In message [EMAIL PROTECTED], Brooke Clarke writes:
http://patft.uspto.gov/netacgi/nph-Parser?patentnumber=5440313
That patent should never have been granted IMO.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
[EMAIL PROTECTED] | TCP/IP since RFC 956
FreeBSD committer |
Most (except for Trimble,..) GPS receivers and antennas
are designed to use 50 ohm cable.
Trimble Bullet GPS antennas have a 50 ohm output impedance.
Trimble literature however is ambiguous in that in the
Resolution T receiver datasheets talk about using RG59
to connect to the antenna.
Bruce,
good to have you in the background with a look for the finer details.
A frequency multiplier, either within the DDS, or external to it is
required to generate a suitable DDS clock from either a 10MHz
or 20MHz input.
Of course! That's why i use a AD9852 which features BOTH an
Christopher Hoover wrote:
Most (except for Trimble,..) GPS receivers and antennas
are designed to use 50 ohm cable.
Trimble Bullet GPS antennas have a 50 ohm output impedance.
Trimble literature however is ambiguous in that in the
Resolution T receiver datasheets talk about using RG59
to
In message [EMAIL PROTECTED], Dr Bruce Griffiths writes:
93 ohm RG62 cables with BNC connectors are not unknown, they were used
in some nuclear instrumentation.
I have a few of these lying around.
Other uses:
93 Ohm: IBM 3270 terminal cabling
75 Ohm: Practically all telecoms
Ulrich Bangert wrote:
Bruce,
good to have you in the background with a look for the finer details.
A frequency multiplier, either within the DDS, or external to it is
required to generate a suitable DDS clock from either a 10MHz
or 20MHz input.
Of course! That's why i use a
Christopher Hoover said the following on 01/28/2007 04:48 AM:
I would also add that BNC and N connectors come in both 50Z and 75Z flavors.
In fact 75Z BNC connectors are pretty common, being used in professional
video applications. (Check surplus BNC patch cords carefully.) On the
other
RG62 was also used for the interconnection between the Heathkit SB303
receiver and SB401 transmitter. I thought that was a strange choice of
cables but at the time there were miles of the stuff being used for IBM 3270
terminals as noted below.
-Original Message-
From: [EMAIL PROTECTED]
Dr Bruce Griffiths wrote:
Christopher Hoover wrote:
Most (except for Trimble,..) GPS receivers and antennas
are designed to use 50 ohm cable.
Trimble Bullet GPS antennas have a 50 ohm output impedance.
Trimble literature however is ambiguous in that in the
Resolution T receiver
Those of you who use multifrequency GPS antennas such as choke ring
antennas may find the following article of some interest.
The new Trimble antenna has better performance than a choke ring antenna
especially if more than 2 frequencies are required.
Didier Juges wrote:
Dr Bruce Griffiths wrote:
Christopher Hoover wrote:
Most (except for Trimble,..) GPS receivers and antennas
are designed to use 50 ohm cable.
Trimble Bullet GPS antennas have a 50 ohm output impedance.
Trimble literature however is ambiguous in that in the
Chris
Christopher Hoover wrote:
Most (except for Trimble,..) GPS receivers and antennas
are designed to use 50 ohm cable.
Trimble Bullet GPS antennas have a 50 ohm output impedance.
Trimble literature however is ambiguous in that in the
Resolution T receiver datasheets talk
I think Jameco has short lengths of this ribbon, I will let you know in a
few weeks it is the right size cable.
Ed
- Original Message -
From: Didier Juges [EMAIL PROTECTED]
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Sent: Saturday, January 27, 2007
Dr Bruce Griffiths wrote:
Didier Juges wrote:
Dr Bruce Griffiths wrote:
Christopher Hoover wrote:
Most (except for Trimble,..) GPS receivers and antennas
are designed to use 50 ohm cable.
Trimble Bullet GPS antennas have a 50 ohm output impedance.
Trimble
Dr Bruce Griffiths wrote:
Chris
Christopher Hoover wrote:
Most (except for Trimble,..) GPS receivers and antennas
are designed to use 50 ohm cable.
Trimble Bullet GPS antennas have a 50 ohm output impedance.
Trimble literature however is ambiguous in that in
From: Ulrich Bangert [EMAIL PROTECTED]
Subject: Re: [time-nuts] Austron PRR-10 GPS discliplined Rb...
Date: Sat, 27 Jan 2007 13:24:48 +0100
Message-ID: [EMAIL PROTECTED]
Hi Magnus,
Hi Ulrich,
Sorry for the delay, but I made a little trip and just came back.
can you supply this manual???
No
I took a picture of my ACE-III test board.
http://www.ko4bb.com/Test_Equipment/ACE-III
There is a picture showing it side by side with the Jupiter. The Jupiter
is a little smaller, but draws about 240mA versus 95 for the ACE-III, so
the ACE-III is much better suited to a portable system.
I
Thank you all for the suggestions and ideas regarding clock hacking for my GPS
clock!
Mark
W8XR
___
time-nuts mailing list
time-nuts@febo.com
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
I power it through a small integrated switcher from National
Semiconductors (old sample), so the current draw at 12V is just about
70mA with the antenna plugged in and nothing gets hot.
If low power is more important than great-timing, the Garmin GPS-18-LVC takes
60 mA @ 5 Vdc.
--
These
HI Didier:
It's my understanding that the term impedance can only be applied when
sine wave signals are being used. So for pulse work you might look at
the harmonic content and try to match all those frequencies.
Long ago Bob Grove promoted the idea of using 75 Ohm TV coax for ham
antennas
On Sun, 28 Jan 2007 13:02:39 -0800, Brooke Clarke [EMAIL PROTECTED]
wrote:
Long ago Bob Grove promoted the idea of using 75 Ohm TV coax for ham
antennas at 2 meters and higher frequencies because it had lower loss
than 50 Ohm coax and was much lower in cost. For ham applications the
VSWR due
Didier Juges wrote:
Dr Bruce Griffiths wrote:
Didier Juges wrote:
Dr Bruce Griffiths wrote:
Christopher Hoover wrote:
Most (except for Trimble,..) GPS receivers and antennas
are designed to use 50 ohm cable.
Trimble Bullet GPS
Didier Juges wrote:
Dr Bruce Griffiths wrote:
Chris
Christopher Hoover wrote:
Most (except for Trimble,..) GPS receivers and antennas
are designed to use 50 ohm cable.
Trimble Bullet GPS antennas have a 50 ohm output impedance.
In message [EMAIL PROTECTED], Dr Bruce Griffiths writes:
I can see the difference between the short 50 ohm cable terminated in 50
ohms and the short 50 ohm cable terminated in 75 ohms.
It would be instructive to repeat this with a short length of 75 ohm
cable terminated in50 and 75 ohms.
The
Poul-Henning Kamp wrote:
In message [EMAIL PROTECTED], Dr Bruce Griffiths writes:
I can see the difference between the short 50 ohm cable terminated in 50
ohms and the short 50 ohm cable terminated in 75 ohms.
It would be instructive to repeat this with a short length of 75 ohm
cable
It is true is that the impedance of a transmission line is not constant
with frequency, particularly at the low end (audio).
At the higher end, a lot of things happen, such as impedance,
attenuation and velocity factor all change (a little) with frequency.
Also, at the higher end, leakage
Accuracy of 10mhz - a simple explanation?
So can any one provide a link or want to try and explain to this layman what
the deal is with the accuracy spec provided by (or should I say claimed by)
the various manufactures and kits out there?
For example my Trimble claims to have accuracy of
[EMAIL PROTECTED] said the following on 01/28/2007 06:11 PM:
Accuracy of 10mhz - a simple explanation?
So can any one provide a link or want to try and explain to this layman what
the deal is with the accuracy spec provided by (or should I say claimed by)
the various manufactures and
Dr Bruce Griffiths wrote:
Didier Juges wrote:
Dr Bruce Griffiths wrote:
Chris
Christopher Hoover wrote:
Most (except for Trimble,..) GPS receivers and antennas
are designed to use 50 ohm
Didier Juges wrote:
It is true is that the impedance of a transmission line is not constant
with frequency, particularly at the low end (audio).
At the higher end, a lot of things happen, such as impedance,
attenuation and velocity factor all change (a little) with frequency.
Also, at the
Didier Juges wrote:
Dr Bruce Griffiths wrote:
Didier Juges wrote:
Dr Bruce Griffiths wrote:
Chris
Christopher Hoover wrote:
Most (except
Didier Juges wrote:
Bruce,
You have done it again. Now, I have more ideas for interesting
experimentation and still not more time :-)
I have 3 coax runs going from my ham shack to the top of my tower to
feed the HF (14 to 30 MHz) and two VHF antennas (6m and 2m, or 50 MHz
and 144 MHz).
Hi Didier:
The Tek 1502 is great for doing this, especially if you have the
optional strip chart recorder. It's what it was made to do.
http://www.pacificsites.com/~brooke/Tek1502.shtml
Have Fun,
Brooke Clarke
w/Java http://www.PRC68.com
w/o Java
I think that the simplest explanation for the BIPM's recommendation that
the antenna cables be matched to the antenna output impedance and the
GPS receivers input impedance is as follows:
If one has gone to the trouble and expense of installing an antenna that
is relatively insensitive to
Hi Didier:
Yes they are on eBay. The tunnel diode models have a narrower pulse
than the later models that use something more rugged. Probably for all
practical purposes one of the newer ones would work well and last
better. I think the military bought boat loads of these and I've heard
A number of vector network analyzers have a time domain function in them. They
use an inverse Fourier transform to get the display.
This is VERY useful in a high RF environment. A number of years ago we had a
problem on a receiver site for the DARA (Dayton) two meter repeater, and it was
located
Certainly a vector network analyzer is the next piece of test equipment
I need to get. We have several HP 8720 and 8722 where I work, and it's
easy to be spoiled...
Unfortunately, that's another quantum leap in cost from the spectrum
analyzers and synthesizers I have, at least for those that
Of course for phase comparison with the input, one actually does not
need much filtering as one is only using the NCO digital output as an
input to a phase comparator... spurs and so forth don't count at all
here as they get filtered out in the subsequent loop filter for the
PLL (which
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