[chbot] Chchrobotics Digest, Vol 141, Issue 4

[Charles Manning]

Or how about better radio tracking gear that is not so susceptible to the
LED interference?

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.
Probably way cheaper than what they are using already.


On Wed, Jun 26, 2019 at 12:57 PM Andrew Errington <erringtona at gmail.com>
wrote:

> How about a simpler headlamp that is just a battery and incandescent bulb?
>
> Or one of these:
> https://en.m.wikipedia.org/wiki/Carbide_lamp
>
> :)
>
> Andrew
>
> On Wed, Jun 26, 2019, 12:45 Eliot Blennerhassett <ewblen at gmail.com> wrote:
>
>> On 26/06/19 12:10 PM, Volker Kuhlmann wrote:
>> > On Wed 26 Jun 2019 10:42:47 NZST +1200, Bevin Brett wrote:
>> >
>> >> How easy would it be to shield a normal commercial head lamp?
>>
>> Note the original question is to shield a *normal commercial* lamp.
>>
>> Worth trying the foil...
>>
>> Also worth taking the receiver into the shop and comparing what kind of
>> wideband RF crap is coming out of different lamps?
>>
>>
>> As others have noted, all sorts of ideas come up if designing your own.
>>
>> My thought: put the battery pack and switcher inside a metal box in your
>> pack, with ferrite etc on the DC output cable...
>>
>>
>> > That'll be the switchmode converters. Does the lamp as a whole meet
>> > regulatory EMC requirements...? ;-)
>> >
>> > Replace down regulator with linear regulator and add a heat sink. If it
>> > has an up regulator you'd have to change the battery configuration
>> > first.
>> >
>> > But you could also try the alu foil / metal mesh idea. You'd have to go
>> > right up to the LED and leave the smallest hole possible there.
>>
>> > Relate
>> > any hole size to the wavelength you're trying to shield (bird
>> > transmitter frequency).
>>
>> The frequency will be VHF (around 160MHz)
>>
>> Ref:
>>
>> http://www.sirtrack.co.nz/index.php/terrestrialmain/vhf/receiversantennas
>>
>> http://www.sirtrack.co.nz/index.php/avian/vhf/leg-band
>>
>> --
>> Eliot
>>
>>
>>
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