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:
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
I’d go one step further. In the event the anchor is not rust proof, after final assembly I’d coat the metal tightening nut of GNSS antenna and part of the threaded area with a thick layer of silicone rubber GE 25yr etc. it will make dissemble much easier down the road.
Don Resor
Sent from someone's iPhone
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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On 7/4/23 1:22 AM, Matt Huszagh via time-nuts wrote:
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.
how big of an antenna? A small "hockey puck" or a big choke ring?
What's the roof surface?
I found a method described by sparkfun that involves using an anchor in
a cinder block:
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?
that works. There's quite a few fairly large antennas on flat roofed
buildings where there's a kind of metal "tripod" weighted down with
bricks or cinder blocks. If you look for what are called "no penetration
antenna supports" you'll get lots of hits.
I've used silicone caulk to "glue" a bracket to a roof tile (concrete
tile roof).
Matt
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Not wanting to drill holes in my roof, I screwed the X bracket that comes with a Starlink V2 (rectangle ~ 12x19 “dish”) to a rectangle made of 2x4 wood and set quantity four 4x8x16 solid cinder blocks on it.
That’s probably overkill, but being the dish can autonomously reposition and it doesn’t seem to position itself horizontal, bird bath style I’d prefer overkill.
The treated wood has a nice friction surface against the shingles.
The phased array being essentially the whole satellite terminal less the indoor power supply would make it costly to replace.
If I were using a ~ 60-100 USD L1L2 patch antenna, I’d probably make some sort of bracket that takes a single solid 4x8x16 cinderblock. If using a larger 18 inch diameter ground plane or a choke ring style antenna that was significantly more expensive to replace, I’d probably opt for at least two.
For me, it depends on what’s on hand for a suboptimal solution versus the mental time and energy to fabricate a more optimal solution. I’m probably not going to setup jigs and weld up just one bracket.
From: Matt Huszagh via time-nuts time-nuts@lists.febo.com
Sent: Tuesday, July 4, 2023 3:22:53 AM
To: Discussion of precise time and frequency measurement time-nuts@lists.febo.com
Cc: Matt Huszagh huszaghmatt@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:
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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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@hotmail.com
"Peace is not the absence of violence, but the presence of Justice" Both MLK and Albert Einstein
From: Matt Huszagh via time-nuts time-nuts@lists.febo.com
Sent: Tuesday, July 4, 2023 2:22 AM
To: Discussion of precise time and frequency measurement time-nuts@lists.febo.com
Cc: Matt Huszagh huszaghmatt@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:
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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To unsubscribe send an email to time-nuts-leave@lists.febo.com
Hi
“Best” pretty much always means tied to something solid. Anything that is sitting
on a deck / porch / patio is at risk of getting displaced somehow.
An alternative to the concrete block is a patio umbrella stand. They come in a variety
of sizes / shapes and weights. The advantage to using them is they already have
a nice tube up the middle to put a mast into. They also have a reasonably low profile
(other than the mast). In some cases that might make them less likely to “wander”.
Any time you put anything down on a roof, it’s best to do some research on how well
the covering that’s there will handle it. There may be reasons to put some sort of pad
between the antenna mount gizmo and what’s there.
Bob
On Jul 4, 2023, at 4:22 AM, Matt Huszagh via time-nuts time-nuts@lists.febo.com wrote:
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:
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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Hi
So, what really matters here?
Number one is coverage. How much of the sky can you see from the antenna? The more
the better. Exactly how you dimension “more” depends on the GNSS system you are tracking.
Next may well be the quality of the antenna. How that is “dimensioned” depends a lot on
the bands you are after and what you will do with the data.
After that comes fun stuff like stable mounts.
The list does go on a bit from here ….
Getting to “best” will always be a combination of things.
Bob
On Jul 4, 2023, at 6:57 AM, Don R via time-nuts time-nuts@lists.febo.com wrote:
I’d go one step further. In the event the anchor is not rust proof, after final assembly I’d coat the metal tightening nut of GNSS antenna and part of the threaded area with a thick layer of silicone rubber GE 25yr etc. it will make dissemble much easier down the road.
Don Resor
Sent from someone's iPhone
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
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
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If you want to go bonkers, there are a number of in-depth documents that
describe locating and mounting GNSS antennas produced by the various bodies
overseeing CORS networks:
https://www.gps.gov/cgsic/meetings/2009/martin.pdf
https://geodesy.noaa.gov/PUBS_LIB/CORS_guidelines.pdf
And if you live in Antarctica, here is a guide just for you:
https://www.geoscience.scar.org/geodesy/monument/guidelines.htm
- Keelan
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
Matt Huszagh via time-nuts writes:
I'm intrigued by the patio umbrella stand idea.
I did that some years back when I built the Chris Trask Monopole antenna.
I used a cheap water-filled plastic parasol stand and added some antifreeze
to the water: Worked great.
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