[time-nuts] sub cables
bruce.griffiths at xtra.co.nz
Thu May 1 17:08:48 EDT 2008
Neon John wrote:
> On Thu, 1 May 2008 11:13:48 +0100, "Alan Melia" <alan.melia at btinternet.com>
>> At least with the optical cables it is only the powerfeed circuit that gets
>> the surge not the amplifier front end as it was in the FDM systems.
>> I always thought the terminal equipment was a slighly lower reliability
>> requirement than the submerged parts but these days the loss of revenue even
>> with an easily accessed terminal is very high.
> Now I'm curious how power is tapped off at each repeater point. I understand
> the daisychain architecture but I'm wondering about the details, what
> components can withstand the intial high voltage surge as the cable is
> charging and how the voltage drop at each repeater is maintained relatively
> constant, even if the repeater fails and quits consuming power.
> Also, is it true that an optical cable will keep working with a single
> repeater failure, that the laser light will pass through unamplified? Seems
> like I read that somewhere but I'm not sure.
> John De Armond
Try a shunt regulator.
This works well because of the constant current feed.
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