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--- antennas:qfh [2024/04/16 20:32] – 2m0vsr
+++ antennas:qfh [2024/04/24 19:15] (current) – 2m0vsr
@@ Line 5: / Line 5: @@
 From Scott - 2M0VSR:
-https://jcoppens.com/ant/qfh/calc.en.php  generates the paper template for the holes.
-Quadrifilar helicoidal antenna - Javascript on-line calculator
+**Credits**
-Compared to solid core wire, it's quite easy to get it into shape, or close enough that it tunes almost smack centre in the band
+Inspired by this build: https://tf1ez.com/qfh-antenna-build/
-I think the rods are M4/5/6 threaded rods. Just make sure the rod will go throw the stell banding holes as they are difficult to enlarge.
+**Summary Instructions**
+The above link has a better guide but the TLDR version is:
+  * Generate and print the paper templates based on the type of PVC pipe you have.  Use: https://jcoppens.com/ant/qfh/calc.en.php
+  * Tape the cut-outs onto the PVC pipe, making due they are aligned down the pipe.
+  * Drill out the holes. The centre ones are not strictly needed but you may find it useful to use some wooden dowel rods to support the banding.
+  * Cut the threaded rods down to size based on the calculator. Leaving them a little long won't do any harm.
+  * Put the threaded rods though and use a washer/nut against the PVC pipe to hold in place.
+  * Cut the Banding so that it stretches to the opposite bottom rod. I'd leave a bit extra and trim.
+  * Use 2 nuts/washers to lock in place the banding on each end.
+  * Attach the Coax ends to the top of the antenna and run it down the tube. Tie it off to the bottom with some zip ties for strain relief.
-Think it was this that gave me the original idea: https://tf1ez.com/qfh-antenna-build/
+**Notes:**
+  * You can use low gauge wire as an alternative to banding but it's much more difficult to work with and get aligned well. I used 10mm earth wire for an earlier build and it worked ok.
@@ Line 21: / Line 32: @@
   * - PVC Pipe (55mm, 1meter or similar)
   * - Galvanised Steel Banding - [[https://www.screwfix.com/p/ced-all-round-band-12mm-x-10m/18298 |Screwfix]]
-  * - 4 x Threaded Rods + Nuts + Washers  (Would probably go with M4 or smaller so that you don't have to cut the banding half-way though a whole.) [[https://www.amazon.co.uk/Pack-Stainless-Steel-Threaded-Bar/dp/B08NDQW87B/|Amazon]] [[https://www.amazon.co.uk/M4-Leryati-Standard-Stainless-Fastening/dp/B0BVZCH1XF/|Amazon]] [[https://www.amazon.co.uk/25mm-Flat-Washer-Stainless-Steel/dp/B0BVMPCVMY|Amazon]]
+  * - M4 Threaded Rods (x4) [[https://www.amazon.co.uk/sourcing-map-Threaded-Thread-Stainless/dp/B0BK52F97W|Amazon]]
-  * - Some Good Quality Coax. (Messi Hyperflex 5 / Ultraflex 7 for example)
+  * - M4 Nuts (x24) [[https://www.amazon.co.uk/Nylock-Nylon-Insert-Locking-Stainless/dp/B07VSCG96L|Amazon]]
+  * - M4 Washers (x24) [[https://www.amazon.co.uk/25mm-Flat-Washer-Stainless-Steel/dp/B0BVMRXXVF|Amazon]]
+  * - Good Quality Coax. (Messi Hyperflex 5 / Ultraflex 7)  [[https://www.hamradio.co.uk/messi-and-paoloni-hyperflex-5-pd-6679|ML&S]]
-Whole thing can be built for less than £20 if you shop around / scavenge a bit more.
+Whole thing can be built for less than ~£25. Less if you shop around / scavenge a bit more.