On 5/18/2013 2:05 AM, IVP wrote: >> For a much smaller, lighter directional antenna, a stepper with direct >> drive might be a solution. > Good thought, but analogue TV is about to be turned off in NZ (OK > news if you're in the aluminium recovery business) so everyone will > have fixed dishes The switch to DTV is what makes TV a challenge for some people here in=20 the US. The government provided vouchers for people to acquire OTA=20 digital TV converter boxes at a discount. I was using cable, so didn't=20 need them, but I got mine, and handed them out to people still using OTA=20 TV. Now, I want one of the boxes, because a small TV that is in the=20 workshop, that kept me company on late nights of programming, does not=20 work with the OTA antenna. I think it is the sensitivity of the built=20 in tuner, whereas the tuners in the converter boxes I've seen is very good. Anyhow, I don't get why NZ's analog TV turn-off will force a switch to=20 fixed dishes. Here, it simply made VHF antennas obsolete. People in=20 the "fringe" areas need a higher gain UHF antenna than they did with=20 analog. > > Perhaps I could think of a triangulation use ? I'm getting off the stepper motor topic here, but I was looking at the=20 issue of aligning the UHF antenna i built. While it was worth it to=20 me to spend quite a bit of time experimenting with antenna direction,=20 including several lengthy "channel scans", it would be hard to make it=20 worthwhile to do it for others. So, my reading about a motorized=20 directional antenna included some reading of some rather dated material=20 about uses for TV tuners at=20 http://hem.passagen.se/communication/tuner.html If people weren't so=20 willing to shell out money to TV providers, and if there were more=20 people in fringe areas looking for cheap OTA TV, I would look into a=20 motorized antenna with a modified TV tuner as a spectrum analyzer, to=20 position antenna, record channel scan results, reposition, lather rinse,=20 repeat. > > A solar tracker would probably get better reception as a project if > I can provide a bit of mechanical assistance, plus there's a lot of other > electronics and principles involved in that for extra interest > >> What about optics? Lots of fun could be had shining a laser pointer >> at a mirror which can be positioned in 2 axis'. Shiny, too! > Spooky. Right at this very minute I'm making a laser display with 3 > computer fans under PIC PWM speed control > > A project I would like to put forward to them with a couple of > reservations > > 1) I'll have to look for a source of front-silvered mirrors. The ones > I've got were scavenged from a very old big-ass HP photocopier > which had several 10" x 2" mirrors. Modern scanners unfortunately > have only a single narrow strip. Traditional back-silvered mirrors > reflect but the image is very ghosty Prisms? Maybe they would be better for spectral analysis. Joe W --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .