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:

And make sure that the flange is being bolted into a stud and not just the
sheathing. A good gust could pop it off especially if the arm is long.

Great idea though!

Dave (who just got a Tbolt and waiting on an antenna)  I am doing a tower
for my ham radio stuff and want to put the Tbolt on the other side of the
house to gain some isolation.

On Sun, Jun 10, 2012 at 4:43 PM, Jim Lux jimlux@earthlink.net wrote:

Yes, all true.  I didn't really want to right a book about it.  Yes there
is flashing around the pipe.  It is handled the same is for other pipes
that come up through the rook to vent plumping.  And yes you ground the
pipe just like you ground an old off-the-air TV antenna mast and so on.
My VHF (two and four meter) antenna and by HF wire antenna all have
lightening arasters and big ground rod systems, and the ground rods are
tried together an.

But you know what?  If you simply place an automotive "puck" type GPS
antenna on your roof you have to do the same thing.  It must be grounded
the same way, same lightening protection and so on.  So in the end you may
as well put up a professional looking and permanent  steel mast.  It is not
that much more work.

Redondo Beach, California

I did that once and thought the bends in the pipe looked ugly.  I wanted a
simple vertical mast.  The simple mast is also stronger because I can use
"U" bolts to secure it to a rafter and a floor joist that are about four
feet apart.  Results in the very strong installation.  It is build exactly
like a plumbing vent, just a long pipe with the last few feet above the
roof.  The coax run is completely 100% out of the weather.

On Sun, Jun 10, 2012 at 7:06 PM, DaveH info@blackmountainforge.com wrote:

--

Chris Albertson
Redondo Beach, California

Totally agree

On Jun 10, 2012, at 19:34, Chris Albertson albertson.chris@gmail.com wrote:

Hi

I was concerned about the appearance before I did the first one. After putting several up, they all look pretty good. The mast portion looks straight from the ground and it's actually smaller than any conventional mast. The black paint does indeed help out a little in hiding the tee it's self.

Yes indeed grounding needs to be done, I figured the post was long enough already.

Bob

On Jun 10, 2012, at 10:40 PM, Chris Albertson wrote:

11/06/2012 13:43

Thanks for the replies, I never intended to have the TB unit itself
outside, just in the roof space, which pretty much follows the
temperature of my room anyway, as I only heat it in very cold weather
as the room pretty much follows the temperature of the rest of the
hose.

The stuff arrived this morning, with regard to the antenna, does it
need to see the sky from horizon to horizon? Or would a mount a few
feet above the gutter of the bungalow be adequate? I am not sure how
many satellites it needs to see to work properly. A mount about 3 feet
above the gutter line would be neat and trivial. Thanks again.

--
Best Regards,
Chris Wilson.

On Mon, Jun 11, 2012 at 3:28 AM, Bob Camp lists@rtty.us wrote:

I've tried camouflaging the masts.  Paint the upper parts sky blue with
puffs of white spray paint over the blue I paint the bottom part black or
dark green.    Not perfect, I have a 40 foot pole on the back yard fence
that is still visible from the street but maybe it helps.  Battle ship
grey works well too.

Chris Albertson
Redondo Beach, California

Hi

Assuming you are in the northern hemisphere ...

You want a good view of the southern sky. You don't need to "see" due north
+/- about 45 degrees unless you are closer to the north pole than I suspect
you are. There are some minor benefits to being well above ground, but once
you get a good sky view things will work well. I would pick a location
that's 12" off the roof with a good view over one that's on a 40' mast in
the trees.

Ideally you would like to control the TBolt's temperature to within a degree
or two. That can be done with fans or a variety of other approaches. What
you want to avoid are rapid temperature ramps. Sun comes up and TBolt goes
up 30 degrees is not a recipe for ultimate stability.

Bob

-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of Chris Wilson
Sent: Monday, June 11, 2012 8:47 AM
To: Chris Wilson; Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Thunderbolt cabling questions

Can

11/06/2012 13:43

Thanks for the replies, I never intended to have the TB unit itself
outside, just in the roof space, which pretty much follows the
temperature of my room anyway, as I only heat it in very cold weather
as the room pretty much follows the temperature of the rest of the
hose.

The stuff arrived this morning, with regard to the antenna, does it
need to see the sky from horizon to horizon? Or would a mount a few
feet above the gutter of the bungalow be adequate? I am not sure how
many satellites it needs to see to work properly. A mount about 3 feet
above the gutter line would be neat and trivial. Thanks again.

--
Best Regards,
Chris Wilson.

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