Generally, it should work most of the time, which is probably good enough
to discipline your local standard.

Obviously, you want it above any foil backed insulation. Generally, near
the ridge would be good, as ridges don't get that much snow cover.

I've had a handhelg Garmin lock up OK in a lab on the top floor of a
house, just below a similar attic.

Generally, it probably won't be as good as outside on a pole, but it
should work well enough.

YMMV,

-John

=====================

I do not know about the Thunderbolt in particular but some GPS
receivers are more sensitive than others and will work acceptably like
you describe.  My house has similar construction and all of my GPS
receivers except maybe for my GPS18-5Hz hockey puck will operate in
the attic under the asphalt shingle roof.  My better ones will operate
with the one ceiling in the way as well.

On Sun, 25 Nov 2012 11:50:31 -0500, Peter Gottlieb nerd@verizon.net
wrote:

My main GPS receiver  used to see four to six satellites at a time when I
used an antenna near a window in my workshop in a singe story house. I moved
the antenna up into the attic near the peak, added 25 feet of TV cable, did
not add any amplification, and now my system acquires and tracks eight to
twelve satellites at a time. I did not want to move the antenna outside in
order to reduce the chance of roof leaks and to avoid having to provide
lightning strike protection. We do not get much, if any snow, and I have not
noticed any problems with rain.

John  WA4WDL

From: "Peter Gottlieb" nerd@verizon.net
Sent: Sunday, November 25, 2012 11:50 AM
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
Subject: [time-nuts] GPS antenna in attic?

On Sun, Nov 25, 2012 at 8:50 AM, Peter Gottlieb nerd@verizon.net wrote:

It will work but it will be far from optimal.  All you need to do is get a
big drill bit and  drill through the roof and put up an iron galvanized
pipe.  Put a pipe flange on the end and bolt the GPS antenna to that.  You
will need some metal flashing and roofing tar and then you will have a
first class setup.  You run the coax down the pipe.  The timing antennas
are pointed on top so snow falls off

Chris Albertson
Redondo Beach, California

There are ways to do it w/o drilling holes. Most all houses have vent
stacks for the plumbing, typically 3 or 4 inch cast iron or thick plastic.

You can clamp a couple of feet of pipe onto one of those and run the wire
to under an eve or through a gable end, adding a drip loop of course.

But, if it were my house and I just wanted to discipline my local
standard, I'd try the attic first. Among other things, you can get to the
antenna w/o climbing on the roof!

New England is not sunny CA.

-John

================

Another possible option is running the cable through the same hole in the roof as the vent pipe. Frequently (for bath exhaust vents and such) there is a ~4-8" tin or aluminum shroud & "hat" around the vent pipe, and in many cases, a gap between the pipe and roofing material (the shroud opening having a mesh to keep out critters). I used the gap to run my old Z3801A cable out before I had my roof replaced. I never replaced it because I upgraded to better cable, and it was too rigid for the old path (it had to bend enough to create a drip loop to keep the water out). I never did get around to rerouting the cable, so it's at ceiling level in the office. The performance is a little worse than I used to get but not bad enough to be a problem. In my case, the vent and main stack are about 2' apart, so mounting the antenna pipe (plastic) to the main stack worked nicely.

-Dave

----- Original Message -----
From: "J. Forster" jfor@quikus.com
To: "Discussion of precise time and frequency measurement" time-nuts@febo.com
Sent: Sunday, November 25, 2012 7:15:05 PM
Subject: Re: [time-nuts] GPS antenna in attic?

There are ways to do it w/o drilling holes. Most all houses have vent
stacks for the plumbing, typically 3 or 4 inch cast iron or thick plastic.

You can clamp a couple of feet of pipe onto one of those and run the wire
to under an eve or through a gable end, adding a drip loop of course.

But, if it were my house and I just wanted to discipline my local
standard, I'd try the attic first. Among other things, you can get to the
antenna w/o climbing on the roof!

New England is not sunny CA.

-John

================

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26/11/2012 08:56

I get a piece of fairly thin aluminium sheet and bend it so it slips
under one roof slate, up towards the ridge, and it has another small
downturn to hook over the top edge of the tile below, to stop the
ali sheet slipping down and out. The exposed edge of the sheet is bent so
it's horizontal. I mount the sensor on the horizontal bit, and the
lead goes through a gap between the tiles, or under a tile. The lead
is thin enough for this. No drilling, no potential water leaks. I have
mine alongside a skylight (Velux window) so I just reached through to
install it.

--
Best Regards,
Chris Wilson.

Hi

I've spent a lot of time putting a lot of antennas in attics of many houses. I can't say any of them "didn't work". However, I never was happy with the performance of any of them. Even a poorly located outdoor antennal outperformed them. … and yes I'm a member of the "no antennas outdoors club".

Bob

On Nov 25, 2012, at 10:15 PM, "J. Forster" jfor@quikus.com wrote:

Or install a frosted dome type skylight as a radome lights the attic and allows for better reception

Sent from my iPhone

On Nov 25, 2012, at 10:15 PM, "J. Forster" jfor@quikus.com wrote:

Or add vent pipe penetrations ~ 1.5" OD PVC pipe and put the GPS antenna
on top of the pipe.
Allows for vertical position variations. and the soft rubber gland
allows for changes later.

Had a new roof put on last year and I added 2 each of these plumbing
vent type roof penetrations.
Also added 6 each passive roof  vents to keep the heat down,
which could also be used for GPS antenna mounting and cable penetration.

Neither roof vents nor the GPS antennas (~ at ridge line) are visible
from the street.

Stan, W1LE

On 11/26/2012 9:22 AM, Scott McGrath wrote:

I considered that about 5 years ago when I reroofed. The roofing
contracctor told me that anything like a skylight is very, very hard to
make and keep leakproof. You really, really don't want a leaky roof.

-John

=================

The tax assessors count the vent pipes when trying
to guess at numbers of bathrooms, sinks, etc. in
your house.  Add too many, and you could be seeing
an increase in your tax bill.

-Chuck Harris

Stan, W1LE wrote:

They are no harder than a chimney to keep leakproof unless they are flush in which case everything said is true.  You need structure and a leakproof membrane and proper flashing to redirect water

Sent from my iPhone

On Nov 26, 2012, at 10:38 AM, "J. Forster" jfor@quikus.com wrote:

Skylights and such are easy to keep leakproof, but you do have to check the plastic parts every once in a while.  Years ago I installed one of those "sun-tunnel" type tubes for a small, windowless bath, and it worked great; however, about the time I replaced the roof, I discovered that the cover dome had cracks in it.  Not just hazing, but cracks you could easily force a finger into!  They had developed within the prior year, and when the rains began, they would have let the water in- not too much, but enough. 

When replacing the dome, I found that it had been acrylic, but a polycarbonate version was available for "harsh climates".  I ordered the latter, even though the helpfull "expert" said it was unnecessary. Yeah, right.

-Dave

----- Original Message -----

From: "Scott McGrath" scmcgrath@gmail.com
To: jfor@quikus.com
Cc: "Discussion of precise time and frequency measurement" time-nuts@febo.com
Sent: Monday, November 26, 2012 10:52:26 AM
Subject: Re: [time-nuts] GPS antenna in attic?

They are no harder than a chimney to keep leakproof unless they are flush in which case everything said is true.   You need structure and a leakproof membrane and proper flashing to redirect water

Sent from my iPhone

On Nov 26, 2012, at 10:38 AM, "J. Forster" jfor@quikus.com wrote:

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