If you are using a Winegard antenna and occasionally lose signal when you adjust the height of the antenna or twist it, then the coax may have a problem. The first step should be to inspect the wiring of the antenna by checking the distribution panel, which connects the part on the roof to the other part of the antenna inside your house.
You can try rotating the antenna 90 degrees to make it easier to access and bring it to the side and use a ladder to get to the antenna on top of your roof for testing. Disconnect the coax from the antenna and turn the distribution amplifier on to 12 volts (measure using a voltmeter) from the coax and the hook while ensuring you don’t short circuit.
Twist the coax; if the voltmeter reading keeps changing when you adjust, your coax has a problem and needs replacement.
It is advisable to contact a professional antenna repair company to help you fix the issue since they are skilled in handling such matters.