The site of DG0SA Wolfgang Wippermann has a large collection of baluns. I replaced the 1:4 guanella balun with the 800 Watt 1:4 balun designed by Wolfgang, goal is to be able use it for higher power. Two ferrite cores are used, the first is a common mode filter to go from unbalanced to balanced for undefined impedance, the second is a 1:2 voltage transformer. I used volcanic wrap tape to isolate the leads between the transformers. As you can see in the images below, PVC tubing of 75 mm is well suited as housing, so this is what you eventually get:
And this is what is inside, the wiring is PTFE AWG18, so teflon coated rugged litze which is somewhat difficult to wind. This was the last view before I glued the cap on the side of the SO239 connector.
And this is a similar view at the other rise, I used plastic and metal rings to keep any water and debris out of the housing. Prefer to leave the cores loose in the tubing, the may generate some heat, once installed it does not move, could be done better but I ran out of ideas here.
And this is what the SWR looks like when I measure it with a 200 Ohm resistor terminated at the end of the balun.