-Original Message-
From: Robert Darlington
Sent: Tuesday, March 12, 2013 5:49 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Interesting looking crystal on ebay
I ended up buying this as I've wanted one for a while. It arrived today
and I swept it w
I ended up buying this as I've wanted one for a while. It arrived today
and I swept it with the network analyzer. At whatever temperature my shop
was at the time I took the measurement, it had a sharp insertion loss at
10.000233MHz. Pretty cool. I can post plots if there is any interest or
just
Hi
CDMA should be good to ~0.0001 ppm when running normally. The driver there is
holdover rather than transmit accuracy. The carrier comes from the same source,
so the accuracy is "free". CDMA is all over the place….
A cheap GPS receiver sounds like a much better solution for NTP. Far more
tru
http://www.evrytania.com/lte-tools/lte-cell-scanner
claims the LTE reference is good to 0.05PPM.
I can verify that 739MHz and 751MHZ are the only LTE frequencies I found
in use in the 700MHz band in the San Francisco Bay Area.
If you want to use the software, I suggest trying 739MHz and 751MHZ
Hi
A few numbers on the 10 (or 5) MHz to 100 MHz stuff:
The most likely frequency range is 100 Hz to 100 KHz. That covers CW
operation/filters as well as reasonable adjacent channel issues on SSB.
At 10 KHz and beyond you likely will be at floor on your 100 MHz oscillator.
With a good design
Hi Ed:
I have a little info at:
http://www.prc68.com/I/Trimpack.shtml#4000
Have Fun,
Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
Ed Breya wrote:
I recently acquired a junker Trimble 4000S GPS surveying unit. It's mid-1980s technology, so very big, but
> >
> > With most modern lightweight Rb's the OCXO is integrated into the same
> heater block as the physics package. That makes it a bit tough to heat one
> without heating the other. .
>
> On LPROs the OCXO sits on the opposite side of the board.
Pretty sure that's not an OCXO. If it is, it's
Hi
The other point that could be made is:
In a contest situation, you have a lot of stations to net to. You really
aren't worried about the stability over 48 hours. You really are concerned
about drift since your last set of contacts. If it takes you an hour or less
to get to your next site, tha
On 3/11/13 6:49 AM, James Peroulas wrote:
Date: Sun, 10 Mar 2013 17:37:13 -0700
From: gary
To: time-nuts@febo.com
Subject: Re: [time-nuts] frequency reference for portable operation
Message-ID: <513d2739.8030...@lazygranch.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
I have
>
> Date: Sun, 10 Mar 2013 17:37:13 -0700
> From: gary
> To: time-nuts@febo.com
> Subject: Re: [time-nuts] frequency reference for portable operation
> Message-ID: <513d2739.8030...@lazygranch.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> I haven't researched this yet, but
Hi
So all you have to do is figure out when the physics package is hot enough
for the line spreading to work well enough to get a lock...
Bob
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Magnus Danielson
Sent: Monday, March 11, 2013
On 11/03/13 12:42, Bob Camp wrote:
Hi
With most modern lightweight Rb's the OCXO is integrated into the same heater
block as the physics package. That makes it a bit tough to heat one without
heating the other. …
On LPROs the OCXO sits on the opposite side of the board.
Cheers,
Magnus
_
Hi
With most modern lightweight Rb's the OCXO is integrated into the same heater
block as the physics package. That makes it a bit tough to heat one without
heating the other. …
Bob
On Mar 11, 2013, at 7:03 AM, Magnus Danielson
wrote:
> On 10/03/13 16:17, Bob Camp wrote:
>> Hi
>>
>> Rememb
Hi
I would not depend on the 10 MHz reference for my phase noise floor at
microwaves. I'd do as Bert suggested and lock up a quiet 100 MHz oscillator to
the 10 MHz. The "best of the best" 10 MHz OCXO isn't going to be able to beat a
100 MHz over a 100 Hz to >=10 KHz bandwidth. The 100 MHz likel
On 10/03/13 16:17, Bob Camp wrote:
Hi
Remember - OCXO's are going to be acceleration sensitive. As you bump about on
back roads, the oscillator is likely moving around by a few ppb. If you are
after a hertz at 10 GHz, that's a lot.
Your GPS will be off by a fairly predictable amount based on
I do the stuff on your list that is easy. Controlling the environment --
orientation, ambient temp, etc. -- is not worth the extra effort. Much
of what I discussed is that perfection isn't necessary.
The quality of the oscillator probably matters a good bit, but recently
I am learning, don't
On 3/10/2013 6:10 PM, Hal Murray wrote:
r...@sonic.net said:
or if you have a beacon in range that you can find to establish your
offset.
What do you do after you determine the offset?
Do you tweak it out with a trimmer (R or C)? Or tell the software? Or do
the corrections with pencil and pa
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