[time-nuts] UCCM arrived

Chris Albertson albertson.chris at gmail.com
Sun Nov 27 01:31:36 EST 2016


Here is my take on this:  Why worry about a few dB of attenuation in the
cable when you have a 100% blockage problem for half the sky?

With GPS receivers, cable attenuation (within reason) is not important.
What matters is if you can see the satellites or not.  It is more of a
binary on/off kind of thing.   The data is digital, you either get the bits
or not.

So, by my above rule you only need to upgrade the cable if cable
attenuation is such that the signal is close to the receivers sensitivity.
  Even then you can usually find a higher gain antenna.   At some point
after maybe 50 meters of cable you might need to consider low loss cable

Nothing in the setup is more important that having an unobstructed view of
the sky

On Sat, Nov 26, 2016 at 6:18 PM, Bob Camp <kb8tq at n1k.org> wrote:

> Hi
>
> For a long term installation, an antenna location that will “see” more
> sat’s is a really good idea.
>
> Bob
>
> > On Nov 26, 2016, at 8:55 PM, Giuseppe Marullo <giuseppe at marullo.it>
> wrote:
> >
> > Hello to all,
> >
> > I connected the unit to a 11m of H-155 cable(assumed 4.79dB loss "worst
> case" at 1.5GHz), thrown the GPS antenna on the balcony horizontally and
> this is what I got:
> >
> > UCCM-P >SYSTem:STATus?
> >
> > ------------------------------------------------------------
> -------------------
> > 57964-80     serial number  87896988     firmware ver  2.0.1.6-01 LINK
>   mode
> > ------------------------------------------------------------
> -------------------
> > Reference Status __________________________   Reference Outputs
> _______________
> > XX Ref 8KHz 0: [Unusable]
> > XX Ref 8KHz 1: [LOS]                          TFOM 2            FFOM
>   0
> > XX Ref 8KHz 2: [LOS]                          UCCM A Status[ACTIVE]
> > XX Ref 8KHz 3: [LOS]
> > >> GPS: [phase:-1.2E-08]
> > ACQUISITION ...................................................[GPS
> 1PPS Valid]
> > Tracking: 4 ____   Not Tracking: 6 ________   Time
> ____________________________
> > PRN  El  Az  C/N   PRN  El  Az                GPS 23:42:46     26 Nov
> 2016
> > 24  45 139   43    25  57 286
> >  6  24  62   38    19  11  42                ANT DLY  -1 ns
> >  2  30 101   46    32  37 279                Position
> ________________________
> > 29  30 206   41    12  70  37                MODE     Hold
> >                    14  26 309
> >                    31   8 309                LAT      N 45:40:29.276
> >                                              LON      E 9:26:51.177
> >                                              HGT +320.96 m (MSL)
> >
> >
> >
> >
> > ELEV MASK  5 deg
> > ------------------------------------------------------------
> -------------------
> >
> > Command complete
> > UCCM-P >
> >
> >
> > Seems to work (? I understand this from GPS phase and FFOM 0, not sure
> about the hold position status) I have somewhat stable 10MHz output,
> tomorrow I will use a mast for the antenna to get it higher slightly above
> the roof, (vertically this time!).
> >
> > - I got the software from the seller but complains about some ancient
> OCX stuff don't want to mess with ActiveX anymore, hopefully Lady Heater
> will support it soon.
> >
> > - Given the attenuation (less than 5 dB) do I really need to change the
> cable for something better?
> >
> > Leds are Yellow Activity solid, red unnamed blinking fast,  Red 1PPS
> blinks once a second and DC green is solid.
> >
> > Anything else special to check?
> >
> >
> > Giuseppe Marullo
> >
> > IW2JWW - JN45RQ
> >
> >
> > PS: the other clock (qrp-labs) is way behind schedule, but hopefully
> will arrive soon
> >
> >
> > `
> >
> >
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-- 

Chris Albertson
Redondo Beach, California



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