Broken CB Antenna
Stellar HDF Member
Joined: Nov 2005
Posts: 3,183
Likes: 836
From: KMHT KFMY
RE: Broken CB Antenna
go to radio shack, the SWR meter is about 20 bucks, tune the antenna. If the VSWR is too high it will blow the finals in the CB.
the idea is to take the swr on say chan 1 and 32, figure out which is lower, and based on that shorten or lengthen the antenna so they balance out. Chan 16 should be the lowest using that method, with the high points on 1 and 32.
why 32 you ask? usually 33 and above is used for SSB CB so unless you are using "silly side" tune for the chans you will use.
Try to get the SWR to 1.5 or lower, click below for more info
http://www.workingpsychology.com/div...echnology.html
the idea is to take the swr on say chan 1 and 32, figure out which is lower, and based on that shorten or lengthen the antenna so they balance out. Chan 16 should be the lowest using that method, with the high points on 1 and 32.
why 32 you ask? usually 33 and above is used for SSB CB so unless you are using "silly side" tune for the chans you will use.
Try to get the SWR to 1.5 or lower, click below for more info
http://www.workingpsychology.com/div...echnology.html
Tourer
Joined: Aug 2004
Posts: 406
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From:
RE: Broken CB Antenna
Antennas that transmit require tuning.
Antennas must function as a 1/4 wave or 5/8 wave to be useful on mobile installations.
The antenna is the radiating unit, the vehicle is the reflecting unit. All transmit antennas need a reflective unit. The ground plate or ground plane (counter-poise) in the pizza box serves as the reflective unit with the motorcycle. If your going to change your antenna on your pizza box to something like a stubby check if its built to operate with a ground plane.
In "no-ground-plane" systems, the coax shield is used for counterpoise.
Operating transmitting radios when the SWR is over 3:1 can damage the radios circuits.
I know of two members in our chapter that “cracked their whip” on their garage doors. They just replaced the HD whip without tuning their antennas. Their radio’s seemed to operate just fine, for now. Maybe they both were lucky or a time bomb was set? I’ve tuned many CB antennas. It’s amazing how little you trim to get it tuned. I know one thing, I’m not risking my crap on improper maintenance. I also want peak performance, same reason I had my bike dyno tuned.
Antennas must function as a 1/4 wave or 5/8 wave to be useful on mobile installations.
The antenna is the radiating unit, the vehicle is the reflecting unit. All transmit antennas need a reflective unit. The ground plate or ground plane (counter-poise) in the pizza box serves as the reflective unit with the motorcycle. If your going to change your antenna on your pizza box to something like a stubby check if its built to operate with a ground plane.
In "no-ground-plane" systems, the coax shield is used for counterpoise.
Operating transmitting radios when the SWR is over 3:1 can damage the radios circuits.
I know of two members in our chapter that “cracked their whip” on their garage doors. They just replaced the HD whip without tuning their antennas. Their radio’s seemed to operate just fine, for now. Maybe they both were lucky or a time bomb was set? I’ve tuned many CB antennas. It’s amazing how little you trim to get it tuned. I know one thing, I’m not risking my crap on improper maintenance. I also want peak performance, same reason I had my bike dyno tuned.
Tourer
Joined: Aug 2004
Posts: 406
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From:
RE: Broken CB Antenna
ORIGINAL: Neggy ZRXOA 5248
go to radio shack, the SWR meter is about 20 bucks, tune the antenna.
http://www.workingpsychology.com/div...echnology.html
go to radio shack, the SWR meter is about 20 bucks, tune the antenna.
http://www.workingpsychology.com/div...echnology.html
Stellar HDF Member
Joined: Nov 2005
Posts: 3,183
Likes: 836
From: KMHT KFMY
RE: Broken CB Antenna
http://www.radioshack.com/product/in...entPage=search
I ooops'd on the price 35 bucks ouch... still cheaper than a fried radio
I ooops'd on the price 35 bucks ouch... still cheaper than a fried radio
Cruiser
Joined: Feb 2006
Posts: 144
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From:
RE: Broken CB Antenna
I also had the same problem with my antenna on my o5 ultra. It came up missing? broke off right above the connection with the rubber boot over it, where the set screw's are. Dealer covered the new one and when it came in it had all the hardware on it. Just pulled the boot off the old and unscrewed what was left of it and the dealer wanted that back to turn in. Put the old boot over the new antenna and screwed it on the old mount, tightened the allen screw covered it with the boot and that was it until it breaks again. I have seen many post's of the same problem on the 05 ultra's?
Good luck, Steve
Good luck, Steve
Tourer
Joined: Apr 2006
Posts: 443
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RE: Broken CB Antenna
yota,
Install the new whip all the way into the base mount and tightn the set screw.
1. Using an SWR Meter Check SWR from the highest channel to the Lowest it should be at its worst on these two channels
2. Check on center freq (Channel Forty channel CB the check on ch 20) should be 1.5.1 at the worst.
3. If this is the case then you are OK, If 1.6.1 or so I would not touch it. Other wise Cut 1/2 inc at atime and recheck. to get the lowest reading.
4. The ground Plane is the Metal inside the tour PAC anf the Coil is the antenna LOAD coil its purpose is to effectively ALLOW the radio at this freq band (27MHZ Area) to be able to utilize this shorter antenna. The coil act like a compacator and and inductor to "FOOL" the radio that it is using and antenna of 102 inches as this is the ideal antenna for this freq range.
5. IF you do not want to do all this then....When you pick up the replacement whip from the dealer takea tape measure and measure a whip on a bike on the floor model, measure from the top (Corona Ball) for static discharge) to the top of the base mount and when you get home add the BASE length to the overall total and cut if needed!!!!
6. OR say screw it and take the new whip to your local two way radio shop and have them do this for you!!!!!!!!!!!!!!!!!!!!!!
(I have been working for 25 years for a M Major Communications Company and started out doing this work! Now I move papers and %itch on some days!!!
Good luck!!
MyRide7...........
Install the new whip all the way into the base mount and tightn the set screw.
1. Using an SWR Meter Check SWR from the highest channel to the Lowest it should be at its worst on these two channels
2. Check on center freq (Channel Forty channel CB the check on ch 20) should be 1.5.1 at the worst.
3. If this is the case then you are OK, If 1.6.1 or so I would not touch it. Other wise Cut 1/2 inc at atime and recheck. to get the lowest reading.
4. The ground Plane is the Metal inside the tour PAC anf the Coil is the antenna LOAD coil its purpose is to effectively ALLOW the radio at this freq band (27MHZ Area) to be able to utilize this shorter antenna. The coil act like a compacator and and inductor to "FOOL" the radio that it is using and antenna of 102 inches as this is the ideal antenna for this freq range.
5. IF you do not want to do all this then....When you pick up the replacement whip from the dealer takea tape measure and measure a whip on a bike on the floor model, measure from the top (Corona Ball) for static discharge) to the top of the base mount and when you get home add the BASE length to the overall total and cut if needed!!!!
6. OR say screw it and take the new whip to your local two way radio shop and have them do this for you!!!!!!!!!!!!!!!!!!!!!!
(I have been working for 25 years for a M Major Communications Company and started out doing this work! Now I move papers and %itch on some days!!!
Good luck!!
MyRide7...........
Thread Starter
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Cruiser
Joined: Jul 2005
Posts: 176
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From:
RE: Broken CB Antenna
So if long is likely gonna be the problem, then whats going on with it when its 2 inches long now. I guess the question is if I get the exact measurement off another ULTRA and take another 1/2 inch off that, whats it doing. Is there also issues with being to short..Next is there anyone that could give the measurement of there antenna..I will assume they are pushed into the mount till they stop so if I know the exact length from the top of where it comes out of the mount to the tip it will get me close for now. I can not get into dealer for at least 1 week but am out on a trip leaving this friday..Anyone out there with an 05 ULTRA that can give me tip to mount measurment..EXACT PLEASE.
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Stellar HDF Member
Joined: Nov 2005
Posts: 3,183
Likes: 836
From: KMHT KFMY
RE: Broken CB Antenna
Ok let me give you the bottom line... I have been an F.C.C. licensed broadcast engineer for 33 years, I am 47 years old.. do the math.
I cut my teeth on tuning 27 mhz radios. Trust me, spend the money and get a meter, or find someone who had a CB back in the 70's and borrow thiers. If you were in Boston I'd be happy to loan you mine.
Antenna length is speed of light/ frequency
So lets assume you are trying to tune for mid CB band 27.195 mhz ( I know somewhere in that spectrum there are skipped frequencies for RC purposes) and you are trying to load a 1/4 wave antenna. We will assume the coaxial cable is cut to the proper lenght so not to add to the SWR issue.... you need to get the antenna to be 103.2542746828461 inches long. This is the length of the whip and the loading coil. Good luck.
I cut my teeth on tuning 27 mhz radios. Trust me, spend the money and get a meter, or find someone who had a CB back in the 70's and borrow thiers. If you were in Boston I'd be happy to loan you mine.
Antenna length is speed of light/ frequency
So lets assume you are trying to tune for mid CB band 27.195 mhz ( I know somewhere in that spectrum there are skipped frequencies for RC purposes) and you are trying to load a 1/4 wave antenna. We will assume the coaxial cable is cut to the proper lenght so not to add to the SWR issue.... you need to get the antenna to be 103.2542746828461 inches long. This is the length of the whip and the loading coil. Good luck.