E-Tag

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Originally Posted by X000BOSS

lol... i thought the beep coming out of the unit would tell a retired techie that there is some sort of battery in there.

Is that right lol!! so tell me how a crystal radio works driving a set of headphones WITHOUT A BATTERY it uses power from radio waves in other words Induction through a coil between the antenna and ground
then again I must be wrong

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[Ghiadude]

As far as im aware they are RF ID type tags and as such are passive devices(no battery but i could be wrong)

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Originally Posted by Ghiadude

As far as im aware they are RF ID type tags and as such are passive devices(no battery but i could be wrong)

Correct now this is not the type I have used but it shows you what I mean the one I have used is a very thin metal wafer http://www.jaycar.com.au/productView...T&SUBCATID=291

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[Zippy7]

Just to add to the comments

A) If you have registered your numberplate with the e-tag, then even if it doesn't beep properly, they will match it back and not charge you any more. I had registered my father's car with my e-tag (before he got his own).
After he got his own, he was stubborn and would not fix it to his windscreen. So when it failed to register, his charge would appear on my account (no penalty fee, just a standard Sydney Harbour Bridge charge).
After a few statements with his charges, I got sick of it and removed his number plate from my account.

B) My father has since changed cars and has a new stubborn place to put his e-tag. He puts it in a dash-drawer, and pops it open when he drives through the gantry area. It generally works on RTA Toll roads, but sometimes it doesn't, but no extra charges!

I reckon you should just test out the sunglass holder placement and see what happens when you cross the bridge next time.