myCB problems

[ccrunner1]

well first of all i can hear my windshield wipers through the radio.(The only real problem) but i don't know what to do with all my extra coax cable.(its just bondled under the radio) Or how to run it a little more permanently.(right now i have it taped to the door frame)

http://i479.photobucket.com/albums/rr154/CC-runner18/cb/IMG_0301.jpg

http://i479.photobucket.com/albums/rr154/CC-runner18/cb/IMG_0305.jpg

http://i479.photobucket.com/albums/rr154/CC-runner18/cb/IMG_0309.jpg

http://i479.photobucket.com/albums/rr154/CC-runner18/cb/IMG_0311.jpg

http://i479.photobucket.com/albums/rr154/CC-runner18/cb/IMG_0312.jpg

[rjppunk]

I don't know much about cb radios but is everything shielded including the cable? For some strange reason it may be picking up your windshield wipers?

[ccrunner1]

the power cable for it is just hooked up to the battery. ill have picks in a sec

[ccrunner1]

its the little red cable

http://i479.photobucket.com/albums/rr154/CC-runner18/cb/IMG_0313.jpg

http://i479.photobucket.com/albums/rr154/CC-runner18/cb/IMG_0314.jpg

http://i479.photobucket.com/albums/rr154/CC-runner18/cb/IMG_0315.jpg

[rjppunk]

this doesnt have to do with ur problem but did you put a fuse on that?

[ccrunner1]

yeah

[Bob Myers]

You may have to run a filter for the radio, to reduce the noise caused by the electric motor. Some radios are more susceptible to noise than others, it seems the Cobra of today is living on their 20 year old reputation and turning out crappy units. With inferior filtering and much light duty componenets, but that is the way of today with all products.
For your coax cable, if you think you are going to leave that antenna there then tuck the cable up under the rubber on the door sills, and run it to your radio. You cab either cut off the excess, if your swr is good now then it will be then too. On a loaded coil antenna coax cable is irrelevant. If you do no wish to cut the cable then the loops you have should be at a 90º angle to each other, not looped as you have it now. If you must run parallel loops then make them as long as few as possible, and if possible separate them from close proximity of each other

[Bob Myers]

get the ground wire off that fender bolt, run it to the battery too, or to some other place where a known good ground can be had.

[ccrunner1]

its not long enough to run it to the battery. and thanks for the help about the coax. its not a cobra

[Bob Myers]

yes it is! Radio Shack current models were built on the same line as Cobra.
If your wire won't go to the battery then find a ground wire going to the body or under dash and put it there with that.

[Wicked_Sludge]

i would shorten the ground wire considerable. there is a large, metal support behind the center of the dash where mine is currently grounded. its close to the radio and dry. a ground loop isolator might help your interference noises, but it could also be from an improperly tuned antenna. do you know what your SWR is? if not, it is worth your time to buy a $10 SWR meter from radio shack or have the system tuned at a radio shop.

i had a magnetic mount antenna for years before i finally "commited" myself with a perminent base. i had to drill a hole in the roof (wince!) and ran the coax up high, along the passanger door pillar, then through the hole located behind the dome light (makes for easy access as you can go in through the dome light hole or the 3rd brake light hole by removing either fixture). i can take pictures of the cable routing and mount for you in the morning if youd like, as i currently have my interior torn apart anyway to track down a leak.

i highly reccoment going with a perminent base for your antenna. it makes for a much cleaner install with more solid connections. plus you can cut your coax to the length of your application (i know your not supposed to, but i did so on all 3 of my vehicles and all 3 have good SWR). ive heard the SWR length thing is a myth :dunno: with my setup i managed about 1.5:1 SWR, and it performs very well.

[Bob Myers]

i would shorten the ground wire considerable. there is a large, metal support behind the center of the dash where mine is currently grounded. its close to the radio and dry. a ground loop isolator might help your interference noises, but it could also be from an improperly tuned antenna. do you know what your SWR is? if not, it is worth your time to buy a $10 SWR meter from radio shack or have the system tuned at a radio shop.

i had a magnetic mount antenna for years before i finally "commited" myself with a perminent base. i had to drill a hole in the roof (wince!) and ran the coax up high, along the passanger door pillar, then through the hole located behind the dome light (makes for easy access as you can go in through the dome light hole or the 3rd brake light hole by removing either fixture). i can take pictures of the cable routing and mount for you in the morning if youd like, as i currently have my interior torn apart anyway to track down a leak.

i highly reccoment going with a perminent base for your antenna. it makes for a much cleaner install with more solid connections. plus you can cut your coax to the length of your application (i know your not supposed to, but i did so on all 3 of my vehicles and all 3 have good SWR). ive heard the SWR length thing is a myth :dunno: with my setup i managed about 1.5:1 SWR, and it performs very well.

Sound advice.
As for coax length, if the antenna is truly resonant the length of the coax is irrelevant, if cutting the length changes SWR then your antenna was not resonant and was feeding voltage back along the feedline any way. I do roof mount NMO mounts on everything I put radios in, my wifes Cherokee had one in the roof, my BroncoII has 2, my F250 has three. None leak, all work as should and have maybe 6" more coax than needed to make the trip from the antenna to the radio

[ccrunner1]

my radio has the swr meter built in and keep it around 1 across the board. what about parking garages with a permanent base? and with cutting the coax how do i hook the end back up

i dont think im ready to drill just yet, but could you take a picture of the metal column you were talking about. its also harder to find an antena because mine recieves the NOAA alerts(which comes in perfectly clear no matter what, WHY)

[Sunk]

I ran a 3ft antenna off the rollbar I had in my truck with a 4" lift, and it was fine in parking garages... Just gave the little flexy spring a workout.

[Wicked_Sludge]

theres a reason they call them "whip" antennas :icon_thumby:

most garages are plenty tall. the ones that arent i can either let the antenna "self clear", or remove it (i keep an el-cheapo 9/16 in the glove box just for this purpous).

ill get pics later this afternoon.

[Wicked_Sludge]

heres the brace i was refering to:
http://i140.photobucket.com/albums/r9/Wicked_Sludge/Truck%20Stuff/DSC05896.jpg
it runs from the transmission hump toward the pedals. see how just before it dissapears into the dash, i drilled a hole and use a self tapping screw to ground items. i have several items grounded here, the CB is on the bottom of the stack.

heres my mount:
http://i140.photobucket.com/albums/r9/Wicked_Sludge/Truck%20Stuff/DSC05899.jpg
the scratches are from the magnetic mount that i had...which was my primary motivation for removing it. note how wide the base is. i went with the mount because its designed to be used on thin items like sheet metal or fiberglass. it has a huge flat washer under the metal that spreads the force out so it doesnt bend the sheet metal.

the antenna:
http://i140.photobucket.com/albums/r9/Wicked_Sludge/Truck%20Stuff/DSC05901.jpg

you can get perminent mounts with a coax screw connection on the bottom, but due to space constraints in that mounting location, i went with a cut+splice type connection. you simply cut the plug off the coax at the length you want, strip away the sheathing and sheilding to expose the inner conductor, then crimp or solder (i soldered) a normal ring terminal onto it. the terminal then bolts to the base of the antenna mount. its very solid and compact.

[htjunkie1]

Coax has to be 18' to get a flat SWR reading. Don't cutthe coax. Some antennas are tunable, meaning that the steel mast can be taken up or down. Some fiberglass ones have a tuning tip on the top of it. The ones that dont have anything like this need to be trimmed. 1/4 inch at a time to get the best SWR reading. If you look, You can see the wire inside the antenna. Also, make sure that the antenna is grounding properly, and on the radio side, try and run the shortest ground possible.Do not "coil" the extra coax that you have. Try and run it up and down under the seats or something. Coiling it will also throw the SWR's off. Hope this helps.

[Wicked_Sludge]

Coax has to be 18' to get a flat SWR reading.

thats what i was talking about. ive heard that is a myth...and my setup seems to support that theory. my coax started out as 18' and i cut several feet off and i still dont get worse then 1.5:1.

[htjunkie1]

You got lucky. I worked at a CB shop for 4 years, and I never saw one that low in with short coax. What brand of antenna and CB are you running? Here's my set up. http://i59.photobucket.com/albums/g286/htjunkie/100_1405.jpg http://i59.photobucket.com/albums/g286/htjunkie/100_1389.jpg http://i59.photobucket.com/albums/g286/htjunkie/100_1390.jpg

[Wicked_Sludge]

cb is a mid-range midland model (wanted a PA). antenna is whatever the local radio shop had in stock. it uses 2 threaded rings at the base of the antenna for tuning (see pic 2), super easy to tune.

how can a guy get lucky when hooking up a CB? it either performs well or it doesnt. i see no reason someone else couldnt copy this setup and get the same SWR readings :dunno:

[htjunkie1]

I meant lucky cause I've never seen one that low with short coax. Remember when tuning SWR's, Your actually tuning the antenna to the truck, So being a smaller truck, that might be the reason for the low SWR's.

[ranger4wd4l]

in my ranger i routed the cb coax through the light in back of the cab. Had to notch the cab alittle bit.. Then just put some putty to make it water prof