[time-nuts] GPS Antennas

[Bob kb8tq]

Hi

The gotcha with putting anything on top of a GPS antenna is that it impacts the phase 
shift from the sat’s. How important that is gets quickly into just how picky you happen to be.

Bob

> On Sep 6, 2019, at 11:07 AM, Nick Sayer via time-nuts <time-nuts at lists.febo.com> wrote:
> 
> I’m late to the party, but my go-to antenna is the Gilsson marine antenna. If it has a downside, it’s that it has a flat top instead of a cone. I’ve got one mounted outside at our vacation home near Lake Tahoe, so we’ll see whether snow loading becomes a problem shortly. The fix would presumably just be a 3D printed plastic gnome’s cap, though even that might not be useful if we get snow like we did last year.
> 
> It has a standard 14 tpi 1” standard thread, though I’ve managed to make do on more than one occasion with 3/4” NPT.
> 
> Under normal circumstances, I routinely get 8 or more satellites with the top SNRs in the 50s.
> 
> I designed a 3D printed mount for mounting it on a flat surface (which I needed to do here): https://www.thingiverse.com/thing:3664978 <https://www.thingiverse.com/thing:3664978>.
> 
> 
> 
>> On Aug 30, 2019, at 11:35 AM, Denny Page via time-nuts <time-nuts at lists.febo.com> wrote:
>> 
>> Could be. They sell a aluminum mounting rod for use with a magnetic base which mates with the unit perfectly, so I sorta assumed it was intentional. Tapering helps prevents over tightening / over extension which could damage the casing.
>> 
>> Denny
>> 
>> 
>>> On Aug 30, 2019, at 10:49, Bryan _ <bpl521 at outlook.com> wrote:
>>> 
>>> Or a mfg. defect and thus why on the surplus market.
>>> 
>>> -=Bryan=-
>>> 
>>> ________________________________
>>> From: time-nuts <time-nuts-bounces at lists.febo.com> on behalf of Denny Page via time-nuts <time-nuts at lists.febo.com>
>>> Sent: August 29, 2019 7:39 PM
>>> To: Discussion of precise time and frequency measurement <time-nuts at lists.febo.com>
>>> Cc: Denny Page <dennypage at me.com>
>>> Subject: Re: [time-nuts] GPS Antennas
>>> 
>>> I think several people have run into that issue, including myself. It seems designed for a slightly tapered rod. Easy to fix with the right tool.
>>> 
>>> Denny
>>> 
>>>> On Aug 29, 2019, at 16:41, Ben Hall <kd5byb at gmail.com> wrote:
>>>> 
>>>> Only issue with mine was that the thread wasn't fully cut, so I modified an old taper tap to be a bottoming tap with the bench grinder and finished tapping the hole to the bottom.
>> 
>> 
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