In the past I thought about putting dielectric grease in the connector so I tried it. What happened is UHF signal strength went down , less signal at the Tv , not good . And as for the weather boot on coax the coax connector and a matching transformer , weather boots take in and hold water. If water proofing is what is to be done then use mastic tape. Here are examples of mastic tape. .
http://www.surplussales.com/antennas/Antennas-7.html .at
http://www.amazon.com type in 50727-BA-5 . . Pull stretch the mastic tape as it is being applied , wound around the coax cable the connector and matching transformer. The mastic tape makes a permanent bond. The only way to remove it is to cut it off. . Electric supply business sell mastic tape.