[time-nuts] Re: Rooftop GNSS antenna mounting recommendations

[Tom Knox]

Hi Matt;
I am most likely stating the obvious, but the important considerations are to place the antenna with an unobstructed view of the sky from roughly 15 degrees above the horizon up. Height is not important like terrestrial antennas, and can actually be counterproductive exposing the antenna to more terrestrial interference. The other very important consideration is coaxial length should be as short as possible.
Additionally using a very low loss cable such as Andrews Helix will make a big difference.
If you are located near obstructions that could potentially cause reflections and multipath there are occasionally affordable Choke Ring antennas to be found which are designed to cancel low angle reflections. GPS antennas are often overlooked since even an antenna placed inside and building or home will see enough satellites for the receiver to lock. But the first link in the low uncertainty chain is providing a clean GPS signal to your receiver.
Enjoy;
Tom Knox
SR Test and Measurement Engineer
Phoenix Research
4870 Meredith Way Apt 102
Boulder, Co 80303
Formerly of:
357 Fox Lane
Superior Co 80027
303-554-0307
actast at hotmail.com

https://www.thedenverchannel.com/news/marshall-fire/superior-man-moving-forward-after-losing-dream-research-lab-during-marshall-fire

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________________________________
From: Matt Huszagh via time-nuts <time-nuts at lists.febo.com>
Sent: Tuesday, July 4, 2023 2:22 AM
To: Discussion of precise time and frequency measurement <time-nuts at lists.febo.com>
Cc: Matt Huszagh <huszaghmatt at gmail.com>
Subject: [time-nuts] Rooftop GNSS antenna mounting recommendations

Hi,

I'll be mounting a GNSS antenna to my roof for timing applications and
would appreciate recommendations for the best way to do this. The
portion of the roof where the antenna will be mounted is flat. I'd
prefer to avoid drilling or screwing into the roof if possible. But, if
there's a safe and reversible way to do this, I'm ok with that.

I found a method described by sparkfun that involves using an anchor in
a cinder block:

https://learn.sparkfun.com/tutorials/how-to-build-a-diy-gnss-reference-station/all#affix-your-antenna

This seems like an easy and low-cost method. Given the weight of the
cinder block, I wouldn't expect the antenna to move. Thoughts? Any
potential problems with this? Other methods that work well?

Matt
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