Extending the length of a coaxial cable

My FF antenna is installed on a mast on the roof of my 3 floor house my FF box is located in the 2nd floor which is long enough for the coaxial cable , am planing to move my FF box from the 2nd floor to the 1st floor which is not long enough for the coaxial cable to reach , can the coaxial cable be modified to extend its length, i need at least another 7 meters

Yes, you can extend it by adding another length of coax with connectors and a coupler.
I don’t know what your connector type is, but here’s one for F-type connectors.

Most likely the cable supplied with Flight Feeder is LMR240 (or equivalent), with N-male at antenna end and SMA-male at Flightfeeder end. (Flightaware staff is requested to confirm)

If I am right, then the one shown below will meet your requirement for extension.

Note: This particular one is given only for your guidance. You should search eBay, Amazon, and Google the web to find more options (different makes/suppliers and prices) to get a good product at competitive price.

Antenna Extension Cable LMR-240 with SMA male and SMA female Connectors (10 ft)

Adding another 7m to the feed line is probably not a great idea, though. The longest cable we ship for FFs is 15m and that is about the longest total length you should use.

Yeah, that would introduce a lot of loss. I have 40 feet/~12m of coax going to my antenna, but I’m using LMR-400.

Thank you guys for the information’s after all i think am going to keep my current setup