If you using a CB radio in your home and you have connected a magmount mobile antenna to it, that is meant to be used for a truck or car, using it to operate your radio, you will need to have an excellent ground to ensure that you are getting out properly and to reduce the amount of power the antenna is reflecting back into the radio, also known as an high swr reading, which is usually above 1.5. A high swr reading can lead to burning the output transistors inside your radio, costing your money to repair it, as they overheat from the excessive power that goes back into the radio. So if you are using a mobile magnetic antenna that is not meant for homebase use, you can still use it indoors, but you have to place the magnetic part at the bottom onto a metal, to act as a groundplane, to ensure its working to its full performing potential, to ensure the swr reading is below 1.5.
Instructions on how to get around this issue:
1) You will need to find something that is metal that is available from your home or garage, something that is large enough for the mobile magnetic base to fit on. You will need to find a metal that is made out of steel because steel makes a very good groundplane, but make sure you dont use metal that is made from the material called aluminum because it doesnt work as effectively as steel and other metals do in this situation. For example if you have spare steel circular disc shaped weight laying around that you dont use and they are big enough for the base of the antenna, you can use it as a ground, or the top of an toolbox.
2) Once you have found the right type of metal, simply hold the top bit of the antenna whip and place the base onto the metal part. I say hold the whip because it is the most safest method, as holding the base can accidentally trap your fingers in between the metal and the base, as the magnetic force is usually very strong when it clinks onto the metal, so please be careful.
3) Then if you have a swr to measure the amount of power be reflected back into the radio, hook it up and check the reading on the meter. If you get a swr reading below 1.5, then that is an safe reading and anything below 1.5 is very superior. If you swr reading is very high, try using a different metal, also try adjusting the length of the metal whip, until you get an acceptable reading on the meter.
4) Once you have got an acceptable reading on the swr meter, you can remove it and connect your antenna directly back onto the radio. Then you are ready to transmit and benefit from adding a grounplane to your setup.
