thebaldgeek Profile picture
If ADSC, ACARS, or Satcom are your thing, you have found the right guy. #osint #avgeeks decoding L & C-Band, HF, VHF ACARS messages. https://t.co/rAkzbse6VL

Jan 27, 8 tweets

I finally got the email that my #DiscoveryDish will be delivered on Wednesday, so I figured I'd better get ready to test it.
@ElbaSatGuy will also be (hopefully) doing the same test.
Turns out, I don't have one of my helix spare to test.
So, lets print one.
So far, so good.
1/

@ElbaSatGuy I decided to go with aluminum pizza pan this time around.
The copper tube needs to be 59 inches or 1.5m long.
Remember, thread the copper backwards out the main coil to keep the natural curve. Do NOT straighten it out.
2/

ANY jar or round thing that is 2.4 inches or 61mm in diam is all you need!
If you don't draw blood, your not getting a well formed coil.
By NOT straightening out the original coil, everything just flows in the right direction and will be easy to pre-wind and then thread onto the print.
3/Image
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Just go 1 turn at a time. Ease the start through each hole and push each turn a little over the length of the frame working your way up to the top at the next hole.
It only takes a few minutes to thread the coil on and I've never broken a print getting it threaded on the frame.
4/

@ElbaSatGuy Measure/mark and drill the reflector.
Two big holes for the frame, two small holes for the bulkhead and one last hole for the center pin of the bulkhead.
I always put the SMA bulkhead in first, then bolt down the frame.
5/

@ElbaSatGuy Heat the tube, then wick the solder onto the center pin.
Keep the first 1/3 turn parallel with the reflector.
End to end its about 20 to 30 min (3 hour print) build.
Last step (throw it on a VNA if you have one) is to take it outside and decode some satcom ACARS.
6/

Working well. As expected.
Ok, now we just need a #DiscoveryDish to assemble and test.
I'm thinking three way test. Dish, rtl-sdr patch and the helix.
Guessing no real difference between the dish and helix, the patch will be a fair way behind. Uh oh, that's a work in progress. Sorry.
EOL

@ElbaSatGuy @threadreaderapp unroll

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