[time-nuts] Power supply for Thunderbolt
Dave Brown
tractorb at ihug.co.nz
Sun Aug 10 01:30:34 EDT 2008
----- Original Message -----
From: "John Miles" <jmiles at pop.net>
To: "Discussion of precise time and frequency measurement"
<time-nuts at febo.com>
Sent: Friday, August 08, 2008 1:21 AM
Subject: Re: [time-nuts] Power supply for Thunderbolt
>
>>
>> It would be interesting to see how the 'red panel' Thunderbolts
>> (the
>> packaged type that run from an included switching supply fed from
>> 24
>> VDC) perform under a test regime such as that TVB used to compare
>> various three rail power supplies. In 'distant past' posts, maybe
>> 18
>> months back, it was suggested that this supply is a particularly
>> good
>> performer, but IIRC no data was supplied to support this statement.
>> Anyone able to oblige?
>
> This (cluttered) graph is indicative of the results I've seen. The
> Lucent
> supply used in the older red-and-black labelled Thunderbolts was not
> very
> clean, and its proximity and orientation adjacent to the
> Thunderbolt's PCB
> didn't help.
>
> Red = the new ("TAPR") Thunderbolt with my old Thunderbolt's Lucent
> supply
> Blue = the old Thunderbolt with its Lucent supply
> Orange = the new Thunderbolt with the supply Tom chose
> Purple = the old Thunderbolt with Tom's supply
>
> The reference for the red trace was somewhat noisier below 100 Hz
> than the
> one used for the others. You should assume that the red trace
> coincides
> with the orange one below 100 Hz.
>
> -- john, KE5FX
Tnx John-looks like the included power supply was not a great
performer in this regard.
DaveB, NZ
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