Since the typical BpBr duplexer uses an adjustable capacitor to tune the notch, I would think that one or more of those capacitors would be the most likely component to be damaged by a lightning-induced surge. For example, a Sinclair Q202G duplexer uses Johanson piston capacitors which have extremely close tolerances to achieve values of 10-30 pF. A digital capacitance meter could be used to measure the value of the notch tuning capacitor in each cavity, to find one that is out of family.
73, Eric Lemmon WB6FLY -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of dan173mi Sent: Wednesday, January 20, 2010 8:43 PM To: [email protected] Subject: [Repeater-Builder] Re: follow up on lightning strike last spring response Most duplexers are passive, mechanical devices. You did say the cavities had been visually inspected and cleaned so we can assume the "cans" themselves are fine. In my opinion the single component on a duplexer that's most likely to fail would be the cable harness and its associated connectors/adaptors. Is this a vhf repeater? What is the power output? Dan K8PLW Livonia, MI --- In [email protected] <mailto:Repeater-Builder%40yahoogroups.com> , "Richard" <rra...@...> wrote: > > Sorry if I've been late in posting. First, the antenna and hard line is ok. We've tested that part out and its working. We think ( I ) that we got zapped through a unused phone line which is mounted behind the repeater rack. > Yes, we have tested the can's using both a IRL (?sp) and a General Dynamics service monitor. They were taken apart and cleaned and retuned. Everything indicated they were functioning normally. Till we put them back in service. I don't know if they were tested with a dummy load. The technicians made many trips to the site: the technicians worked for the company that we rent the site from. We replaced all of the connectors and only found one that had scorched indications on it, but that was all. > I asked if any of you knew how to find out if a can was operational, because all the test equipment that was used indicated they were ok. We finally found a workable solution. We added a fifth can, tuned to the transmit freq. That stoped the crackling noise. > Now we're going to replace the can's, and go with a 6 can configuration. this is what was reconmended by the technician. > > Rich K8JX
