Hi Pete, You can use your MFJ 259 to measure loss through your bias-T setup.
100 microhenries should be adequate; however, a properly designed bias-T should always have two inductors at the injection and and two at the far end of the coax cable. The series inductor isolates the power injection port from the RF path and and an inductor to ground protects the RF electronics (preamps and transceivers) from damage if the series capacitor feeding that port should short. My bias Ts use simple homebrew inductors, just a few turns of wire on a ferrite core. Use your MFJ-259 to optimize the inductors. 73 Frank W3LPL ----- Original Message ----- From: Pete Smith N4ZR <n...@contesting.com> To: Topband@contesting.com Sent: Thu, 14 Nov 2013 07:58:47 -0500 (EST) Subject: Topband: bias tee I am using my coax to feed 12 VDC to my remote RX antenna locations, using a traditional bias tee, but am having some trouble with performance. I'm using 100 uH Radio Shack chokes in my bias tee, and am wondering if perhaps that is insufficient inductance for 160 meter operation. If so, what would be an appropriate value? -- 73, Pete N4ZR Check out the Reverse Beacon Network at http://reversebeacon.net, blog at reversebeacon.blogspot.com. For spots, please go to your favorite ARC V6 or VE7CC DX cluster node. _________________ Topband Reflector _________________ Topband Reflector