FYI, got a lightning bug, and it indeed makes rather impressive arcs about 1 mm long across dual "shooter" wire mounted on the secondary side of what I assume are step-up transformers on the main and drogue outputs. Transformers are potted, so I can't tell anything about them. If I spread the wires to 5 mm on the secondary side, the arc jumps that gap, too, so it's some pretty serious voltage. Mounted a Telemetrum next to it, on 434.550 MHz, and powered it up in "pad" mode. At the same time, listened on my Yaesu on the same frequency, and heard the beeps as usual. Firing the lightning bug arcs close by caused no problems at all with the Telemetrum, and the arcs were not audible on the Yaesu. I had pilot lights across the main and apogee outputs of the Telemetrum and nothing flashed. Telemetrum stayed in pad mode the whole time. Next step is to give it a ride in something, once our field reopens from COVID. -Harold Larson
-----Original Message----- From: Bdale Garbee <bd...@gag.com> To: burnwuf...@aol.com; Altus Metrum <altusmetrum@lists.gag.com>; altusmetrum@lists.gag.com <altusmetrum@lists.gag.com> Sent: Mon, Apr 26, 2021 8:25 pm Subject: Re: [altusmetrum] Does Telemetrum play well with other altimeters for redundant dual-deploy? burnwuf...@aol.com writes: > Also saw a video about a "lightning bug" dual-deploy altimeter > (https://www.youtube.com/watch?v=IroVZC5ZbF4&t=10s) that uses a > step-up transformer to produce an arc that lights charges without > e-matches. Interesting, but I wonder how well that would work with a > Telemetrum in the same rocket. That's a great question! The short answer is we don't know. Because the ignition process is basically the same as an old-school arc transmitter in the radio world, we can guess that during the actual pyro firing there's a burst of radio noise across a broad frequency range. I'd be surprised if that causes any "harm" to an Altus Metrum product nearby, and if you're doing the usual things like twisting leads to switches and match terminals, I wouldn't expect the induced noise to cause any unexpected pyro events, etc. But there's just no substitute for actual ground testing! I see that Apogee sells these, so perhaps give them a call and ask what they think they know about the product? https://www.apogeerockets.com/Electronics-Payloads/Altimeters/Lightning-Bug-Dual-Deployment-Altimeter Bdale
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