Desktop 12 VDC (13.8) Distribution

I go through small 13.8 VDC linear power supplies like they're candy. I keep several around since they're vital to my station. They run my antenna switching system, stack switches, antenna switches, Beverage antennas, BPF (band pass filter), rotator controllers, and much more. They are prone to failure due to lightning and other mishaps.

My problem was ease of connection and disconnection, and cable management. Having a multitude of peripherals makes this difficult. I had to manually disconnect multiple wires on the +ve and -ve power supply terminals while preventing shorts and loose wires. 

It is made more difficult since the power supplies are located on the sub-shelf so that I have to squat down behind or underneath the operating desk which inevitably causes unintended damage, such as to my head. 

Wires inevitably go astray when connecting several to one screw terminal. Some of the DC cables end up snaking and tangling amongst other cables, making them difficult to route and connect. I can never remember which peripheral is connected to which power supply, and it can change frequently. Tracing cables is time consuming. 

I have to do this often since my station is constantly evolving. There are partially built projects on the operating desk while I'm building and testing them. In short, it's a maddening mess. I finally decided to do something about it.

My solution is not novel, or even particularly interesting. But it's necessary, and that makes it worth a brief description. If you're looking for excitement, this article isn't it.

Standards

There are many connectors, both standard and proprietary. We are not talking about high current or demanding applications so there is no need to do anything fancy. My solution is that of all my DC powered peripheral equipment: 2.5 x 5.5 mm DC power connectors. There are similar connectors in different sizes but these are what I've chosen.

They are commonly found in smaller devices on our desktops. They're cheap and effective. However, do take care that the ones you order online are not so cheap that they have unwelcome problems. Some require unreasonably large chassis holes, have unexpected threads, might need the male connector to be jammed in full depth and so forth. Paying double the price for good connectors is still cheap.

Interconnection cables are also cheap to buy if you don't want to build your own. For this project you need male connectors on both ends of the cable. The only bare wire connection is to the power supply terminals.

Power supply choice

I recommend against using the DC supply powering your rigs. Although they may have the headroom to deal with a few extra amps there are other considerations.

In my station, many of my peripherals support antenna switching systems deployed in the field, either on the towers or on the ground. These systems are at risk of lightning damage. In a pinch I once connected my peripherals to my 35A Astron linear power supply and lightning fried several components. I eventually fixed it but I have never made that mistake again. They're expensive to replace and can be difficult to diagnose and repair. 

Small linear supplies of 3 to 4 amps are flea market bargains. Buy a couple of them so that you always have a spare. If you are unfortunate enough to experience lightning damage they are cheap to replace and perhaps not worth the trouble of repairing them. Lightning protection is worth considering, such as GDT (gas discharge tubes) which are inexpensive and effective.

Distribution

I don't want to see the DC power supply and cables. They're necessary and nothing more. However they must be accessible for station changes and periodic reconfiguration for multi-op contests. That requires proximity of the connections to each station and to equipment that is never moved. Long cables should be avoided since they can create a mess and are prone to RFI.

I built two connector strips that are wired together. They are constructed from ¾" aluminum angle with holes for the connectors and strain relief. Holes on the other face are for #6 wood screws to affix the strips to the underside of the desk -- ensure that connectors and wires don't block hole access. Most stations only need one strip, but I wanted two so that the cable runs are kept short when I set up for multi-op contests. 

There are numerous other variations that might be preferred. For example, one power supply per strip, or strip interconnection with a DC power cable (occupies one connector on each strip). It is also possible to add RFI and lightning protection on the distribution strips if it isn't present elsewhere.

Installation 

The only important question is where to place the connector strips. I placed mine under the backside of the desktop. However the power bars and a few other items had to be temporarily removed to make space for a screwdriver. One final electrical test and I was done.

I now need to be more serious about attacking the rest of the spaghetti cabling. I always start with good intentions so that every time I first set up a desk it's pretty clean. It gradually deteriorates with every station change or shuffling of equipment.

That was a boring project, wasn't it? Keep in mind that a worthwhile project does not have to be exciting. More like a chore than a project, but still important to do.

I'll return to more interesting topics after I deal with non-radio matters that are currently occupying my time.