CB antenna height

[jjohnsonphx]

Do you need a Ham License?

Well, that is a good question. I've been a Ham operator for over 15 years, and one thing has taught me is that Ham's are great people and very willing to help out other Ham's. With that said, deepening on the frequency Ham's can talk on their radios from as short as standing right next to you, to half way around the Earth. I’m not bashing CB Radio, but the 11M HF band that CB is in, can only transmit hundreds of miles on 4 watts when conditions are just right, and occasionally thousands. And most of the time they are not just right. With ham radio you have up to 2kW of transmit power depending on the frequency and what you want to spend. Most radios are anywhere from 15W to 100W out of the box, and handheld radios are limited to 5W by the FCC. On the HF bands (there are many HF bands available to the correctly Licensed Amateur) 100W is plenty of power to get your message out. Even on VHF or UHF 45W is enough to transmit 50, 100 or more miles. The hobby has been set aside by the FCC as a non-profit emergency communications mode for anyone carrying a license and for use by licensed Ham’s for fun. Recently Ham’s in the Haiti disaster have been carrying traffic for Doctors and Relief workers back to the USA.

In my opinion, YES you should get an Amateur Radio License.

But don’t rule out having a CB also. More radios are always better. It gives you more choices/options. On a side note, 102" whip or Wilson are great choices. I tend to stay away from the fiberglass antennas because I've seen too many split and/or break under extreme conditions. Choose one that best fits your need and fits the vehicle and placement. Then take it to either a experienced shop to tune, or find a Ham willing to tune it for you. A tuned CB and antenna combination will preform much better and make the radio last longer. Not tuning any transmitter can create reflected power that can burn out the finals (part of the transmit circuit) in the radio. This doesn't always happen but it can. Then when you need it, it will be junk.

N7XDK

 

[Scenic WonderRunner]

Does CB Radio Antenna Height.....have Anything to do with Ham Radio?





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[alexrex20]

does your post have anything to do with CB antenna height? does mine?

no and no.

 

[jjohnsonphx]

By Antenna height I assume you mean the length of the antenna element for a omnidirectional antenna. On CB radio most vehicle installs use a vertical antenna. Meaning that the element is in a vertically orientation and is a portion of the Wave Length. Wave Length is the inverse of the Frequency. So with some basic math you can take the Frequency and calculate the length of any antenna for any know Frequency. CB radio is in the 11 meter band. Which means that the frequencies are centered around 11 meters or approximately 29Mhz.

So what does this really mean. As the frequency goes up, the antenna gets shorter. This is based on RF physics. For CB radio the antenna length is 102 inches for a quarter wave antenna. So then the next thing to talk about is what is a quarter wave, half wave and so on. Basically any vertical omnidirectional antenna can be built on a half multiple of the full Wave Length starting with a half wave with some exceptions. But when you get down below a eighth wave the antenna performance goes to hell. Most antenna are half, quarter, 5/8, and so on. Without getting into too much technical detail, the 102" and Wilson antennas preform quite well for CB. Technically there are some differences with each of these antenna, but at 4 watts out of a CB, these differences are quite small.

As I mentioned before, any antenna out of the box need to be tuned to the installation and radio. Tuning basically moves the antenna length to reduce the Standing Wave Ratio (SWR) to an acceptable limit. Usually less than 2:1 for most radio systems. You do this with a SWR meter and move the antenna length up or snip small amounts off the antenna until the SWR is within limits. A good shop can do this for you. It takes a bit of experience to do it correctly, and to know which direction to go. Please don't try this unless you know how to read an SWR meter and understand basic RF principals.

So more to the point. All radio systems (CB, Ham Radio, Commercial Radio, TV, Police Radio, etc) need to be matched to their Antenna. So the short answer is yes, the length of an antenna has direct relation to the Frequency and must be designed for that Frequency or for a small range of Frequencies.

To give you an idea of the Frequencies we are talking about, HF or High Frequency Bands operate anywhere from 300Khz to 30Mhz. With CB being about 29Mhz. VHF or Very High Frequency is from 30Mhz to 300Mhz and UHF or Ultra High Frequency is from 300Mhz to 3Ghz. And not one antenna can be used for all these Frequency Bands, and preform well for all the bands. That is why there are so many choices when it comes to antennas. Ham Radio Operators have privileges to transmit on bands within each of HF, VHF and UHF. Check out http://www.arrl.org/ for more info on Ham Radio and it uses. The ARRL has many books on how to get your license and even Antenna design books.

Personally I recommend the Wilson 1000 line of antenna. They preform well and are usually almost dead on SWR out of the box.

 

[Scenic WonderRunner]

By Antenna height I assume you mean the length of the antenna element for a omnidirectional antenna. On CB radio most vehicle installs use a vertical antenna. Meaning that the element is in a vertically orientation and is a portion of the Wave Length. Wave Length is the inverse of the Frequency. So with some basic math you can take the Frequency and calculate the length of any antenna for any know Frequency. CB radio is in the 11 meter band. Which means that the frequencies are centered around 11 meters or approximately 29Mhz.

So what does this really mean. As the frequency goes up, the antenna gets shorter. This is based on RF physics. For CB radio the antenna length is 102 inches for a quarter wave antenna. So then the next thing to talk about is what is a quarter wave, half wave and so on. Basically any vertical omnidirectional antenna can be built on a half multiple of the full Wave Length starting with a half wave with some exceptions. But when you get down below a eighth wave the antenna performance goes to hell. Most antenna are half, quarter, 5/8, and so on. Without getting into too much technical detail, the 102" and Wilson antennas preform quite well for CB. Technically there are some differences with each of these antenna, but at 4 watts out of a CB, these differences are quite small.

As I mentioned before, any antenna out of the box need to be tuned to the installation and radio. Tuning basically moves the antenna length to reduce the Standing Wave Ratio (SWR) to an acceptable limit. Usually less than 2:1 for most radio systems. You do this with a SWR meter and move the antenna length up or snip small amounts off the antenna until the SWR is within limits. A good shop can do this for you. It takes a bit of experience to do it correctly, and to know which direction to go. Please don't try this unless you know how to read an SWR meter and understand basic RF principals.

So more to the point. All radio systems (CB, Ham Radio, Commercial Radio, TV, Police Radio, etc) need to be matched to their Antenna. So the short answer is yes, the length of an antenna has direct relation to the Frequency and must be designed for that Frequency or for a small range of Frequencies.

To give you an idea of the Frequencies we are talking about, HF or High Frequency Bands operate anywhere from 300Khz to 30Mhz. With CB being about 29Mhz. VHF or Very High Frequency is from 30Mhz to 300Mhz and UHF or Ultra High Frequency is from 300Mhz to 3Ghz. And not one antenna can be used for all these Frequency Bands, and preform well for all the bands. That is why there are so many choices when it comes to antennas. Ham Radio Operators have privileges to transmit on bands within each of HF, VHF and UHF. Check out http://www.arrl.org/ for more info on Ham Radio and it uses. The ARRL has many books on how to get your license and even Antenna design books.

Personally I recommend the Wilson 1000 line of antenna. They preform well and are usually almost dead on SWR out of the box.

CB RADIO FREQUENCIES....

I have NO Idea where 29 came from! OMG!

No wonder everyone hates CB Radios! They have No Idea!





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[jjohnsonphx]

WOW, pick up on my one mistake. The general principals are still the same, no matter if my example was a couple Mhz off...... I did say approximately. In fact Ham's take 11 meter(102") and cut them down for our 10 meter band. Which is, by the way, 28Mhz to 29.7Mhz.

By the way, you did read the part I said about, do both CB and HAM didn't you? I still think having a CB is a good thing even if you are a Ham. The fact is that Ham radio polices them selves. And CB, anything goes, including loose language. That is why I prefer Ham Radio to CB. However my HF radios have the CB frequencies in them. Just in case I need to talk to one of my non-Ham friends. Don't focus on the small stuff. The original posters questions are still legitimate and deserve a good answer.

 

[Scenic WonderRunner]

WOW, pick up on my one mistake. The general principals are still the same, no matter if my example was a couple Mhz off...... I did say approximately. In fact Ham's take 11 meter(102") and cut them down for our 10 meter band. Which is, by the way, 28Mhz to 29.7Mhz.

By the way, you did read the part I said about, do both CB and HAM didn't you? I still think having a CB is a good thing even if you are a Ham. The fact is that Ham radio polices them selves. And CB, anything goes, including loose language. That is why I prefer Ham Radio to CB. However my HF radios have the CB frequencies in them. Just in case I need to talk to one of my non-Ham friends. Don't focus on the small stuff. The original posters questions are still legitimate and deserve a good answer.

I Read Everything.


This is the problem with any CB Radio Thread.

Ham dudes will chime in and call a CB Radio junk. But YOU did not even know the Freq!

The CB Radio will do what it is designed to do if you set it up properly, and use a quality antenna, and set the SWR Properly. If you don't set it up properly, and with a good antenna, you will call it junk.

2 Meter is better and will go farther.


I would never slam a 2 meter radio or a perfectly set up CB Radio. They both serve their purpose.

Both belong in our trucks.



Too bad more CB Radio dudes don't take the time to set up their systems properly.


By the way! 10 Meter IS NOT CB! And is not what the original poster asked! So off topic...I don't have anything more to say!



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[Herbie]

This is the problem with any CB Radio Thread.

Ham dudes will chime in and call a CB Radio junk. But YOU did not even know the Freq!

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From the OP:

and what's the deal with ham radio licenses?

The OP put HAM "on the table" as far as this thread was concerned. jjohnsonphx was responding to the OPs question from the first post. As for calling him out for 27MHz vs. 29MHz., that's weaksauce. Quick, without looking, what's the frequency for CB channel 27? You'll have to forgive a Ham, who has HUGE chunks of spectrum to play with, relatively speaking, for an error of 2MHz. Heck, the standard channel spacing for the input/output frequencies of a 70cm repeater is 5MHz all by itself.

We're all relieved and impressed that you were able to call for rescue with a CB. jjohnsonphx, and just about every other Ham in a CB thread will advocate both radios. Since CB is basically an "11-meter DX rig" in Ham terms, failing to point out the legal power limitation of CBs would be almost negligent. 4 Watts is 4 watts. Properly tuned and with the right conditions it'll skip way farther than most people realize, but 4 Watts is 4 watts.

 

[RHINO]

heck i'm not a ham yet and i advocate both,,, the cb will be around forever maybe,, its just a cheap reliable way to communicate over short distances. ham is great for calling out over long distance, and crystal clear for talking to your buds a couple camps over but not many average joe's will ever have ham

so what is the OP to do? i'll tell ya, get yourself a cb,,, if you want i'll tell you exactly what brand of everything and you'll be chatting up for well under $100. then, later if you feel so inclined go for the ham.

 

[jjohnsonphx]

Don't forget about FRS and GMRS radios. There are a lot of them out there and real cheap. I bought a 2 pack for $40. I usually use my FRS with my wife when we are in close proximity, but too far to yell.

 

[762X39]

Too bad more CB Radio dudes don't take the time to set up their systems properly.
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I think this is the jist of the whole thread right here.I was a tech in the CF and it was my job to make sure the radios our comm sqn used were serviceable before going out on ex.Scenic Wonder, you have to lighten up a bit. I saw a lot of good information posted about antennas here and the hams didn't pan cb use.The original poster asked about a full length whip and needing a ham licence. I use a full length whip mounted to my Mogs front bumper and have taken the time to tune it for optimal performance with my cb.Of course I also have a 2 metre rig and satphone when needed.Whatever works, works!

 

[KG6BWS]

i've talked with truckers over 60mi away on my untuned CB. bounce it off the overcast clouds and you have incredible range.

Awhile back, using the skip wave running lower side band, i was able to talk to a guy in Sydney, Australia. Contacts in 22 states, including Alaska and Hawaii.

I LOVED my 102" whip!!!

 

[PhulesAU]

Low power like the CB, just means it is a MUST!!! to tune it properly. it works just fine for it's intended use. at 4 watts It's what Hams call QRP. Basically seeing how far you can talk to others using the least amount of power. With the right set-up international QSO's are a regular occurence. It's all in the tweaking and tuning of your system. Just another excuse to spend hours out in the driveway........:sombrero:

 

[KG6BWS]

Low power like the CB, just means it is a MUST!!! to tune it properly. it works just fine for it's intended use. at 4 watts It's what Hams call QRP. Basically seeing how far you can talk to others using the least amount of power. With the right set-up international QSO's are a regular occurence. It's all in the tweaking and tuning of your system. Just another excuse to spend hours out in the driveway........:sombrero:

LOL!!! If I had done my tuning and tweaking in my driveway rather than on a mountain top during school hours, I probably would have done better in high school!!! :sombrero:

 

[Scenic WonderRunner]

LOL!!! If I had done my tuning and tweaking in my driveway rather than on a mountain top during school hours, I probably would have done better in high school!!! :sombrero:

.....:elkgrin:

Now just where is my "nose in book" smiley....when I need him!



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