[time-nuts] time-nuts Digest, Vol 104, Issue 37
jimlux at earthlink.net
Mon Mar 11 10:13:10 EDT 2013
On 3/11/13 6:49 AM, James Peroulas wrote:
>> Date: Sun, 10 Mar 2013 17:37:13 -0700
>> From: gary <lists at lazygranch.com>
>> To: time-nuts at febo.com
>> Subject: Re: [time-nuts] frequency reference for portable operation
>> Message-ID: <513D2739.8030107 at lazygranch.com>
>> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>> I haven't researched this yet, but the SDR crowd is using GSM and LTE
>> for tuning their sample clocks.
>> I have no idea what kind of accuracy you can get from a tower.
> GSM and LTE (and WCDMA and TD-SCDMA for that matter) are spec'd for 50 PPB
> accuracy. However, these networks are 'often' synchronized to an external
> reference which would presumably be GPS. This would give better long term
> accuracy, but the short term accuracy would depend on the actual
> implementation of the basestation.
> P.S. I'm the author of LTE-Cell-Scanner.
There might also be a problem getting a decent signal at some of the
locations (remote mountain tops for instance). For several years, we
did JPL Amateur Radio Club Field Day up on top of Mt Gleason, and it
was notorious for no cell coverage. (I suspect it's better today..
that was at least 6-7 years ago)
But a battery powered OCXO seems to be a "good enough" and self
contained as well.
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