Month: June 2014

Atlanta Hamfest, Electronics Recycling

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June 7th, 2014 is the day of the Atlanta Hamfest!  Put on by the Atlanta Radio Club and the Kennehoochee Amateur Radio Club at Jim Miller Park in Marietta, GA.  Adults are $6 at the gate, kids 17 and under are free.  Talk-in frequency at 146.820(-) PL 146.2Hz via the W4DOC repeater.  Please bring any junk electronics you want to have recycled, too!

Atlanta Hamfest

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Weekend Projects, pt. 2: Anderson Powerpoles 12V DC Power Distribution Network

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radio_powerpole_full_setup

Anderson Powerpoles are the gold standard in amateur radio DC power distribution, and they provide connectors stable to 15A, 20A, 30A, 45A, and more current ratings.  Grab some red/black low gauge zip cord wire, a crimper, and go.  I like to throw in a little bit of heatshrink and other things, so here goes.

Basic Needlenose Crimp Pliers
Basic Needlenose Crimp Pliers

You need a tool.  Some are better than others.  It all depends on how many crimps you need.  I don’t need a lot very often, so I got an inexpensive crimper.  See those interlocking half-moon grooves and the pair of circular grooves in the mouth of the pliers?  Those are the powerpole crimpers.  They also work pretty well on other types of crimp type terminals.  You put the seam of the crimp terminal over the protruding half-moon, and the back into the recessed one, and press down.  Then you close it off in the circular grooves.  Let’s move on.

Solid Core 12 AWG and Terminals on Perfboard
Solid Core 12 AWG and Terminals on Perfboard

These terminals are great, but they don’t work worth a flip if you don’t have a heavyweight current distribution bus.  You can go commercial and get the heavy duty RigRunners and MFJ buses, but those cost money.  They’re good, but I had everything on hand I needed to fabricate a bus.  I crimped the 30A terminals onto 12 AWG solid core copper wire, and cut down some perfboard to size enough to fit inside the smallest Radio Shack projecct box I could find.  I had to drill out the holes that corresponded to the wires, and then I pushed the whole thing flush and wrapped it with a rubber band.

Soldered and Clipped
Soldered and Clipped

Well, that’s great, but it’s not a circuit.  I added positive and negative rails in the form of another 12 AWG wire that I wraped the other leads around and soldered a bead around the joint.  I knew I needed to make a cut out of the top of the project box to accommodate the headers.

Wrapped Up
Wrapped Up

After some drilling and cutting and sanding, I had a decent opening for the headers.  A lot of hot glue was used to make sure there was a sizeable amount of insulation was around the buses and to secure the circuit board.  Onward to more crimping!

Spade Terminal Adapter
Spade Terminal Adapter

I needed a spade terminal adapter for my power supply.  I was very tired of just screwing down the bare wire, and wanted this to be the input to the bus.  I guessed well on the dimensions, and it fit perfectly on the first try.

Fuse Caddy
Fuse Caddy

A trip down to Ham Radio Outlet to get the Powerpole adapters also had me picking up a few other things.  After cutting up a 6 pin Molex connector I picked up for a rig, I found a quick target for some more crimping.  I pulled the fuse caddy and radio power plug out and got to work.

6 Pin Molex Connector
6 Pin Molex Connector

Overall, everything works out.  I’m ashamed to admit how much glue I went through, but it went towards a good cause.  I completely ran through my supply of Powerpole connectors, and there’s always bound to be something I could pick up from the radio store again, hihi!

Well, it’s getting late.  73 DE KK4TSJ.

Weekend Projects, pt. 1: toroidal 1:1 current balun

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I got the bug to get some weekend projects going in the workshop, and this is the first of those.  I decided that I needed a 1:1 current balun for an upcoming ZS6BKW/G5RV ladder line fed doublet antenna, but it’s pretty important to make use of a 1:1 current balun to choke off the RF of the coax shield.  I also want something that will handle a full 100W safely without risk of sparking, overheating, or breaking down in some way.

I started with a 4″ x 4″ project box made by Hammond Manufacturing and a green 3″ diameter toroidal ferrite core made by Amico.  Not sure they’re the best, but it’s not a huge deal at HF frequencies.  It’ll likely have enough inductance to form a LC filter with the antenna as the capacitor (that’s what antennas are electrically to an AC signal) squelching off UHF and probably higher VHF frequencies from the feedline system.  I doubt it’ll affect 6M operation, but I lack the test equipment to know that for sure.

I then wrapped about 14 turns of 12 AWG zipline around the toroid and zip tied the ends in place.  I had a number of SO-239 panel mount sockets laying around, and I soldering the red lead to the center conductor.  I crimped and soldered a ring terminal to the black lead (it is the grounded shield…), and screwed that down with the socket to some holes I drilled in the project box.  I then crimped on ring terminals to both leads on the other end of the zip core wires, and then secured them with some #10 bolts, nuts, and washers I also had laying around the shack.  The KK4TSJ shack can be somewhat messy at times, but there is a system to the chaos.

Toroidal 1:1 Current Balun for HF Doublet Antenna
Toroidal 1:1 Current Balun for HF Doublet Antenna

After a lot of hot glue, the front panel, and some electrical tape, here’s the finished product.  I haven’t quite figured out mount to the mast system, but it’ll need to be mounted at a standoff to keep the mast from interacting with the ladder line up to the center insulator.  The Atlanta Hamfest is next weekend, June 7th, so I’m looking to pick up the rest of the supplies to complete the larger antenna mast project.

Ready for Hose Clamps
Ready for Hose Clamps

73 for now, DE KK4TSJ