From 0ace6348eb41b337efa2c5b8832d7cf844945587 Mon Sep 17 00:00:00 2001 From: LongHairedHacker Date: Sat, 9 Sep 2017 00:54:50 +0200 Subject: [PATCH] Added a readme --- readme.md | 63 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 63 insertions(+) create mode 100644 readme.md diff --git a/readme.md b/readme.md new file mode 100644 index 0000000..a039fd7 --- /dev/null +++ b/readme.md @@ -0,0 +1,63 @@ +3DP-QFH +======= + +3DP-QFH is a quadrifilar helicoidal antenna for 137MHz, +build out of 3D-printed connection elements, PVC-tubing and welding rod. + +![dimensions](images/qfh_3dp.jpg) + +The dimensions have been calculated using the [calculator](https://www.jcoppens.com/ant/qfh/calc.en.php) by John Coppens. + +![dimensions](images/QFH_dimensions.jpg) + +The 3D printed parts are designed to account for all the odd distances, +allowing the PVC parts to be cut to nice full centimeter lengths. +The welding rods are copper coated steel which provides stability to the antenna, +while it is still possible to solder the coax to them. + +BOM +--- +* About 2m of 15mm diameter PVC-Tubing +* 5 screw terminal blocks (aka. [Lüsterklemmen](https://commons.wikimedia.org/wiki/File:Screw_terminal_with_crimped_wire.jpg)) +* A few meters of RG316 with your preferred connector at one end +* 8 WIG welding rods 3mm diameter (and longer then 50cm) or any other type of sturdy conductive wire +* Epxoy glue +* 3D printed parts + +Construction +------------ +1. Print the parts + * one top part + * one middle part + * one bottom part + * two cap parts (stl contains two different types, print twice) +2. Cut the PVC-tubing according to [lengths.pdf](lengths.pdf) + * one piece 32cm + * one piece 29cm + * two short loop supports 13cm + * two long loop supports 14cm +3. Glue the top part into the 32cm piece +4. Glue the bottom part into the 29cm piece +5. Mark the upper side of the middle part (same orientation as in the stl file) +6. Glue the short support tubes over the upper two arms of the middle piece +7. Glue the long support tubes over the lower two arms of the middle piece +8. Glue the middle piece between the other 2 assemble parts, + ensure that arms for the short loop on the bottom piece (the upper two) are + rotated 90° with respect to the support arms. + Also make sure that the arms of the top piece line up with the support arms. +9. Plug the endcaps into the support arms, without glueing them in yet. + Make sure to plug the larger ones into the shorter support arms. +10. Bend the welding rods. The dimensions are not too critical. + * bend 4 pieces after 15.4cm for the long loop + * bend 4 pieces after 14.6cm for the short loop +11. Insert the pieces and cut longer ends at the support arms. + Make sure your helix turns counter-clockwise. +12. Use the screw terminals to connect the pieces inside the support arm caps and the bottom piece +13. Glue the support arm end caps in place +14. Feed the coax through the tubing from the bottom to the top +15. Strip the coax and solder it to the welding rods according to the following schematic. + ![top wiring](images/qfh_top.jpg) + (Schematic taken from [https://www.jcoppens.com](https://www.jcoppens.com/ant/qfh/adapt.en.php)) + A and B are the connections of the long loop. + You can use a piece of PCB or solder directly to the rods. +16. Test your new antenna