not yours.

In CB I suspect this is a large problem with trying for 5 mile links. I see too many poorly mounted antenna on trucks and motorhomes. Manytimes I see 2 or 3 diffrent antennas mounted within inches or a foot of each other and at the close space each one affects the others.

BradandJanee · 12-01-2006, 12:20 PM

I want to thank all five who responded: John, depchief, troth, TXiceman, and FLYTYER. You certainly are helpful; right on target. I especially liked the link from troth....Tuning CB antenna. I see that we are trying to get the LOWEST SWR. I would have gone for the highest. Since my Cobra CB has some meter on the front, I will see if it is a SWR. Otherwise I will buy one. To answer your question FLYTYER, my antenna is mounted on the left front on top of the coach. Its mounted on fiberglass and was the standard Winny factory antenna that comes with the coach.

Again, thank you everyone.

AFChap · 12-01-2006, 02:46 PM

A good antenna is the best thing you can do for a CB. I have a K40 on my toad and was very clearly hearing conversation 6 exits ahead of me on a very cheap Midland CB this afternoon.

I borrowed an SWR meter from a friend to check my Winnebago OEM antenna a few months ago. I had to get the rings absolutely as high on the antenna as I could get them to go to get a barely tolerable level. I have a Cobra 75WST with all the controls in the mic. I'm wondering now if I can replace the antenna without having to take it loose from the roof ...just replace what is on the outside ...haven't really examined it closely to see.

peter griffin · 12-01-2006, 05:03 PM

if that is an off the shelf cb it will not perform well with any antenna...you need to stop a truck stop and have them tweak it for about 30 to 40.00 bucks...then you will see a big difference...

TXiceman · 12-01-2006, 05:08 PM

By law, the CB (11M) band is limited to 5 watts as peak poer on AM. Peaking the radio is illegal.

ken

wagonmaster2 · 12-01-2006, 06:57 PM

I hope someone will find a way to adjust the Winnebago installed CB antenna to a decent SWR reading. I've been trying for over 2 years to get my SWR down below 8:1 or 9:1 so I can use the CB. I know 1.5:1 is best but I would be tickled to even get down to 3:1. I have grounded the radio case every way I can find and run the adjusting rings from top to bottom of the antenna but channels 1 & 40 always read almost identical. I don't know whether to buy another radio or SWR meter, there are no truck CB shops within 120 miles of here.
Wagonmaster2
2004 Meridian 36G

dengraham · 12-01-2006, 08:26 PM

For 2007 (recta) the pre-installed antenna is no longer offered. You need to buy the antenna with the CB radio. Therefore, I don't have either one. I own a handheld unit and was wondering of one of the window antenna would work? On, do I need to drill a bole for a better antenna?

peter griffin · 12-02-2006, 04:32 AM

if you want people on the highway to talk back to you ....you need to get it tweaked because they will not be able to hear you...you can listen...the cb and antenna you have will only work within sight distance of other vehicles on the highway...as for illegal ...there is no radio police driving around arresting people for tweaked cbs that ridiculous...

AFChap · 12-02-2006, 11:57 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">if you want people on the highway to talk back to you ....you need to get it tweaked </div></BLOCKQUOTE>
I've had a variety of CB's since the 1970's, have never had any of them "tweaked," and have talked and listened at very respectable distances mostly with K40 antenna's, but also with some cheap antennas.

vicsryd · 12-03-2006, 12:15 PM

I gave up on the Winnie antennae even after having a pro shop tune the SWR. I bought a 3ft marine "ugly stick" (designed for fiberglass with no ground plane). It threaded onto the the Winnie "conduit" spring mount from the factory antenna perfectly. Haven't measured the SWR but I receive 5-7 miles and regularly other receive clear transmissions 3-5 miles. For me for going down the interstat in a caravan it's perfect.

Only concern is it is 3 feet tall on a 11ft+ roof. So far I've only encountered a few tree limbs and the spring flexes well given the additional mass of the larger antennae and no damage to the antenna.

If I'm going into an area where low clearance is going to be a constant problem (e.g. trees) then I get the step ladder out and from the drivers side of the coach I'm able to reach the screw on the spring base and fold the whole thing flat. By definition that kind of area isn't going to be good for CB reception anyway.

Pusherman · 12-04-2006, 03:17 PM

As previously stated in this forum, the '07s do not come with a CB antenna.

Would anyone recommend the glass mount antennas from Camping World?

whoopie · 12-09-2006, 04:07 PM

A quick and easy (and Cheap) way to tune the antenna is to adjust the antenna for maximum received signal strength as you listen to the radio. If you can see the S meter, use that, if not just listen for the received signals to "peak" on a mid channel, 19 is good. This technique works great on AM signals,especially if you are near a busy highway.

Tenn.Vol. · 12-09-2006, 06:21 PM

roadfolks has it right, he is tuning the CB in the receive mode. With a SWR meter
the CB is tuned (matched to the antennna) in the transmit mode.

I turn teh CB to ch.20, turn the squelch all the way down, and the vol. up so that
I can hear the background static. Then I tune the ant. for MAX noise or static.

A CB is one step above two cans annd a string, and anything that hits the ant.
will be amplified. (noise and signal) A good ant. needs tuning with a SWR meter.
The one that comes on a MH, a POS on a good day. Antenna is 90% of the system,
so put the big bucks into a GOOD ant. TENN.......

FLYTYER · 12-11-2006, 04:36 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Pusherman:
As previously stated in this forum, the '07s do not come with a CB antenna.

Would anyone recommend the glass mount antennas from Camping World? </div></BLOCKQUOTE>

I use one. It installed easy and out if the box I did not have to make any SWR adjustments. I like it because it is a "no-holes drilled" install.