Hi
The tempco gotcha' with the10811 relates to crystal yields.
With a true SC, the operating point on the 10811 is very close to the middle
of the crystal curve (inflection temperature). You can indeed have a crystal
with no turning points (temperature zero TC points). All it has to do is to
Lester Veenstra-“No, Andover Maine.”
The white Dacron fabric dome of the station in Andover,
Maine, really stood out and could be seen by hikers on the
tops of mountains miles away. Somewhere I have photos I
took looking down at that white speck in the
The other thing is that something like a quad helix or patch doesn't have the
same cross-pol over the hemisphere. It could be real good in one direction and
not so good in others. Just like isotropic antennas, you can't physically
realize the same cp in all directions (cf hairy ball theorem)
Magnus Danielson wrote:
On 10/08/2010 03:35 AM, jmfranke wrote:
When I said the feed would work, I was meaning it would work if LHC.
The illustrations and text imply you could just place a normal GPS
receiver at the feed location, but the polarization would be wrong.
Which was what I reacted
Yep, a Cassegrain antenna would work.
John WA4WDL
--
From: Bill Janssen bi...@ieee.org
Sent: Friday, October 08, 2010 11:52 AM
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] GPS backup for
Bill Janssen wrote:
Magnus Danielson wrote:
On 10/08/2010 03:35 AM, jmfranke wrote:
When I said the feed would work, I was meaning it would work if LHC.
The illustrations and text imply you could just place a normal GPS
receiver at the feed location, but the polarization would be wrong.
Hi Jim:
I've got a spare Ku band satellite dish and would like to use it for GPS.
In an ideal application the GPS antenna would be mounted in the normal
manner and above it would be a sub-reflector aimed at the Ku dish.
That way the antenna might pickup sats near the horizon directly and
from
I've been half following this thread and can't make out the reason for a
less than hemispheric antenna pattern. GPS needs several birds to lock up,
and if you look at a single bird, Dopplar will make the signal useless as
a frequency reference.
Best,
-John
=
Hi Jim:
I've got a
The Doppler is dramatically reduced by looking only at the WAAS bird(s).
John WA4WDL
--
From: J. Forster j...@quik.com
Sent: Friday, October 08, 2010 1:27 PM
To: bro...@pacific.net; Discussion of precise time and frequency
measurement
On Oct 8, 2010, at 10:27 AM, J. Forster wrote:
GPS needs several birds to lock up,
To get a position fix, this is true; 3 birds minimum for a 2D fix, 4 birds
minimum for a 3D fix.
and if you look at a single bird, Dopplar will make the signal useless as
a frequency reference.
Only if you
KISS. This seems like a lot of work for not particularily good results.
Among other things, you have no closure so no measure of how good your
measuremwent is.
FWIW,
-John
On Oct 8, 2010, at 10:27 AM, J. Forster wrote:
GPS needs several birds to lock up,
To get a
On 10/8/2010 10:44 AM, J. Forster wrote:
KISS. This seems like a lot of work for not particularily good results.
I think the point is that the results are amazingly better than the
alternative if the medium-orbit GPS sats are all destroyed and/or
there's jamming coming from all over the
Brooke Clarke wrote:
Hi Jim:
I've got a spare Ku band satellite dish and would like to use it for GPS.
In an ideal application the GPS antenna would be mounted in the normal
manner and above it would be a sub-reflector aimed at the Ku dish.
That way the antenna might pickup sats near the
J. Forster wrote:
I've been half following this thread and can't make out the reason for a
less than hemispheric antenna pattern. GPS needs several birds to lock up,
and if you look at a single bird, Dopplar will make the signal useless as
a frequency reference.
If you're looking at boosting
Matthew Kaufman wrote:
On 10/8/2010 10:44 AM, J. Forster wrote:
KISS. This seems like a lot of work for not particularily good results.
I think the point is that the results are amazingly better than the
alternative if the medium-orbit GPS sats are all destroyed and/or
there's jamming
On Oct 8, 2010, at 10:44 AM, J. Forster wrote:
KISS. This seems like a lot of work for not particularily good results.
Among other things, you have no closure so no measure of how good your
measuremwent is.
Single-satellite timing mode is already commonly implemented in timing
receivers;
On 10/08/2010 07:27 PM, J. Forster wrote:
I've been half following this thread and can't make out the reason for a
less than hemispheric antenna pattern. GPS needs several birds to lock up,
and if you look at a single bird, Dopplar will make the signal useless as
a frequency reference.
If you
On 10/08/2010 08:07 PM, Matthew Kaufman wrote:
On 10/8/2010 10:44 AM, J. Forster wrote:
KISS. This seems like a lot of work for not particularily good results.
I think the point is that the results are amazingly better than the
alternative if the medium-orbit GPS sats are all destroyed and/or
On 10/08/2010 08:22 PM, jimlux wrote:
Brooke Clarke wrote:
Hi Jim:
I've got a spare Ku band satellite dish and would like to use it for GPS.
In an ideal application the GPS antenna would be mounted in the normal
manner and above it would be a sub-reflector aimed at the Ku dish.
That way the
We had similar dome in Sunnyvale (Ca) until the late 80's, but I can't remember
who owned it, maybe GE?; it's all housing now.
Dave
- Original Message -
From: Arthur Dent golgarfrinc...@yahoo.com
To: time-nuts@febo.com
Sent: Friday, October 8, 2010 5:06:34 AM
Subject:
I have a section of the radome material, and the aluminum reflector surface
(honeycomb backing structure) at home.
Lester B Veenstra MØYCM K1YCM
les...@veenstras.com
m0...@veenstras.com
k1...@veenstras.com
US Postal Address:
PSC 45 Box 781
APO AE 09468 USA
UK Postal Address:
Dawn Cottage
Where? Off 401 near the Blue Cube?
-John
=
We had similar dome in Sunnyvale (Ca)Â until the late 80's, but I can't
remember who owned it, maybe GE?; it's all housing now.
Dave
- Original Message -
From: Arthur Dent golgarfrinc...@yahoo.com
To: time-nuts@febo.com
Magnus Danielson wrote:
On 10/08/2010 08:22 PM, jimlux wrote:
B
You might do just as well with a flat cookie sheet.
Well, a 1 m dish gives you 48 dB gain at L1 if I calculate correctly.
I don't think so..48dBi would be huge...A numerical gain of 48 I can
believe:
let's say we have
48dBi is way way too big
18 I might go for
Look at aperture. Say it's six square wavelengths(40x60 cm). A dipole is about
1/8th square wave lengths..so the gain is 48 times that of a dipole. Say about
17dB +2dB or 19 dBi
On Oct 8, 2010, at 3:05 PM, Magnus Danielson
20 log(base10) (diameter in meters) + 20log(frequency in ghz) +17.8 = dbi
On 10/8/2010 8:39 PM, jimlux wrote:
Magnus Danielson wrote:
On 10/08/2010 08:22 PM, jimlux wrote:
B
You might do just as well with a flat cookie sheet.
Well, a 1 m dish gives you 48 dB gain at L1 if I calculate
Hi John:
The WAAS birds may be too weak to receive with an omni antenna, hence
the desire to get some gain.
The normal GPS sats will pass through the beam and the GPS antenna will
pick up some sats directly so you do get some TRAIM.
Doppler is not an issue in timing mode (i.e. position is
Brian Kirby wrote:
20 log(base10) (diameter in meters) + 20log(frequency in ghz) +17.8 = dbi
That assumes some nominal efficiency?
I'll have to remember that one.. 17.8
It's like the 32.44 dB for free space loss between isotropes 1 km apart
at 1 MHz
(+20log10(dist in km) + 20log10(freq
You mean near the intersection of 401 and 537? Close to 385 also.
(I took the liberty of keeping up the code and adding 300 to everything.)
-Rex
On 10/8/2010 6:26 PM, J. Forster wrote:
Where? Off 401 near the Blue Cube?
-John
=
We had similar dome in Sunnyvale (Ca)Â until
The received WAAS signal strength is designed to be similar to that from
regular GPS satellites. And, I find that to be true in practice.
John
--
From: Brooke Clarke brooke95...@att.net
Sent: Friday, October 08, 2010 2:09 PM
To: j...@quik.com;
These were formulas I had written in my notes about 30 years ago, when I
worked in Satcom for the military and NASA.
I think they used an efficiency of 55 percent
another was 20log D(feet) + 20log F(mhz) - 52.4 = dbi
and the main formula of gain in db = k(pi*D/wave)squared showing
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