LORAN C

[Michael Kennedy]

This started out as a repair issue, my LORAN unit wasn't getting a signal. I
thought it was broken. I have been gone from the USA for 2 years and but
after some research I have found out that in my time gone that the
government has decided that we no longer need LORAN or any form of backup
for GPS.

I can only hope that we will see the LORAN system come back in some form in
the future. Is it just me or does it seem stupid to do away with out only
backup system for GPS?

LORAN is robust where as GPS seems qite frail in comparison. I have lost GPS
signals in bad weather but never LORAN, but maybe this is just my
observations and not a true representation of the facts.

 

[Jeff Liebermann]

On Wed, 1 Sep 2010 15:13:11 +0900, "Michael Kennedy" <mike@com> wrote:

This started out as a repair issue, my LORAN unit wasn't getting a signal. I
thought it was broken. I have been gone from the USA for 2 years and but
after some research I have found out that in my time gone that the
government has decided that we no longer need LORAN or any form of backup
for GPS.

Yep. The US pulled the plug earlier this year:
<http://www.navcen.uscg.gov/?pageName=loranMain>
Also Canada, Africa, and Russia.

Some European countries still have their systems running:
<http://www.loran-europe.eu/viewpage.php?page_id=23>
<http://www.loran-europe.eu/viewpage.php?page_id=5>
but my guess is when Galileo is fully operational, Europe will also
pull the plug. That may be many years with the current rate of
funding and progress:
<http://en.wikipedia.org/wiki/Galileo_Navigation_System>
Meanwhile their Loran-C system is still up mostly because they want to
rely on a US controlled GPS system.

I can only hope that we will see the LORAN system come back in some form in
the future. Is it just me or does it seem stupid to do away with out only
backup system for GPS?

It depends on what you're trying to accomplish. Seen any cell phones
with Loran-C for E911 location? Vehicle navigation systems with
Loran-C? For many things, GPS is the only way it can be done (or done
economically). Nobody wants a 10ft long amplified Loran antenna
hanging off their cell phone.

I don't think you'll see the Loran zombie rise from the dead.

LORAN is robust where as GPS seems qite frail in comparison. I have lost GPS
signals in bad weather but never LORAN, but maybe this is just my
observations and not a true representation of the facts.

GPS has its problems, but the latest units are sufficiently sensitive
to work even in a storm. Location is important and having your
receiver antenna below deck may cause reception problems. Try some of
the newer "high sensitivity" GPS receivers and see if it works any
better. If below deck on a handheld, thing about a docking station
and external mast mounted antenna:
<http://en.wikipedia.org/wiki/High_Sensitivity_GPS>


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[N_Cook]

Jeff Liebermann <jeffl@cruzio.com> wrote in message
news:fi1s76pkapdrpdlbfk1134pb7t2squgufk@4ax.com...

On Wed, 1 Sep 2010 15:13:11 +0900, "Michael Kennedy" <mike@com> wrote:

This started out as a repair issue, my LORAN unit wasn't getting a
signal. I
thought it was broken. I have been gone from the USA for 2 years and but
after some research I have found out that in my time gone that the
government has decided that we no longer need LORAN or any form of backup
for GPS.

Yep. The US pulled the plug earlier this year:
http://www.navcen.uscg.gov/?pageName=loranMain
Also Canada, Africa, and Russia.

Some European countries still have their systems running:
http://www.loran-europe.eu/viewpage.php?page_id=23
http://www.loran-europe.eu/viewpage.php?page_id=5
but my guess is when Galileo is fully operational, Europe will also
pull the plug. That may be many years with the current rate of
funding and progress:
http://en.wikipedia.org/wiki/Galileo_Navigation_System
Meanwhile their Loran-C system is still up mostly because they want to
rely on a US controlled GPS system.

I can only hope that we will see the LORAN system come back in some form
in
the future. Is it just me or does it seem stupid to do away with out only
backup system for GPS?

It depends on what you're trying to accomplish. Seen any cell phones
with Loran-C for E911 location? Vehicle navigation systems with
Loran-C? For many things, GPS is the only way it can be done (or done
economically). Nobody wants a 10ft long amplified Loran antenna
hanging off their cell phone.

I don't think you'll see the Loran zombie rise from the dead.

LORAN is robust where as GPS seems qite frail in comparison. I have lost
GPS
signals in bad weather but never LORAN, but maybe this is just my
observations and not a true representation of the facts.

GPS has its problems, but the latest units are sufficiently sensitive
to work even in a storm. Location is important and having your
receiver antenna below deck may cause reception problems. Try some of
the newer "high sensitivity" GPS receivers and see if it works any
better. If below deck on a handheld, thing about a docking station
and external mast mounted antenna:
http://en.wikipedia.org/wiki/High_Sensitivity_GPS


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

I hope LW RDF is still going , I liked the morse ident feature and its
simplicity. I doubt , over some distance , it is any less accurate than
Loran and no hyperbolic plots to deal with

 

[Geoffrey S. Mendelson]

N_Cook wrote:

I hope LW RDF is still going , I liked the morse ident feature and its
simplicity. I doubt , over some distance , it is any less accurate than
Loran and no hyperbolic plots to deal with

Even if it is still transmitting, the likelyhood of you being able to receive
it is dropping every day. Out in the ocean, on a sailboat, you can turn off
all of the devices that radiate noise on those frequencies, but on land
you can't.

In many large urban areas, it's just a large "cloud" of noise up to 15 mHz or
so, with most of it below 4mHz.

So you will be able to clearly receive the noise but not find a signal.

On the other hand if you are out in the ocean with an RDF, you can just
point it to the noise and find land. It may not be the land you want,
but it will be land.

Geoff.

--
Geoffrey S. Mendelson N3OWJ/4X1GM
To help restaurants, as part of the "stimulus package", everyone must order
dessert. As part of the socialized health plan, you are forbidden to eat it.

 

[Meat Plow]

On Wed, 01 Sep 2010 15:13:11 +0900, Michael Kennedy wrote:

This started out as a repair issue, my LORAN unit wasn't getting a
signal. I thought it was broken. I have been gone from the USA for 2
years and but after some research I have found out that in my time gone
that the government has decided that we no longer need LORAN or any form
of backup for GPS.

I can only hope that we will see the LORAN system come back in some form
in the future. Is it just me or does it seem stupid to do away with out
only backup system for GPS?

LORAN is robust where as GPS seems qite frail in comparison. I have lost
GPS signals in bad weather but never LORAN, but maybe this is just my
observations and not a true representation of the facts.

I'm sure aviation and military GPS units are as robust as loran. Consumer
units might be helped by a better antenna.



--
Live Fast, Die Young and Leave a Pretty Corpse

 

[Jeff Liebermann]

On Wed, 1 Sep 2010 10:30:59 +0100, "N_Cook" <diverse@tcp.co.uk> wrote:

I hope LW RDF is still going , I liked the morse ident feature and its
simplicity. I doubt , over some distance , it is any less accurate than
Loran and no hyperbolic plots to deal with

Yep. They're still alive and well. I still have a Taiho automagic
mechanically rotating LW RDF that I use for demonstrations. It's fun
to watch the loop seek and maybe point. Some of the LW beacon
stations are sending DGPS which have largely been replaced by WAAS
technology. Hearing LW beacons more than a few miles from shore is
tricky without a big antenna. You would probably be more successful
using AM, FM, and TV stations for coastline navigation, than using the
few LW stations.
<http://www.beaconworld.fotopic.net/list_collections.php>

Incidentally, the big problem with Loran-C was that it really didn't
work more than about 100 miles offshore. That limitation sold
considerable number of (pre-GPS) Transit and Omega systems as "backup"
for Loran-C. At least they worked in mid ocean. Incidentally, I
still have my Tamaya sextant and a Magnavox TRANSIT receiver in
storage.

If you want to do it thyself, it's possible to do 2D TRANSIT(NAVSAT)
doppler navigation if you can hear some LEO satellites, know the
Keplarian elements, and can accurately measure and record the doppler
shift as it passes overhead, using triangulation and trilateration.
The NIMS system may still be alive on 149.985 and 399.970 with
telemetry on 136.650 MHz although Keps appear to be lacking:
<http://www.zarya.info/Frequencies/Frequencies150.php>
Have your spherical geometry reference book handy. I've never
actually tried it, but it should be possible:
<http://en.wikipedia.org/wiki/Trilateration>

The Origins of GPS:
<http://www.gpsworld.com/gnss-system/gps-modernization/the-origins-gps-part-1-9890>
<http://www.gpsworld.com/gnss-system/gps-modernization/the-origins-gps-part-2-fighting-survive-10010>


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[GregS]

In article <mu0t761s85hgq8f1vnv3vhelfppfc43af4@4ax.com>, Jeff Liebermann <jeffl@cruzio.com> wrote:

On Wed, 1 Sep 2010 10:30:59 +0100, "N_Cook" <diverse@tcp.co.uk> wrote:

I hope LW RDF is still going , I liked the morse ident feature and its
simplicity. I doubt , over some distance , it is any less accurate than
Loran and no hyperbolic plots to deal with

Yep. They're still alive and well. I still have a Taiho automagic
mechanically rotating LW RDF that I use for demonstrations. It's fun
to watch the loop seek and maybe point. Some of the LW beacon
stations are sending DGPS which have largely been replaced by WAAS
technology. Hearing LW beacons more than a few miles from shore is
tricky without a big antenna. You would probably be more successful
using AM, FM, and TV stations for coastline navigation, than using the
few LW stations.
http://www.beaconworld.fotopic.net/list_collections.php

If we got a big solar storm, and most or all satellites got knocked out,
along with ground power, the beacons may be the only route home.

I remember having to record Loran D, just another experimental site.

Incidentally, the big problem with Loran-C was that it really didn't
work more than about 100 miles offshore. That limitation sold
considerable number of (pre-GPS) Transit and Omega systems as "backup"
for Loran-C. At least they worked in mid ocean. Incidentally, I
still have my Tamaya sextant and a Magnavox TRANSIT receiver in
storage.

If you want to do it thyself, it's possible to do 2D TRANSIT(NAVSAT)
doppler navigation if you can hear some LEO satellites, know the
Keplarian elements, and can accurately measure and record the doppler
shift as it passes overhead, using triangulation and trilateration.
The NIMS system may still be alive on 149.985 and 399.970 with
telemetry on 136.650 MHz although Keps appear to be lacking:
http://www.zarya.info/Frequencies/Frequencies150.php
Have your spherical geometry reference book handy. I've never
actually tried it, but it should be possible:
http://en.wikipedia.org/wiki/Trilateration

The Origins of GPS:
http://www.gpsworld.com/gnss-system/gps-modernization/the-origins-gps-part-1-9
890
http://www.gpsworld.com/gnss-system/gps-modernization/the-origins-gps-part-2-f
ighting-survive-10010

 

[Michael Kennedy]

"GregS" <zekfrivo@zekfrivolous.com> wrote in message
news:i5m6pq$jf8$1@usenet01.srv.cis.pitt.edu...

In article <mu0t761s85hgq8f1vnv3vhelfppfc43af4@4ax.com>, Jeff Liebermann
jeffl@cruzio.com> wrote:
On Wed, 1 Sep 2010 10:30:59 +0100, "N_Cook" <diverse@tcp.co.uk> wrote:

I hope LW RDF is still going , I liked the morse ident feature and its
simplicity. I doubt , over some distance , it is any less accurate than
Loran and no hyperbolic plots to deal with

Yep. They're still alive and well. I still have a Taiho automagic
mechanically rotating LW RDF that I use for demonstrations. It's fun
to watch the loop seek and maybe point. Some of the LW beacon
stations are sending DGPS which have largely been replaced by WAAS
technology. Hearing LW beacons more than a few miles from shore is
tricky without a big antenna. You would probably be more successful
using AM, FM, and TV stations for coastline navigation, than using the
few LW stations.
http://www.beaconworld.fotopic.net/list_collections.php

If we got a big solar storm, and most or all satellites got knocked out,
along with ground power, the beacons may be the only route home.

I remember having to record Loran D, just another experimental site.

snip

My thoughs exactly.. Unfortuantely loran could have been a backup
useful for boats and airplanes within the range of the system.

 

[Andy]

On Sep 1, 3:08 am, Jeff Liebermann <je...@cruzio.com> wrote:

On Wed, 1 Sep 2010 15:13:11 +0900, "Michael Kennedy" <mike@com> wrote:
This started out as a repair issue, my LORAN unit wasn't getting a signal. I
thought it was broken. I have been gone from the USA for 2 years and but
after some research I have found out that in my time gone that the
government has decided that we no longer need LORAN or any form of backup
for GPS.

Yep. The US pulled the plug earlier this year:
http://www.navcen.uscg.gov/?pageName=loranMain
Also Canada, Africa, and Russia.

Some European countries still have their systems running:
http://www.loran-europe.eu/viewpage.php?page_id=23
http://www.loran-europe.eu/viewpage.php?page_id=5
but my guess is when Galileo is fully operational, Europe will also
pull the plug. That may be many years with the current rate of
funding and progress:
http://en.wikipedia.org/wiki/Galileo_Navigation_System
Meanwhile their Loran-C system is still up mostly because they want to
rely on a US controlled GPS system.

I can only hope that we will see the LORAN system come back in some form in
the future. Is it just me or does it seem stupid to do away with out only
backup system for GPS?

It depends on what you're trying to accomplish. Seen any cell phones
with Loran-C for E911 location? Vehicle navigation systems with
Loran-C? For many things, GPS is the only way it can be done (or done
economically). Nobody wants a 10ft long amplified Loran antenna
hanging off their cell phone.

I don't think you'll see the Loran zombie rise from the dead.

LORAN is robust where as GPS seems qite frail in comparison. I have lost GPS
signals in bad weather but never LORAN, but maybe this is just my
observations and not a true representation of the facts.

GPS has its problems, but the latest units are sufficiently sensitive
to work even in a storm. Location is important and having your
receiver antenna below deck may cause reception problems. Try some of
the newer "high sensitivity" GPS receivers and see if it works any
better. If below deck on a handheld, thing about a docking station
and external mast mounted antenna:
http://en.wikipedia.org/wiki/High_Sensitivity_GPS

--
Jeff Liebermann je...@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Andy comments:

I designed the TI Loran C for aircraft 30 yrs ago and found that
a 22 inch antenna
would deliver the same S/N ratio as a longer antenna, since the
antenna
would pick up atm. noise and signal in the same ratio, and 22 inches
was
about where the noise figure of the electronics would exceed the
atmospheric noise........ Still, a 22 inch antenna on a cell phone
would make it hard to carry in your pocket. .... so your point
is well taken.

:&gt)) Andy in Eureka, Texas

 

[Andy]

On Sep 1, 6:36 am, Meat Plow <mhyw...@yahoo.com> wrote:

I'm sure aviation and military GPS units are as robust as loran. Consumer
units might be helped by a better antenna.

Andy comments:

The only way the antenna can be "better" is to have more gain.
That
requires the antenna to be more directional. Such is not a good idea
'in GPS since one needs a hemispherical pattern, to account for
where all the satellites are.

It's true that some GPS units have a poor antenna, but that's a
matter
of cosmetics more than anything else. Many military units are
handheld
and therefore have the same problem. Any unit with a remotely
mounted antenna will perform about the same as any other unit,
whether military or commercial, since they are all designed to
have a hemispherical pattern.

Just feel like talking....

Andy in Eureka, Texas

 

[Jeff Liebermann]

On Thu, 9 Sep 2010 06:26:04 -0700 (PDT), Andy <andysharpe@juno.com>
wrote:

I designed the TI Loran C for aircraft 30 yrs ago and found that
a 22 inch antenna
would deliver the same S/N ratio as a longer antenna, since the
antenna
would pick up atm. noise and signal in the same ratio, and 22 inches
was
about where the noise figure of the electronics would exceed the
atmospheric noise........ Still, a 22 inch antenna on a cell phone
would make it hard to carry in your pocket. .... so your point
is well taken.

:&gt)) Andy in Eureka, Texas

<http://www.prc68.com/I/TI9100.shtml>
If so, nicely done. The commercial marine version was not so nice:
<http://smithsonianchips.si.edu/texas/t_357.htm>
At $2100 in 1978, that's about $6200 in todays dollars. Ouch.

You're right about atmospheric noise being greater than what the what
would justify a low noise front end. This limits the maximum
sensitivity of all HF receivers. My problem was overload. There was
so much noise (and signal) that I had to use a front end RF amp that
dissipated about 1/2 watt just to remain linear. The amp had to be
near the antenna to prevent picking up electronics crud via the
antenna line and so we could use cheap coax.

The 8 or 10ft fiberglass whip antenna was a no brainer for marine use.
The typical HF antenna 10ft and a matching antenna looked nice on the
other side of the vessel. It it were done on an airplane, I'm sure
the size would have been more of an issue. Shakespeare does make a
4ft Loran antenna. The Loran antenna has also morphed into a DGPS
antenna.



--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Jeff Liebermann]

On Thu, 9 Sep 2010 06:32:06 -0700 (PDT), Andy <andysharpe@juno.com>
wrote:

On Sep 1, 6:36 am, Meat Plow <mhyw...@yahoo.com> wrote:


I'm sure aviation and military GPS units are as robust as loran. Consumer
units might be helped by a better antenna.


Andy comments:

The only way the antenna can be "better" is to have more gain.

Ummm....
1. Better match (VSWR)
2. Better front to back ratio
3. Fewer side lobes
4. Better looking pattern.
5. Smaller, cheaper, lighter, easier to build, etc.
6. Grounded design to avoid static electricity buildup.
Gain is not the only thing that's important in antennas.

That
requires the antenna to be more directional.

True. Antennas only redirect RF. The don't create any. If you need
more signal in one direction, you have to steal it from another
direction.

Such is not a good idea
'in GPS since one needs a hemispherical pattern, to account for
where all the satellites are.

Not really. I've built a perfectly functional GPS antenna that has a
pattern similar to a donut (torus) elevated off the ground with no
gain directly overhead. For location purposes, overhead satellites
are nearly useless because there's no doppler shift.

It's true that some GPS units have a poor antenna, but that's a
matter
of cosmetics more than anything else.

Ahem... There are two basic types of GPS antennas. Patch antennas
and quadrifilar (QFA) antennas. Both have roughly a hemispherical
pattern. The QFA antenna is "better" for some applications because
the radiation angle extends closer to the horizon and below than does
the patch antenna. There's no benefit for 2D positioning, but the
lower radiation angle offers better altitude information. A patch
antenna becomes less circular polarized and more towards elliptical
polarization hear the horizon. Well, at the horizon, it's
horizontally polarized which is good for a -3dB gain loss. QFA
antenna remains fairly RHCP at the horizon.

If you look inside some of the higher end handheld and vehicle mounted
GPS antennas, you'll find a QFA antenna. Garmin GPS 76
<http://i36.photobucket.com/albums/e8/KiwiGPS/Inside%2076CS/76CSInsideViews1Large.jpg>
Kinda looks like it was designed to fit either a patch and QFA.

Many military units are
handheld
and therefore have the same problem. Any unit with a remotely
mounted antenna will perform about the same as any other unit,
whether military or commercial, since they are all designed to
have a hemispherical pattern.

Agreed. The differences are small but if you're trying to squeeze the
last bit of performance out of a handheld, it can be important.

Just feel like talking....

Andy in Eureka, Texas

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
# http://802.11junk.com jeffl@cruzio.com
# http://www.LearnByDestroying.com AE6KS

 

[Jeff Liebermann]

On Fri, 10 Sep 2010 19:48:43 -0700, Jeff Liebermann <jeffl@cruzio.com>
wrote:

On Thu, 9 Sep 2010 06:32:06 -0700 (PDT), Andy <andysharpe@juno.com
wrote:
The only way the antenna can be "better" is to have more gain.

A bit more detail on GPS antenna gain that might be of interest. The
usual assumption is that all GPS patch antennas have the same gain.
Nope. From one of my previous rants on iPhone GPS performance:

Sarantel makes ceramic QFA antennas with -2db to -3dBic gain:
<http://www.sarantel.com/downloads/specifications/geohelix-p2.pdf>

For ceramic substrate backed antennas, size is everything. This has
nothing to do with the iPhone 3G antenna, but does explain why a
ceramic substrate quadrifilar antenna has -2dBic gain, while the much
larger air dielectric version has +5dBic gain. I couldn't find
comparative data for various size quadrifilar antenna, but the
following on patch antennas shows the problem:
<http://www.taoglas.com/images/product_images/original_images/TAOGLAS%20-%20GPS%20Active%20Patch%20Antenna%20Application%20Note.pdf>
Typical peak gain for GPS patch antennas on standardized
ground planes are following.
25mm Patch 5 dBi
18mm Patch 2 dBi
15mm Patch 1 dBi
12mm Patch 0.5 dBi
10mm Patch -2 dBi

The effective bandwidth of a GPS antenna is usually measured
by the frequency band below -10dB return loss. A GPS ceramic
patch bandwith narrows with size. Typical bandwidths for
GPS patches are as follows
25*25*4 mm 20 MHz
18*18*4 mm 10 Mhz
15*15*4 mm 8 Mhz
12*12*4 mm 7 MHz
10*10*4 mm 5 MHz
Therefore the smaller the antenna, the more chance it will
have that frequency shifts in the device will cause it to
perform very poorly, thus necessitating that the antenna
bandwidth be retuned to have the effective bandwidth at the
GPS 1.5754 GHz frequency.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558