can a CB antenna be grounded to a rack?
01-04-2009, 07:14 PM
#1
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can a CB antenna be grounded to a rack?
I just finished wiring in my CB. I have 18' of coax going to the roof rack on my Cherokee. I had my neighbor try to talk to me, he could hear me loud and clear but I cant here him very well at all. It makes an obnoxious noise when he talks. I was able to listen in on other peoples conversations, and they didnt have the noise. I am running a 102" whip on a spring, and its grounded to the roof rack. Is the rack an ok place for the ground or is that my problem? PLEASE 
THANKS
THANKS
01-04-2009, 08:01 PM
#4
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I think as long as the rack has a clean ground to the roof, you should be fine.
If your contact point has paint there, it probably is not grounded to you jeep that good.
If your contact point has paint there, it probably is not grounded to you jeep that good.
01-04-2009, 08:10 PM
#5
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Thats probably the case, it has been powder coated but I ground it down. Maybe not enough. The rack is fairly good size, of course I don't know how much "ground" a CB antenna needs. I will try that later.
01-04-2009, 08:17 PM
#6
CF Veteran
if it's a gutter mounted rack, it should be fine.
if it's just clamped to the stock rack, the ground will be weak if at all.
if someone can make this part into a sticky,
Please see the diagrams above... See that nylon spacer? It looks like this...
See the bevelled edge? That's important, because it locates the nylon bushing, so that it does not move. It holds the HOT pin on the stud so it does not touch the mount.
The COAX fitting itself has a HOT and GROUND, the ground is on the outside, the hot is inside (the pin).
Everything ABOVE the nylon spacer is HOT. For that reason the stud, should not touch the mount. If you flip the nylon bushing and put it on the bottom, you are causing a DIRECT DC Short between the HOT and GROUND (because the stud is now contacting the metal of the mount and will quickly fry your CB radio.
If in doubt - do this simple test with a multimeter.
The following should NOT have continuity
- Antenna cable centre pin and ground, radio body, tub, antenna mount
- Antenna cable centre pin and antenna cable ground (round spinning part)
The following SHOULD HAVE continuity
- Antenna cable centre pin and antenna and upper stud
- The Mount, ground, tub and radio body.
Important information about GROUNDS...
A DC Ground is not an RF Ground.... A DC ground means you have electrical connectivity between 2 things. An RF ground is different, it means there is a specific relationship between the antenna and surrounding reflecting metal. So simply running a ground wire will not cut it - the mount must be METAL, connected to METAL. No Plastic. (it's more complicated than that, but you get the point). However, a DC Ground is a good indication that you are at least close.
MORE important information....
See this wire...
That wire is used for antenna matching. DO NOT GROUND IT! Under no circumstances should it be grounded unless a qualified person who has a meter connected to your equipment tells you to ground it. That lead is for fixing REALLY bad SWR. I've installed dozens of Wilson and Firestik antenna's and I have never used this wire.
That's all, hope this is helpful. Attached Thumbnails
Attached Images
and this....
Things Every CB'er Should Know
Compliments of Firestik® Antenna Company Technical Support Team
Copyright © 1996 Firestik® Antenna Company
1. Every industry has its bottom dwellers. We cannot protect you from them. Consumers who make decisions based strictly on price, or on what someone says instead of what they can do, will often fall prey to the bottom dwellers.
2. Beware of information from "experts" (real or self-proclaimed). There is antenna theory and there is antenna reality. We have yet to see a vehicle that simulates a lab. While theory is a good starting place...experience is invaluable when it comes to real problems. The knowledge gained from the best book on theory will not necessarily produce the best antenna design.
3. Some "experts" may "claim" 5/8 wave mobile antennas are not possible because they would need to be 23 feet high. They are wrong! Physical length and ground wave performance are not the same. If you ever hear someone make that claim, ask them how a handheld CB can have a 1/4 wave antenna 8 inches long and mobile 1/4 wave antennas can be anywhere from 12-60 inches long in spite of the fact that a physical 1/4 wave is 108 inches.
4 .Never key up or attempt to operate your CB without a working antenna or "dummy load" (non-radiating antenna simulating device) connected to the radios antenna jack, unless you have extra money to buy another radio, or know a good repairman.
5. All mobile and base transmitting antennas need counter-poise, more commonly called ground plane. The antenna is the reactive unit, the ground plane is the reflective unit. Neither is more important than the other. In mobile installations with standard antenna systems, the vehicle metal (body, frame, etc.) acts as the ground plane. In "no-ground-plane" systems, the coax shield is used for counterpoise.
6. Most, but not all, manufacturers pre-tune their mobile antennas on a test bench. To protect your radio's circuitry and achieve optimum performance, mobile transmitting antennas (CB, cell phone, amateur, etc.) need to be tuned on the vehicle.
7. Before transmitting, you should check your antenna system for shorts or opens. If you have continuity between the center pin of the connector and the outer threaded housing, you may have a short. Don't transmit! If you do not find continuity between the center pin of the coax and the antenna base, you have an open. Fix it. (See "Testing Continuity") Exceptions: Some base loaded antennas use a center tap design and there will be continuity from ground to center conductor. Also, Firestik "No Ground Plane" antenna kits will have coaxial center pin to ground continuity.
8. SWR that pegs the needle on all channels almost always indicates a short in your antenna system. Do not attempt to tune the antenna until the short is fixed. Operating with high SWR will probably damage your CB's internal circuits.
9. Make sure that the antenna you are using is the right antenna for your application. Don't use a TV antenna or an AM/FM antenna for your CB. Do not operate your CB without an antenna or dummy load.
10. Transmitting antennas are sensitive to objects in their "near field of radiation." Tune your antennas in an open area. Never tune inside or next to a building, near or under trees, near or under power lines, and never with a person holding or standing next to the antenna. Try to simulate normal operating conditions.
11. If you mount two or more antennas close to each other, you will alter the transmission patterns of each one. The affect may be either positive or negative. We recommend that a minimum of 12" exist between your CB antenna and other types of antennas.
12. Your radio cannot tell one component from another. As far as the radio is concerned, the coax, stud mount, mounting bracket, antenna and vehicle is ONE unit. Don't be too quick to fault your antenna until you are sure that all of the other components have been given equal consideration.
13. Of all antennas returned to Firestik for warranty service, 75% show no signs of being tuned to the vehicle. All antennas should be checked prior to use. Most will require some adjustment. Less than 3% of all returned antennas have actual performance causing problems. Of those, half of the problems are user or installer created. High SWR and other performance problems are 20 times more likely to be caused by bad coax, bad connections, shorted mounts, poor installation location or faulty test meters.
14. In almost every instance, once you get the same SWR reading on channels 1 and 40, further antenna tuning will not improve the readings. If the SWR is still over 2:1, you have other problems to conquer. Exception: There are rare occasions when the ground plane is so small or large that the system is way out of phase (especially with high-performance antennas). If you have high SWR on all channels and have confirmed that you have no opens or shorts in the feedline, try making a small tuning adjustment in the antenna. There are times when the SWR will drop equally across all channels under unusual ground plane conditions. If you find this to be the case, carefully adjust the antenna.
15. SWR that is high on all channels (over 2:1 but not pegging the needle) after the antenna has been tuned usually indicates insufficient ground plane, ungrounded antenna mount or that a coax cable problem exists.
16. The doors, mirrors, spare tire racks, luggage racks, etc. on many vehicles are insulated from a good ground with nylon or rubber bushings. This also stands true for fiberglass vehicles. Make sure that your antenna mount is grounded, even if it entails running a ground wire to the vehicle chassis. Bad hard ground at the mount generally equates to less than optimum performance. Exception: No ground plane antenna kits do not require a grounded mount.
17. If you are hearing whining noises from your radio while your vehicle is running, it is probably due to "dirty power" being supplied to the radio. Under dash power may be more convenient, but the "cleanest" power will be found by running the radio's power leads straight to the battery.
18. You can never buy coax cable that is too good for your system. Never compromise quality for cost when purchasing coax. Your best bet is to stick with coax that has a stranded center conductor and 90% or higher shielding.
19. Most manufacturers of high performance antennas recommend a specific length of coax cable. If your antenna manufacturer suggests a specific length, give priority to that recommendation.
20. If your ground plane is good, your mount grounded and, your antenna favorably located, coax length rarely becomes an issue. But, if one or more mismatches occur, you may find high SWR. This can often be corrected by using 18 feet lengths of high quality coax.
21. Excess coax between your radio and antenna mount should never be wound into a circular coil of less than 12" in diameter. Doing so can cause system problems. Your best option for handling excess coax is to serpentine the cable into a 12 to 18 inch yarn-like skein. Secure the skein in the center with a wire tie and tuck it away.
22. Single antenna installations require coax with approximately 50 ohm's of resistance (RG-58/U, RG-58 A/U or RG-8X). Dual antenna installations require the use of 72 ohm cable (RG-59/U or RG-59 A/U).
23. Coaxial cables with foam (polyfoam) center conductor insulation should be your last choice for use on mobile (vehicle) installations. Even though it will work initially, it has limited life and does not stand up to the conditions encountered in the mobile environment. Choose coax with polyvinyl insulation when doing mobile installs.
24. Coax cables should never be cut and spliced together like common electrical wire. Line losses will occur.
25. Coaxial cable with holes in the outer insulation, severe bends, or door, trunk or hood caused pinches will cause performance problems. Treat your coax with care.
26. If you live in an area where rain and/or sleet is common, wipe your antenna down with a rag that has been coated with WD-40, Armor-All, Pledge, light oil, etc. This trick prevents ice build up that can overload and cause your antenna to break. In an emergency use butter, cooking oil or anything else that will repel water.
27. When tuning your antenna(s), make sure that you do so with the vehicle doors, hood and trunk closed. If left open, they can cause inaccurate SWR readings. Try to simulate actual operating conditions.
28. Mobile antennas, for best performance, should have no less than 60% of their overall length above the vehicles roof line. For co-phased antennas to perform optimally, the space between the top 60% of the two antennas needs to be unobstructed.
29. Remember, all transmitting antennas need ground plane (counterpoise). Base antennas, much like "no ground plane" antennas, build it in. Do not use mobile antennas for base station applications unless you know how to build your own ground plane.
30. If you are installing a single antenna on one side or the other of your vehicle, best on-the-road performance will be realized if the antenna is on the passenger side of the vehicle (Passenger cars and light trucks) Large trucks or vehicles pulling large trailers should put the antenna on the drivers side to avoid the signal from being blocked by the trailer and to keep from hitting road side trees.
31. Co-phased (dual) antenna installations create a radiation pattern that favors communication directly in front and back of the vehicle. This is why co-phase systems are popular with people who do a lot of highway driving. Co-phase antennas must be center or top loaded. Top loaded antennas are the best.
32. Some people believe that co-phased antennas must be separated by a minimum of nine (9) feet. We have successfully used co-phase antenna systems with spacing as little as four (4) feet. Space alters the pattern and not always negatively. Each vehicle will be different.
33. Co-phase antennas can improve performance on vehicles that lack good ground plane characteristics (fiberglass motorhomes, trucks, etc.). Instead of using available metal to reflect the radiated energy, the antennas use each others field.
34. When tuning co-phased antennas (dual), it is best to adjust both antennas an equal amount to maintain equality in their individual resonant frequency.
35. On a co-phase system, if you try to tune each antenna independently using RG-58 type coax and then connect them to the co-phasing harness, you will almost always find that they will appear electrically short as a set. We recommend that you first assemble the entire system. Take all measurements and make all adjustments with both antennas in place.
36. If you are experiencing SWR that is high across the entire band and have eliminated shorts, opens, groundless mounts and coax as potential problems, suspect lack of ground plane. Try adding a spring or quick disconnect to the antenna base. In some cases, the repositioning of the antenna relevant to available ground plane will solve the problem.
37. One of the greatest benefits of the FS series (patented tunable tip) antenna is noted when there is lack of available ground plane. If the tuning screw reaches its "maximum out" position before satisfactory SWR is realized, a common 1/4-20 threaded bolt or screw of a longer length can be used to replace the supplied tuning screw. If the vinyl cap is too short to remain in place, the user can disregard it or clip a hole in the top for the longer screw to pass through.
38. In rare instances, like antennas mounted in the middle of a metal van roof, excess ground plane can cause a problem. This usually shows up as high SWR across the band. In these cases, a tunable tip antenna may not be the best choice. The reason being, the antenna is too long and the tunable tip cannot adjust down far enough (see line 40). If you suspect this, an antenna that wire can be removed from will usually fit the bill (i.e. KW or RP series).
39. There may be situations when a tunable tip will bottom out before optimum tuning is achieved. If this happens, try removing the knurled jam nut and finger tighten the tuning screw against the o-ring. If still too long, remove the tuning screw altogether. If total removal causes the antenna to go short, cut the tuning screw in half and re-insert it into the tuning extender and re-test. The following items on the FS Series "tunable tip" antennas, when removed, will have an effect on SWR (in order from least effect to most effect). O-ring, jam nut, tuning screw mass (cutting off length), vinyl cap, tuning screw complete.
40. The vinyl cap on any "tunable tip" Firestik antennas is optional. However, your antenna needs to be tuned as it will be used . . . with or without the tip.
41. Magnetic mounts should be used in temporary situations only. If you leave them in the same spot for a long period, the paint will not age like that of the uncovered areas and/or moisture will be trapped between the mount and vehicle causing rust or discoloration. Periodically lift the magnet and gently clean off the underside of the magnet and the vehicle surface.
42. It is a bad idea to use magnetic mounts and amplifiers together. Magnetic mounts rely on capacitance grounding. This situation can literally cause the paint under the mount to bubble or discolor due to excessive heat build up.
43. On wire-wound antennas that require wire removal for tuning purposes, best overall performance will be achieved by keeping the loose end of the wire pressed down tightly against the wire coil. If you use power amplification on top loaded antennas and do not process the end of the wire load so it can dissipate its heat into other adjacent coils, you can melt the tip of the antenna.
44. Generally speaking, center loaded antennas perform better than base loaded antennas, and top loaded antennas perform better than all. For any given antenna design (base, center or top loaded), the taller the antenna the better. With length comes a wider bandwidth (lower SWR over more channels), more power handling capability and overall performance increases.
45. When ultimate mobile performance is desired, function should be given precedence over mounting location convenience and appearance.
46. Don't confuse SWR with overall performance. You should seek SWR of 2:1 or lower on channel 1 and 40, but keep in mind that best performance may not be found at the lowest SWR readings. For the most part, if you get your SWR below 2:1, on both ends of the band, don't be overly concerned about using meter tricking procedures that bleed off energy.
47. The SWR meters built into CB radios are okay for general readings, but are rarely sensitive and/or accurate enough for fine tuning of antennas. Use them mostly to indicate serious high SWR problems only.
48. Firestik has tested literally hundreds of SWR meters. A large percentage of these have shown to be off by 0.3 to 0.7 when compared to a piece of certified equipment. There is no standard among production meters. However, unless a unit is defective, most will indicate the most serious problems that you might encounter
49. Aside from cost, the type of wire used in or on antennas (copper, silver, aluminum, gold, tinned, etc.) has negligible effect on antenna performance. The antenna must be designed to resonate with the wire type and gauge chosen by the designer. However, larger wire gauges will normally increase the bandwidth and heat dissipation abilities of the antenna.
50. Copper is 55% better than aluminum, 27% better than gold and 578% better than tin insofar as conductivity is concerned. Silver will conduct AC/DC current less than 2.5% more efficiently than copper, but the cost to performance is generally unjustified and any gain, insofar as RF transmission is concerned, is negligible.
51. If devices other than an SWR meter are going to be used between the CB radio and antenna, always tune the antenna system first without that device in line. If SWR is high with the other device in line, you will know where the problem is.
52. In "no ground plane" systems, it is best to choose a system that terminates the coaxial ground at the radio end of the cable. These systems are far less reactive to cable routing errors and will almost always outperform systems that are terminated at the antenna base or antenna end of the coax.
53. Cables and antennas from standard & no-ground plane kits are not interchangeable. The "No Ground Plane" antennas from Firestik have a yellow band near the base.
54. Wire wound antennas with a plastic outer coating will greatly reduce audible RF static when compared to metal whip antennas.
55. If you leave your antenna on your vehicle permanently, remove the rubber o-ring that is found on the threaded base of some antennas. Tighten permanent antennas with a wrench. Add a lock washer if you want.
56. If you use mirror mounts and often find yourself in areas with overhead obstructions, tighten the bolts just enough to keep the antenna vertical at highway speeds. If the antenna contacts something overhead, the mount will rotate on the mirror arm and protect your antenna.
57. If you use long antennas and find that they bend too far back at highway speeds, tilt them forward if possible. When under a wind load, they will end up in a relatively vertical position.
58. On antennas that are topped off with a vinyl tip, make sure that you take your SWR measurements with the tip in place. If you tune your antenna with the tip off and then reinstall the tip, your SWR will change.
59. Without advocating the use of power amplifiers or unauthorized channels, take note that the Firestik II tunable tip antennas have a fairly large metal tip that broadens the bandwidth and dissipates a considerable amount of heat.
60. It is illegal to use power amplifiers with CB radios. It is illegal to "tweak" the radios internal circuits to increase output power. The transmitter power of a legal, FCC certified CB radio is 4 watts AM.
61. If having one antenna for CB/AM/FM is appealing, use a CB antenna and a splitter that allows it to be connected to your AM/FM radio. Devices that let you use your AM/FM antenna for CB use will leave you disappointed.
62. On a budget? Buy a cheap radio and a good antenna. Aside from added bells and whistles, all CB's are FCC regulated to transmit no more than 4 watts of power. A good antenna on an inexpensive radio will almost always outperform a bad antenna on an expensive radio.
63. Beware of the wire wound mobile antennas mentioned in ads that claim them to be "full-wave" or "wave and a half". At best, you are being deceived by the misleading association of wire length to actual performance characteristics. Wire length, for all intents and purposes, is irrelevant. With "very" few exceptions, antennas must function as a 1/4 wave or 5/8 wave to be useful on mobile installations. For example, Firestik and Firestik II antennas between 2 foot and 5 foot have a radiation pattern similar to a 5/8 wave reference antenna. However, wire lengths range from 20 feet to 32 feet (0.6 to 0.9 of a full wave length). If wire length was relevant, each antenna would need 22.5 feet of wire.
Firestik Antenna Company - 2614 E Adams St - Phoenix, AZ 85034 - (Tel) 602-273-7151 - www.firestik.com
1 Date/Time Tuesday, July 6, 2004 – 2:49 PM
Subject Re: Thing's every cb'er should know
To Bill Reid
From Firestik767
Message Thank you for writting.
Our best customers are educated ... how they get the education isn't important ... if having the article on your site helps the process then by all means, post it on your site. Thank you for giving us the credit for the article. You might even consider a link to our tecnical library as there are many articles that will expand on, and/or offer more detail to some of the subjects discussed in the in the "Things ... " article.
Happy Jeeping!!
Rick Vincent Sr.
Bill Reid -GP- wrote:
> I just did a web search on CB's and I came upon your article titled Thing's
> every CB'er should know.
> I belong to a Jeep chat site called jeepkings.ca and I would like to do a
> copy and paste of this article on our site as I think it would help answer
> some of the questions that keep coming up on our site about CB's.
> Of course I would credit your site as the author of this information.
> Please advise if this would be permissible
>
> Regards
>
> Bill Reid
--
This message sent to you from: rv1@firestik.com
************************************************** **********************
Firestik Antenna Company - 2614 E Adams Street - Phoenix, AZ 85034-1495
International Headquarters in the United States of America since 1962
(Tel) 602-273-7151 - (Fax) 602-273-1836 - (Web) http://www.firestik.com
if it's just clamped to the stock rack, the ground will be weak if at all.
if someone can make this part into a sticky,
Please see the diagrams above... See that nylon spacer? It looks like this...
See the bevelled edge? That's important, because it locates the nylon bushing, so that it does not move. It holds the HOT pin on the stud so it does not touch the mount.
The COAX fitting itself has a HOT and GROUND, the ground is on the outside, the hot is inside (the pin).
Everything ABOVE the nylon spacer is HOT. For that reason the stud, should not touch the mount. If you flip the nylon bushing and put it on the bottom, you are causing a DIRECT DC Short between the HOT and GROUND (because the stud is now contacting the metal of the mount and will quickly fry your CB radio.
If in doubt - do this simple test with a multimeter.
The following should NOT have continuity
- Antenna cable centre pin and ground, radio body, tub, antenna mount
- Antenna cable centre pin and antenna cable ground (round spinning part)
The following SHOULD HAVE continuity
- Antenna cable centre pin and antenna and upper stud
- The Mount, ground, tub and radio body.
Important information about GROUNDS...
A DC Ground is not an RF Ground.... A DC ground means you have electrical connectivity between 2 things. An RF ground is different, it means there is a specific relationship between the antenna and surrounding reflecting metal. So simply running a ground wire will not cut it - the mount must be METAL, connected to METAL. No Plastic. (it's more complicated than that, but you get the point). However, a DC Ground is a good indication that you are at least close.
MORE important information....
See this wire...
That wire is used for antenna matching. DO NOT GROUND IT! Under no circumstances should it be grounded unless a qualified person who has a meter connected to your equipment tells you to ground it. That lead is for fixing REALLY bad SWR. I've installed dozens of Wilson and Firestik antenna's and I have never used this wire.
That's all, hope this is helpful. Attached Thumbnails
Attached Images
and this....
Things Every CB'er Should Know
Compliments of Firestik® Antenna Company Technical Support Team
Copyright © 1996 Firestik® Antenna Company
1. Every industry has its bottom dwellers. We cannot protect you from them. Consumers who make decisions based strictly on price, or on what someone says instead of what they can do, will often fall prey to the bottom dwellers.
2. Beware of information from "experts" (real or self-proclaimed). There is antenna theory and there is antenna reality. We have yet to see a vehicle that simulates a lab. While theory is a good starting place...experience is invaluable when it comes to real problems. The knowledge gained from the best book on theory will not necessarily produce the best antenna design.
3. Some "experts" may "claim" 5/8 wave mobile antennas are not possible because they would need to be 23 feet high. They are wrong! Physical length and ground wave performance are not the same. If you ever hear someone make that claim, ask them how a handheld CB can have a 1/4 wave antenna 8 inches long and mobile 1/4 wave antennas can be anywhere from 12-60 inches long in spite of the fact that a physical 1/4 wave is 108 inches.
4 .Never key up or attempt to operate your CB without a working antenna or "dummy load" (non-radiating antenna simulating device) connected to the radios antenna jack, unless you have extra money to buy another radio, or know a good repairman.
5. All mobile and base transmitting antennas need counter-poise, more commonly called ground plane. The antenna is the reactive unit, the ground plane is the reflective unit. Neither is more important than the other. In mobile installations with standard antenna systems, the vehicle metal (body, frame, etc.) acts as the ground plane. In "no-ground-plane" systems, the coax shield is used for counterpoise.
6. Most, but not all, manufacturers pre-tune their mobile antennas on a test bench. To protect your radio's circuitry and achieve optimum performance, mobile transmitting antennas (CB, cell phone, amateur, etc.) need to be tuned on the vehicle.
7. Before transmitting, you should check your antenna system for shorts or opens. If you have continuity between the center pin of the connector and the outer threaded housing, you may have a short. Don't transmit! If you do not find continuity between the center pin of the coax and the antenna base, you have an open. Fix it. (See "Testing Continuity") Exceptions: Some base loaded antennas use a center tap design and there will be continuity from ground to center conductor. Also, Firestik "No Ground Plane" antenna kits will have coaxial center pin to ground continuity.
8. SWR that pegs the needle on all channels almost always indicates a short in your antenna system. Do not attempt to tune the antenna until the short is fixed. Operating with high SWR will probably damage your CB's internal circuits.
9. Make sure that the antenna you are using is the right antenna for your application. Don't use a TV antenna or an AM/FM antenna for your CB. Do not operate your CB without an antenna or dummy load.
10. Transmitting antennas are sensitive to objects in their "near field of radiation." Tune your antennas in an open area. Never tune inside or next to a building, near or under trees, near or under power lines, and never with a person holding or standing next to the antenna. Try to simulate normal operating conditions.
11. If you mount two or more antennas close to each other, you will alter the transmission patterns of each one. The affect may be either positive or negative. We recommend that a minimum of 12" exist between your CB antenna and other types of antennas.
12. Your radio cannot tell one component from another. As far as the radio is concerned, the coax, stud mount, mounting bracket, antenna and vehicle is ONE unit. Don't be too quick to fault your antenna until you are sure that all of the other components have been given equal consideration.
13. Of all antennas returned to Firestik for warranty service, 75% show no signs of being tuned to the vehicle. All antennas should be checked prior to use. Most will require some adjustment. Less than 3% of all returned antennas have actual performance causing problems. Of those, half of the problems are user or installer created. High SWR and other performance problems are 20 times more likely to be caused by bad coax, bad connections, shorted mounts, poor installation location or faulty test meters.
14. In almost every instance, once you get the same SWR reading on channels 1 and 40, further antenna tuning will not improve the readings. If the SWR is still over 2:1, you have other problems to conquer. Exception: There are rare occasions when the ground plane is so small or large that the system is way out of phase (especially with high-performance antennas). If you have high SWR on all channels and have confirmed that you have no opens or shorts in the feedline, try making a small tuning adjustment in the antenna. There are times when the SWR will drop equally across all channels under unusual ground plane conditions. If you find this to be the case, carefully adjust the antenna.
15. SWR that is high on all channels (over 2:1 but not pegging the needle) after the antenna has been tuned usually indicates insufficient ground plane, ungrounded antenna mount or that a coax cable problem exists.
16. The doors, mirrors, spare tire racks, luggage racks, etc. on many vehicles are insulated from a good ground with nylon or rubber bushings. This also stands true for fiberglass vehicles. Make sure that your antenna mount is grounded, even if it entails running a ground wire to the vehicle chassis. Bad hard ground at the mount generally equates to less than optimum performance. Exception: No ground plane antenna kits do not require a grounded mount.
17. If you are hearing whining noises from your radio while your vehicle is running, it is probably due to "dirty power" being supplied to the radio. Under dash power may be more convenient, but the "cleanest" power will be found by running the radio's power leads straight to the battery.
18. You can never buy coax cable that is too good for your system. Never compromise quality for cost when purchasing coax. Your best bet is to stick with coax that has a stranded center conductor and 90% or higher shielding.
19. Most manufacturers of high performance antennas recommend a specific length of coax cable. If your antenna manufacturer suggests a specific length, give priority to that recommendation.
20. If your ground plane is good, your mount grounded and, your antenna favorably located, coax length rarely becomes an issue. But, if one or more mismatches occur, you may find high SWR. This can often be corrected by using 18 feet lengths of high quality coax.
21. Excess coax between your radio and antenna mount should never be wound into a circular coil of less than 12" in diameter. Doing so can cause system problems. Your best option for handling excess coax is to serpentine the cable into a 12 to 18 inch yarn-like skein. Secure the skein in the center with a wire tie and tuck it away.
22. Single antenna installations require coax with approximately 50 ohm's of resistance (RG-58/U, RG-58 A/U or RG-8X). Dual antenna installations require the use of 72 ohm cable (RG-59/U or RG-59 A/U).
23. Coaxial cables with foam (polyfoam) center conductor insulation should be your last choice for use on mobile (vehicle) installations. Even though it will work initially, it has limited life and does not stand up to the conditions encountered in the mobile environment. Choose coax with polyvinyl insulation when doing mobile installs.
24. Coax cables should never be cut and spliced together like common electrical wire. Line losses will occur.
25. Coaxial cable with holes in the outer insulation, severe bends, or door, trunk or hood caused pinches will cause performance problems. Treat your coax with care.
26. If you live in an area where rain and/or sleet is common, wipe your antenna down with a rag that has been coated with WD-40, Armor-All, Pledge, light oil, etc. This trick prevents ice build up that can overload and cause your antenna to break. In an emergency use butter, cooking oil or anything else that will repel water.
27. When tuning your antenna(s), make sure that you do so with the vehicle doors, hood and trunk closed. If left open, they can cause inaccurate SWR readings. Try to simulate actual operating conditions.
28. Mobile antennas, for best performance, should have no less than 60% of their overall length above the vehicles roof line. For co-phased antennas to perform optimally, the space between the top 60% of the two antennas needs to be unobstructed.
29. Remember, all transmitting antennas need ground plane (counterpoise). Base antennas, much like "no ground plane" antennas, build it in. Do not use mobile antennas for base station applications unless you know how to build your own ground plane.
30. If you are installing a single antenna on one side or the other of your vehicle, best on-the-road performance will be realized if the antenna is on the passenger side of the vehicle (Passenger cars and light trucks) Large trucks or vehicles pulling large trailers should put the antenna on the drivers side to avoid the signal from being blocked by the trailer and to keep from hitting road side trees.
31. Co-phased (dual) antenna installations create a radiation pattern that favors communication directly in front and back of the vehicle. This is why co-phase systems are popular with people who do a lot of highway driving. Co-phase antennas must be center or top loaded. Top loaded antennas are the best.
32. Some people believe that co-phased antennas must be separated by a minimum of nine (9) feet. We have successfully used co-phase antenna systems with spacing as little as four (4) feet. Space alters the pattern and not always negatively. Each vehicle will be different.
33. Co-phase antennas can improve performance on vehicles that lack good ground plane characteristics (fiberglass motorhomes, trucks, etc.). Instead of using available metal to reflect the radiated energy, the antennas use each others field.
34. When tuning co-phased antennas (dual), it is best to adjust both antennas an equal amount to maintain equality in their individual resonant frequency.
35. On a co-phase system, if you try to tune each antenna independently using RG-58 type coax and then connect them to the co-phasing harness, you will almost always find that they will appear electrically short as a set. We recommend that you first assemble the entire system. Take all measurements and make all adjustments with both antennas in place.
36. If you are experiencing SWR that is high across the entire band and have eliminated shorts, opens, groundless mounts and coax as potential problems, suspect lack of ground plane. Try adding a spring or quick disconnect to the antenna base. In some cases, the repositioning of the antenna relevant to available ground plane will solve the problem.
37. One of the greatest benefits of the FS series (patented tunable tip) antenna is noted when there is lack of available ground plane. If the tuning screw reaches its "maximum out" position before satisfactory SWR is realized, a common 1/4-20 threaded bolt or screw of a longer length can be used to replace the supplied tuning screw. If the vinyl cap is too short to remain in place, the user can disregard it or clip a hole in the top for the longer screw to pass through.
38. In rare instances, like antennas mounted in the middle of a metal van roof, excess ground plane can cause a problem. This usually shows up as high SWR across the band. In these cases, a tunable tip antenna may not be the best choice. The reason being, the antenna is too long and the tunable tip cannot adjust down far enough (see line 40). If you suspect this, an antenna that wire can be removed from will usually fit the bill (i.e. KW or RP series).
39. There may be situations when a tunable tip will bottom out before optimum tuning is achieved. If this happens, try removing the knurled jam nut and finger tighten the tuning screw against the o-ring. If still too long, remove the tuning screw altogether. If total removal causes the antenna to go short, cut the tuning screw in half and re-insert it into the tuning extender and re-test. The following items on the FS Series "tunable tip" antennas, when removed, will have an effect on SWR (in order from least effect to most effect). O-ring, jam nut, tuning screw mass (cutting off length), vinyl cap, tuning screw complete.
40. The vinyl cap on any "tunable tip" Firestik antennas is optional. However, your antenna needs to be tuned as it will be used . . . with or without the tip.
41. Magnetic mounts should be used in temporary situations only. If you leave them in the same spot for a long period, the paint will not age like that of the uncovered areas and/or moisture will be trapped between the mount and vehicle causing rust or discoloration. Periodically lift the magnet and gently clean off the underside of the magnet and the vehicle surface.
42. It is a bad idea to use magnetic mounts and amplifiers together. Magnetic mounts rely on capacitance grounding. This situation can literally cause the paint under the mount to bubble or discolor due to excessive heat build up.
43. On wire-wound antennas that require wire removal for tuning purposes, best overall performance will be achieved by keeping the loose end of the wire pressed down tightly against the wire coil. If you use power amplification on top loaded antennas and do not process the end of the wire load so it can dissipate its heat into other adjacent coils, you can melt the tip of the antenna.
44. Generally speaking, center loaded antennas perform better than base loaded antennas, and top loaded antennas perform better than all. For any given antenna design (base, center or top loaded), the taller the antenna the better. With length comes a wider bandwidth (lower SWR over more channels), more power handling capability and overall performance increases.
45. When ultimate mobile performance is desired, function should be given precedence over mounting location convenience and appearance.
46. Don't confuse SWR with overall performance. You should seek SWR of 2:1 or lower on channel 1 and 40, but keep in mind that best performance may not be found at the lowest SWR readings. For the most part, if you get your SWR below 2:1, on both ends of the band, don't be overly concerned about using meter tricking procedures that bleed off energy.
47. The SWR meters built into CB radios are okay for general readings, but are rarely sensitive and/or accurate enough for fine tuning of antennas. Use them mostly to indicate serious high SWR problems only.
48. Firestik has tested literally hundreds of SWR meters. A large percentage of these have shown to be off by 0.3 to 0.7 when compared to a piece of certified equipment. There is no standard among production meters. However, unless a unit is defective, most will indicate the most serious problems that you might encounter
49. Aside from cost, the type of wire used in or on antennas (copper, silver, aluminum, gold, tinned, etc.) has negligible effect on antenna performance. The antenna must be designed to resonate with the wire type and gauge chosen by the designer. However, larger wire gauges will normally increase the bandwidth and heat dissipation abilities of the antenna.
50. Copper is 55% better than aluminum, 27% better than gold and 578% better than tin insofar as conductivity is concerned. Silver will conduct AC/DC current less than 2.5% more efficiently than copper, but the cost to performance is generally unjustified and any gain, insofar as RF transmission is concerned, is negligible.
51. If devices other than an SWR meter are going to be used between the CB radio and antenna, always tune the antenna system first without that device in line. If SWR is high with the other device in line, you will know where the problem is.
52. In "no ground plane" systems, it is best to choose a system that terminates the coaxial ground at the radio end of the cable. These systems are far less reactive to cable routing errors and will almost always outperform systems that are terminated at the antenna base or antenna end of the coax.
53. Cables and antennas from standard & no-ground plane kits are not interchangeable. The "No Ground Plane" antennas from Firestik have a yellow band near the base.
54. Wire wound antennas with a plastic outer coating will greatly reduce audible RF static when compared to metal whip antennas.
55. If you leave your antenna on your vehicle permanently, remove the rubber o-ring that is found on the threaded base of some antennas. Tighten permanent antennas with a wrench. Add a lock washer if you want.
56. If you use mirror mounts and often find yourself in areas with overhead obstructions, tighten the bolts just enough to keep the antenna vertical at highway speeds. If the antenna contacts something overhead, the mount will rotate on the mirror arm and protect your antenna.
57. If you use long antennas and find that they bend too far back at highway speeds, tilt them forward if possible. When under a wind load, they will end up in a relatively vertical position.
58. On antennas that are topped off with a vinyl tip, make sure that you take your SWR measurements with the tip in place. If you tune your antenna with the tip off and then reinstall the tip, your SWR will change.
59. Without advocating the use of power amplifiers or unauthorized channels, take note that the Firestik II tunable tip antennas have a fairly large metal tip that broadens the bandwidth and dissipates a considerable amount of heat.
60. It is illegal to use power amplifiers with CB radios. It is illegal to "tweak" the radios internal circuits to increase output power. The transmitter power of a legal, FCC certified CB radio is 4 watts AM.
61. If having one antenna for CB/AM/FM is appealing, use a CB antenna and a splitter that allows it to be connected to your AM/FM radio. Devices that let you use your AM/FM antenna for CB use will leave you disappointed.
62. On a budget? Buy a cheap radio and a good antenna. Aside from added bells and whistles, all CB's are FCC regulated to transmit no more than 4 watts of power. A good antenna on an inexpensive radio will almost always outperform a bad antenna on an expensive radio.
63. Beware of the wire wound mobile antennas mentioned in ads that claim them to be "full-wave" or "wave and a half". At best, you are being deceived by the misleading association of wire length to actual performance characteristics. Wire length, for all intents and purposes, is irrelevant. With "very" few exceptions, antennas must function as a 1/4 wave or 5/8 wave to be useful on mobile installations. For example, Firestik and Firestik II antennas between 2 foot and 5 foot have a radiation pattern similar to a 5/8 wave reference antenna. However, wire lengths range from 20 feet to 32 feet (0.6 to 0.9 of a full wave length). If wire length was relevant, each antenna would need 22.5 feet of wire.
Firestik Antenna Company - 2614 E Adams St - Phoenix, AZ 85034 - (Tel) 602-273-7151 - www.firestik.com
1 Date/Time Tuesday, July 6, 2004 – 2:49 PM
Subject Re: Thing's every cb'er should know
To Bill Reid
From Firestik767
Message Thank you for writting.
Our best customers are educated ... how they get the education isn't important ... if having the article on your site helps the process then by all means, post it on your site. Thank you for giving us the credit for the article. You might even consider a link to our tecnical library as there are many articles that will expand on, and/or offer more detail to some of the subjects discussed in the in the "Things ... " article.
Happy Jeeping!!
Rick Vincent Sr.
Bill Reid -GP- wrote:
> I just did a web search on CB's and I came upon your article titled Thing's
> every CB'er should know.
> I belong to a Jeep chat site called jeepkings.ca and I would like to do a
> copy and paste of this article on our site as I think it would help answer
> some of the questions that keep coming up on our site about CB's.
> Of course I would credit your site as the author of this information.
> Please advise if this would be permissible
>
> Regards
>
> Bill Reid
--
This message sent to you from: rv1@firestik.com
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Firestik Antenna Company - 2614 E Adams Street - Phoenix, AZ 85034-1495
International Headquarters in the United States of America since 1962
(Tel) 602-273-7151 - (Fax) 602-273-1836 - (Web) http://www.firestik.com
01-04-2009, 10:25 PM
#7
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Year: 1995 2WD & 1988 4WD
Model: Cherokee
Engine: 242
Some radios if they have been peaked and tuned or have an amplifier in line will sound over modulated if your too close.
Check your SWR, 102" whips are the best antennas in my opinion,
its what all other cb antenna strive to be like.
Even with a small amount of ground with a 102 will still perform, your roof rack will act as a ground plane even if you dont have it grounded since it is metal
-but you should ground it.
- you dont have clearance problems with it that tall ?
Check your SWR, 102" whips are the best antennas in my opinion,
its what all other cb antenna strive to be like.
Even with a small amount of ground with a 102 will still perform, your roof rack will act as a ground plane even if you dont have it grounded since it is metal
-but you should ground it.
- you dont have clearance problems with it that tall ?
Last edited by X-J; 01-04-2009 at 10:36 PM.
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01-05-2009, 06:40 PM
#8
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Year: 1996
Model: Cherokee
Engine: 4.0L HO
Yeah but I dont go through drive throughs. hahaha So my mount has to be grounded? Because its not. On the coax I bought, it has the plug that screws into the end of the CB then it has two "wires" running out the other end. One is shielded and one is just a weave that wraps around the shielded wire. The shielded wire is hooked to the antenna and the weave one is connected to the roof rack. IS THIS WRONG? If it is please let me know.
This is my rack
This is my rack
Last edited by fivendime; 01-05-2009 at 06:44 PM.
01-05-2009, 07:34 PM
#10
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Year: 1996
Model: Cherokee
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Well, he was only about 200 feet away so that may be the problem. My radio seems to have allot of funny noises. It does make a squeely noise when I turn my heater fan on and it changes loudness as I turn the fan up.
I forgot to mention he has a tweeked radio with 2-102" whips.
I forgot to mention he has a tweeked radio with 2-102" whips.
01-05-2009, 07:39 PM
#11
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Year: 1991
Model: Cherokee
Engine: 4.0
Well, he was only about 200 feet away so that may be the problem. My radio seems to have allot of funny noises. It does make a squeely noise when I turn my heater fan on and it changes loudness as I turn the fan up.
I forgot to mention he has a tweeked radio with 2-102" whips.
I forgot to mention he has a tweeked radio with 2-102" whips.
01-05-2009, 07:47 PM
#12
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Year: 1996
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my roof rack is just clamped on so I have no idea if its getting contact with the body. Could that be the problem. I was thinking no because they make antennas for fiberglass cars so the rack as a ground should be sufficient. I still think my ground may be a little bad though. I am running my ground from the CB to the frame of the dash. I am running the power to the acc on the fuse block all by itself.
01-05-2009, 08:10 PM
#13
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Year: 1991
Model: Cherokee
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my roof rack is just clamped on so I have no idea if its getting contact with the body. Could that be the problem. I was thinking no because they make antennas for fiberglass cars so the rack as a ground should be sufficient. I still think my ground may be a little bad though. I am running my ground from the CB to the frame of the dash. I am running the power to the acc on the fuse block all by itself.
if you have some extra wire run a temporary ground from your rack to the frame
if that fixes the problem find a more permanent way to ground it
01-05-2009, 10:31 PM
#14
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Year: 1996
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I managed to get a hold of a family friend who is a trucker tonight and he looked at it. Told me it was hooked up fine and the rack is just fine for the ground. We didn't work on the ground point which I still have to do, but he told me to get the antenna tuned which I haven't done yet. I am going to get that done when I have time, which is not very often. We tested the range by just using the cb in a truck while driving away from each other We figured that I have a distance now of about 2 miles max while moving. Sitting still would be better but I dont sit still very often either. hahaha
I have no clue with the noise, which I completely forgot to tell him.
I have no clue with the noise, which I completely forgot to tell him.
01-05-2009, 11:00 PM
#15
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Year: 1995 2WD & 1988 4WD
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Engine: 242
Try to run the power and ground straight from the battery,
you might be getting interference from the fuse block as your accessories draw power from that source causing unwanted RF like the fan motor.
- Read through this website >>
> http://www.signalengineering.com/ult...ax_basics.html
-Also you relly cannot tune a 102" whip.
someone may say to shorten the coax a little or even trim the top of your antenna, They make a "antenna Tuner" or "Matchbox" to lower your swr, but in some cases it will read a good SWR but all you are doing is fooling the radio , in turn you get less signal in both directions.
I'll bet your swr is good, 102's are great whips, if your need your swr lower try improving the ground or mounting it in different locations,
you might be getting interference from the fuse block as your accessories draw power from that source causing unwanted RF like the fan motor.
- Read through this website >>
> http://www.signalengineering.com/ult...ax_basics.html
-Also you relly cannot tune a 102" whip.
someone may say to shorten the coax a little or even trim the top of your antenna, They make a "antenna Tuner" or "Matchbox" to lower your swr, but in some cases it will read a good SWR but all you are doing is fooling the radio , in turn you get less signal in both directions.
I'll bet your swr is good, 102's are great whips, if your need your swr lower try improving the ground or mounting it in different locations,
Last edited by X-J; 01-05-2009 at 11:14 PM.