David asks "Due to foam core, what is the smallest coil diameter for LL400? Thanks"
Answer:
The tightest installation coil radius is 1", so roughly about a 3" diameter (measured outside) of a completely round coil would be the tightest you should go. As long as your SWR is low, you won't get enough heating in the cable to melt the foam core. If you have an impedance mismatch with your antenna resulting in a high SWR along with using high RF power, that may cause enough heating to worry about the foam melting. Use an antenna tuner to keep your SWR in the cable low and under normal circumstances heating is not an issue.
Please let us know if you have any other questions!
-A.J. with JEFA Tech
