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Re: [Discuss-gnuradio] Mobile Power Supply for USRP
From: |
Greg Troxel |
Subject: |
Re: [Discuss-gnuradio] Mobile Power Supply for USRP |
Date: |
Wed, 09 May 2007 11:45:13 -0400 |
User-agent: |
Gnus/5.110007 (No Gnus v0.7) Emacs/21.4 (berkeley-unix) |
Matt Ettus <address@hidden> writes:
> Daniel O'Connor wrote:
>>
>> I think you could use DC-DC converter that outputs 5V.
>>
>> The dropout on the regulator used is 1.5V, and 3.3 + 1.5 = 4.8V. Not
>> a lot of headroom but it should work OK.. Right? :)
>
> Most of the daughterboards regulate the 6V down to 5V, so you really
> need about 5.5 to 5.75 V to operate correctly.
>
> Matt
I don't mean to question Matt's advice, but I'll note that we used 12-5V
DC-DC converters at BBN (from a lead-acid battery, no vehicle charging
while in use), and found that the 802.11 receive performance only
dropped a dB or so compared to the wall wart supply. So I concluded
that it hurt us, but didn't kill it, but since this is clearly on thin
ice at best you really should get a 6V output converter.
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