Howdy all, I am trying to make a Quadrifilar Helicoidal antenna ( did I get that right) and wanted to get some input on stuff?

SatNOGS Hardware
1

So I was looking at this post and was thinking of making an antenna like this.

  1. would the entire antenna being in an ABS enclosure cause any issues with reception?

and now a few questions in one. On this site it gives some calculations and I see the definitions at the bottom of the page, but I just wanted to ask a few things and confirm a few things that I think I got figured out.

  1. conductor diameter. What acctully is this part? the copper antenna wire diameter? what does definition mean by tube or coaxial cable? I think this may be talking about the core of the antenna? the grey vertical plastic rod in the pictures?
  2. if I am doing nothing fancy and just want good general reciption for cube sats and the like. Should the rest of the settings be left default ( cept bend radius, will ask that in question 4 :stuck_out_tongue: ) so twists, length of one turn, width height ratio all stock? like I kinda get the definitions, but is why would I use lets say 2 wavelength circumference for length of one turn vs default of 1?
  3. is this bending radius talking about how much it takes to bend the blue wire in the pics? i.e. it is used to calcuate the diffrence between D1 and Dc1 or D2 and Dc2? if not what is this used for?
  4. why does it refrence a bigger and smaller loop? are 2 out of the 4 big and other 2 small? or something else going on?
  5. Lastly what is the briefest article about assemble and what not that would also likley answer the above questions LOL.

Thanks for any help all! just trying to get some stuff setup and wanted to give this antenna a go!

2

Welcome zawalonka,

  1. I do not know, probably not, you can experiment and tell us!

  2. QFH antenna are constructed with many different materials. You can do it with electrical cable, with copper pipes or with coaxial cable. Depending on what you use the calculator need the diameter. In the case of coaxial cable it need the external diameter that is the “inner conductor + dielectric + braid”.

  3. Because you may want a bigger antenna, with more gain.

  4. The bending radius depends on the material you use, try bending 1,5mm2 and 6mm2 cables, or 1/2inch copper pipe and you 'll see the difference!

  5. QFH antenna in practice is 2 loop antennas. a small loop and a big loop.

  6. It depends again, on material used :slight_smile: