Archive for January, 2014

Wifi BiQuad Antennas

Saturday, January 18th, 2014

I needed some simple wifi antennas so I made some using 12 gauge copper wire and SO-239 couplers


Start by hollowing out the coupler

There is a small ridge the keeps the insulator at the end of the pin


The easiest way to remove it is to chuck it in a drill and file it off


Them you can cut the edge of the outer casing into a small tab. Then reassemble the guts but without that ridge the insulator will go all the way down

I cut the edge to match that depth


Now you can solder on a BiQuad of about 1.2 inches per side and find a suitable reflector

I used a 5 1/4 floppy drive platter


Other stuff like steel switch plates works too as wel as regular chassis mount SO-239’s. i think the coupler makes adjusting the reflector position easier


Not as cool as the circularly polarized WiFi antennas I made for a long range link


They also have SO-239’s so I can use the same radios


N connectors would have been a better choice

Routing PC Boards

Saturday, January 18th, 2014

My friend John was over and asked me if the CNC machine could be used to drill PC boards. I said sure, it could even route them too

So I decided to give it a try. I found a simple QRP transmitter design which I could use for an arduino project and tried to make a couple










I built a 20M and a 40M board. They worked so well I’m going to route 2 more for 80M and 160M


Saturday, January 18th, 2014

I started building CNC machines long ago. My first inspiration came from Bruce Shapiro’s eggbot. I tried a few variations of it and even the board from evil mad scientist.

One day my friend Joe told me he was interested in CNC. I told him I had played with it for years but never seriously committed to it. We decided to build one at work over lunch. Doing a little bit each week. We only have one day a week we can get together

It is so close but only using 3 or 4 hours a week has been a little limiting. We got the x and y done and some tuning so it can now plot pictures using a sharpie. We just have to finish the z axis

I recently completed a similar machine at home using some old printer parts and a dremel.

The base is a side panel from a computer UPS. A dot matrix printer gave it life to become the main carriage and the rails from an antique laserdisc player completes the z axis




It’s driven by an arduino mini running GRBL 0.8c.

There are 4 PIC 12c508 support chips. 3 handle the step direction deciding for the three axis and the 4th converts the z axis set and directions signals the a relay closure to operate a diode laser for simple engraving tasks.

I used 6 toshiba h bridge chips to drive the bipolar steppers. There are 2 solid state relays one for the dremel and the other is for a shop vac. An old compaq notebook supply runs everything.

Spindle codes control the dremel and flood coolant commands control the shop vac

The first few pieces came out pretty good

I used a dial indicator in place of the dremel initially to level the table. I managed the get it to within .008 in. It’s not really crooked but cupped slightly in the center

So far that hasn’t been a problem

Here are the first tries….




I was pretty happy with the results.