Is the problem my CB antenna?

Running the coax behind the sleeper is a good idea, then you can probably mount a taller antenna...But I wouldn't use RG 58...RG mini-8 or RG 8/u would be better, or even RG 213. There are others too like the LMR Coax all of which are 50 ohm coax...RG 58 is the very basic and cheapest coax...If I was going to go to the trouble of replacing my coax, I would go with something better rated...And if your just going to run one antenna, the length of the coax really doesn't make that big a deal...I would just use whatever it takes to get from point A, to point B...18' is not necessary unless tha is what you need to get from the radio to your mount.

IMO, only time you need to use certain lengths of coax is when your trying to co-phase, or build a beam set-up and make your antenna's more directional like a Two Hot set-up, or bounce back set-up. Also when running Amps you may want to make your jumpers certain lengths to get the amps tuned to your antenna...Other than that, just use whatever it takes to get from the radio to the antenna mount...

Taller the antenna, the better it will perform. Anything shorter than 58-60" just wont work near as well as antenna's 60" and up...Just the way it is on 11 meter.

By the way...K40's site is right about manufacturers using the cheapest coax available...Which is the RG 58 stuff!

 

The minimum clearance on Interstates are 13'6"and not 16'. On I-83n in PA has at least one 14'2". And here in MD I-895 tunnel it's 13'6". And I-95 it's 15', if you are over it's a $400 fine. And yes they do stop you for antennas setting off the alarm. So watch how high your antennas are.

 

You want to get a length of antenna up above the roof line for better transmission distance. As a general rule, longer antennas just work better. The exception to the rule are antennas with a loading coil. Please note that antennas with loading coils are almost always more expensive than antennas without loading coils. A 4 foot long antenna is generally accepted as the minimum length for a CB antenna on a large commercial vehicle. Personally, I suggest a 4 1/2 to 5 1/2 foot antenna.

As JesseJamesDallas stated above, there is no requirement that coax cable be 18 feet long. 18 feet is long enough to mount an antenna at the rear bumber of a car and still connect to the radio. If you are mounting an antenna on the antenna mount on the vehicle door [as in a commercial vehicle], then 18 feet of coax is grossly overkill and an unnecessary expense. And the excess length can cause problems if it is tightly coiled.

There are several different types of coax that can be used. For a single antenna installation, RG 58 is appropriate when you are using short lengths of coax and the radio setup is not amplified. RG 58 coax has the advantage of being more flexible and less expensive.

RG 8x coax is an upgrade from RG58 for a single antenna setup. It costs more, is larger in diameter and less flexible than RG58. It is good stuff but if you are on a tight budget it is just not cost effective for an non-amplified CB setup.

When comparing signal loss between the radio and the antenna, RG 8x losses are 3.96% at 18 feet and 2.64% at 12 feet. While RG58 losses are 6.12% at 18 feet and 4.08% at 12 feet. The difference between 18 feet of RG8x 3.96% and 12 feet of RG58 4.08% is only an insignificant 0.12%.

RG59 is the coax that is used in a two antenna co-phased antenna setup. Do not use RG 59 with a single antenna setup.

 

only 14 ft even on the NY thru way

 

Where are you getting your info on overpasses on Interstates being a minimum of 16'? Lot's around Dallas 14'...Besides that, I find it hard to believe you only drive on Interstates...Unless you Live, Eat, Sleep, and have someone bring you out fuel...At some point your going to have to get off the Freeways, and get on roads which may have bridges under 14'....

 

My personal opinion...your SWR reading is incorrect (maybe the meter is broken or not adjusted properly). It definately sounds like an SWR issue to me. As for the duel anntennas...it is a fact that the second anntenna (one on the right side) will cut your reception by 1/2. Ask any good CB tech and he will tell you the same thing. The above comment mentioned using the second as looks only. The guys I run with, as well as myself, all have "big radios"...NONE of us run duel, and the ones that do have 2 anntenna will flat out tell you that the second one is purely cosmetic. 9 outta 10 of us have tested duels only to come back with the same result...less reception and a much shorter talking distance.
Anyway...it certainly sounds to me like you an SWR issue. Try using only one anntenna (adjusted properly) and see what that does.
Hope you get it figured out! If you use your CB as much as I do...being without one can really suck!

 

You have obviously never been on the PA Turnpike, I-81, I-66, even some parts of I-95. You've been driving for 10+ yrs thinking all interstates have a min 16 clearence???? I can literally think of dozens of overpasses on the interstates mentioned above that are 14 ft! I really hope a newbe doesn't take your "rule of thumb" as the biblical truth of interstate overpasses!

 

Originally Posted by Diantane


The minimum clearance of an overpass on the Interstates is 16 feet so as long as I keep the height of the antenna below that I should be fine




what i said in the NY thru way only has 14 ft even of clearance, we are only permitted to be 13 ft 6 inch tall

 

What I responded was there is only 14 ft clearance on the NY THRUWAY{turnpike} at 14ft 2 inches you will hit overpasses .

 

those factory antennas on the new petes and cascadias suck. the cophased ones on trucks are a joke anyway, there is not enough space between the two to properly set up the distance needed to take advantage of the cophasing.

there are several companies that make aftermarket brackets that bolt to a doorjamb bolt or behind the cab. i am running a car trunk mount K40 on my 05 Volvo. i have the standard mirror mount, and i drilled a hole in the mount and was able to tighten the lock nut on the K40 bracket inside of the hole that was drilled. works like a charm, and i can hear about 15 miles each direction provided the conditions are right.