[chbot] Chchrobotics Digest, Vol 141, Issue 4

[Eliot Blennerhassett]

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