Ah a few additional comments and corrections please.
Merz Donald S wrote: > Comments about the user's use of the Matchbox are summarized as: > > 1. It's a balanced tuner. Running it with an unbalanced output from a > transceiver could be unpredictable. The input to the MatchBox can be 50 or 75 ohm input determined by the tape point on the input coil, however direction is important here, The input to the matchbox is from an unbalanced driver (the transceiver) The output of the MB is to either a Balanced feedline to the antenna, or an unbalanced feedline (Coax) to the antenna, The purpose of the MB is to present 50 ohms impedance to the source (transceiver). > 2. It has a T/R relay that defaults to R. Was the T/R relay properly > energized? The relay defaults to receive true, however the receiver contacts are NOT for a 50 ohm receiver input, it is more on the order of 100 to 300 ohms and ONLY available at the terminals on the strip not the coax connector , which is normally connected to the transmitter. Left side rear as you face the unit. > 3. Icom's literature says that the IC-735 does have thermal overload > protection against high SWR. Why didn't it work? Not known, but there could be several reasons! The user needs to clarify that. > 4. The meltdown could have occurred due to a violent mismatch into which the > operator let the TX transmit too long. Again, if the operator was trying to transmit into the coax connector with the unit (MB) in receive mode there would be no load for the transmitter in this case, and reading his front panel meter on his transceiver would have indicated that. Sounds like a severe case of "SOP READ YOUR MANUAL" going on there. You can't be responsible if the new owner wasn't familiar with his equipment. > > So I guess I still have a decision to make. I am not sure what I will do yet. Input, need more INPUT! FWIW Jim WB2FCN with three MatchBox units 2 1KW models and 1 250 watt model, all with T/R switching functional.
