Chris,

You would be better off having the T'boldt inside and just run more coax cable to
the antenna.  The T'boldt is not weather protected in any way, so having it
exposed to the elements is definitely not a good idea.  As for the outside
location, you want as much South facing clear view that you can get.

Also, you will want to isolate the T'boldt from gross ambient temperature
shifts.  For instance, house it inside of a Styrofoam container such as a those
cheap 6 pack beer ones you can get a the grocery store.  You can leave the power
supply outside of the container.

Bill....WB6BNQ

Chris Wilson wrote:

I did about the same thing, added some long some long cables but did it
differently.  You can better performance if the T-bolt is in a space where
the temperature is controlled.  ANY place is better than an attic which has
hot in the day and cold at night.  My T-bolt is on the top shelf of a
walk-in closet housed with its power supply in a plastic case that has some
vents.  The temperate in the box remains stable.

What I'd suggest in your case is moving the t-bolt to a living space in the
house and using a longer antenna lead.  You can make the antenna lead as
long as you like.  If you go over say 100 feet then you'd ned a higher
gain antenna but it can work with cables even longer.

On the other end the cable carrying the PPS can be long, but remember to
terminate it if you use a long coax.  How long the RS232 can be depends a
little bit not the quality of the serial port on the computer.  Many are
"fake rs-232" and use TTL voltages.  With extenders can be any length you
like.  I was able to go 50 feet using a serial cable I made with cat-5
network cable.  The PPS did NOT do well at all using 50 feet of that
cable.

As I said, I found after experiments the the t-bolt is best located closer
to where it is unneeded and in heated living space.  Antenna cable is
cheap.  Use that 75 Ohm cable TV stuff.

On Sun, Jun 10, 2012 at 2:30 PM, Chris Wilson chris@chriswilson.tv wrote:

--

Chris Albertson
Redondo Beach, California

Hi Chris,

Even if this is the datasheet of a later version, it gives an overall
picture of what you ask about.

http://trl.trimble.com/docushare/dsweb/Get/Document-383329/022542-010B_Thunderbolt-E_DS_0807.pdf

The Tbolt perform (even) better with stable temperature surroundings. 3m
of antenna cable is no problem. Antenna position is more important than
the exact type of antenna. I'd rather have a decent antenna at a very good
site, than a very good antenna at a slightly worse antenna site.

My Tbolt with internal 24VDC PSU draws 200mA at 24V -> ca 5W. This is in
steady state at about 22C.

--

Björn

Hi

Get a chunk of RG-6 quad shield satellite TV coax from your local big box store. If the TBolt is 50' away from the antenna that's fine. Unless you have a very unusual home, you should be able to hit the antenna with 50' of cable. As others have said, you want the TBolt in a well controlled environment.

Bob

On Jun 10, 2012, at 5:30 PM, Chris Wilson wrote:

On Sun, Jun 10, 2012 at 2:50 PM, bg@lysator.liu.se wrote:

3M is trivial.  30M will work fine too.

I agree about the location really mattering more than anything else.  What
I did was drill a 2" hole through the roof up from the attic and push a 10
foot gallanvised iron plumbing pipe up.  The antenna sits on thop ithe
pipe and is higher then the roof top ridge and then the cable go down the
center of the pipe.  I pipe flange on top  of the pipe makes a perfect
mounting platform.  I used a timing antenna comes inside a white pointed
plastic radome.  These sell for just under $30 on eBay.  Maybe it is
coincidence or not but the four holes pin the standard pipe flange match up
with the four holes in the bottom of my antenna and there is enough room
inside the hole in the center for an "N" connector.  It is worth getting
the antenna "done right" because it is the most important part of the
entire system.    Those dome type antenna are worth it.  the shape is
designed to shed both bird poop, and snow.  Birds can be an issue with a
flat top antenna, no snow here.
Chris Albertson
Redondo Beach, California

The Trimble Bullit antenna has a 1" thread that will mate with a plumbing
pipe directly. The F-connector will fit through it. Be a bit careful,
since the pipe will have conical threads you might break the antenna if
using to much force.

--

Björn

On 6/10/12 4:24 PM, Chris Albertson wrote:

you would probably want appropriate flashing around that to prevent
water (and vermin) ingress.

The antenna sits on thop ithe

You probably get snow every few decades (it snowed in Malibu a couple
years ago, for instance), but I wouldn't worry about snow loads, even
so. <grin>

HOWEVER, your scheme is going to be tricky to pass muster with the
National Electrical Code.  Two aspects need attention:
You need to have a ground wire from the mast to the ground point
and
You need to have some form of ground of the coax shield at the point
where the coax enters the building.  (a "listed antenna discharge unit"
is the usual way).

While Southern California isn't exactly the lightning capital of the
world, we do get some.  A bigger concern (and the primary reason for the
code requirement) is that above ground power lines can come down and
touch your antenna.

And someone living in a more lightning prone area is going to want to
take those precautions.

The installations I've seen typically use the same general "pipe" scheme
(using rigid conduit, which looks a lot like pipe, but has a smooth
inside with no burrs) to a box on the roof, and then regular conduit
running down the outside of the building.  Then at the point of
entrance, the ground bonding conductor goes from the conduit to ground,
and there's a coax grounding block in a box at the place where the hole
in the wall is.

Granted, if lightning does hit, everything connected to the antenna is
going to fry, unless you have some sort of reradiation scheme to provide
an air gap.  That's what we do when we test GPS receivers destined for
space, where you don't want to take the risk of killing the expensive
flight hardware.

On Jun 10, 2012, at 7:43 PM, Jim Lux wrote:

Hi

Sorry for the blank…

The easy way to mount the antenna:

Head over to Home Depot and get a 1" Tee, a 1" flange, a 1" nipple, a 12" to 18" 1" pipe, and a 6" long 1" pipe.

The antenna goes on top of the 18" pipe. That screws into the tee. The bottom of the Tee gets the 6" pipe. Coax runs straight through the 18" and 6" pipe. Nipple goes to the flange and the tee. Flange mounts to the house. If you need to get a bit further out,  change out the nipple for a piece of pipe.

Spray paint it all black ( or what ever) and move on.

Bob

On Jun 10, 2012, at 7:43 PM, Jim Lux wrote: