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CB Radio - Grounding the Antenna

cb radio citizens band roof antenna

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#1 hermanmullins

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Posted 23 October 2009 - 10:16 AM

We have a 40-channel CB (all in the Mic.) that has very bad reception. I have always understood that the antenna needs a good ground. Such as a mag, ant. mounted on the metal roof of a car. Monaco doesn't have a metal roof. My antenna is mounted on the fiberglass. Has anyone ever heard of grounding the antenna at the box inside of the coach? I don't use the CB that often, but when we are travling with some other people it is better then using the cell phone all the time. Look forward to your thoughts.
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"Fair winds and Following Seas"

Herman & Bobbie Mullins, F302225
Whitewright, TEXAS
'02 Monaco Dynasty, 40-foot 400 HP ISL
Chevrolet Silverado (M & G air brakes)
U.S. Navy PR-3 1956 to 1964

Southern Region Vice President for Six-State Rally Association
Lone Star Chapter FMCA Past President
South Central Lucky Rollers
Rally in The Pasture


#2 gsoilea1

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Posted 23 October 2009 - 01:26 PM

We are having the same problem. Took our motorhome to a very good RV shop, and they told us it is because our antenna is mounted on fiberglass. The factory roof mounted antenna wasn't that great either. I hope you find an answer so we will know too.
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#3 JackNichols

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Posted 23 October 2009 - 04:04 PM

I have written this note three times, and either get off into technical items not relevant to your antenna, or get lost. So, if you have a little extra time to read some theory to understand what is happening to your antenna, maybe this will help.

CB (and most other) antennas work on a "dipole" system, and have elements that oppose each other - that is how they get the signal off into the air. Some antennas CAN be mounted on fiberglass, because their construction has the dipole effect built into it. Many, if not most, boat antennas are designed that way, and if your CB was factory installed, it is probably that type.

Coax feeding the antenna has two conductors - the center connector typically goes into the vertical element, and the braid (shielding) conductor goes to the magnetic mount on some or the mounting screw down gadget on an antenna intended to be mounted on a metal surface that can act as a "ground plane". The "ground plane" can be thought as a reflector of the vertical element. All this stuff has to be designed to be electrically in balance, and when you think about it, it is a wonder it works at all. :rolleyes: Normally you do not have to know about that or be aware of it, because the antenna manufacturer engineers proper connections into the system.

"Grounding" can have unintended consequences, because it may defeat the design of the antenna system. Unless specifically addressed in installation instructions, do not Willy-nilly ground things - you can create a "ground loop" situation that can be harmful to the radio, or interfere with your signal output.

Power supplied to CBs is often less than optimal, and you can get interference from all the electrical stuff in the vehicle. One inexpensive upgrade that will improve most CB installations is a fairly heavy (#10) two conductor wire attached directly to the battery, both wires fused to avoid shorts. Stray interference can still get into the power wire, but that will eliminate most of it.

Now, to your system. No, grounding the antenna at the "box" is not going to help - grounding for the antenna shield is provided when you use the connector on the end of the antenna coax to attach it. Steps I would take to check and improve your system:

1. I would remove and replace the antenna coax connectors from both the transmitter (box the "all in one" microphone is attached to) and the antenna. Loose connections and corrosion are very common. Check that the microphone control cord is firmly attached too. I use dielectric grease to coat wires and connectors exposed to the elements. You can get dielectric silicone grease at any electrical or auto parts store.

2. Once you get the connections squared away, I would borrow or buy an antenna tuner meter (bought one for $12 MANY years ago at Radio Shack) or better yet, borrow a neighbor that has one and buy him a beer. A simple tune up will often help, or if the system will not tune, you probably have a coax and/or antenna problem and can deal with it. If that is the case:

3. Replace your coax with a premium type - CBs do not have much power to work with, so the antenna system is critical to their working well. If your coax is routed through walls, floors, ceilings and roofs, you might want to do anything else first. Might replace the connectors (handy HAM friend good there - two beer job) on the end of the coax - I have had that help.

4. If your CB system was installed at the factory, it probably has the correct design antenna that does not need a ground plane or need to be mounted on metal. Antennas get tired, weather exposure, limbs whacking them, insulation leaks causing corrosion. If nothing else works, install a marine antenna, or one that is designed for fiberglass connection. If you would rather play around with the existing antenna (my style), you might mount it on a flat piece of metal that can act as a ground plane - at least two feet square, or on top of an air conditioner cover. Or, you can build antenna radials out of coat hanger wire, electrically bond them to your mounting hardware (not the antenna radiating element) and put them under the antenna in a symmetrical cross configuration. Tape them down until you see if it helps, then permanently secure them if it does. Probably will not.

5. Consider buying a new CB - you can get one fairly inexpensively from most truck stops. Do not consider Radio Shack unless you find a huge deal. I bought one (designed and manufactured by Cobra, with Radio Shack name on it) on sale for a good price, then saw the exact Cobra radio for fifty dollars less in a truck stop. My deal was not HUGE enough. Check a truck stop for the antenna tuning meter too - they come with good instructions, and most modern CBs are designed so they are hard to hurt - don't be afraid to experiment a little, and watch for smoke.

I also have one of the "controls all in the handle" CBs, and after I cleaned off the antenna connection on top it works pretty well. I do not travel that much, and if communications was more important, I would take the Cobra out of the toad and rig an antenna for it.

Note about radio tune-ups: Some people will offer you a "tune up" for your radio that will increase the power. Or they may offer you an "antenna booster" box that will amplify your signal. "Boosting" CB radios is illegal, not that you will ever be called on it, but more important is it rude. Amplification outside design parameters will result in a marginal quality signal so distorted it is hard to understand, and you will shorten the life of your radio components drastically. If you have listened to CB much, you will hear dumb axx drivers with too much amplification, reverberation, signal modification, beeps, boops and who knows what else. They can broadcast fifty miles or more, but can still only listen two or three miles. It is such a perfect example of our current cultures "me first, screw you" attitude it has become my pet peeve, if you have not guessed.

(Deep breath) OK, now off soap box. I am sure other HAMs here will correct or expand on the above, and I can be of any assistance, please let me know.
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#4 hermanmullins

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Posted 24 October 2009 - 05:44 AM

I have written this note three times, and either get off into technical items not relevant to your antenna, or get lost. So, if you have a little extra time to read some theory to understand what is happening to your antenna, maybe this will help.

CB (and most other) antennas work on a "dipole" system, and have elements that oppose each other - that is how they get the signal off into the air. Some antennas CAN be mounted on fiberglass, because their construction has the dipole effect built into it. Many, if not most, boat antennas are designed that way, and if your CB was factory installed, it is probably that type.

Coax feeding the antenna has two conductors - the center connector typically goes into the vertical element, and the braid (shielding) conductor goes to the magnetic mount on some or the mounting screw down gadget on an antenna intended to be mounted on a metal surface that can act as a "ground plane". The "ground plane" can be thought as a reflector of the vertical element. All this stuff has to be designed to be electrically in balance, and when you think about it, it is a wonder it works at all. :rolleyes: Normally you do not have to know about that or be aware of it, because the antenna manufacturer engineers proper connections into the system.

"Grounding" can have unintended consequences, because it may defeat the design of the antenna system. Unless specifically addressed in installation instructions, do not Willy-nilly ground things - you can create a "ground loop" situation that can be harmful to the radio, or interfere with your signal output.

Power supplied to CBs is often less than optimal, and you can get interference from all the electrical stuff in the vehicle. One inexpensive upgrade that will improve most CB installations is a fairly heavy (#10) two conductor wire attached directly to the battery, both wires fused to avoid shorts. Stray interference can still get into the power wire, but that will eliminate most of it.

Now, to your system. No, grounding the antenna at the "box" is not going to help - grounding for the antenna shield is provided when you use the connector on the end of the antenna coax to attach it. Steps I would take to check and improve your system:

1. I would remove and replace the antenna coax connectors from both the transmitter (box the "all in one" microphone is attached to) and the antenna. Loose connections and corrosion are very common. Check that the microphone control cord is firmly attached too. I use dielectric grease to coat wires and connectors exposed to the elements. You can get dielectric silicone grease at any electrical or auto parts store.

2. Once you get the connections squared away, I would borrow or buy an antenna tuner meter (bought one for $12 MANY years ago at Radio Shack) or better yet, borrow a neighbor that has one and buy him a beer. A simple tune up will often help, or if the system will not tune, you probably have a coax and/or antenna problem and can deal with it. If that is the case:

3. Replace your coax with a premium type - CBs do not have much power to work with, so the antenna system is critical to their working well. If your coax is routed through walls, floors, ceilings and roofs, you might want to do anything else first. Might replace the connectors (handy HAM friend good there - two beer job) on the end of the coax - I have had that help.

4. If your CB system was installed at the factory, it probably has the correct design antenna that does not need a ground plane or need to be mounted on metal. Antennas get tired, weather exposure, limbs whacking them, insulation leaks causing corrosion. If nothing else works, install a marine antenna, or one that is designed for fiberglass connection. If you would rather play around with the existing antenna (my style), you might mount it on a flat piece of metal that can act as a ground plane - at least two feet square, or on top of an air conditioner cover. Or, you can build antenna radials out of coat hanger wire, electrically bond them to your mounting hardware (not the antenna radiating element) and put them under the antenna in a symmetrical cross configuration. Tape them down until you see if it helps, then permanently secure them if it does. Probably will not.

5. Consider buying a new CB - you can get one fairly inexpensively from most truck stops. Do not consider Radio Shack unless you find a huge deal. I bought one (designed and manufactured by Cobra, with Radio Shack name on it) on sale for a good price, then saw the exact Cobra radio for fifty dollars less in a truck stop. My deal was not HUGE enough. Check a truck stop for the antenna tuning meter too - they come with good instructions, and most modern CBs are designed so they are hard to hurt - don't be afraid to experiment a little, and watch for smoke.

I also have one of the "controls all in the handle" CBs, and after I cleaned off the antenna connection on top it works pretty well. I do not travel that much, and if communications was more important, I would take the Cobra out of the toad and rig an antenna for it.

Note about radio tune-ups: Some people will offer you a "tune up" for your radio that will increase the power. Or they may offer you an "antenna booster" box that will amplify your signal. "Boosting" CB radios is illegal, not that you will ever be called on it, but more important is it rude. Amplification outside design parameters will result in a marginal quality signal so distorted it is hard to understand, and you will shorten the life of your radio components drastically. If you have listened to CB much, you will hear dumb axx drivers with too much amplification, reverberation, signal modification, beeps, boops and who knows what else. They can broadcast fifty miles or more, but can still only listen two or three miles. It is such a perfect example of our current cultures "me first, screw you" attitude it has become my pet peeve, if you have not guessed.

(Deep breath) OK, now off soap box. I am sure other HAMs here will correct or expand on the above, and I can be of any assistance, please let me know.


Thanks Jack, as you said that was a very indepth answer.
I will check all connections for any problems. When you said to tune up the antenna did you mean to get an SWR meter?. I had one years ago (many friends and a few beers and its gone).

I have always ask people that talk about their 1,000 watt amps, "What do you have to say that is so important?" That doesn't go over too big with them.
Back on the antenna, My factory antenna has the base portion that is about the size of a broom handle (Black) with the spring mount on top then the antenns. Is that the type that is set for Marine or RV's?

Again thanks for the answers.
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"Fair winds and Following Seas"

Herman & Bobbie Mullins, F302225
Whitewright, TEXAS
'02 Monaco Dynasty, 40-foot 400 HP ISL
Chevrolet Silverado (M & G air brakes)
U.S. Navy PR-3 1956 to 1964

Southern Region Vice President for Six-State Rally Association
Lone Star Chapter FMCA Past President
South Central Lucky Rollers
Rally in The Pasture


#5 hermanmullins

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Posted 24 October 2009 - 05:48 AM

Jack I saw that you are from Plainview, TEXAS. Did you know Ralph Culver that owned Plains Welding Supply? I have known him since the early 70's.
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"Fair winds and Following Seas"

Herman & Bobbie Mullins, F302225
Whitewright, TEXAS
'02 Monaco Dynasty, 40-foot 400 HP ISL
Chevrolet Silverado (M & G air brakes)
U.S. Navy PR-3 1956 to 1964

Southern Region Vice President for Six-State Rally Association
Lone Star Chapter FMCA Past President
South Central Lucky Rollers
Rally in The Pasture


#6 Guest_Wayne77590_*

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Posted 24 October 2009 - 10:39 AM

Jack gave a very good reply. One has to remember that it is called "antenna theory." In one way, theory is that it identifies abserations as a phenomena. So, whatever works, is good. You can get as fancy and expensive as you would like and you may achieve the same results as going plain and cheap.

Example: In 1971 I was transferred to Guantanamo Bay Cuba. i was not a "HAM" until 1974. I was an avid CB user. Somewhere in the transfer of household goods, my base station antenna came up missing. I could have ordered one through the catalog, but I was impatient. CB's were not authorized on base, but there were works in the making to get them authorized. I was one of the ones that assisted the writer of the rules and regulatioins that we would follow by proofing and offering suggestions. Some taken, some not. We did get the authority to operate on-base.

Now my delema of a base station antenna. I took about a 30-40 foot piece of RG-8 Coax and skinned back the rubber insulator by 109 inches, based on the center channel frequency at the time being channel 11. Once the rubber was removed I moved the shielded part, like a Chinese finger lock, down the remaining part of the rubber insulator. I now had 109 inches of dielectric insulator with a center conductor encapsulated in it, and 109 inches of shield pulled back down over the rubber insulator. I tied a string to the tip of the dielectric insulator and hoisted it into a tree outside the window. Using an SWR (Standing Wave Ratio) meter I checked, lowered and snipped small amouths of the end of the conductor and insulator, and repeated the process several times unitl my SWR was down around 1.6:1. Did it work? It worked very well for around the base when I was in the mobile and DW was at home. And when conditions were just right I talked to the U.S., but don't tell the CO - I didn't talk long!!

So, in theory, what ever works for you is good and you will only know through experimentation. For a short run of coax of 20 feet or less, SWR'S of 3:1 or less will not drastically damage your radio, but will dramatically limit your transmission power and, believe it or not, reception some.

I have run magnetic mount antennae from inside the trunk of a car when it was impossible to mount (including magnet - rental car) an antenna. Did it work? Yes, about 2-5 miles, sometimes more, down the highway. I had to move it around a few times, and using a field radiation signal strenght meter, determined the best radiation pattern for "down the highway. Any RV'er should try and do the same thing, before you drill hour hole. Difficult to do, depending on the antenna.

Antenna theory is not an exact science, but an observed science, as far as I'm concerned. The purchased types have been observed to work in most environments, but may not work in yours. Some have had great luck with "through the glass" mount antennas, (The Shack) and others have not. I havehad good luck with them, being careful in mounting and adjusting SWR, both for CB and VHF radios.

Good luck and let us know what you get to work.

I like this guy's way of thinking. It's how I thought back in 1971. I used a velocity factor of .5 for RG-58 back then.
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#7 JackNichols

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Posted 24 October 2009 - 01:10 PM

Herman, yes a SWR meter is what I was referring to. I have had several through the years, including a beautiful Diowa (sp?) twin needle one I had for my base station, and still the only one I need is that beat up 30 year old meter with a scratched and cracked face. It does not get me the respect of the pretty one, but works fine. The pretty one is like a trophy wife that cannot cook that well, and the old one is a trusted friend that does it all. I digress. Again.

The configuration of your antenna suggests it may have a counterpoise built into it, exactly what you need for working off a nonreflective (electronically reflective) surface, but the only way I would be comfortable saying one way or the other is to find a manufacturers name on it and get into a catalog. Lots of advertising monkey business going on in antennas, depending on the "theory" part of the physics to sell something complicated. Tear it apart, and you may find rejected lamp zip cord cut to approximate length, and covered with a pretty exterior. See "Trophy Wife" comment above. It may work as well as a titanium, iridium and gold plated one, or not. If it works, as Wayne commented, it does not matter. Waynes explination of "Theory" is right on. That is part of the fun of amateur radio.

Back in the 1960s I was one of six licensed CB operators in Austin, Texas (KQT3538), and had an old HAM (and electrical engineer, Army signal corps) help me understand antenna theory. He was a hoot, loading up drainpipes and aluminum deck chairs for antennas. I am sure the radiation from all his equipment sterilized most of his city block - he had a garage full of high power ex-military stuff. Lights would dim in town when he really cranked it up.

I do not personally know Mr. Culver, but have heard his name forever, and he is one of the mainstays in Plainview. I moved away in the mid 1950's, called away by the bright lights and big city (and several trophy wives - what was I thinking?) and will probably move back there when I get off the road. Old friends and a small town are precious to me.

There will be a HAM group, called a HamFest, in Quartzite in January, and anyone interested in amateur radio is invited. I may get the itch to get involved in it again. At my age a learning curve is a real imposition on my retirement, and I would have to start all over again, so maybe not.

Another thought on high powered CB linear amplifiers - could it be that they are over compensating for short comings in other areas? :rolleyes:
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Jack Nichols

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2003 40' Country Coach
1993 Toyota Land Cruiser
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Be kinder than you have to be. Most people are fighting some sort of demon in their lives.
Before the internet, the village idiot stayed in his village

#8 Guest_2driftrs_*

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Posted 26 October 2009 - 06:42 AM

For everything you ever wanted to know and more about any CB antenna, go to www.firestik.com. These folks are the best at describing what to do, how to do it, and in a language you can understand. We have a co-phased trucker antenna system to get around the ground plane problems. We also ran 12 gauge copper ground wires from the mounts to a chassis ground. SWR is 1.2 on channel 19.

#9 JackNichols

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Posted 26 October 2009 - 06:08 PM

Firestick has good engineering, and their fiberglass antennas are a mainstay in many places - BUT - if the fiberglass whips are whacked on limbs, rocks, etc, they will fatigue and break. I have seen more than ten do that. Admiitedly, those failures probably would have done in most any antenna except the Mayberry Special (whoosh, whoosh) 102" whip. The long whips are not real handy to deal with, so I chose a base loaded 4' whip (Radio Shack) ten years ago that has done well.

Firestick has a good product, within its limits. Good website and help there.
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Jack Nichols

Full timer since July 2008
2003 40' Country Coach
1993 Toyota Land Cruiser
Escapees
Workampers
KA5IFU

Be kinder than you have to be. Most people are fighting some sort of demon in their lives.
Before the internet, the village idiot stayed in his village

#10 Spedball

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Posted 26 October 2009 - 10:24 PM

Any type of Antenna can be used as long as you use a ground trap to one of the screws that goes through the fiberglass [/color]and the other end of the ground strap attaches to any metal beam of your coach.
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#11 JackNichols

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Posted 26 October 2009 - 11:51 PM

True, it might work fine. What I know of antenna theory, and what Wayne pointed out, means some goofy things work, while a fully engineered system may not work.

The small amount of power in CB systems requires a well balanced system to operate at its maximum. Optimum operation is not necessary to do the job, however. A SWR reading of three to one is hard to distinguish from a SWR reading of 1 to 1, a perfect match.

As a hobbyist I want to tweak the system to the max, just to see if I can. When I key up you will hear a fairly quiet background and intelligible, well modulated signal. Getting that last 5% of signal takes instruments to measure, and way more trouble than most people want to fool with. I can hear people saying "Woah, man, get a life." ;*)

For a purely functional system maybe all that is needed is a coat hanger stuck in the back of the radio, key the mike, contact someone 500 yards away, (or something that works) and be happy.

So, we are talking about two different things here. I cannot argue with your statement that it works or may work.
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Jack Nichols

Full timer since July 2008
2003 40' Country Coach
1993 Toyota Land Cruiser
Escapees
Workampers
KA5IFU

Be kinder than you have to be. Most people are fighting some sort of demon in their lives.
Before the internet, the village idiot stayed in his village

#12 Guest_2driftrs_*

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Posted 27 October 2009 - 04:49 AM

Our first CB radio had tubes, a crystal for the channel on which you wanted to operate, and you still needed an FCC license. Things have come a long way since then! To alleviate the tree bashing our dual antenna setup has to endure, both masts are spring loaded. The vinyl coating gets scraped a bit, but it's easily repaired with the same stuff you dip screwdriver handles into to give them that rubbery feel (plasti-dip).

#13 FMCABrad

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Posted 17 November 2009 - 05:52 PM

I read all the posts on NGP CB antenna systems with interest. I am not clear on one issue. I often hear about "special" coax cable for NGP systems. What is "special" about this cable. At first I thought it was nothing more than how the antenna end of the coax was terminated. Now I an not so sure. On my rig, the manufacturer used a cheap coax that continually broke. I replaced it with 27' of high quality RG-58A/U, connecting the center conductor to the antenna and leaving the braided shield floating. Was I correct?
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#14 Guest_2driftrs_*

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Posted 18 November 2009 - 05:29 AM

Firestik.com has all the answers. They have a whole tech section devoted to RV installations. Check them out - - they are undoubtedly the best source of info re CB installations in RV's. BTW, I push Firestik because I have 25 years of successful experience with their products!

#15 Guest_Wayne77590_*

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Posted 18 November 2009 - 11:16 AM

FMCABrad,
Not really. A properly terminated antenna is theoretically better than one that is not terminated correctly. As pointed out a little earlier, putting the shield to a grounding shield would be better than no grounding at all. But, that is "in theory."

Let me give you an example. In 1966 I was in charge of setting up a communications van on top of Camp Smith, Hawaii to communicate to Vietnam every time General Krulak flew in-country. Our attempt at using the standard vertical antenna, pushing 750 watts voice, 1000 watts CW on the HF frequencies (CB is HF) did not give us optimal results. General Krulak needed reliable communications for decisions he may have to make while in transit.

Well, it's theory, right. Alright Marines, go cut me down 3 trees (saplings) at least 20 feet of straight length. They looked at me quizzically, but did what I asked. Now, radio waves do not travel in a straight line. They follow the curvature of the earth. A radio wave also follows its radiation pattern, and there will be many radiation patterns off of an antenna, with, typically, one being the major lobe. We calculated the great circle path. Using a compass I set a line on the azimuth of the great circle path to Vietnam from Hawaii. I had the troops (me helping) raise a tree along the back side of the communications van. Then we set up the other two trees a few wavelengths out from the middle of the frequency spectrum in the form of a "V", keeping the center line between the "V." I ran wire from each end of the V to the communications van. I used a 12 AWG wire. One end terminated at the screw on post for the antenna at the communications van. The other went to a grounding lug on the base plate of the antenna. In theory, and using a field strength meter for verification, the maximum lobe(s) were pretty darn close to down the center of the "V." The wire attached to the center post was the primary source of RF, and the other wire terminated to ground was "induced" causing radiation to flow through it. This maximized the major lobe in the center of the beam. Radio waves do not come off of an antenna in concentric circles, but in varying degrees based on the frequency of the signal, and the wavelength of the antenna.

So, as stated and in theory, 1 watt and a wet string could allow you to communicate around the world. (I've done that, but not with 1 watt and a wet string - that's another story.)

Guess I got a little vociferous on this post. Oh well, I'm known to do that on occasion.

Only a field strength meter is going to tell you the effectiveness and direction of your signal. Try it with and without the grounding. You can even solder the braided shield to the base of the antenna taking care not to melt the insulator, or solder to the center conductor. That would provide you with a better system than leaving it ungrounded.

As for coaxial cable, well, there are cheap ones with very little braided shield and even solid aluminum foil as a shield. I don't care for the aluminum foil. Also there are coax cables that are double shielded and these provide a less of a signal loss than the single braided shields. You can search on the key words "coax cable" and come up with some charts that will give you all the information, and more, that you can use in determining what to purchase.

Good luck.

(Expensive doesn't always mean the best.)

#16 JackNichols

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Posted 18 November 2009 - 12:01 PM

I wonder if you had any roast seagulls with that antenna setup and 1,000 watts? ;*)

Great example of practical antenna work.

Jack
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Jack Nichols

Full timer since July 2008
2003 40' Country Coach
1993 Toyota Land Cruiser
Escapees
Workampers
KA5IFU

Be kinder than you have to be. Most people are fighting some sort of demon in their lives.
Before the internet, the village idiot stayed in his village

#17 FMCABrad

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Posted 18 November 2009 - 03:01 PM

Thanks guys. :rolleyes: I appreciate the advice. Here is the bottom line: Went to Firestik. Best advice received.

I terminated the ends of the cable correctly. That is the shield is left floating at the antenna end and the PL-29 connector attached at the radio end. However, I destroyed the system performance on two counts.

First, the coax is indeed special. It isn't really 50 ohm cable. Playing with it and my ohm meter it appears much like leaky coax. I know know this is to achieve the optimum counterpoise which is made up only by the shield.

Second, the length of the cable is precisely turned, a fact I didn't appreciate. I achieved some performance by blind luck. I guess I just need to purchase a NGP kit.

On a related subject, I could easily have been on the other end of Wayne's Camp Smith HF system. Yes, Wayne, I will check my system with my field signal strength meter. At one time I was a communications system engineer and had access to some very smart antenna engineers, "real engineers." The only explanation I ask of them was would it work? In retrospect, I should have made them teach me something.
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#18 Guest_Wayne77590_*

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Posted 18 November 2009 - 06:32 PM

I don't believe that you can accurately mesure the impedance of a coax cable without an impedance meter, and one that will generate a pulse on the line and read the return (or lack of return).

If the CB radio is properly grounded, then when you attach the PL-259, with the shield correctly soldered to the PL-259, you have grounded the antenna if the shield is attached to the non-center conductor of the antenna. The shield will act as the counterpoise, albeit not a very good one.

Did I mention making an antenna with nothing but COAX? Remove 108 inches (I used 109 and trimmed) of rubber jacket, slide the shield bacward onto the remaining rubber jacket, attache a string to the end of the center conductor with insulator material still attached, and haul up into a tree. Worked well for about 5-10 miles, and when the Ionosphere was right - 1000's of miles.

#19 hermanmullins

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Posted 19 November 2009 - 08:30 AM

We have a 40-channel CB (all in the Mic.) that has very bad reception. I have always understood that the antenna needs a good ground. Such as a mag, ant. mounted on the metal roof of a car. Monaco doesn't have a metal roof. My antenna is mounted on the fiberglass. Has anyone ever heard of grounding the antenna at the box inside of the coach? I don't use the CB that often, but when we are travling with some other people it is better then using the cell phone all the time. Look forward to your thoughts.



WOW! I can't beleive the responce to my question. I would love to be at a campfire with all of you gentlemen. Oh what a night that would be. With all of the great responces I have come to one very good answer. Herman (me) you need to take your coach to a CB tech. and have him check out my radio and make the adjustment needed.

Thank you all again for the many great answers.
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Whitewright, TEXAS
'02 Monaco Dynasty, 40-foot 400 HP ISL
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#20 wrongagain

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Posted 21 January 2010 - 10:50 PM

You can really tell how old a person is when they tell you their FCC cb license #, by the way mine was KAMD4093.
I used a firestik on the bus because it was near impossible to find anywhere to mount it that fit the bill as well as handle the high power I was running.
Everywhere else I use a wilson 5000, I would prefer the 102" whip but it is less than practical.
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