If I'm following this correctly, we call that steel reinforced concrete
in the US.
Some high end buildings use ICF made out of Neopor 2300, which is the
best (or worst) of both worlds. The 2300 variant is infused with
graphite, so it makes a Faraday shield, albeit not very low resistance,
and
Hi David yes its ferro-concrete which makes quite a good screen (a lot worse
than domestic brick) but the windows are not coated I think. (BT Labs at
Martlesham)
[]
The windows are SW I think but give a good view of a quadrant of the sky. It
will be interesting to see how long it takes to lock up
I'll be curious to hear more details from Alan (the original poster.) I agree
it's not a slam dunk that the device in question is a GPSDO that supports hold
over.
I also agree with Bill that we may be missing some details regarding this
matter.
Re: [time-nuts] GPS antenna??
Bob Camp Mon,
Ever hear the riddle about the guy driving a black car with the headlights
off? The streetlights are all off, too. A black dog runs in front of the
car, but the driver avoids hitting it. How did he do that?
The answer is that the environment was broad daylight. Of course the lights
were off. As a
On 4/8/13 2:12 PM, Tom Van Baak wrote:
Alan,
Google for words like GPS re-radiator or GPS repeater. There are also units on
eBay. If not to buy, at least to study examples.
The one I have is made by www.gpssource.com but it seems you could build one
yourself. It's easy to test by looking at y
On 4/8/13 9:59 AM, Alan Melia wrote:
Hi all an interesting problem you may have encountered, I want to use a
GPS frequency standard inside a building with no opening windows
(opening windows are known as air conditioning in the UK :-)) )
This is part of a two day amateur microwave conference so
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Hi
I'm not sure that the "real" application here is a GPSDO. If it is, then
holdover may well be the easy answer.
Bob
On Apr 8, 2013, at 6:29 PM, Mark Spencer wrote:
> In my experience in the northern hemisphere if the window is more or less
> south facing and the window isn't coated with so
In my experience in the northern hemisphere if the window is more or less south
facing and the window isn't coated with something that absorbs RF energy then
an antenna located inside and near the window will frequently (but not always)
provide enough signal for a GPS timing receiver to work but
Hi
If the windows are of the permanently fixed variety - how about a rock …:)
Since most windows are likely pretty good sized, and this *is* a microwave
conference …. how about some sort of meter square purpose built antenna?
For the uber-exotic approach - modulate a laser with the GPS signal
I tried a much stronger signal on XM radio inside on the window ledge. Worked
well in the car, but not the kitchen. Finally realized that I had UV coated
windows and the signal was almost not there. Opened the window, put the puck
outside, scrunched the mini-cable under the closed window and
I have to run Lady H again. My recollection is I couldn't get the map
(plot) to work. I have a Symetricom, not a Thunderbolt. The control
language is close but perhaps not identical. I know some features of
Lady H didn't work on the Starloc.
In any event, north pointing looks like a bad idea.
Hi Tom Ah I didnt realise there were such beastsI probably have not the
time left now but it is one to consider.
Yes I might have to watch the patch polarisation. I did consider two L-band
waveguide transitions at one stage but thought that might be going too far
:-)) I thought of the on-gla
Hi Alan and Tom,
Note that under the Wireless Telegraphy Act 2006 here in the UK, active GNSS
repeaters have to be licenced. See
http://194.33.160.59/radiocomms/ifi/enforcement/gpsrepeaters/
and
http://stakeholders.ofcom.org.uk/enforcement/spectrum-enforcement/gpsrepeaters/
Even a "normal" acti
Hi David yes its ferro-concrete which makes quite a good screen (a lot worse
than domestic brick) but the windows are not coated I think. (BT Labs at
Martlesham)
Thanks all for some thought stimulating ideas .GPSDO outside might not
be too easy1U rack case mains poweredno power ava
Alan,
Google for words like GPS re-radiator or GPS repeater. There are also units on
eBay. If not to buy, at least to study examples.
The one I have is made by www.gpssource.com but it seems you could build one
yourself. It's easy to test by looking at your indoor SV count and reception
levels
Hi Tom yes I have produced some similar plots I think they get "cold feet"
about 70deg N. I'm not sure of the actual value it is a long time since I
played with that last.
Alan
- Original Message -
From: "Tom Van Baak"
To: "Discussion of precise time and frequency measurement"
Sent:
Hi
More or less there aren't any GPS sats due north unless you can "see" over
the pole. That does assume you are in the northern hemisphere. If you watch
a "sats in view plot" for a couple days, Your odds of finding something are
best towards the equator and diminish as swing around towards the po
Hi all an interesting problem you may have encountered, I want to use a GPS
frequency standard inside a building with no opening windows (opening
windows are known as air conditioning in the UK :-)) )
This is part of a two day amateur microwave conference so we should have the
expertise.
I inten
> Aren't GPS birds all over the sky. South facing is for the Clarke belt.
Well, mostly all over, but with higher probability facing up, east, west, and
towards the equator compared to significant "black hole" towards the pole. For
example, see the GPS reception sky map of John's TBolt:
http://
What you are saying is that at some point in your signal chain there will
be glass. Why place the glass where it cuts a very weak signal?. If you
place the GPSDO outdoors then you can pass the 10MHz signal through the
glass with basically a transformer (with glass between the primary and
secondar
As Bill suggests, the best way to achieve any-frequency performance with the
newer FE-56xx devices is to pull out the Rb reference frequency and run an
external DDS off it.
I found that the Rb loop frequency in the one I played with was exactly
60MHz, rather than the 50.255MHz of the older uni
Hi Bob yes it is South facing.I may have todo that anyway because the
window may be too far above ground level (the land slopes away from the
ground entrance.. pity I had totally forgotten that.
Thanks
Alan
G3NYK
- Original Message -
From: "Bob Camp"
To: "'Discussion of preci
Aren't GPS birds all over the sky. South facing is for the Clarke belt.
-Original Message-
From: "Bob Camp"
Sender: time-nuts-boun...@febo.com
Date: Mon, 8 Apr 2013 15:28:14
To: 'Discussion of precise time and frequency measurement'
Reply-To: Discussion of precise time and frequency meas
Hi
Is the proposed window south facing? If not, you will need enough cable
outdoors to get your second antenna to a south facing location.
Assuming it's south facing and reasonable sky view, have you tried a patch
antenna on / at the window? That should at least give you some idea of how
likely
Since this for a demonstration, why not use an RbO ? No antenna needed.
73, Dick, W1KSZ
On 4/8/2013 9:59 AM, Alan Melia wrote:
Hi all an interesting problem you may have encountered, I want to use
a GPS frequency standard inside a building with no opening windows
(opening windows are known as
Hi all an interesting problem you may have encountered, I want to use a GPS
frequency standard inside a building with no opening windows (opening
windows are known as air conditioning in the UK :-)) )
This is part of a two day amateur microwave conference so we should have the
expertise.
I in
Hi Mike,
try typing:
s: Survey
a: Antenna
s: Signal
in that sequence from main menu.
73s Achim, DH2VA
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