All it took was 15 feet of #8 copper wire, 8 feet of 1/4" aluminum rod, a 10 foot section of 1" PVC pipe and a few common bits of hardware. I believe the material costs (excluding the coax cable) were less than $20. The only hard to find component is a short (< 2 feet) piece of RG-62 coax used to create the phasing line between the two antenna loops. This is a 93 ohm impedance coax and isnât commonly available. As it happens I have a bunch of it I picked up 30 years ago that I have been salvaging the braded copper shield from for grounding straps.
Construction was easy and took about half a day. Drilling nice square and correctly aligned holes through a round plastic pipe can be a pain so I designed and printed a simple plastic drilling guide to make this easy. If there is any interest, I can probably write up a construction article and provide the STL file for my drill guide.
I cut the antenna elements for 137.1 MHz and so far the test performance has been very good.
Last week i also made a few eggbeaters (one for 435MHz and one for 144MHz).
This seems like a good starting point for setting up a âno ratatorâ gs.
As phasing line between the two antenna loops I used 2 pieces of RG58 paralel.
Testings with a RTL-SDR v3 are planned, and then putting everything in/on its final place.
The software in the RPI is something different, I have no linux skills, so this will be my first linux experiment ever;))
But weâll get there ⌠eventually.
I did some testing with a rtl-sdr.com v3 and the reception of the noaaâs and ISS is fine.
Also at 70 cm the reception in FMN of some satelites was good.
Yet also noticed that a few very strong stations on 169.625MHz and 169.650MHz ( on jo20tv) overloaded the receiver.
The antennas are now moved to their fixed location and everything has to be reconnected again.
There are no plans, everything is done with pen and paper and the drilholes are just measured and pointed on a PVC tube.
The sizes of the square are taken from Jerryâs (K5OE) eggbeater 2.
There are no 3D prints in this construction.
Sorry, I am on the road this week and donât have access to the file that I offered to share.
What I did was design a 3d printable drill guide suitable for use with common (in the US at any rate) 1" PVC plastic pipe. If you have a 3d printer and you are using this kind of pipe, it will help you get the holes properly aligned. If you are using another (metric perhaps) pipe size, most 3d printers allow you to scale a part without too much difficulty. I will be home late tomorrow and will post the file and additional details this weekend.
Print the drill guide, scaling it to fit snugly over the plastic pipe you are using to make your antenna.
Mark a straight line along the length of your pipe.
Slip the guide on your pipe and align the line on the top of the guide with the mark on your pipe. Note that there are 2 marks on the top of the guide. One for the small set of holes and one for the big set of holes.
Hold the guide in place and run your drill through the holes into your pipe.
