[time-nuts] Re: Regarding GNSS antenna radomes... (Motorola Timing 2000...)

[Bill]

Hi,

The antenna phase center will vary depending on the angles of incidence 
- and timing will depend somewhat on this.  Phase center variation is 
mainly a function of antenna design, but radomes will affect this as 
well.  A good reference antenna will have a phase center that will 
remain within mm or sub mm over its main radiation lobe.


Cheers

Bill


On 07/08/24 09:03, Ulf Kylenfall via time-nuts wrote:
>   
>
>    
> Regarding these:
> It was disovered at the Onsala Space Observatory, that when using cones as radomes, the precisionof the timing/positioning signals was impaired by the uneven refractionof signals reaching the internal antenna structure from satellites of differentaltidudes/angles.
> This when using antennas from Leica. The internal structure of the offered items may of course be different.
>
> At the Onsala Space Observatory, the cones was replaced by spherical radomeswhich improved the performance both for Swepos (Swedens nationalgeographic positioning system) as well as the support structuresused for geodetic VLBI.
> A true time-nut will of course be exploring the use of spheres for his/hersown timing and frequency standard lab set up...
>
> :-)
>
> Cheers
> Ulf Kylenfall - SM6GXV
> SR Research Engr, (Ret)Onsala, Sweden.
>
>
>
>
>
>
>    1. Motorola Timing2000 GPS “L1” Antenna (Gregory Beat)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sat, 3 Aug 2024 09:45:39 -0500
> From: Gregory Beat <w9gb at icloud.com>
> Subject: [time-nuts] Motorola Timing2000 GPS “L1” Antenna
> To: time-nuts at lists.febo.com
> Message-ID: <A5EFC6E2-AF19-43B7-8BA1-7A2CDBF6C870 at icloud.com>
> Content-Type: text/plain;Â  Â  Â  charset=utf-8
>
> These Motorola brand GPS “L1” antennas (circa 2000) have appeared on the Surplus market (used, eBay, elsewhere), as Mobile/cellular sites perform upgrades.
> Prices / condition range from a Used few $$ to New in Box at $100 + .
>
> Electronic Goldmine (Scottsdale, AZ) has listed the Motorola Timing2000 GPS antenna (they don’t know model) and
> it’s matching Motorola Pole Mount at Electronics Surplus in Mentor, OH
>
> Motorola GCNTM20A3A : Timing2000 Antenna (Outdoor), Goldmine.
> https://theelectronicgoldmine.com/products/g28183
> <snip>
>      
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