Can the CB be damaged if you take it out of the box and use it without setting the SWR?
2006-09-10 12:39:24 · 4 answers · asked by Robert 1 in Consumer Electronics ➔ Other - Electronics
No. Read the instructions.
2006-09-10 12:45:59 · answer #1 · answered by Anonymous · 0⤊ 1⤋
Yes, a high SWR (typically greater than 1.5:1 to 2:1) can cause overheating of the transistors in the final amplifier, ultimately causing damage to the unit.
Now, your question mentioned "setting" the SWR... When you set your SWR, what you are really doing is calibrating the SWR meter so that the SWR reading is in proper relation to the forward power (wattage) applied to the coax and antenna circuit. The act of setting the SWR, therefore, is merely a step that is necessary in obtaining a relatively accurate SWR reading, and in no way does it change the actual SWR.
A high SWR (lets say >1.8:1) is generally an indication of an impedance mismatch between the radio and the antenna. Common causes of mismatch can range from damaged coax to moisture in the connectors to an antenna cut to the wrong length.
For most CB applications, the SWR will be the lowest in the middle of the band (ie: channel 20), and gets higher as you go toward channel 1 or 40.
Serious radio operators will often solve high SWR problems by inserting an antenna tuner (a.k.a. antenna matcher) between the radio and the antenna. Other times, a high SWR may be reduced by trimming the antenna length so that the antenna is tuned (or resonant) to the frequency that you most often use. Any knowledgable CB shop should be able to help you resolve such issues.
2006-09-10 20:24:26 · answer #2 · answered by Terry 2 · 1⤊ 0⤋
Maybe. Maybe not. In general, Terry summarized it pretty well. At the very least, you may have very poor transmit/receive performance. In the worst case, you may damage the radio. At 2:1 SWR, you would have as much as 50% of the power reflected in the line. What does that mean? Imagine the radio transmits energy in one direction... toward the antenna. If the antenna is not tuned properly (ie high SWR), the energy is not accepted by the antenna and radiated to free space. Instead, the energy is "trapped" in the feedline and reflected back and forth from transmitter to antenna and back. This can create higher than normal voltages on the final output transistor and the feedline. In both cases the result is added stress, much of it in the form of heat, which can result in premature failure.
2006-09-10 23:38:56 · answer #3 · answered by Sleepy Greg 2 · 0⤊ 0⤋
No..just poor reception
2006-09-10 20:16:31 · answer #4 · answered by R W 6 · 0⤊ 1⤋