Just the T and a DC block. 1/4 wave at 60 kHz is far, far longer than any
cable you have.
This is time-nuts. Somebody is likely to do something most of us would
consider, well, nutty.
It's probably reasonable to make a lumped-circuit approximation of a long
transmission line at 60 KHz or
What about mounting the antenna on the side of the metal pole, with the top of
the pole extending a foot or more above the antenna?
The idea is to have the lightning bolt strike the pole, but not the antenna.
The cable shield would need to be insulated from the pole, but grounded on
entry to
A lightening strike anywhere within 10ft will probably total your antenna, the
coax and the GPS receiver attached to it.
D.
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf
Of Heinzmann, Stefan (ALC NetworX GmbH)
Sent: 12 April 2012
There are commercial re-radiators for GPS. I found these on Google:
http://www.gps-repeating.com/?gclid=COTV88D6rq8CFcwTfAodhSKvmQ
http://gpsnetworking.com/GPS-re-radiating-kits.asp
One of my old suppliers in the UK was marketing a range of these, but I seem
to remember some problem in getting
This is a good idea, and I know has been used in the past. I believe that
Datum Austron used to recommend something like this for areas where
lightning was a problem.
Rob Kimberley
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of
I have a couple of BNC-to-scope_probe adapters...
On Thu, Apr 12, 2012 at 9:56 AM, Hal Murray hmur...@megapathdsl.net wrote:
Just the T and a DC block. 1/4 wave at 60 kHz is far, far longer than any
cable you have.
This is time-nuts. Somebody is likely to do something most of us would
Stefan,
my mushroom type of gps antenna is mounted on a metallic cantilever arm abt.
0.6 m aside a pole that extends 1 m above the height of the gps antenna.
Then a 2 m long vertical amateur radio antenna is mounted on top of the
pole. The pole is exactly in the east of the gps antenna. I attach
Time-nutters--
So-- How do GPS signal re-radiators work?
How do you place a GPS antenna on top of a building,
pick up the signal with an LNA, amplify it to re-transmit
on an inside antenna without the amplified re-transmitted
signal getting back into the roof-top receiving antenna?
I can see
Hi
The re-radiators are active devices. They are every bit as much a lightning
attractor as the GPS it's self. They also cost more than a TBolt (even at
current prices).
Bob
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Michael
Time-nutters--
Around here (N. Central Flori-DUH) it is not uncommon for
near-by lightning strikes to damage underground cables and
wiring. This is why buried wiring to things like driveway
gate-openers are often placed in conduit rather than done
with direct-burial wiring so that if lightning
If the isolation is good and the clear view signal is reasonably strong,
the passive system works well in hangers, metalclad warehouses, ferry lorry
decks.
The passive system in the UK used to be refered to as the Matlock
Repeater.
Alan
G3NYK
- Original Message -
From: Michael Baker
Passive UHF TV repeaters were in use in Italy too. Nowadays, for the DVB-T
TV, active gap-fillers are used instead. Active gap-fillers are
same-channel repeaters with the necessary, sophisticated echo suppression
technique. We have developed our echo suppression signal processor on a
Xilinx
On 4/12/12 2:09 AM, Rob Kimberley wrote:
There are commercial re-radiators for GPS. I found these on Google:
http://www.gps-repeating.com/?gclid=COTV88D6rq8CFcwTfAodhSKvmQ
http://gpsnetworking.com/GPS-re-radiating-kits.asp
One of my old suppliers in the UK was marketing a range of these, but
On 4/12/12 6:22 AM, Michael Baker wrote:
Time-nutters--
Around here (N. Central Flori-DUH) it is not uncommon for
near-by lightning strikes to damage underground cables and
wiring. This is why buried wiring to things like driveway
gate-openers are often placed in conduit rather than done
with
True if you do not include the cost of the burned down house which is a
possibility.
Bert Kehren
In a message dated 4/12/2012 9:59:08 A.M. Eastern Daylight Time,
jim...@earthlink.net writes:
On 4/12/12 6:22 AM, Michael Baker wrote:
Time-nutters--
Around here (N. Central Flori-DUH) it
I have 2 TBolts but now I'm thinking to buy others to save them from the
sacrifice...
On Thu, Apr 12, 2012 at 3:58 PM, Jim Lux jim...@earthlink.net wrote:
On 4/12/12 6:22 AM, Michael Baker wrote:
Time-nutters--
Around here (N. Central Flori-DUH) it is not uncommon for
near-by lightning
GPS being extremely time-dependent, any delay introduced will affect
positioning precision. Also, the signal is too weak for such an
amplification/echo cancelling signal chain.
Passive relaying, or using at most a simple amplifier with low enough
gain, and short signal delay, remain the only
Hi
Is your house hit multiple times per year now? If so, I'd suggest that's the
issue that needs to be solved. If not, then mount the antenna lower than the
peak of the house and move on.
Bob
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Only if it's not part of the sacrificial ritual...
On the more serious part, while the lightning processes, and effects are
scientifically researched for ages, an efficient lighting protection
still borders black magic.
On 4/12/2012 5:01 PM, ewkeh...@aol.com wrote:
True if you do not
A very efficient solution would be to get the signal/power conducting
cables out of the lightning path - that means a GPS receiver near the
antenna, with a local power supply (photo cell panels / buffer
accumulator) and signal transmission over optical fiber. Quite feasible,
as a GPS Rx has
Well, the saga continues...
A replacement part (for which a thorough check was specifically asked)
has arrived. It boasts a Checked OK written with a marker pen on the
label. Promising...
With high expectations, the necessary connections were made, power
applied, and after warming up it locks
On Thu, 12 Apr 2012 17:39:57 +0300
MailLists li...@medesign.ro wrote:
Regarding the TBs, even if they are the only ones directly connected to
the antenna, the cable is already punching through the house Faraday
cage, and chances are quite high that the lightning discharge won't stop
at
The time/position fix would be from the location of the receiving
antenna of the repeater, degraded only by noise.
This should work if both antennas have good back-side rejection
(choke-rings are particularly good for this but perhaps any good timing
antenna could meet this), the
You're right, but it's highly depending on the used construction
materials... The building I live in, is quite like a Faraday cage -
reinforced concrete. Even higher frequency radio signals have a tough
time entering, mostly through the windows.
What I wanted to underline is that, even if the
David's comment on the direct and retransmitted signals is right on point.
You are creating a multipath environment with increased signal strength and
matching polarization. Even with no amplification between the antennas, you
are generating multipath signals for you and your neighbors.
Not quite, the delay of the antenna cable is affecting less the
horizontal position (it depends also on the current received
constellation geometry), but mostly the height ASL of the fix point,
prolonging simultaneously all the paths from the satellites with a fixed
value.
Also, the
David,
That is correct, the signal is delayed by at least the run length as well. We
had to tweak the ublox parameters on our GPSDOs for a particular data center
application that used a re-radiator to make it work as the default ublox
parameters would get the unit confused due to residual
Not at all!
The (first) receiving antenna defines the position you get out of a long
antenna cable or a reradiating system. The delays in LNA, filters, cables,
rerad antenna, free air between rerad antenna and final receiving antenna
ALL goed into the receiver clock error. This is clear both from
Delay of the complete ensemble of signals results in a time shift much like
the addition of cable between the antenna and receiver. The position
solution will be the location of the first receiving antenna.
John WA4WDL
--
From: MailLists
One interesting fact: frozen ground is a bad conductor.
The ground potential around your house may go up many 1000s of volts even with
just a proximity strike, while the power feed stays down, blowing up anything
connected to ground. Thus the special Nordig surge protection requirements
for TV
You must read:
http://transition.fcc.gov/eb/Orders/2005/DA-05-2998A1.html
Which discusses a FCC complaint with Navtech for selling GPS receivers.
An exert is presented below:
``Please note: re-radiation kits are currently only
available for purchase to International Customers and in
You must read:
http://transition.fcc.gov/eb/Orders/2005/DA-05-2998A1.html
Which discusses a FCC complaint with Navtech for selling GPS repeaters.
An exert is presented below:
``Please note: re-radiation kits are currently only
available for purchase to International Customers and in
I meant to type GPS repeaters not GPS receivers
John WA4WDL
--
From: jmfranke jmfra...@cox.net
Sent: Thursday, April 12, 2012 12:28 PM
To: time-nuts@febo.com
Subject: Re: [time-nuts] Best location for a GPS antenna...?
You must read:
Hi
The lightning hit is both a great big voltage and a wallop of current. The
voltage is the thing many people get worried about. Almost all of the damage
I've had has come from current induced into near by conductors and similar
magnetic field issues.
That said, the voltage spike has likely
Rerad-systems are getting controlled in Europe too.
http://www.etsi.org/deliver/etsi_en/302600_302699/302645/01.01.01_60/en_302645v010101p.pdf
Any reports on how quick this is going? Where I live, there are rules, but
not many are aware of them.
--
Björn
You must read:
On Wed, Apr 11, 2012 at 3:08 PM, Bob Camp li...@rtty.us wrote:
Hi
If the antenna is no higher than your house, it's no more likely to get hit
than the house.
If it's higher than the house by a few feet, the increase in hit probability
is vanishingly small.
Antenna do not have to be
Interesting... have to check my LPFRS now: only tested for the lock
indicator when received and then put aside to complete first the
discipliner.
On Thu, Apr 12, 2012 at 5:00 PM, MailLists li...@medesign.ro wrote:
Well, the saga continues...
A replacement part (for which a thorough check was
On Thu, 12 Apr 2012 09:20:37 -0700
Said Jackson saidj...@aol.com wrote:
One interesting fact: frozen ground is a bad conductor.
The ground potential around your house may go up many 1000s of volts
even with just a proximity strike, while the power feed stays down,
blowing up anything
Fortunately, it seems that lightning is not as frequent in high
northern and southern latitudes as is in tropical regions.
I was told about a story of a group of Swedish scientists
involved in thunderstorm studies, having built a little lab
in the village with the best reputation of high
On Thu, 12 Apr 2012 12:41:51 -0400
Bob Camp li...@rtty.us wrote:
GPS is pretty close to the noise as received. A fully passive system with
significant cable loss and low / no gain antennas does not sound like it's
going to do a very good job.
GPS is pretty much under the noise as received :-)
Hi
Some of the people posting to the thread seem to be concerned about the
house burning down because they put up a GPS antenna...
Receivers can die from a lot of causes. A TBolt like GPS being killed by
input overload from a strike 100 feet away would not be very high on my list
of likely
On Thu, Apr 12, 2012 at 7:22 AM, Bob Camp li...@rtty.us wrote:
Hi
Is your house hit multiple times per year now? If so, I'd suggest that's the
issue that needs to be solved. If not, then mount the antenna lower than the
peak of the house and move on.
Did you not read the first post in this
Purely geometrically, the fix solution is computed as the intersection
point of spheres with the radii determined by the propagation time, and
the centers by the positions of the satellites (practically not all
spheres intersect in the same geometrical point, so an average is computed).
If the
Since I am used to figuring the cable (and additional propagation)
delays, I did forget to mention that for timing. :-)
On the other hand, I would not be using a repeater except for just
functional testing of a payload system.
David
On 4/12/12 12:15 PM, b...@lysator.liu.se wrote:
Not at
Timing GPS receivers have the cable delay parameter to account for the
cable delay.
added path delays would mostly cancel out
How can delays cancel out?
On Thu, Apr 12, 2012 at 7:33 PM, MailLists li...@medesign.ro wrote:
Purely geometrically, the fix solution is computed as the intersection
Over at http://tf.nist.gov/tf-cgi/wwvbmonitor_e.cgi there is a relative field
strength plot for each of the monitoring stations. I'm trying to correlate
LaCrosse with my own measurements in St. Paul (AGC voltage in my Spectracom
8164) and it's very bothersome that this graph has no scale and
Yes, but the propagation times are the times from each satellite antenna
phase center to the phase center of the receiving antenna. From that point
forward, the relative time delays are unchanged. It is the same as if one
was to record the RF signals at the back of the receiving antenna and
On 4/12/2012 1:10 AM, Heinzmann, Stefan (ALC NetworX GmbH) wrote:
What about mounting the antenna on the side of the metal pole, with the top of
the pole extending a foot or more above the antenna?
The idea is to have the lightning bolt strike the pole, but not the antenna.
The cable shield
On Thu, 12 Apr 2012 18:41:43 +0200
b...@lysator.liu.se wrote:
Rerad-systems are getting controlled in Europe too.
http://www.etsi.org/deliver/etsi_en/302600_302699/302645/01.01.01_60/en_302645v010101p.pdf
Any reports on how quick this is going? Where I live, there are rules,
On Thu, 12 Apr 2012 15:02:48 -0400
David McGaw n1...@alum.dartmouth.org wrote:
Best would be to have a lightning rod in the vicinity of and above the
antenna. A sharp-pointed rod does not attract lightning, it REPELS it
and has a cone of protection under it. While the effect is not
On Thu, Apr 12, 2012 at 11:56 AM, Randy D. Hunt randy_hunt...@yahoo.comwrote:
On 4/12/2012 1:10 AM, Heinzmann, Stefan (ALC NetworX GmbH) wrote:
What about mounting the antenna on the side of the metal pole, with the
top of the pole extending a foot or more above the antenna?
Typically when
On Thu, Apr 12, 2012 at 12:02 PM, David McGaw n1...@alum.dartmouth.orgwrote:
Best would be to have a lightning rod in the vicinity of and above the
antenna. A sharp-pointed rod does not attract lightning, it REPELS it and
has a cone of protection under it. While the effect is not understood,
li...@medesign.ro said:
GPS being extremely time-dependent, any delay introduced will affect
positioning precision.
I think you will just get the position of the receiving antenna for the
repeater. It will get the time when the signals arrived at that antenna.
Consider what happens if you
I'd suggest getting Dr. Uman's All About Lightning as a starter. You could
read it in an afternoon, so to be correct, the book is all about lightning, but
it doesn't contain all the world's knowledge. ;-). It isn't very technical,
though he has written technical books as well.
Regarding
I took a look and as it says its relative. Don't think there is a trusted
relationship.
Good to hear you have everything going. I believe outside is important not
so sure huge height much matters at 60Khz. I ran at the 45 level on a tower
for years and have to say 6 foot in the woods seems to
It seems to me that the rebroadcast signal will need to be really low to avoid
interference with the original signal, at that level multipath could be a big
problem. From my experience fiber is the method of choice commercially for both
lightning protection and long cable runs. But those
hmur...@megapathdsl.net said:
I think you will just get the position of the receiving antenna for the
repeater. It will get the time when the signals arrived at that antenna.
Consider what happens if you replace the air between the repeater's transmit
antenna and the GPS receiver with a
It is well known that vertical accuracy is worse by about 1.8 times the
horizontal accuracy. It is true this is geometrically caused. In indoor
scenarios high sensitive receivers have a vertical bias due to excessive
multipath. More or less all received signals have bounced multiple times
to reach
Just found on the auction site:
Item number: 220957196441
Specs available at the manufacturer's website.
I have no idea if it is worth the price.
Might be of interest.
Antonio I8IOV
Note: I'm not affiliated.. etc ...etc..
___
time-nuts mailing list --
Hi Attila,
if I remember correctly, the issue is that the ground at the house is
not a real ground when the earth is frozen, as the resistance of frozen
earth goes up substantially over non-frozen earth. So it's like not having
grounded the wires at all.
This is a real issue for cables
Said,
The ground is a decent thermal isolator. And will in nordic countries not
often go deeper than about 1 meter. You need to build your houses
foundation deep enough to stand on non frozen ground. Otherwise your
house will move to much with the seasons and likely break. It is not that
hard to
Hi,
I have a personal reference: In the Deep Space tracking facility where
I used to work some 20 years ago it was very common to have
minicomputers damaged by strikes in the antenna. This antenna was
located about 1000' from the control room and there were an elaborate
grounding system
Hal wrote:
How many of you have used the Tek scope-probe to BNC adapter? I tried a bit
but couldn't find anything on the web. The idea was (roughly) that you put a
BNC Tee in the line you wanted to watch and this magic gizmo on the Tee.
I have some. I don't use them often, but they are
I have one, it is OK.
On Fri, Apr 13, 2012 at 12:19 AM, iov...@inwind.it iov...@inwind.it wrote:
Just found on the auction site:
Item number: 220957196441
Specs available at the manufacturer's website.
I have no idea if it is worth the price.
Might be of interest.
Antonio I8IOV
Note: I'm
Hi Bjoern,
Possibly, I am just reciting what I read in the Nordig requirements a
looong time ago. Maybe they are worried about far north permafrost scenarios
that go deeper? The requirements for receiver RF input surge protection were
much higher than the usual US requirements..
bye,
I think I know why. I worked on such computers, and they were very
sensitive to ESD. If you touched the cabinet during the winter, when it's
very dry, the spark would be enough to crash the computer, although
permanent damage was rare. The problem was that the computers were
under-designed
Hi
In the same area of what I have seen. I used to live in a neighborhood where
strikes were quite common. It was a rare summer month that there was not one or
more hits in the neighborhood. Nobody's house burned down. They (I) did not
loose every electronic device within 100' or 1000' of the
On 04/13/2012 12:19 AM, iov...@inwind.it wrote:
Just found on the auction site:
Item number: 220957196441
Specs available at the manufacturer's website.
I have no idea if it is worth the price.
It feels mechanically indestructible, and works.
I have a tbolt powering it, and a 3.3V
ESD is not an issue for chips that don't touch the outside world. It is only a
handling issue.
If anything, ESD has got worse over the years as geometries have decreased.
Latch-up, a potential issue with boards that get surges, has improved over the
years with epi or dielectric isolation
I was a guest in a home that lost power due to a lightning strike on the power
pole across the street. Once the power company replaced the transformer on
the pole the power came back on and as far as I know there was no lasting
damage to any of the electronics in the house. I was sleeping
On 4/12/12 12:50 PM, li...@lazygranch.com wrote:
I'd suggest getting Dr. Uman's All About Lightning as a starter. You could
read it in an afternoon, so to be correct, the book is all about lightning, but it
doesn't contain all the world's knowledge. ;-). It isn't very technical, though he has
On Thu, Apr 12, 2012 at 2:21 PM, Bob Camp li...@rtty.us wrote:
Hi
Do you have a reference for 100' distant strikes routinely destroying
receivers?
Bob
The ARRL's QST magazine Aug - Nov 1986 is very good and many people here
would have access to it.
They talk about EMP from both atomic
On 4/12/12 12:02 PM, David McGaw wrote:
Best would be to have a lightning rod in the vicinity of and above the
antenna. A sharp-pointed rod does not attract lightning, it REPELS it
and has a cone of protection under it. While the effect is not
understood, it apparently discharges the surrounding
Hi
Oddly enough I've actually worked with an EMP simulator. They indeed put out a
lot of energy. The lightning hits I've experienced are no where near EMP level
events.
Bob
On Apr 12, 2012, at 9:07 PM, Chris Albertson wrote:
On Thu, Apr 12, 2012 at 2:21 PM, Bob Camp li...@rtty.us wrote:
Early streamer emission...thems fightin' words!
On 4/12/2012 6:03 PM, Jim Lux wrote:
Controversial is an understatement.
When there was an IEEE journal paper (well reviewed) essentially saying
that they don't work, one of the manufacturers of such devices sued the
author and the IEEE
Hopefully someone out there has a stash of what I'm looking for. I
need 4 ea IC type CA3130E. Need this specific number. It's an 8 pin
DIP. I've tried DigiKey and Mouser. No luck.
Thanks,
Burt, K6OQK
Burt I. Weiner Associates
Broadcast Technical Services
Glendale, California U.S.A.
Supposedly in stock:
http://www.futurlec.com/ICLinearOpAmps1.shtml
I've dealt with this company several times in the past, no problems other
than very slow shipment to the usa.(Some cases 2-3 months)
Steve
On Fri, Apr 13, 2012 at 12:46 AM, Burt I. Weiner b...@att.net wrote:
Hopefully someone
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