Presentation – A 3 band Moxon for 6M, 4M & 2M


This is a presentation by Bryan Page which describes how he constructed a 3 Band Moxon for 6M, 4M & 2M, mainly out of surplus plastic Plumbing pipes and clips etc, and also details of how the diamensions were calculated.

A3-band Moxon for6m, 4m and 2m

Deciding on the frequency

For the purpose of my Moxon I chose center frequencies of:6m – 50.250MHz

4m – 70.250MHz

2m – 144.200MHz and then used the calculator at:

http://w4.vp9kf.com/moxon_design.htm

 

Mark and drill the clip holes and centre hole, then screw the 22mm pipe clips to the acrylic sheet, ensuring the screw/bolt heads are countersunk and don’t protrude into the clip.

Secure the centre

When you’ve attached all the pipe clips, turn the acrylic over and push the connector through till it rests on the work surface, place brackets on the acrylic sheet up against the connector, drill and screw to the connector and then drill through the acrylic, do not bolt to the acrylic at this time.

Turn the acrylic the right way up. Bolt brackets to the upper side using the holes drilled, then drill and bolt into the connector.

When is is all done take a length (I 400mm) of 50mm pla pipe and glue it into the connector.

The Moxon Arms

Going back to the calculations you will note dimension “F” on the 3 calculations, taking the dimension for the 6m calculation make 4 lengths of 22mm plastic tubing about 100mm longer than the “F” dimension.

Push the 4 arms into their respective clips, I drilled through the centre most clips and through the end of the pipes, then placed a nut and bolt through the holes to secure the arm.

Now taking each “F” dimension, measuring from the centre of the acrylic sheet (centre of the 50mm connector), measure in an outward direction on each arm and mark the arm, you will end up with 3 marks per arm.

You are now r to make the dipole centre…

Thedipolecentre(1)

Checking the “E” dimension of the 6m band, cut a length of 22mm plastic pipe just over half the “E” dimension.

Push the plastic pipe into the 2 remaining pipe clips on the perspex sheet.

Measure from the centre of the 50mm connector in an outward direction along the dipole centre mark the half “E” dimensions of all bands on the pipe, you will end up with 3 marks.

The dipole centre(2)

Take 3 22mm plastic pipe connectors, remove the ridge in the inside centre of the connectors (you can do this with a penknife), this will enable the connectors to slide along the length of the pipe.

The dipole centre(3)

Using the mould line on the connector, dril a pilot hole central to the length on both sides. Repeat for the other 2 connectors.

The dipole centre(4)

Remove the dipole pipe from the pipe clips and slide the connectors over the pipe and line up a pilot hole on each connector on a mark on the pipe, ensure all connectors are in line.

Drill through both sides of each connector into the pipe and remove the onnectors from the pipe.

The dipole centre(5)
You will need 6 nuts, bolts and washers for the connectors – open out the pilot holes in the connectors to the size of the screw threads.

Place a screw from the inside of the connector putting a washer and nut on the outside, repeat this for all the connectors, ensure the nuts are as tight as possible, you will end up with the below:

The dipole centre(6)
Taking the dipole centre pipe, open out the pilot holes large enough to accommodate the screw/bolt head on the inside of the connectors.

Cut the pipe through the centre of each hole, you will end up with 4 pieces of pipe, do NOT mix up the order!

Taking a connector, glue the leftmost pipe piece into the connector ensuring the screw/bolt head locates in the half hole. Now take the next pipe piece and glue it into the other side of the connector, repeat until all pipe pieces are glued into the connectors, ensure all the bolts line up correctly.

Preparing the arms
There are 3 marks on each arm and 4 arms. Take 12 22mm pipe clips and drilla hole through the bottom side, large enough to take the 1.2mm wire.

Now push the pipe clips onto each arm lining up the centre of the clip with the mark on the arm, the clips must be mounted upside down.

The bands(1)

For each band, cut 2 wires of half “A” dimension plus “B” dimension and add 50mm, cut one length of “A” dimension plus 2 “D” dimension and add 50mm Solder a tag to on nd of both the shorter lengths.

The bands(2)
Prepare the spacers with holes drilled the correct distance (dimension “C”) apart.

Take a piece of insulated copper wire and attach it to one of the end screws on the dipole centre, run it to the centre screw on the same side and loop it round, then take the wire to the end screw and loop it round, repeat for the other side..

The bands(3)
Connect each pair of tagged wires to their respective screws/bolts, line up andtighten.

Thread each wire through its wire clip. Place an insulator on the end of each of the wires at the correct position, repeat for all driven elements.

The bands (4)
Thread the reflectors through the remaining clips and attach to the other endsof their respective insulators.

Adjust the position of the clips (by sliding them) until the wires are taut. Mount the Moxon, check the SWR and make any adjustments necessary. Have fun!

Here is tyhe LINK to the pdf presentation 3BandMoxon