I made some tests with the POTY feed. I made a small cone using 0,06mm aluminium foil. The foil is from a alum. plate you’re using when you like to make a pie in the oven. What I notised in Gqrx signal scale ( left side of the spectrum) was, that with that cone both rx and tx was 5 units smaller and overall noise stayed very same. The photos shows silver coated POTY with and without the alum. cone.
73 de ismo