[time-nuts] NTBW50AA Power Consumption

GandalfG8 at aol.com GandalfG8 at aol.com
Tue Sep 10 05:48:25 EDT 2013


I've monitored the power input against voltage for a couple of the uncased  
versions of these units, both fitted with Datel TPB-5/5-12/1-Q48 power  
converters and both well "warmed up", and it does increase somewhat with  
increasing input voltage. 
 
On both units the input power to the DC to DC converter is  approximately 
500 to 600 mW higher at 48 Volts than it is at 24 Volts, just  for reference 
that was with an ambient temperature of around 23 to 24  degrees C, and the 
change does seem to be reasonably linear with respect to  voltage.
As would be expected there's very little change in the output voltages so  
this does represent extra dissipation within the converter itself.
 
Using identical Motorola patch antennas one unit consumes approx 6.30W  at 
24V and 6.85W at 48V with the other consistently 200mW lower across the  
range.
Switching over to a couple of Symmetricom timing antennas, for  example, 
increased the input power in each case by approx 200mW.
 
This does suggest there is actually some benefit to be gained by  running 
them at the lower voltage, but if this sort of  difference really becomes all 
that significant then perhaps it might  also suggest a need for heading 
back to the drawing board:-)
 
Regards
 
Nigel
GM8PZR
 
 


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