What's the best small diameter (0.25) low loss coax? I need to run
about 30' from my GPS antenna to a TBolt.
Best,
Dick
If the antenna has a pre-amp, then just use satellite TV cable, even
though the losses and impedance aren't quite what you might like.
Cheers,
David GM8ARV
--
SatSignal
Once again, thanks to all. The Lucent bullet antenna has an N connector on the
base, so I'll just use RG-6 which I have enough of, and live with a bigger
trough through the window frame or just go ahead and bore through the wall -- I
originally cut the slit in the window frame to accommodate
Hi Dick,
See page 27 of this document (as numbered at the bottom of the page, or PDF
page 29):
http://trl.trimble.com/docushare/dsweb/Get/Document-388613/ThunderboltE_UG_1B.pdf
The Trimble Bullet antenna for the TBolt has 28dB gain and they recommend
RG-59 coax. Brooke's page (
And like the biological mushrooms they resemble, have a tendency to multiply.
At least for Time Nuts...
--
Russell
At 6:30 PM -0400 2011/06/12, William H. Fite wrote:
And an old, weathered bullet might resemble a morel.
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Googling flat coax cable returns a number of hits. Apparently, these flat
cables can be had for a few $/piece in the US.
Thanks for the suggestion.
Didier KO4BB
Sent from my BlackBerry Wireless thingy while I do other things...
-Original Message-
From: b...@lysator.liu.se
Sender:
Funny thing.
I use free cable tv .5 hardline low loss stuff but at 1575 Mhz 3.12 db per
100'.
I have used a lot of RG6 and kind of funny at 1575 its 7.89 db per 100'. So
I must say the work needed to install the .5 cable is a lot more trouble
then the 4 db of loss.
Though these days I have the
Every time I switch on my Thunderbolt (cold start) Lady Heather tells me that
there are no
almanac data. It takes a few tens of minutes before they are collected again.
I was under the impression that TB had some sort of non volatile memory, and it
must have it,
as it is capable of remembering
Hi Alberto,
Why almanac data are not kept ? Not enough space in that non volatile
memory ?
the thunderbolt is meant for permanent installation in mobile base
stations where power outages are pretty rare, so I guess the designers
didn't see it worthwhile.
Chris
At 10:49 AM 6/13/2011, Alberto di Bene wrote...
Why almanac data are not kept ? Not enough space in that non volatile
memory ?
Flash and EEPROMs have a limited number of write cycles available. For
a timing receiver, position changes rarely - almanac data changes
frequently.
EEPROM's do have a finite number of write cycles to any particular memory
location, but it's about 100,000 or more. That's 11 years worth if written
to once an hour round the clock (the same location in memory, that is).
This is probably not the issue. I personally never noticed but then again,
On 06/13/2011 06:02 PM, Christian Vogel wrote:
Hi Alberto,
Why almanac data are not kept ? Not enough space in that non volatile
memory ?
the thunderbolt is meant for permanent installation in mobile base
stations where power outages are pretty rare, so I guess the designers
didn't see it
On 06/13/2011 02:27 PM, Russell Rezaian wrote:
And like the biological mushrooms they resemble, have a tendency to
multiply.
At least for Time Nuts...
The term has already been used to illustrate the antenna testing at the
Meinberg facility. :)
I haven't picked any mushrooms there, will
We had the REAL Lady Heather on TV last night here in New Zealand!
It was the CSI episode about cats.
Any tenuous connection with Time-Nuts, perhaps?
Murray
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Lady Heather dishes out discipline. The time references are disciplined
oscillators. The connection is a bit more than tenuous.
--Original Message--
From: Murray Greenman
Sender: time-nuts-boun...@febo.com
To: time-nuts@febo.com
ReplyTo: Discussion of precise time and frequency
Hello,
I have an upcoming need for a GPS disciplined NTP server in a low cost
project. Checking price
on commercial units shows that these are out of reach so I have been looking
into the possibility
of building an NTP server. I understand that the Soekris net4501 single
board computer is still
On Mon, Jun 13, 2011 at 1:37 PM, Per Molund pmol...@gmail.com wrote:
Hello,
I have an upcoming need for a GPS disciplined NTP server in a low cost
project. Checking price
on commercial units shows that these are out of reach so I have been looking
into the possibility
of building an NTP
I've done this recently and have bought several Symmetricom GPS time servers
(S200, S350, etc). I've also built the net4501 up as a time server and do
not recommend it. Mine was extremely flaky and I couldn't trust it to stay
up unless it was on very clean power (big UPS) and even then it
Hi
The Net4501 servers I've made up have been very reliable boxes. They are low
power and simple to run. If you put an OCXO in them, their accuracy is as
good as it gets with NTP. The clock multiplier chip wiring can be a bit
exciting, that's the only crazy part.
Cost wise, an Atom based
I've been moving my 24 7 tasks to an Intel Atom PC, mostly to be
green. It's not all that cheap since I used a SSD in the construction.
Anyway my point is running an old PC to be er um frugal might turn out
to be more expensive than running an intel atom. It all depends on your
power costs.
Unfortunately, my D525 mobo doesn't have a serial port and my symetricom
doesn't like the usb converter. One of these days somebody is going to
make a usb coverter that really looks like a serial port. I'm probably
going to buy a serial card for the box
On Mon, Jun 13, 2011 at 2:25 PM, gary li...@lazygranch.com wrote:
I've been moving my 24 7 tasks to an Intel Atom PC, mostly to be green.
It's not all that cheap since I used a SSD in the construction. Anyway my
point is running an old PC to be er um frugal might turn out to be more
expensive
$400 Plus shipping. Working without any problems.
Questions or pics, drop me a note.
Norm n3ykf
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and follow the instructions
Sadly, the Lyttleton Time Ball completly collapsed in yesterday's, Mon 13th,
after-shocks. There were two quite major shocks of 5.5 at 1pm followed by a
6 at 2:20pm centered around the Sumner suberb which is close to Lyttleton.
Cheers, Steve
--
Steve Rooke - ZL3TUV G8KVD
The only reason for
This is raising an interesting point, only vaguely relevant, but we have
been
testing some software for amateur radio astronomy purposes that controls
intruments over serial lines RS-232 or RS-485. Whilst many application run
with out problems for days on internal serial cards, we seem unable to
On Mon, 13 Jun 2011 23:25:54 +0100
Alan Melia alan.me...@btinternet.com wrote:
Of the USB converters the best seemed to use the FTDI chip and driver, but
even
these have shown fails suggesting the problem is deeper inside the PC. All
problems have been on the PC reception leg, causing
I think it may be the voltage. Do the USB converts use rs232 levels
or only 5 volts?
For NTP the issue is different. The PPS signal coming from the GPS
needs to go into a hardware serial port so the PPS handler sees a very
low but more importantly a predictable latency.The PPS depends on
a
I have to disagree with the person that said the Net4501 is not stable. I have
two (soon to be 3) that run NTPns and they have never
needed to be touched. I've powered them down a couple times during really bad
storms because I didn't want lightning to zap them (or
my other GPS equipment).
If
Dissapointing - I remember it being pointed out to me as we pulled
into port there once. Are there others scattered around the globe?
Brent
On Mon, Jun 13, 2011 at 6:19 PM, Steve Rooke sar10...@gmail.com wrote:
Sadly, the Lyttleton Time Ball completly collapsed in yesterday's, Mon 13th,
On Mon, 13 Jun 2011 15:37:13 -0700
Chris Albertson albertson.ch...@gmail.com wrote:
For NTP the issue is different. The PPS signal coming from the GPS
needs to go into a hardware serial port so the PPS handler sees a very
low but more importantly a predictable latency.The PPS depends on
Same here, my Net4501 has been running over 2 years without a reset.
A Soekris-based NTP server uses the counter/timer built-in to its
embedded processor to give you better precision interval measurement
than a serial port, but if you're not interested in anything better
than ms accuracy then it's
In message BANLkTi=i4u-ng7ly6o2ybl_ypcqp95v...@mail.gmail.com, Eric Williams
writes:
Same here, my Net4501 has been running over 2 years without a reset.
That is more a matter of power-supply than anything else:
critter phk ssh root@xdcf uptime
11:04PM up 764 days, 4:01, 0
Hi Attila you got it in one (givethe man a kewpie doll :-)) ) Yes it was so
far on windows machines I have not got to the Linus machine yet but I am
expecting better performancethe trouble is 70-80 or our users will use
Windows.
Thanks for your comments that is very reassuring.
Alan
-
At 06:25 PM 6/13/2011, Alan Melia wrote...
Of the USB converters the best seemed to use the FTDI chip and driver,
but
I agree. The Prolific ones seem not to be as reliable, plus I
understand that many don't use a real Prolific chip, but a Chinese
clone which is even worse.
I've got a Moxa
OK so the USB works at the ms level. That compares to the us level
I'm getting. So I have 500 to 1,000 times better performance using an
$85 Intel Atom board. That's $85 with the CPU and the serial port
soldered down on-board. I did need to add a 1GB RAM and a micro-atx
size case but I'm
When I set up gpsd (linux gps daemon), I noticed it has a hook to discipline
your RTC, much like NTP.
I have no idea if it is any good.
As far as I can tell, gpsd isn't a real daemon. That is, it doesn't show up
under services. You have to start it up by other means.
I have seen no pictures of the current site but the quakes have downed
several more buildings and many more are now added to the list of those that
will need to be demolished. It will become a ghost town if this continues to
happen. People are sick of the shocks and more are leaving as they are
tick# uptime
1:12AM up 844 days, 16:52, 1 user, load averages: 0.03, 0.03, 0.00
Yes, that's true, but only when the system's basic reliability reaches
a very high level. (QED)
--
eric
On Mon, Jun 13, 2011 at 4:05 PM, Poul-Henning Kamp p...@phk.freebsd.dk wrote:
In message
As far as I can tell, gpsd isn't a real daemon. That is, it doesn't show up
under services. You have to start it up by other means.
[I know next to nothing about Windows so if under services means Windows,
this may be irrelevant.]
gpsd works fine as a daemon. The details depend upon which
And like the biological mushrooms they resemble, have a tendency to
multiply.
Do they grow in fairy rings?
http://en.wikipedia.org/wiki/Fairy_ring
-
well.. when you put a puck on top of a 6 foot length of conduit, it really
does look like a mushroom (sort of like Enoki)
Some
'Before' and 'after' yesterdays quake - pix of the timeball station plus an
item about it that appeared in a suburban newspaper last week.
http://homepages.ihug.co.nz/~tractorb/timeball/
DaveB
Christchurch, NZ
- Original Message -
From: Steve Rooke sar10...@gmail.com
To: Discussion
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