Topband: Best Outlet sttrip

[MU 4CX250B]

Sent from my iPad

> On Oct 8, 2013, at 19:06, Jim Brown <jim at audiosystemsgroup.com> wrote:
>
>> On 10/8/2013 2:42 PM, Tom W8JI wrote:
>> the system should not be that sensitive to common mode issues on ports.
>
> Right. But first, we're not talking about common mode, we're talking about chassis-to-chassis noise coupling into unbalanced interconnects, like computers feeding radios, with or without various interfaces. And yes, unbalanced interfaces are a lousy way to do it, but I don't know of a single ham rig that has balanced interconnects for audio or accessories.
>
> So unless a ham wants to rebuild every rig and all accessory gear with balanced interfaces, the simple power and bonding concepts I've outlined are the lowest cost, most  reliable, and a very robust solution.  Yes, we could add transformers, but transformers cost more, and shielded transformers cost a LOT more.
>
> As Vice Chair of the AES Standards Committee Working Group on EMC, I was a principal author of all AES Standards on the topic. It took a while to reach a consensus, because some purists were unwilling to write Standards to work with real world equipment. The path we took, and that the cool heads worked very hard to achieve, was to write Standards defining the RIGHT ways to do it, both inside and outside of equipment, but to define the right way to work with vintage gear that was badly designed/built. Our first EMC Standard, AES48, attacked the Pin One Problem, which was the most critical root cause, both at baseband and at RF. We then wrote the protocols for balanced interconnects, including the advice that when the cable shield needed to be interrupted to prevent shield current, the interruption should always be at the receiving end. This is counter-intuitive, but Bill Whitlock showed that it is the only right way.
>
> The point of this digression is that there's no way in hell that hams are going to replace our gear with stuff having balanced I/O for audio and control, simply because it doesn't exist, and to assume that such gear will exist in the foreseeable future is wildly unrealistic. Heck -- we can't every get manufacturers to build gear without Pin One Problems.
>
> 73, Jim K9YC
> _________________
> Topband Reflector