AJ, I can not tell you about the Telewave, however I can tell you about the DB units I have looked at. They have a short on all ports, and the DB Engineers that I have spoken to report this is the design. They are DC Short design just like the folded dipole antennas. Resonate at frequency of operation.\ I hope this helps a little. Charles Miller
_____ From: [email protected] [mailto:[email protected]] On Behalf Of AJ Sent: Tuesday, February 03, 2009 11:49 PM To: [email protected] Subject: [Repeater-Builder] Nominal impedance of a Telewave T-1560 Dual Isolator??? What exactly should the nominal impedance of a VHF Telewave T-1560 Dual Isolator be? The reason I ask... I broke out the DMM this evening trying to make some sense of a repeater issue we've been having... Removed each one of the 35 watt dummies off of the load port of the isolator, one at a time, and verified they sit right at 52 Ohms from pin to shield (male N-type connector). Then I check the load ports on the isolator itself where the 35 watt dummies were connected - 0 Ohms (direct short) from pin to shield. I then checked the in and out ports of the isolator (tx and antenna ports). These both showed a direct short from pin to shield. I also verified that there is a direct short from pin to pin on all 4 connectors (tx, ant, load 1, load 2), along with shield (chassis/ground) to shield all around. So... My question is... Should there be a direct short from center pin to chassis on this isolator? 73s, AJ, K6LOR/R 147.080+ 444.750+
