cb

apfrizz · 08-09-2011, 07:30 AM

Have 2010 Newmar it has factory cb ant. I installed two differnt radios and can not get them to match up with my antenna help.

**"007"** · 08-09-2011, 07:41 AM

Welcome apfrizz to Newmar forum and irv2.
You have found correct ANT lead plus the battery, with twist nut fitting?
Have never had a problem with ANT itself. There is a twist nut on ANT to adjust the collar for frequency that may have come loose and needs to be adjusted.

apfrizz · 08-09-2011, 08:07 AM

sorry not the problem fitting the ant. it's swr meter get it to match up to the ant. the radio performs very poorly. thank you

wa8yxm · 08-09-2011, 08:10 AM

My best guess is the "Factory" antenna, if it exists, is a short "rubber duck" type on the roof. and not worth the time it takes to type "Antenna" and I type fast.

Get a real antenna, like a firestick,

soricobob · 08-09-2011, 08:25 AM

I wouldn't swear to that, as my CB antenna is a foot+ whip (I have several little rubber antennas as well). My CB antenna is over the driver (on the roof), and when new it dropped off on two occasions, but Pappy attached it well. I'd check the status of your antenna first, and work back from there.

Romeo · 08-09-2011, 11:08 AM

Quote:

Originally Posted by apfrizz

sorry not the problem fitting the ant. it's swr meter get it to match up to the ant. the radio performs very poorly. thank you

Antenna matching, SWR, signal strength, quality of received signal can be a complex issue.

First of all my CB is the factory installation. It never has worked well, but I am not interested in talking around the world, only up and down the road a mile or so and it seems to do that. I have noticed that occasionally I get better received signals... signals coming in from across the U.S. That will happen will increased "sun spot" activity and is called "skip". Sun spot activity is another aspect of radio transmission that can cause good or bad reception and transmission.

I don't keep up with sun spot activity any more so don't know what the current conditions are, but that can cause poor radio performance (but not high SWR).

If you have a high SWR (Standing Wave Ratio) it means that all power being pumped into the antenna is not exiting the antenna, a portion is being reflected back to the radio and can cause over heating of the final stage amplifier. And, of course, poor transmission performance, but very little effect on received signals.

Several things can affect SWR, however, the most common is the antenna and tuning thereof. Antennas can be "tuned" by lengthening or shortening the antenna or the tip of the antenna. If yours is a rubber-duckie, then the probably nothing to adjust, unless there is some sort of "twist nut on ANT to adjust the collar for frequency as 007 mentioned.

If it is a rubber-duckie antenna, and you need better performance, the best thing to do is to replace it as wa8yxm suggests.

If I wanted to spend time to figure your problem out, I would first check that the antenna coax has continuity to the antenna. Disconnect the coax from the radio and check from the radio end to the antenna. Another way that is not as easy, is to check for signal out with an external signal strength meter, or a simple method using a neon bulb. A neon bulb will light when placed near the antenna (one inch of so) when a signal is being transmitted (mic keyed). That would require someone on the roof holding a neon bulb and someone keying the mic. BTW, one can receive RF burns by touching an antenna when a signal is transmitted, and 4 watts will burn.

If there is continuity, and the SWR is less than 3:1, and a signal is being transmitted, and sun spot activity is not causing poor transmission, and transmission is poor, then the next step would be to put up a REAL antenna.

Well, got a little carried away with this, but that pretty well tells you what you REALLY need to know... good luck!

Romeo · 08-09-2011, 12:04 PM

wa8yxm,

Are you sure the the CB antenna is the rubber-duckie. I have the standard two antennas on the roof; the rubber-duckie, and the spring based short whip antenna (no bottom load coil). I have thought that the rubber-duckie was the FM antenna.

I have always wanted to figure out which was which, but never had anyone to help so havent done it yet. I was going to use the "neon" bulb test to figure it out... if I can find my neon bulb. Hope I didn't dump it at the last Ham Fest where I unloaded my lifetime load of Ham junk... think I dumped my little sig strength meter... I knew I would reget it!

**"007"** · 08-09-2011, 06:56 PM

Ron, most Newmar's I have had the ANT was the metal whip with the spring at base mount. The rubber is for FM radio.

siggyd · 08-09-2011, 08:40 PM

My 2011 DSDP has only rubber duckie antennas,one is for the CB, there is NO metal whip antenna on my roof. The rubber duckie antenna for the CB is a bad joke.
I agree 300% with WA8YXM. Just bought a Firestick antenna (NGP),that should take care of it.
Siggy D.

Romeo · 08-09-2011, 09:30 PM

Thanks 007, I thought that was the case. However it appears that has changed in the later years (per Siggyd).

Rubber duckies are ok for handie talkies, but not much for a mobile installation.

clarkgriswold · 08-09-2011, 11:31 PM

Probably doesn't apply to your RV but on my RV I have two rubber ducks for FM radio and metal base load antenna for CB. By the way, you can also shorten coax length to adjust SWR. That use to be the way we did it with 102" 'whip' antennas on CB freqs.

Romeo · 08-10-2011, 12:12 AM

Quote:

Originally Posted by clarkgriswold

...By the way, you can also shorten coax length to adjust SWR...

Sorry, but for the sake of those reading this thread, I have to beg to differ with that statement.

It's been too long since I have dealt with this subject to explain here why shortening coax may APPEAR to lower SWR, but suggest that anyone tempted to use this method, research it before trying.

This method was a popular belief among CBers back in the '70s.

lostagain · 08-10-2011, 04:50 AM

Quote:

Originally Posted by Romeo

Sorry, but for the sake of those reading this thread, I have to beg to differ with that statement.

It's been too long since I have dealt with this subject to explain here why shortening coax may APPEAR to lower SWR, but suggest that anyone tempted to use this method, research it before trying.

This method was a popular belief among CBers back in the '70s.

X2...shorting the coax does not adjust the SWR's (Standing Wave Ratio).