I would suggest these settings.
push the RF gain button ( maybe hold it for 2 seconds and then rotate the dial and turn it to it's maximum setting I believe that's 5
with RF set to the maximum setting it will allow all signals to come in....most people have it at max unless you're in a caravan and don't want to hear people several miles away
then set your mic gain to max.
I always run the noise blanker ON
I always run the ANL ON
I always run the High Cut ON if your radio has it
working nights the radio will work good.... during the daytime signals bounce all over the world so when you turn on 19 during the daytime you are receiving so many signals that the channel is pretty useless, unless someone was very close to you.... after the sun goes down all that noise will go away and you will be able to communicate several miles away.
don't be afraid to ask for a radio check... many times I hear no one and think no one is on the CB... but if you ask for a radio check you might find someone else is out there too..... you may only get a few miles range... so finding someone in a 3 mile radius that will answer a radio check may be difficult to find.... a really good 5 foot minimum tall antenna may double the 3 mile range.
during the daytime signals are bouncing all over the country and if you turn on 37 or 38 LSB and make up a four digit number..... say 1234
you can key the mic and say does anyone have a copy on 1234 in ( insert the state you're located in) and you may find people responding to you from the other side of the country...... if the voice responding to you sounds a little goofy you must adjust the clarifier turn it slowly until the voice comes in as clear as possible.... keep the clarifier in the middle position until you need to adjust it.
now the BIG question.... WHAT ARE YOU USING FOR AN ANTENNA????
the antenna should be as close to the center of the roof as possible
..... plugging the radio into the cigarette lighter will greatly hurt performance... but I understand it's not your truck and you need to move it from truck to truck..... many truck drivers take a tool box and cut a place for the radio in it so they can easily carry it from truck to truck... the cigarette lighter plug is not great but will work for what you're trying to do.
the antenna is the most important part of your CB system
you need a GOOD 5 foot tall antenna to have a CB that will work... anything less is more of a toy and won't work very well for you.
if you can I would try to find a good ground and connect a wire from say a seat bolt to the negative on the radio. perhaps with some alligator clips so you can keep it easy to move from truck to truck.
this video on the 980 SSB looks pretty good I skimmed it over and I think the guy covered what you need... but you do need to adjust your antenna or you could damage your radio.... so check the SWR on the radio, the below video will show you how to check it on your radio... and you can go to YouTube when you need to adjust the antenna to set the SWR.
when adjusting the antenna a 5 minimum foot tall antenna will adjust fairly easy... the smaller antenna's can be very difficult to adjust and moving the antenna to different places on the roof will also affect the SWR
remember If your SWR is high on channel 40, it generally means your antenna is too long and needs to be shortened
If your SWR is high on channel 1, it typically means your antenna is too short and needs to be lengthened
the SWR will be different on channel 1 and channel 40.... you want to get it as best you can.... channel 20 will give you your average.
if you need to lower the antenna and it bottoms out... VERIFY you need to lower it and then cut a 1/4 inch off the bottom of the antenna and try again... only cut a 1/4" at a time until you get the SWR set... again only cut it if you find the SWR is too high on Channel 40.
good luck.