Weather Station Hardware > Blitzortung
My home-made ferrite antennas
W0BTU:
Very well! I plan on getting some of those. After I catch up with paying work here.
I'm in the process of moving my E-field antenna probe from that noisy location on the upstairs balcony to near the H-field antennas. Someday... :grin:
quailvalleywx:
I wound a set of these antennas. Thank you Don for posting the instructions! Station 2319, https://www.lightningmaps.org/blitzortung/america/index.php?bo_page=statistics&bo_show=station&bo_sid=2319&bo_page=statistics&bo_show=station&bo_sid=2319 has been running with them for a few weeks now (300mm x 7.5). For mechanical support inside the PVC I just wrapped the antennas in paper towel. I've got some EMF from the ground level power company distribution transformer in my backyard that limits real good detection at the moment. At one point I tried grounded aluminum foil for one rotation within an outer layer of the paper towel wrap but found the transformer noise was magnetic field (not 60Hz sine but more like an arcing impulse at amplitude peaks). The aluminum foil is no longer in there.
Another observation - I found the twisted pairs in typical non-shielded CAT cable work fine for noise rejection. Even with 75ft of CAT cable in my backyard noise was ~zero with the antenna/preamp not plugged in. It definitely came in via the antenna and was worse closer to KCPL's transformer. System Blue's differential input noise rejection (and power supply decoupling caps) are excellent.
If you are too lazy to make a trip to Harbor Freight to get a heat gun then a "half baked idea" is to throw the antennas in the oven with the roast :-) At ~275F the ends of the shrink tubing collapse first pressing the rods together. Don't go too long though since the ferrites can warp (< ~1 min). I had minor warping on one of the antennas.
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W0BTU:
--- Quote from: robo on June 28, 2014, 05:58:58 PM ---Wolfgang Friese
http://www.friese-electronic.de/sfericsempfang/komponenten/ferritantennen/
cu Robo :)
--- End quote ---
Latest archived copy of that website at https://web.archive.org/web/20200224202534/http://www.friese-electronic.de/sfericsempfang/komponenten/ferritantennen/.
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