Re: HP 10811-60111 info

Talbot Andrew <actalbot@...>

 All GPS modules you can buy off-the-shelf have a 1 PPS output.  If you are using that to lock a good OXCO then expect a lock up time of a few  minutes to several hours depending on how you want to trade off the PLL parameters, trading instantaneous frequency accuracy against lockup.  I believe the CT1 design allows you to customise the loop parameters as you want.

GPS receivers themselves give a short term timing variation of a few parts in 10^-9 over tens of seconds to minutes so for microwaves, at least above 5.7GHz, its nice to smooth this out otherwise you'll end up with a tone that wanders just about audibly.  A

THe Motorola Oncore in many of its variants (M12, GT, UT) is one of the easier to drive modules, as is the Garmin Family (GPS25, 35).  The Jupiter-T has a 10kHz output which makes frequency locking a lot simpler, but it not such a nice board to drive if you are interresteed in the data from it.

Take a look at the presentation I gave to the HFC a few weeks ago on using GPS.  

It can be found at:


Andy  G4JNT

 -----Original Message-----
From: G0RUZ Conrad [mailto:conrad@...]
Sent: 26 October 2005 19:31
To: ukmicrowaves@...
Subject: [ukmicrowaves] HP 10811-60111 info

Hello I recently purchased an HP 10811-60111 OXCO from eBay and would like
to commence work on locking it to GPS. I have a CT1DMK gen-lock board from
John G8ACE and I would like to find a suitable GPS RX. Do they all output 1
pps and if so how lock does it take to achieve stability in practice?

The HP OCXO came on a board marked D42903F 05328-20027 does anyone have
details of this board or at least the connections for the edge connector? I
hope to build a nice reliable 10 MHz source and then lock all my transverter
local oscillators to this. When the crystals arrive I should have OCXOs for
13 and 3cms to start with.


Conrad G0RUZ

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