Hello Paul and others. You are quite correct as there is common mode protection on all of those Hi-Z 8 circle antenna input lines. One problem with 8 element arrays is that there is a significant problem of common mode due for one thing the long length of the element connecting cables. Personally I would not recommend using an isolated barrel connector to a metal panel as you suggest. I think the capacitance to ground and to the other elements as a result might decrease the common mode rejection. I think it would be better if you could make a small panel for all 8 connectors of single sided circuit board to fit into your aluminum plate. Then remove any copper around the use of more common type barrel connectors for a through connection. The fewer connections inline will be better so I don't recommend using different series adapters. Not only is the extremely low signal levels on these lines but there is also 13.8 VDC at 40 ma. The fewer connections the better to limit any possible micro arcing on these low signal lines. P.S. Do not use cheap Chinese barrel connectors or you WILL have a problem with connection. Experience speaking.
Lee K7TJR Hi-Z Antennas -----Original Message----- From: Topband <topband-boun...@contesting.com> On Behalf Of Paul Christensen Sent: Sunday, October 21, 2018 12:08 PM To: topband@contesting.com Subject: Topband: Isolated F81 F Barrel Connector Google isn't my friend today... I am looking for an isolated "F" barrel connector, commonly known as the F81. I am designing an aluminum interface plate for use with a Hi-Z 8-circle receive array. The panel will contain multiple F81 barrel connectors that attach to the side of a large PVC tool box with gasket weather seal. An isolated F81 is probably a very odd item since it's a connector that's not normally used for baseband signal distribution like video and data. Each of the RG-6 lines run into a Hi-Z switched phasing box where each line is connected to a toroid transformer. As such, measuring resistance from the ground of one antenna port to another shows about 30 ohms resistance, necessitating isolation at my connection plate. The Hi-Z phasing box is made of PVC material and each antenna input is isolated by virtue of the plastic box. In the alternative, I could use isolated BNC or TNC connectors with F between-series adapters. Insulating each F81 with its own insolation strip is definitely not an option in this application. The last option is to run all lines directly into the large box and make a direct connection to the Hi-Z phasing unit. However, I would really like the option to disconnect on the *outside* of the box so that it can be quickly wheeled in for maintenance. Thoughts? Paul, W9AC _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector