Hi guys It's been a while since I last visited this forum. I wanted to share some info about a db420b antenna that has been acting up for some time. This antenna is duplexed on an amateur radio repeater and has been causing popping and cracking when the tx is on. When first installed new about 5 years ago it functioned great however about a year later the popping started. Not beleiving the antenna could be the trouble only a year old I tried everything I could think of to resolve the trouble. I read on here where someone else had trouble with their phasing harness. So I pulled the antenna and tested it on the ground connected to the repeater. Whith the service monitor on the repeaters input frequency I brought the repeater up and while monitoring the output with an ht I started wiggeling the Y connections on the harness (15 of them). To my suprise one was melted and most of them caused popping. I guess if it was a comercial job you would just buy a new harness but being the amateur that I am I took it home and cut the plastic off all the Y connections to reveal the problem. The center conductors at the connection point on the 3 cables that make each Y are layed side by side with about a 20 guage wire wrapped around them and then soldered. The Y that was melted was never soldered properly from the factory, the solder was not wicked all the way through. Most of the other connections looked soldered ok but some how were pulled loose, solder broken. I repaired the harness by replicating the factory solder connection process, wrapped in teflon tape, then cold shrink rubber tape, then covered with soldered copper braid, and then covered the whole connection with heat shrink tubing (the water proof kind with hot melt glue). I tested the antenna again on the ground after repaires it has no popping or cracking. The antenna is back up and working good lets hope it lasts a while because each connection took about 3 hours to fix. Lets see 3 hours X 15 connections, I still can't believe I spent 45 hours fixing a stupid harness. It seems to me that Andrew/Decibel owes me something for my trouble but I realize it would be futile to aproach them. Any way I just hope this info helps someone else that may be having problems with their db420.
Mark Ramsey
