> My club repeater system consists of a KRP-5000 feeding (what > we think is) a DB-224 mounted on a watertower at about 140'. > The feedline is about 170 feet of one-inch helix.
Wow... the feedline is probably standard 7/8 inch size unless it's something really a non standard item. > We'd been getting some comments from users about decreased > coverage. > At the site, a quick power check revealed the problem. 9 watts > forward, 3 watts back You probably have a problem with the pipe (feedline) and or something at the other end (the antenna). > The next step was to put a TDR on the line. Everything appeared > to be okay up to the antenna, but the termination point (antenna) > looked pretty ragged. What does a DB-224 (or similar) antenna > look like on a TDR? Based on the age of the antenna and extra long feedline length I probably would not trust a TDR to give the complete story. It's only telling you what it can see from a distance. All bets are off if the line and the antenna have multiple problems. > I need to add that we DO NOT have access to the water tower. > Previous club leadership pulled some fast ones on the county > and we are forbidden from climbing the tower. You need to start a serious healing campaign with the the County and do a lot of public service PR to remove the ah-$h1t from your track record. It will take a lot of atta' boys and good behaviour (plus some behind kissing) to get back toward square one. > Whatever needs to be done, we must use the same crew the county > uses and pay all costs. Also, we're the only ones on the tower, > so there is no routine maintenance done on the tower that we can > piggy-back on. Be glad you can actually get on the tower... > Bottom line. we need to figure out what we need to do and have > everything in place if we need to hire a crew to come out and > do the work for us. Forget all the trouble shooting when the tower crew costs so much. Plan to replace the antenna with something new or near new and be suspicious of the feedline. Plan to remove the feedline ends for inspection. Blow a lot of dry air (nitrogen) through the opened line if you can. Clean everything on the hardline/connector inferface and reseal the top first... leaving the bottom open. Finish the tower top work asap to keep costs under control. You might allow a bit of time for the lower end of the open line to drain any water/moisture content. Next day or when you can replace the lower connector and get on with the program using the new antenna. If you were smart... you'd buy a dual band splitter (aka diplexer) and place a quality UHF Antenna at the top with the VHF Antenna. Since you're paying for the work... go full boat for not much more money. Then you can later add a UHF Sister Repeater when you have the time and resources available. Ask the tower crew for a special club beggers quote when they have idle time to do small jobs. Don't spend time with an old antenna at a hard to access location. Get replacement known good hardware up in the air and enjoy the system again. Sometimes you have to shotgun replace equipment and get on with things. Your story is probably one such example of... cheers, skipp
