Cb advice

I won,t even begin to argue the fine points of tuning a cb, i,ve done many in my time and alway found that sweet spot, so do this, run it how you like and figure out swrs by the wallet, many do, thats why cb shop make money.

 

Exactly but many do not have the tools or know how to get the right length. So if you are buying it off the shelve the 3 foot lengths get you close enough to give you a decent CB. Mine is actually 8.6 feet so yes it dosent have to be a certain length. But off the shelf easy install decent CB equals 3,6,9,18.

Sent from my SAMSUNG-SGH-I897 using Tapatalk

 

that gave me a little laugh

 

Lets see

A 50 ohm antenna into 50 ohm coax into a 50 ohm match radio.

The coax length is what you need to get there .....

 

I think ya'lls discussion has gone way over his question, with all due respect. I think after he calibrates the meter, he is going to swr setting to check swr's and then back up to s/r to check his output. There are 3 different scales on the meter. Being near the red on keying down the mike in send/receive mode is o. k. Go back and check your owners manual about the 3 way switch and reading the meter. No offense to anyone, but ya'll are talking theory, and laws of electronics, and he just wants to know if he's doing it right. Cobra 29, if the switch is all the way up in send receive mode, the needle should go near the red/green line. Keep in mind, I am no expert by any means, and some of these folks have forgot more than i will ever know.

 

The three foot thing I got from an old CB tech that retired who by the way was the best tech I have ever seen.As far as the radio station antenna set up. Its called a beam basically one big ### antenna with one mane coax.

 

Are you using a meter or the meter in the radio which are junk and way off.

 

No they are call phased arrays. Each antenna is feed by a delayed line. Which is determined by the tower spacing and what direction they want the beam pattern.

Normally, such setup is when the station has to change the patterned between day and night transmission.

Leon
kc0iv

 

The first problem is that the halfwave length of the CB frequency is 18 feet ONLY when the signal is traveling through air. We send the signal from the radio to the antenna through coax cable. The halfwave length of the CB frequency when traveling through metal such as the center conductor of the coax cable is actually 11 feet 10 inches...Since 18 feet of coax is more than 50% longer than the halfwave length of the CB frequency through the coax you are using, it should not work. But, it does in fact work. Therefore, the halfwave length of the CB frequency does not have anything to do with what length of coax you need to use...Excess coax length can cause you a problem, if it is not stored properly. Coil it in the shape of a figure "8" that is approximately 12 to 14 inches in length and secure its shape with tape. If excess coax is coiled in a tight loop, it can act like an electronic coil with its own impedance that will throw off the tuning accuracy of the antenna...If your SWR reading is 3.0 or higher, you have a connection problem. Tuning the antenna will not correct the problem. Most likely you will have to interconnect or "Bond" the large metal components of the vehicle together to form a large antenna ground plane. Bonding does not have anything to do with the electrical system...As for coax cable itself, if you are running a single antenna, any 50 ohm coax cable will work. For an amplified setup, higher quality coax may be necessary. For a factory stock radio setup, RG 58 will work well enough at the short lengths we use in connecting an antenna to the radio. ..If you want to upgrade a non-amplified CB setup, you will get more performance for your money by upgrading the antenna instead of the coax cable.