<div dir="ltr"><div>Or how about better radio tracking gear that is not so susceptible to the LED interference?</div><div><br></div><div>It seems to me that an RTL SDR + a cellphone should be capable of doing the radio direction finding with heaps of filtering so that it ignored the LEDs.</div><div>Probably way cheaper than what they are using already.<br></div><div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Jun 26, 2019 at 12:57 PM Andrew Errington <<a href="mailto:erringtona@gmail.com">erringtona@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="auto">How about a simpler headlamp that is just a battery and incandescent bulb?<div dir="auto"><br></div><div dir="auto">Or one of these:</div><div dir="auto"><a href="https://en.m.wikipedia.org/wiki/Carbide_lamp" target="_blank">https://en.m.wikipedia.org/wiki/Carbide_lamp</a><br></div><div dir="auto"><br></div><div dir="auto">:)</div><div dir="auto"><br></div><div dir="auto">Andrew</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Jun 26, 2019, 12:45 Eliot Blennerhassett <<a href="mailto:ewblen@gmail.com" target="_blank">ewblen@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">On 26/06/19 12:10 PM, Volker Kuhlmann wrote:<br>
> On Wed 26 Jun 2019 10:42:47 NZST +1200, Bevin Brett wrote:<br>
> <br>
>> How easy would it be to shield a normal commercial head lamp?<br>
<br>
Note the original question is to shield a *normal commercial* lamp.<br>
<br>
Worth trying the foil...<br>
<br>
Also worth taking the receiver into the shop and comparing what kind of<br>
wideband RF crap is coming out of different lamps?<br>
<br>
<br>
As others have noted, all sorts of ideas come up if designing your own.<br>
<br>
My thought: put the battery pack and switcher inside a metal box in your<br>
pack, with ferrite etc on the DC output cable...<br>
<br>
<br>
> That'll be the switchmode converters. Does the lamp as a whole meet<br>
> regulatory EMC requirements...? ;-)<br>
> <br>
> Replace down regulator with linear regulator and add a heat sink. If it<br>
> has an up regulator you'd have to change the battery configuration<br>
> first.<br>
> <br>
> But you could also try the alu foil / metal mesh idea. You'd have to go<br>
> right up to the LED and leave the smallest hole possible there. <br>
<br>
> Relate<br>
> any hole size to the wavelength you're trying to shield (bird<br>
> transmitter frequency).<br>
<br>
The frequency will be VHF (around 160MHz)<br>
<br>
Ref:<br>
<br>
<a href="http://www.sirtrack.co.nz/index.php/terrestrialmain/vhf/receiversantennas" rel="noreferrer noreferrer" target="_blank">http://www.sirtrack.co.nz/index.php/terrestrialmain/vhf/receiversantennas</a><br>
<br>
<a href="http://www.sirtrack.co.nz/index.php/avian/vhf/leg-band" rel="noreferrer noreferrer" target="_blank">http://www.sirtrack.co.nz/index.php/avian/vhf/leg-band</a><br>
<br>
--<br>
Eliot<br>
<br>
<br>
<br>
_______________________________________________<br>
Chchrobotics mailing list <a href="mailto:Chchrobotics@lists.ourshack.com" rel="noreferrer" target="_blank">Chchrobotics@lists.ourshack.com</a><br>
<a href="https://lists.ourshack.com/mailman/listinfo/chchrobotics" rel="noreferrer noreferrer" target="_blank">https://lists.ourshack.com/mailman/listinfo/chchrobotics</a><br>
Mail Archives: <a href="http://lists.ourshack.com/pipermail/chchrobotics/" rel="noreferrer noreferrer" target="_blank">http://lists.ourshack.com/pipermail/chchrobotics/</a><br>
Meetings usually 3rd Monday each month. See <a href="http://kiwibots.org" rel="noreferrer noreferrer" target="_blank">http://kiwibots.org</a> for venue, directions and dates.<br>
When replying, please edit your Subject line to reflect new subjects.</blockquote></div>
_______________________________________________<br>
Chchrobotics mailing list <a href="mailto:Chchrobotics@lists.ourshack.com" target="_blank">Chchrobotics@lists.ourshack.com</a><br>
<a href="https://lists.ourshack.com/mailman/listinfo/chchrobotics" rel="noreferrer" target="_blank">https://lists.ourshack.com/mailman/listinfo/chchrobotics</a><br>
Mail Archives: <a href="http://lists.ourshack.com/pipermail/chchrobotics/" rel="noreferrer" target="_blank">http://lists.ourshack.com/pipermail/chchrobotics/</a><br>
Meetings usually 3rd Monday each month. See <a href="http://kiwibots.org" rel="noreferrer" target="_blank">http://kiwibots.org</a> for venue, directions and dates.<br>
When replying, please edit your Subject line to reflect new subjects.</blockquote></div>