As you may have heard, the 147.000 repeater had been experiencing sporadic crackling noises on weaker signals over the past year. It was determined that the cause of this problem was not in the repeater itself, but in the antenna system. This finding is of no surprise, due to the fact that we had this same issue almost 5 years ago.
The repeater antenna is a commercial grade Super Stationmaster that is built to withhold the toughest conditions and comes with a price tag of over $1,000. SEMARA originally installed this antenna model in 1999 when the current 180 foot tower was built. Unfortunately, that antenna had to be replaced in 2006 due to the same recent crackling problem. Faced with the fact that we must replace the antenna once again, it appears that our average life span with this antenna is only about 5 years (it is advertised to be 15-20).
The repeater committee received a recommendation from Tony, NN1D to purchase a consumer grade Tram 1481 (a Diamond X-500 equivalent). This low cost $100 antenna has been in use on Tony’s 146.805 repeater for a few years now with positive results. SEMARA recently purchased this same antenna and on the morning of Tuesday, July 20, 2010, NETCOM arrived at the tower site make the antenna swap (the receive antenna for the Dartmouth Police Department‘s new 450 MHz P25 digital system was also installed).
The end result? A very clean sounding repeater with improved coverage! Repeater committee member Dave, W1DJG is now able to hold the repeater (without help from tropo) until the end of MA Route 24 in Canton at the I-93 split during his commute to Boston. The current plan is to keep this antenna in place until any future issues arise. Even if we had to replace this antenna once per year after a harsh New England winter, it is still half of the overall cost of replacing a $1,000 antenna every five years.