Better Power Distribution for Portable Ops. November 3, 2018 by Julian OH8STN

Hello Operators

We’ve done lots of work on the channel with portable power for portable ops. We’ve even discussed power distribution on the channel but it’s always been from a “ham shack” perspective.

All of the examples of power distribution boards found in ham radio shops, are designed to be mounted to a wall. In some cases, we find styles meant for the desktop. What we never see are the design ergonomics for the portable operator. We are given a one-size-fits-all solution which only fits the needs of the ham Shack. This happens because designers of these boards have no real field experience, with power distribution. So we need to DIY a reasonable power distribution cable ourselves.

The main problem with off the shelf is the Anderson powerpole connectors are facing upward. This puts a lot of strain on the solderjoint underneath the powerpole connectors connecting to the circuit board. For the active operator, it will lead to eventual failure. What we want is a backpack friendly power distribution cable with 2, 3, or 4 power pole connectors, and a USB or 5v port. This would be good enough for your radio, your laptop, and charging your mobile phone for example. Or it could be your radio and Raspberry Pi. Whichever combination it is, we have one input, and the various outputs meeting our requirements. There’s one more feature it should have, but I’ll wait a little while before I explain it.

I’ve made several different variations of this cable. This one is capable of running a 100 watt radio, Raspberry Pi, and charge my tablet or laptop simultaneously. Of course it also depends on the battery pack we’re using with it. Naturally I’m using the battery packs with built on the channel with this power distribution cable. This allows the battery to stay in a safe place, with a cable coming out of a pack and only exposing the distribution block on the head of the cable.

The most important aspect of this distribution cable is the distribution block. The Anderson powerpole connectors are in line with the entire cable, laying flat without placing any strain on the solder joints. On one end we have a flexible silicone coated 14 gauge cable. In the middle we have the circuit board with a 25 amp fuse. Coming off of the circuit board we have 4, 45 amp power pole connectors, in parallel and supporting one another. The circuit board is covered with Vulcanizing tape. Heat shrink is applied around the fuse leg towers, preventing any “shocking” mishaps. Finally, vulcanizing tape is applied around the power pole connectors on both ends and onto the cables, to provide strain relief.

I could have made the circuit board for this project myself, but instead I decided to order and adapt the four Port board from k9jeb.com you can see, even Johns boards have the power-pole connectors facing upward. With a few pieces of adequate wire, we could turn that distribution board into something awesome for the portable operator.

If you haven’t seen my portable off-grid battery and solar power for amateur radio series yet, you can browse through it at the playlist below.

Portable Off-Grid Battery & Solar Power for Amateur Radio:

73
Julian oh8stn