Re: [LAD] [OT] 3ghz coax and soldering...

On Tue, Jan 18, 2011 at 10:59:59PM +0100, Jörn Nettingsmeier wrote: Can't really answer this. But BNC seems to be the standard connector for this, so it's probably OK. This is probably just a question of being practical. Wiring up a patch bay to things outside the rack (or the equipment it is part of) without connectors leaves you with something that is more or less cast in stone. It can also be quite difficult to install. I recently wired up a 96 point audio patchbay without rear connectors (i.e. soldered), with almost all of the connections going outside. Luckily these cables had the other end free and didn't go into some wall. But I'll avoid to do that again... I doing another one these days (the Sala dei Concerti - you know the system needs some rewiring :-) but this time the patchbay has rear connectors - it would be near impossible get it wired up otherwise. Haven't seen it. When I was working at Alcatel, all HF racks we constructed had back panels with double through-panel BNCs for external connections. No external cable would ever be attached directly to any of the equipment inside the rack. And more often than not, the same through-panel BNCs were used on the actual equipment boxes themselves, with an internal BNC-SMA cable to connect to the PCBs. So any signal going in or out would pass via at least 4 BNCs, and 4 again if routed to another rack. I often worried about this (since we mostly did equipment doing very precise phase measurements etc.), but the HF 'old hands' told me each time that I shouldn't. For really critical stuff at 2 GHz and above they would prefer SMA, and if things were really extreme the coax cables would be replaced by rigid tubes, welded to the SMA connectors using special HF induction welding equipment. SMA handles much higher frequencies than BNC, but I don't think it matters for SDI. That could well be cause for concern. Is there really any advantage to recessed BNCs ? The connector itself is usually solid enough, and once a cable is attached to it the Neutriks are as vulnerable as any other. Unsolder itself ? Most BNCs today are crimped rather than soldered. If done using the correct tools and procedure this should actually be better. Ciao, -- FA There are three of them, and Alleline.