CB WORK
- Thread starter ROSCOE
- Start date
Lurch830
messin' with sasquatch
- Joined
- Mar 1, 2007
- Location
- Wilton & Albemarle, NC
Same here....pm me some info
RRADFORD9ER
New Member
- Joined
- Dec 3, 2006
- Location
- Asheville
x3, where's terrell?
BigClay
Knower of useless ZJ things
- Joined
- Sep 24, 2008
- Location
- Winston-Salem
I would also like to know
kilby
Member
- Joined
- Mar 17, 2005
- Location
- Charlotte, NC
ditto... my cb turns on but doesn't transmit.
C138 Kaysone
New Member
- Joined
- Sep 23, 2008
- Location
- Burlington, NC
Ill keep this in reference, once i get my vic or truck 
ill be sure to let you know, Hey can i use a VHF/UHF antenna instead of the big thick antenna that comes with the CB or will it not work? but an antenna is an antenna
ill be sure to let you know, Hey can i use a VHF/UHF antenna instead of the big thick antenna that comes with the CB or will it not work? but an antenna is an antennaNo i dont think it will work. You need 18ft coax good mount and 102 steel whip antenna. This will be the best for the trial. Plus if you want to you can use a linear amp with this antenna.Ill keep this in reference, once i get my vic or truck
C138 Kaysone
New Member
- Joined
- Sep 23, 2008
- Location
- Burlington, NC
had a friend who stuck a VHF on his but eh, Ill be looking anyways for good antennas, need the best i can find
hscrugby
Well-Known Member
- Joined
- Mar 22, 2005
- Location
- Raleigh, NC
Grumble grumble grumble 18' coax myth.
Anyway, this guy sums it up a lot better than I will as to why that's not valid:
http://www.stu-offroad.com/misc/myth-1.htm
Basically 18' is about half wavelength over the air. But since it changes in cable(depending on type of cable used), you'd need a shorter length to get that "magic half wave"
Which doesn't matter anyway.
Oh well, enough pointless rambling. Just always annoys me with the 18' thing.
Ok that guy makes since.(NOT HSCRUGBY) (This one http://www.stu-offroad.com/misc/myth-1.htm) But if your (ant) light comes on and stays on with that 9 foot coax and you burn your final out dont cry to me. You can use a 9 ft coax if you set the swrs on the antenna. Now that you know more about it try it and you will see. You want your swrs low you dont want them to high.
Lizooki
Samurai Frogger
- Joined
- Mar 21, 2005
- Location
- Stokes Co. NC
18 ft. coax ..... 
SWRS ?
Have Golden Screwdriver ... will travel.
lol
Matt
Wait ..WAIT ! I've got one ..... Explain to me how a handheld CB works without 18' of coax and a 102 " whip.
SWRS ?
Have Golden Screwdriver ... will travel.
lol
Matt
Wait ..WAIT ! I've got one ..... Explain to me how a handheld CB works without 18' of coax and a 102 " whip.
Lurch830
messin' with sasquatch
- Joined
- Mar 1, 2007
- Location
- Wilton & Albemarle, NC
Coax is a type of cable that has a 'signal' wire insulated from an outter sheild/ground wire insulated from anything else { shield ( 'signal') shield }. This setup works for high frequency applications such as CBs and other RF devices.
SWR = Standing Wave Ratio.....the lower you can get it the better. Some radios have a built in meter, some don't. I've got a stand alone meter if anybody wants to check theirs...just have to find it first.
I'm not up on the 18' of coax deal or the 102" whip, but you do need coax to connect the CB to the antenna. The longer the antenna, the better the signal. 102" w/ 6" spring is 1/4 of the CB wavelength (36') so the antenna is a 14 wavelength antenna. The higher the fraction the better the setup. 3' = 1/12 wavelength antenna which will work, but not as well as 9' (102" + 6" spring).
^I think all that is right (or at least in the ballpark)...but somebody might come along and debunk it.
SWR = Standing Wave Ratio.....the lower you can get it the better. Some radios have a built in meter, some don't. I've got a stand alone meter if anybody wants to check theirs...just have to find it first.
I'm not up on the 18' of coax deal or the 102" whip, but you do need coax to connect the CB to the antenna. The longer the antenna, the better the signal. 102" w/ 6" spring is 1/4 of the CB wavelength (36') so the antenna is a 14 wavelength antenna. The higher the fraction the better the setup. 3' = 1/12 wavelength antenna which will work, but not as well as 9' (102" + 6" spring).
^I think all that is right (or at least in the ballpark)...but somebody might come along and debunk it.
- Joined
- Mar 20, 2005
- Location
- Morganton NC
I don't know about all of this 102" whip, 18' of coax, but.....
I cringe every time I see a long whip out on the trail. I have come close to getting whipped by one, and have friends who did. It hurts, it's out of control and dangerous. Most everyone I know wheels with a 4' fiberglass with a spring for bending under trees and so forth. I don't have 18' of coax, just enough to get it from antenna to radio.
Big trucks some times have two antenna's, like two 3' ones. Not sure of coax length, but they sure sound good.
My Cobra had some work done to it, and things changed. I bought it from a truck driver. I have no clue how to adjust it. Things get turned when they shouldn't and I have to work to get it back right. But, when it's adjusted right, I usually have one of the better radios on the trail, and can usually get out better than most.
I cringe every time I see a long whip out on the trail. I have come close to getting whipped by one, and have friends who did. It hurts, it's out of control and dangerous. Most everyone I know wheels with a 4' fiberglass with a spring for bending under trees and so forth. I don't have 18' of coax, just enough to get it from antenna to radio.
Big trucks some times have two antenna's, like two 3' ones. Not sure of coax length, but they sure sound good.
My Cobra had some work done to it, and things changed. I bought it from a truck driver. I have no clue how to adjust it. Things get turned when they shouldn't and I have to work to get it back right. But, when it's adjusted right, I usually have one of the better radios on the trail, and can usually get out better than most.
All you need is a SWR meter and a jumper cable, to put it in series, and the instructions from firestick below. Of course you will have to adjust your antenna according to the type/brand you have per the OEM instructions.
Setting the SWR of Your Antenna
Compliments of Firestik® Antenna Company Technical Support Team
Copyright © 1996 Firestik® Antenna Company
SWR (standing wave ratio), is a measurement of how efficiently your antenna system will radiate the power available from your radio. In simple terms, your radio would like to radiate all of its power, but can only do so if the other components cooperate. Bad coax and mounts, or inefficient antennas and ground plane can cause system bottlenecks. The easiest way to understand the concept is to think of it in terms of water flow. That is, if you put a one inch faucet on a two inch pipe, your potential output will be restricted by the one inch outlet. So goes antenna systems. Setting your antennas SWR will reduce the restriction of radiated power.
If all radios only transmitted on one channel, it would be a much easier task to design antennas. As it is, on CB alone, there are 40 channels to contend with. Mobile antennas can only be made to resonate at one specific frequency (channel). The goal of the antenna manufacturers is to build the antenna to resonate at a frequency in the middle of the available band (channel 19 on CB) and make it broad- banded enough to keep the off-frequency related SWR at the two extreme ends of the band below 2.0:1. It should be noted that if you communicate on one or two adjacent channels anywhere within the band, you can tune your antenna to achieve optimum performance on those channels. Most people, however, prefer to use the entire bandwidth when tuning.
THINGS YOU WILL NEED
1. Knowledge of what not to do .... read previous sections.
2. Properly installed antenna system (mount, coax and antenna) that was made for the type of radio you will be using and has been tested for shorts and opens in continuity. (See "Testing Continuity")
3. Functional radio.
4. SWR meter. (See "SWR Meter Hook-Up")
5. Short piece of coaxial cable (jumper) with PL-259 connectors on both end.
SWR METER HOOK-UP
The SWR of the antenna, without feedline, can be measured by placing the SWR meter in-line at the antenna instead of at the radio. However, the coax can help or hinder performance. In the end, your SWR should be checked at the radio end because all components will be a part of the final operational system being used.
SWR TESTING REMINDERS:
1. Remember to check for continuity, shorts and opens in your coax and mount installation first.
2. Take measurements in an open area with the vehicle's doors and hatches closed.
3. All measurements should be taken with antenna tip on, unless you do not plan to use the tip in normal use.
THE SET UP
If already connected, disconnect the coaxial cable from the radio. Connect the coax cable that normally connects to the back of the radio to the SWR meter connector marked "Antenna" or "Ant". Now, connect one end of the jumper cable to the back of the radio and the other end to the SWR meter connection marked "Transmitter" or "Xmit". Your SWR meter is now in series (in-line) with your radio and antenna.
Since you've already read the previous parts of this pamphlet, you should now have your vehicle in an open area, with all doors closed. Turn your radio on and tune to channel one or the lowest channel on your radio. If your radio has side band operation, make sure you are in AM mode before doing SWR tests.
The following assumes that your SWR meter has a standard set of switches, knobs and meters. That is, there will be at least one switch with the marking Forward (FWD) in one position and Reference (REF or SWR) in the other. There will also be a knob or sliding controller marked "Set" or "Adjust". Most meters come with full instructions. If the common configuration does not match your meter you will need to rely on the meters manual for assistance.
With the radio on the lowest channel (1 on CB) and the SWR meters switch in the Forward (FWD) position, depress the transmit switch (key up) located on the microphone. While holding the unit in this transmit mode, adjust the meter needle to the set position using the Set or Adjust knob on the meter. As soon as the needle is in alignment with the corresponding mark on the meter face, flip the switch to the Reference (REF) position. The meter is now showing your SWR on channel one. Note the value and quickly release the microphone switch. Record this reading on your paper to the nearest 1/10th. i.e. 1.8, 2.3, 2.7, 1.4, etc.
Now, switch your radio to the middle channel (19 on CB). Place the meter switch in the Forward (FWD) position, depress the microphone switch and adjust the meter to place the needle on the Set position of the meter face. Once in the set position, place the meter switch in the Reference (REF) position and note the reading. Release the microphone switch and write this value down to the nearest tenth of a point. Note: If your antenna system is closely matched to the radio you may get little or no movement from the meter needle on this channel. This is normal.
Finally, place your radio on the highest number channel (40 on CB). Place the meter switch in the Forward (FWD) position, depress the microphone switch and adjust the meter to place the needle on the Set position of the meter face. Once in the set position, place the meter switch in the Reference (REF) position and note the reading. Release the microphone switch and write this value down to the nearest tenth of a point.
With these three readings, you can determine many things about your system. For instance ...
* If SWR on channels 1, 19 & 40 is below 2.0, your radio can be safely operated on any channel without causing damage to the radio's circuitry.
* If SWR on all channels is above 2.0 but not in the "red zone" (normally over 3.0), you may be experiencing coaxial cable reaction (bad quality, wrong length, etc.), insufficient ground plane, or have an ungrounded antenna mount.
* If SWR is in the "red zone" on all channels, you probably have an electrical short in your coax connectors, or your mounting stud was installed incorrectly and is shorted. DO NOT USE YOUR RADIO UNTIL YOU HAVE FOUND THE PROBLEM.
* If SWR on the lowest channel is higher than it is on the highest channel, your antenna system appears to be electrically short. See the following section title "Adjusting Short Antennas".
ADJUSTING LONG ANTENNAS
If the SWR on channel 40 is greater than that on channel 1, your antenna is considered to be "LONG" and reduction of physical height and/or conductor length will correct this situation. Depending upon antenna model, this entails screwing down the tunable tip (Illustration #1: Firestik II, Firefly), or, removing the tip, making short slits in the plastic covering and unwinding and clipping off wire (Illustration #2: Firestik, Road Pal). Firestik Designer Series antennas require loosening the allen screws and lowering the metal whip (Illustration #3).
ADJUSTING SHORT ANTENNAS
If SWR on channel 1 is greater than that on channel 40, your antenna is considered to be "SHORT" and increasing the physical and/or electrical length of the antenna is required to correct this situation. Because we make our antennas extra long, readings which indicate "Short" normally stem from ground plane deficiency (lack of vehicle metal surface for the antenna to reflect its signal rom). This condition is often corrected by adding a spring and/or quick disconnect to increase the physical height. Ground plane deficiencies can also be compensated for by using dual (co-phased) antennas or special no-ground-plane antenna kits.
Lengthening of the Firestik II and Firefly is accomplished by turning the tuning screw further out (Illustration #1). On Firestik and Road Pal models, it requires tip removal, short slits in the plastic covering and, the separation and upward repositioning of three or more wire turns (Illustration #4). Firestik Designer Series antennas require loosening the allen screws and raising the metal whip (Illustration #3).
NOTE: The shorter the antenna, the more sensitive it is to adjustments. For example, removing two wire turns on a 4 foot antenna might move the SWR by 0.3; the same amount removed from a 2 foot antenna may move the SWR by 1.0. Make smaller adjustments on shorter antennas.
DUAL ANTENNAS
Measurements and determination of short or long conditions are the same as the single antenna procedure. However, when tuning co-phased antennas, if you adjust one antenna, it is advisable to adjust the other in equal amounts to keep them in perfect balance.
Firestik Antenna Company - 2614 E Adams St - Phoenix, AZ 85034 - (Tel) 602-273-7151 - www.firestik.com
Return to Index Go to Home Page
Last Revised: June 6, 2006
Setting the SWR of Your Antenna
Compliments of Firestik® Antenna Company Technical Support Team
Copyright © 1996 Firestik® Antenna Company
SWR (standing wave ratio), is a measurement of how efficiently your antenna system will radiate the power available from your radio. In simple terms, your radio would like to radiate all of its power, but can only do so if the other components cooperate. Bad coax and mounts, or inefficient antennas and ground plane can cause system bottlenecks. The easiest way to understand the concept is to think of it in terms of water flow. That is, if you put a one inch faucet on a two inch pipe, your potential output will be restricted by the one inch outlet. So goes antenna systems. Setting your antennas SWR will reduce the restriction of radiated power.
If all radios only transmitted on one channel, it would be a much easier task to design antennas. As it is, on CB alone, there are 40 channels to contend with. Mobile antennas can only be made to resonate at one specific frequency (channel). The goal of the antenna manufacturers is to build the antenna to resonate at a frequency in the middle of the available band (channel 19 on CB) and make it broad- banded enough to keep the off-frequency related SWR at the two extreme ends of the band below 2.0:1. It should be noted that if you communicate on one or two adjacent channels anywhere within the band, you can tune your antenna to achieve optimum performance on those channels. Most people, however, prefer to use the entire bandwidth when tuning.
THINGS YOU WILL NEED
1. Knowledge of what not to do .... read previous sections.
2. Properly installed antenna system (mount, coax and antenna) that was made for the type of radio you will be using and has been tested for shorts and opens in continuity. (See "Testing Continuity")
3. Functional radio.
4. SWR meter. (See "SWR Meter Hook-Up")
5. Short piece of coaxial cable (jumper) with PL-259 connectors on both end.
SWR METER HOOK-UP
The SWR of the antenna, without feedline, can be measured by placing the SWR meter in-line at the antenna instead of at the radio. However, the coax can help or hinder performance. In the end, your SWR should be checked at the radio end because all components will be a part of the final operational system being used.
SWR TESTING REMINDERS:
1. Remember to check for continuity, shorts and opens in your coax and mount installation first.
2. Take measurements in an open area with the vehicle's doors and hatches closed.
3. All measurements should be taken with antenna tip on, unless you do not plan to use the tip in normal use.
THE SET UP
If already connected, disconnect the coaxial cable from the radio. Connect the coax cable that normally connects to the back of the radio to the SWR meter connector marked "Antenna" or "Ant". Now, connect one end of the jumper cable to the back of the radio and the other end to the SWR meter connection marked "Transmitter" or "Xmit". Your SWR meter is now in series (in-line) with your radio and antenna.
Since you've already read the previous parts of this pamphlet, you should now have your vehicle in an open area, with all doors closed. Turn your radio on and tune to channel one or the lowest channel on your radio. If your radio has side band operation, make sure you are in AM mode before doing SWR tests.
The following assumes that your SWR meter has a standard set of switches, knobs and meters. That is, there will be at least one switch with the marking Forward (FWD) in one position and Reference (REF or SWR) in the other. There will also be a knob or sliding controller marked "Set" or "Adjust". Most meters come with full instructions. If the common configuration does not match your meter you will need to rely on the meters manual for assistance.
With the radio on the lowest channel (1 on CB) and the SWR meters switch in the Forward (FWD) position, depress the transmit switch (key up) located on the microphone. While holding the unit in this transmit mode, adjust the meter needle to the set position using the Set or Adjust knob on the meter. As soon as the needle is in alignment with the corresponding mark on the meter face, flip the switch to the Reference (REF) position. The meter is now showing your SWR on channel one. Note the value and quickly release the microphone switch. Record this reading on your paper to the nearest 1/10th. i.e. 1.8, 2.3, 2.7, 1.4, etc.
Now, switch your radio to the middle channel (19 on CB). Place the meter switch in the Forward (FWD) position, depress the microphone switch and adjust the meter to place the needle on the Set position of the meter face. Once in the set position, place the meter switch in the Reference (REF) position and note the reading. Release the microphone switch and write this value down to the nearest tenth of a point. Note: If your antenna system is closely matched to the radio you may get little or no movement from the meter needle on this channel. This is normal.
Finally, place your radio on the highest number channel (40 on CB). Place the meter switch in the Forward (FWD) position, depress the microphone switch and adjust the meter to place the needle on the Set position of the meter face. Once in the set position, place the meter switch in the Reference (REF) position and note the reading. Release the microphone switch and write this value down to the nearest tenth of a point.
With these three readings, you can determine many things about your system. For instance ...
* If SWR on channels 1, 19 & 40 is below 2.0, your radio can be safely operated on any channel without causing damage to the radio's circuitry.
* If SWR on all channels is above 2.0 but not in the "red zone" (normally over 3.0), you may be experiencing coaxial cable reaction (bad quality, wrong length, etc.), insufficient ground plane, or have an ungrounded antenna mount.
* If SWR is in the "red zone" on all channels, you probably have an electrical short in your coax connectors, or your mounting stud was installed incorrectly and is shorted. DO NOT USE YOUR RADIO UNTIL YOU HAVE FOUND THE PROBLEM.
* If SWR on the lowest channel is higher than it is on the highest channel, your antenna system appears to be electrically short. See the following section title "Adjusting Short Antennas".
ADJUSTING LONG ANTENNAS
If the SWR on channel 40 is greater than that on channel 1, your antenna is considered to be "LONG" and reduction of physical height and/or conductor length will correct this situation. Depending upon antenna model, this entails screwing down the tunable tip (Illustration #1: Firestik II, Firefly), or, removing the tip, making short slits in the plastic covering and unwinding and clipping off wire (Illustration #2: Firestik, Road Pal). Firestik Designer Series antennas require loosening the allen screws and lowering the metal whip (Illustration #3).
ADJUSTING SHORT ANTENNAS
If SWR on channel 1 is greater than that on channel 40, your antenna is considered to be "SHORT" and increasing the physical and/or electrical length of the antenna is required to correct this situation. Because we make our antennas extra long, readings which indicate "Short" normally stem from ground plane deficiency (lack of vehicle metal surface for the antenna to reflect its signal rom). This condition is often corrected by adding a spring and/or quick disconnect to increase the physical height. Ground plane deficiencies can also be compensated for by using dual (co-phased) antennas or special no-ground-plane antenna kits.
Lengthening of the Firestik II and Firefly is accomplished by turning the tuning screw further out (Illustration #1). On Firestik and Road Pal models, it requires tip removal, short slits in the plastic covering and, the separation and upward repositioning of three or more wire turns (Illustration #4). Firestik Designer Series antennas require loosening the allen screws and raising the metal whip (Illustration #3).
NOTE: The shorter the antenna, the more sensitive it is to adjustments. For example, removing two wire turns on a 4 foot antenna might move the SWR by 0.3; the same amount removed from a 2 foot antenna may move the SWR by 1.0. Make smaller adjustments on shorter antennas.
DUAL ANTENNAS
Measurements and determination of short or long conditions are the same as the single antenna procedure. However, when tuning co-phased antennas, if you adjust one antenna, it is advisable to adjust the other in equal amounts to keep them in perfect balance.
Firestik Antenna Company - 2614 E Adams St - Phoenix, AZ 85034 - (Tel) 602-273-7151 - www.firestik.com
Return to Index Go to Home Page
Last Revised: June 6, 2006
Oh, and if you or one of your buddies don't have a SWR meter, you can get on pretty cheap.
http://www.google.com/products?q=swr+meter&oe=UTF-8&scoring=p
http://www.google.com/products?q=swr+meter&oe=UTF-8&scoring=p
Bigben75ford
Well-Known Member
- Joined
- Oct 4, 2007
- Location
- Asheboro,NC
I heard that the coils take away alot of output power for your antenna is that true?I run an almost 8 foot whip and it works just fine for me.
Lizooki
Samurai Frogger
- Joined
- Mar 21, 2005
- Location
- Stokes Co. NC
Thanks for the reply Lurch. You were pretty close.
I know what those things are and have a license from the FCC to prove it......I was just poking fun at the OP.
In truth, the best way to go is the big whip, but it's only 102".... it's designed to be used with the big diameter 6" spring mount.
I have one and used it forever....until I started wheelin'. I only wheeled one trip with that thing swattin' at the world.
Coils do use up a percentage of power ..... but a legal CB only puts out 4 watts, so the percentage and signal loss are small.
Firesticks are good, and I have used them in the past, but they are really nothing more than a fiberglass stick with 1/4 wavelength of wire ( get this ..... 108" ) wrapped around it. Now some
sticks are 5/8 wave. just more wire with a coil at the bottom to offset impedence differences.
NO .... vhf/uhf antennas won't work.
I have built my own CB antenna out of a coat hanger and it worked as good as anything.
From a performance standpoint.....
1- 102" whip
2-short stainless steel whip with the coil at the bottom
3-Firestick type
4-I wouldn't even consider the one with the coil in the middle of the whip
I do prefer the kind that adjust like fig. 3 in the above post. ( nice info btw )
I have an antenna analyzer and would be happy to help anyone out with antenna issues.
All you are really doing when you are tuning an antenna is making it longer or shorter.
Matt KF4ZGZ
btw- you only need enuff coax to get to the antenna from the radio.
I know what those things are and have a license from the FCC to prove it......I was just poking fun at the OP.
In truth, the best way to go is the big whip, but it's only 102".... it's designed to be used with the big diameter 6" spring mount.
I have one and used it forever....until I started wheelin'. I only wheeled one trip with that thing swattin' at the world.
Coils do use up a percentage of power ..... but a legal CB only puts out 4 watts, so the percentage and signal loss are small.
Firesticks are good, and I have used them in the past, but they are really nothing more than a fiberglass stick with 1/4 wavelength of wire ( get this ..... 108" ) wrapped around it. Now some
sticks are 5/8 wave. just more wire with a coil at the bottom to offset impedence differences.
NO .... vhf/uhf antennas won't work.
I have built my own CB antenna out of a coat hanger and it worked as good as anything.
From a performance standpoint.....
1- 102" whip
2-short stainless steel whip with the coil at the bottom
3-Firestick type
4-I wouldn't even consider the one with the coil in the middle of the whip
I do prefer the kind that adjust like fig. 3 in the above post. ( nice info btw )
I have an antenna analyzer and would be happy to help anyone out with antenna issues.
All you are really doing when you are tuning an antenna is making it longer or shorter.
Matt KF4ZGZ
btw- you only need enuff coax to get to the antenna from the radio.
champts20
New Member
- Joined
- Jan 7, 2009
- Location
- stokedale, nc
radio work
do you also diagnose cbs, i got a cobra that wont get out, hears good and hit on channels just cant hear me. not sure the condition of antenna and coax was a handmedown from trucker.
do you also diagnose cbs, i got a cobra that wont get out, hears good and hit on channels just cant hear me. not sure the condition of antenna and coax was a handmedown from trucker.