Rob_P Posted June 20, 2013 Share Posted June 20, 2013 Hi, I am putting together a simple outboard rack for smaller PA jobs. I have a 6u ABS rack that currently holds a 2x31 graphic, a 2x15 graphic, a reverb unit, and a pair of Sennheiser XSW mic receivers (Chan 38). I plan to add an SD card player soon for backup playback etc. In the past I have always just used the standard antennas on the back of the receivers, but all of the other kit in this rack is deeper than the receivers, so this won't work. Without getting into external paddles or expensive antenna distribution kits, the obvious answer seems to be to use some very short patch cables and mount the 4 antennas on blank rack panel on the back, via BNC feed-through connectors. My question is: Should I use earthed or insulated feed-through connectors? I am assuming that earthed ones would be best so that the rack panel will act as a ground-plane of sorts, but I am happy to be corrected! Thanks! Link to comment Share on other sites More sharing options...
Lamplighter Posted June 20, 2013 Share Posted June 20, 2013 I have always used the earthed type of BNC/TNC sockets, mounted on a 1U panel on the upper rear of the rack case. I have not experienced any problems to date on systems from VHF through to channel 70.Brian Link to comment Share on other sites More sharing options...
paulears Posted June 21, 2013 Share Posted June 21, 2013 I must admit to having both versions - one rack has the plastic D size blanks with the BNC isolated, while the other has the same feedthroughs mounted to steel 1U panels.The RF side of things with a 1/4 wavelength aerial requires a ground plane to provide 'balance' and just needs to be the raised off the floor equivalent of the earth. It doesn't need to be electrically connected, as it's purpose is to provide a reflective plane. However, the receivers tend to bond the output socket to the metal case, and thus, through the rack ears, electrically the rack is already connected to the RF connector outer. Link to comment Share on other sites More sharing options...
Rob_P Posted June 21, 2013 Author Share Posted June 21, 2013 Thanks Chaps. The blue-room has come up trumps again. Grounded connectors it is then. Link to comment Share on other sites More sharing options...
paulears Posted June 21, 2013 Share Posted June 21, 2013 Being honest, I suspect that's the best choice. My IEM rack uses a metal punched panel, with the sockets all grounded together, and I chose this for the marginal SWR improvement over the 1/4W on the insulated version. For receivers - I can't really say one is better. I do know that if I was doing another, I'm sufficiently unworried that I'd use whatever was on the shelf! Link to comment Share on other sites More sharing options...
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