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

[Bob Camp]

Hi

As long as you can keep the antennas low and small ( as in a foot high and the pinwheel ), 
the typical cast metal versions at ~20 pounds should work. 

https://www.amazon.com/Topeakmart-22lbs-Umbrella-Outdoor-Garden/dp/B08Y1C6WTL/ref=sr_1_8?crid=1FRJVHF6DMH6V&keywords=patio+umbrella+stand&qid=1688829480&sprefix=patio+umbrella+stand%2Caps%2C110&sr=8-8

You can get some versions that you fill with sand. They allow you to get up into the 50 pound 
range. That should be ok for a full up choke ring at the same sort of height. 

https://www.amazon.com/Simple-Deluxe-Round-Heavy-Umbrella/dp/B09S9YPC9W/ref=sr_1_15?crid=1FRJVHF6DMH6V&keywords=patio+umbrella+stand&qid=1688829480&sprefix=patio+umbrella+stand%2Caps%2C110&sr=8-15

GPS antennas typically are set up to screw into “survey poles”. 

https://www.amazon.com/Extending-Surveying-Section-Rotating-surveying/dp/B09T5SCD1S/ref=sr_1_16?crid=A51HREEIDL6U&keywords=survey+pole&qid=1688829900&sprefix=survey+pole%2Caps%2C126&sr=8-16

You can get them in all sorts of lengths and colors. You also can get “kits” that have many 
sections and cost quite a bit less per section.  I use those sections for multiple antennas rather 
than putting an antenna up higher. 

The survey poles are a bit smaller in diameter than the typical patio umbrella. Some amount of 
shimming may be needed to clamp them into the stand. 

With asphalt shingles some sort of rubber mat is a good idea. The shingles do a lot better with
some sort of spacer between them and a weight. 

A simple test once you get it up there: give it a bit of a shove. If it moves more than you think it
should, go find some sand bags and put them on the stand. I’ve never had one go wandering 
when used as an antenna mount (and never needed additional weight). 

If you can rope it off to something structural, there’s no downside to that. In the event of an
issue it likely would help. 

Keep in mind, this is all assuming the roof is dead flat / horizontal.

Bob

> On Jul 6, 2023, at 1:07 PM, Matt Huszagh via time-nuts <time-nuts at lists.febo.com> wrote:
> 
> Thanks for the recommendations everyone.
> 
> Here are answers to some of the questions raised:
> 
> I'll probably mount two antennas as far separated as I can make them
> (and obviously on separate mounts). One antenna is a Trimble choke ring
> (L1/L2) and the other antenna is a Novatel pinwheel (L1, L2, L3, L5, B1,
> B2, E1 and E5a/b).
> 
> The roof material is asphalt shingle.
> 
> My roof is one of the tallest in the area and mostly the surrounding
> trees are about the same height or lower and far enough from my house.
> 
> I'm in Oakland, CA, about 38deg latitude. We get storms here, but
> certainly nothing tropical. Snow is pretty rare and generally not much
> when it happens.
> 
> The elevation is just a bit above sea level. The house is reasonably
> tall, but nothing out of the ordinary.
> 
> I'm intrigued by the patio umbrella stand idea. That seems like it would
> be a bit better/easier than the cinder block. Assuming the antennas are
> max a few feet off the roof, what's the ballpark minimum weight I would
> need?
> 
> Matt
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