CB Antenna Placement

[RCP Phx]

I made a mount at the front of the Heep so it would lay down on the hood when going through trees. It looks redneck but works great. I can see it get whacked and it makes a good "tree feeler". I get super low SWR's, around 1.0.

SWR's dont have anything to do with the pattern,they reflect your radio's reponse to your rig,not the power output.What Im trying to say is placement can be as much/if not more than anything else,You can have "perfect" SWR's and still have shitty comunications!

 

[XJ98Jeep]

I have the 5 ft antenna mounted to my roof rack, and my SWR is like 1.2, and I get great reception. I do hit drive through signs and such and I have to take it off for parking garages, but it isn't a big deal. Hop out, unscrew the antenna and toss it in the back, put it back on whenever I get around to it. I also have a medium duty spring that I cut down as short as I could, it still waves around in the wind but not as much as before I cut the coils on the spring.

 

[xjmud]

i got a marine (boat) base it folds down when im not useing it.. i have a 6.5 inch lift on 33s and it stands about 12 feet..if not more .... and when its down its like 2 inchs off my roof i have never had it catch on any thing...and theres a lot of trees around here

 

[LR_2000_XJ]

SWR's dont have anything to do with the pattern,they reflect your radio's reponse to your rig,not the power output.What Im trying to say is placement can be as much/if not more than anything else,You can have "perfect" SWR's and still have shitty comunications!

He didn't mention "swr" and pattern, he was just mentioning that his CB is only getting a 1.0 swr with his setup. And, swr doesn't reflect radio response to the rig, it is "signal wave return", which is caused by the antenna not being tuned to the frequency wave transmitted from the CB, causing the power or watts of the frequency "wave" to return and eventually burn out the transmitting radio. This frequency is very close between channel 1 and 40, so usually, you get better swr readings on the lower channels than the higher channels, but you can just tune the CB to the channel you use the most. Now if you had a high swr reading, you can do damage to the CB and blow out the finals, which are the "final" signal amplifiers in the circuit, before going to the antenna. Also, if you have the perfect setup, you can achive almost no swr and, if you know how, tweak your modulation, and have a well heard signal that will squash other distant channel users.

 

[Daedalus454]

He didn't mention "swr" and pattern, he was just mentioning that his CB is only getting a 1.0 swr with his setup. And, swr doesn't reflect radio response to the rig, it is "signal wave return",

<rant>
Please get your facts straight before you go telling folks they are wrong. SWR is an abbreviation for Standing Wave Ratio, and it has nothing to do with proximity to the AM/FM radio antenna. Note the word "Ratio" in the name, it's impossible to have an SWR of "1," it must be a ratio, ie, 1:1. The most common cause of a high SWR is an impedance mismatch. If you are really interested in what SWR and VSWR are and how they affect a radio transmissions, a very good explanation can be found on the ARRL's web site in these PDFs:
http://www.arrl.org/tis/info/pdf/49470.pdf
http://www.arrl.org/tis/info/pdf/q1106037.pdf

And I don't agree with your explanation of phased array antennas (sometimes called co-phased). Phased array antennas are used to increase the gain and directionality of an omni-directional or directional antenna.

Two antennas placed 1/4 wavelength apart, operated in phase with one another, act as a directional antenna, providing ~3dbi of gain by directing more of the signal fore and aft and less of the signal off to the side. This works well for truckers since they are on the highway, and it works well for them to have more of the signal broadcast fore and aft, up and down the highway.

I know the guy in that link you gave says that's a "misconception," but I cannot find anyone who agrees with his synopsis. Check out this guy here: http://www.bellscb.com/cb_radio_hobby/antennas/antarray.html

His radiation patterns (produced in something other than MS Paint) show that a moderate amount of fore and aft gain can be realized by putting two omnidirectional antennas 1/4 wave apart. For CB frequencies, 1/4 wave a 2.7 meters, or about 9 feet, that's why truckers can get the benefit of phased array antennas while us narrow XJ drivers would have to come up with some way to get the antennas 2.7 meters apart in order to work properly.
</rant>