Can a pinched coax cause high SWR?

Damaged coaxial cable is a big reason behind high SWR readings. A coax can get twisted, shorted, or pinched while routing through the vehicle.

Can bad coax cause high SWR?

Just like potential coax problems, if the wire in your antenna is broken you'll experience high SWR.

Does coax cable length affect SWR?

Coaxial Cable Length Does Not Change Antenna SWR.

Why is my CB SWR so high?

The most common cause of a high SWR is an antenna shorted to ground. There are two places a short can occur in a CB antenna system, in the coax and in the antenna stud.

What can cause erratic changes in SWR readings?

Does Coiling Coax Cable Hurt Your SWR?

How high is too high SWR?

For instance a SWR too high (over 3:1) all over the band can be an indication of a bad part or junction, poor ground or poor location. An SWR too low over the whole band (1:1 for all 40 channels) can indicate a low efficiency antenna or lossy component. Safe operation of your CB should be with an SWR of 2:1 or less.

What happens as the frequency of a signal in coaxial cable is increased?

The greater the surface area of a conductor, the lower the resistance, and vice versa – small surface area means higher resistance. As signal frequency increases the skin effect becomes more pronounced. That is, the “depth” within the conductor through which currents flow becomes reduced as frequency increases.

How do you lower the SWR on a dipole antenna?

To raise the frequency of minimum SWR, trim the antenna shorter. Cut each of the dipole's segments by equal amounts so that the two halves maintain equivalent lengths. If the minimum SWR is minimized at a higher frequency than desired, you must lengthen the wire segments.

What does an SWR reading of 4 1 indicate?

What does an SWR reading of 4:1 indicate? Loss of -4 dB.

What is the best length of coax for CB radio?

We recommend 18 feet of coax even if you don't need that much. If you use a length that is shorter or longer, you might risk having trouble achieving good SWR readings. Properly store any excess coax in a figure 8, about one foot in length, and bound in the middle- it should look like a long, skinny 8.

Is it OK to coil coaxial cable?

There's nothing inherently wrong with “looping up” extra coaxial cable. In fact, a neatly wound coil of coax can function as an air-core choke balun (“ugly balun”) which is useful for some antenna systems when located at the feed point of the antenna.

How far can you run coax for antenna?

The signal arriving at the receiver from anything longer than 100 feet of RG8X is probably going to cause trouble. Runs over 200 feet without amplification are only a dim possibility. There is no hard and fast rule for how far you can stretch RG8X with in-line amplification.

Does CB coax need to be grounded?

If you're using a standard CB antenna (i.e., anything except a no ground plane, or NGP, kit), you'll need to make sure your antenna mount is solidly grounded to the vehicle's chassis. A bad ground will result in an un-tunable antenna and sky-high SWR levels.

What SWR can damage a radio?

SWR 3.0+: Performance will be severely affected, and you're likely to damage your radio with extended transmission use. You SHOULD NOT transmit with your CB at SWR levels above 3.0.

Does SWR matter on receive?

Simplified answer: There is no relationship between SWR and receive performance. There is one condition for this simplification to be true: the received RF noise floor must be above your receiver's noise floor.

How high should a dipole be off the ground?

For best results, dipoles should be at least 1/2 wavelength above ground level. For the lower bands, especially 160-40 meters, this can become impractical--place your dipole as high as your situation allows.

How long should my dipole antenna be?

When determining how long to make each leg of a Dipole antenna, dividing the frequency in MHz into 468 will give the overall length. To find the half wave, divide that number by two. This will give you the length of each leg of the antenna.

Does length of coax affect signal?

Does Length of Coaxial Cable Affect Signal Loss? Yes, the greater the length of coax cable you use, the more signal loss you will experience.

Do coax connectors reduce signal?

All connectors introduce a small signal loss, about -0.5 dB. Some antennas and televisions only have a twin-lead connection and need an adapter to connect to a coax cable.

What happens when there is an impedance mismatch between the coaxial cable and the load?

Called impedance mismatching, this creates a situation in the circuit where only part of the intended voltage is reaching the load. The rest rebounds back through the cable as standing waves - a phenomenon called reflection - which in turn creates echo problems for the signal still passing through the cable.

What is the maximum distance for coaxial cable?

Coaxial cable can be cabled over longer distances than twisted-pair cable. For example, Ethernet can run approximately 100 meters (328 feet) using twisted-pair cabling. Using coaxial cable increases this distance to 500m (1640.4 feet). For LANs, coaxial cable offers several advantages.

What is the maximum frequency of coaxial cable?

The drawing below shows all the transmission lines used in RF, from KHz to GHz, the coaxial cable line is the most used and most cost-effective, it can be used by up to 110 GHz with the current technology.