Hi all,i live in a flat with no garden so am very restricted on antanna options,,for a number of years i used to join the barrometric net on 3.775khz,that was fine with a wire dipole at my old place but not possible here,firstly i had a 40ish foot 2" mast with a 2/70/6m colinear on it,i insulated the mast and shunt fed it using a 9-1 unun,i used all the copper water pipes as a ground/counterpoise,it works fine for contacts 2000miles plus but rubbish for inter G working,low angle radiation i suppose being a verticle,sevcond trie was using 2x 80m helicaly wound whips on a 3/8 inch dipole center,the swr is at 1.3-1 at 3.775mhz,its up at about 12 foot,it seems totaly rubbish on rx and tx,i have a 30khz 2-1 bandwith,the feeder is rg-213 about 70ft long,its had water in it in the past and the center conductor has gone black,would the coax cause such poor performance or do i look elsewhere?,ive ordered new coax but thought i would ask here,73 m3vuv