[time-nuts] Effects of Simple GPS jamming on GPSDO's ?

Mark Goldberg marklgoldberg at gmail.com
Sat Sep 1 11:43:12 EDT 2018


On Sat, Sep 1, 2018 at 3:49 AM, Dana Whitlow <k8yumdoober at gmail.com> wrote:
>
> Question for Mark re metal foil under the antenna:
>
> What's the nature of the improvement?  Between the large tilt angle and
the
> shape of the
> foil piece, I'd certainly not expect any material improvement in the
> multi-path department.

It's just a ground plane. Having a ground plane under the antenna improved
signal strength by 5-10 dB over just putting the antenna in the window.
I covered a box to get the antenna up a little higher and to have the
ground plane be bigger than 1/4 wave at the L1 frequency. It's ugly but it
works.
It's for a Trueposition GPSDO, not that sensitive. Mounting the antenna
inside did not work well.

I've also been known to hold my phone in the upper corner of the balcony on
a cruise ship to use it as a corner reflector to catch wifi from shops on
the dock. That worked surprisingly well too.

>
> Also, are the Venetian blinds seen in the photo made of metal, or plastic
> (or wood)?
> Is there a screen on the window?  If so, ditto question regarding the
> composition.
>

The blinds are metal. There is no screen in the window, which also made a
huge improvement over windows with metal screens.

Regards,

Mark


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