What should I consider when setting the standing wave on a CB radio?
Hello I would like to adjust the standing wave on my albrecht ae CB radio station 8000 where should I pay attention to it I have a built-in Swr meter where the needles must be in the red area or where
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Please note:
If you measure the SWR on ALL channels, you can create a curve that shows you exactly whether the antenna is too short or too long.
ATTENTION: The order of the CB radio channels is
41 42 …. 79 80 1 2 3 …. 39 40 ( https://hobbyfunk.de/04_cb/frequencies.php )
Channels 41 to 80 are located BELOW channels 1 to 40 in terms of frequency (for historical reasons).
Rule of thumb:
VERY IMPORTANT:
A bad SWR damages the radio!!!
The standing wave ratio should ideally be 1. As far to the left as possible.
If the radio wavelength fits the antenna exactly, all of the energy goes into the antenna and is radiated. If the wavelength doesn't fit the antenna perfectly, some of it is reflected, resulting in a standing wave ratio greater than 1. The reflected energy then travels backward through the cable to the transmitter and "fights" with the transmitter. The transmitter then loses energy and emits less energy as a radio wave. This means that twice as much energy reaches the antenna. Simply because some of the energy travels back and steals the transmitting energy.
By adjusting the cable and antenna, you then need to set the standing wave ratio as low as possible. Ideally, but not achievable, "1" is the ideal value, meaning the pointer remains at the left stop.
The further the pointer moves to the right, the less range you have when sending.
You can only adjust the standing wave "perfectly" for one frequency. You then have to consider whether to optimize your home channel or the frequency in the middle of the range you're using.
If you want to use the middle frequency, remember that channel 41 is the lowest frequency and 40 is the highest. The upper channels (41 to 80) are below the standard 40 channels (1-40). So, if you're operating on 80 channels, then 80 or 1 is the middle frequency. If you only have 40 channels, then channel 20 is the middle.
Just to supplement the display of the photographed station has an auxiliary label "Cal" in the right area of the scale to aid calibration.
Correct. You have to follow the instructions on how to use it.
Normally, you have to unscrew the device and use an internal adjustment screw to set the pointer to "CAL." You then have to connect the device in a specific way to get a defined amount of energy "running back," to which you can then set the pointer.
PS:
The most important thing in radio etiquette is to only set the standing wave when the channel is free. And then announce beforehand, and ideally during the setting, that you're setting your standing wave.
Otherwise you will be considered a "carrier pusher", ie someone who deliberately disrupts radio traffic.
Then you can adjust the antenna base or use a compensating circuit in front of the antenna which you can then adjust.
The "CAL" only serves to calibrate the circuit that measures the energies of the directional coupler, so to speak to tell the pointer what 100% is.
This is quite possible if the antenna tip itself cannot be mechanically calibrated by fine length adjustment.