Austron 2100F LORAN-C Frequency Monitor
& 2100T Timing Receiver
2100F Frequency Monitor
2100T Timing Receiver
1290A 24 Volt Standby Power Supply
Pickard & Burns Model 601 Loran-C Receiver
The LORAN-C system was originally designed for marine
coastal navigation but has since been used for other purposes.
Aircraft LORAN-C receivers added the low cost capability to fly
directly from point A to point B. Prior to LORAN-C most
flew radials either to or from the location of a navigation aid.
Additional LORAN-C chains were added to the central U.S. so
users on land and on lakes could take advantage of this precise
Prior to LORAN-C the highest quality frequency standard in the
was the WWVB radio station on 60 kHz. There are similar LF
stations on nearby frequencies in other countries. Note
can be used both as a frequency reference and by decoding it's
time signal can be used to set clocks and watches. LORAN-C
provides a much more stable frequency monitoring capability than
had using WWVB and this is the application the Austron 2100F
Frequency Monitor was built to serve.
The stock LORAN-C system currently does not have any digital
containing time or date information so can not be used as a way
a clock. But by knowing the epoch date and time of the
system it is possible to know when the synchronization point on
station being received matches the UTC second exactly. The
Austron 2100T was designed for this Time Of Coincidence (TOC)
2007 - There is Enhanced
(eLORAN) experimental work going on now. Part of this is
(LDC) that will add data packets to the existing LORAN-C
stations. It works by adding a new pulse after all
existing pulses hence existing receivers will not notice the new
one. It's Pulse Position Modulation whrere the new pulse
shifted to one of 32 (from memory) different time slots. A
of these make up one data packet. One of the data packets
date and time information so you could set a clock, just like
from GPS or WWVB. Other packets have the Lon and Lat of
antenna and other ID info. As of June 2007 these stations
broadcasting the Data Channel:
- Jupiter, FL 7980-Y
- Las Cruces , NM 9610-X
- Seneca, NY 8970-X
- Gillette, WY 8290-X
- Grangeville, LA 7980-Y
The stations listed below are capable of but not currently
broadcasting the Loran Data Channel.
Another aspect of the eLORAN
will be a change from the current Master -delay- Slave timing
system. This way of timing made sense in the old days since
quality of the position fix depended on the time delays and if the
master station drifted it was not important. But as the
stations get upgraded to atomic standards corrected by phase micro
steppers the timing can switch to a system based on UTC. The
existing single chain LORAN-C receivers will not be affected by
change, but it then opens up the possibility of an "All in View"
LORAN-C receiver working in a fashion similar to GPS where all the
stations that can be heard are used for the position or time
I'd guess that if you throw a dart at a globe at that point you
receive all of one chain and maybe a station or two or more from
adjacent chains, but not enough adjacent stations to get a fix
them alone. So an all in view receiver will do better
adding any new transmitting stations.
- Middletown, CA 9940-X (* Middletown was testing the
channel a few months ago)
- Dana, IN 9960-Z
- George, WA 5990-Y
The 2100F works by comparing the external reference
frequency with the selected LORAN-C station. This is done
generating a pulse from the external reference at the GRI rate
noting the change in the time interval between it and the
that's being tracked. The result can be seen either in
the time offset (O/FS) or as a stability number like
This 2100F Frequency Monitor does not have a built in
and so needs a 1, 5 or 10 MHz input signal that is an accuracy of
or better in addition to an antenna and power. I'm using the
AMRAD active LF whip and it works
My Stanford Research PRS10 GPS
Rb oscillator is the source of 10 MHz fed into the 2100F.
After letting the 2100F receive the Middletown, CA station that
less than 1 degree of Lat and Lon from me (Status 2 Noise = 0)
frequency offset displayed 1.0E-13. I don't understand why
jumps around to 4.0 E-12 because the phase error value (status
There may be a need for the 2100F to run for some hours to
stabilize temperature in order to track properly. When
turned on it would quickly lock on Middletown but would not lock
the chain master station. After a few hours it would
something when "Advance Station" was
Whent he Advance button is pressed the display is supposed to show
time difference between the master and the station being tracked.
But so far it does not add up. (LORAN-C station locations rounded
|miles @ degrees
||233 mi @ 94.8
||570 mi @ 16.5
||46 mi @ 127.8
||532 mi @ 117.5
|2100F "station advance" delay
|delay based on known location
Station Advance - when this button is pressed a number will
appear if the 2100F has been able to see the master station pulse,
no master station
then the display will show ------. Each time you press
<station advance> a new number will appear indicating
be tracked. To change stations enter the number of stations
then press station advance and the receiver will go into acquire
5 May '03 - After a few weeks of rainy weather where only the
would lock up the receiver would not sync onto the chain master by
But when <1><ACQ> is done for a new acquisition
and other slave stations were found. So it appears that this
forced manually. The stations are now 0 (Fallon master),
43668 (Searchlight), and today Geroge is not there, but may show
Stations Received at 39N 123W:
chain 59900 George, WA delay 27000
chain 96100 Bosie City, OK delay 0
NM delay 41600
chain 99400 Fallon, NV delay 0
By using an oscilloscope that is
from the 2100F and displaying the raw received signal you can see
of the signal and by using the time base trigger delay function
time window being viewed through the complete GRI space.
other stations in the chain to be seen. But the problem is
is designed to receive only a single station and so it's gain is
that station. When receiving Middletown which is very strong
is turned down making it difficult to impossible to see weak
When acquiring a GRI the first time it is not clear which
the receiver locks onto. It does not seem to always be the
the strongest station.
The amplitude of the signal has some form of amplitude
modulation. It is slow and can be seen in this 1.4 MB AVI
that lasts about 8 seconds. In my browser after the file
see a still
picture on a white background. Clicking on the still plays
10 Feb 2003 - I called the Middletown LORAN-C station and
about this and they said no modulation like that was being
Some time ago there was a program to add modulation, but it
canceled for lack
This must be something caused by all my electronic equipment
is in the Austron receiver.
4 Feb 2005
The timing version of the Austron
receiver uses Time Of Coincidence to synchronize its 1 PPS
the UTC 1 PPS edge. Like GPS there are a number of
that need to be made to get the edges lined up and the manual
that rather than trying to account for all of them that a visit
atomic clock be used to determine the offsets, not just for the
station being tracked for for a number of stations so that they
be available as backups.
The Stanford Research Systems FS700 Loran-C receiver does NOT
Of Coincidence capability, it's more like the A2100F.
LORAN-C will survive GPS
When GPS became operational other
based navigation systems, like Omega, were shut down and the
the LORAN-C system was uncertain. But in Nov. 2004 the report
seems to indicate that the LORAN-C system will stay on the air
and be upgraded
a needed backup to the GPS system for mission critical
applications like commercial aircraft landing systems.
LORAN-C is a navigational system and does not send any
codes so you can not set a clock using Loran-C. But the
system has an epoch date of 00:00:00 hours (UTC), Jan. 1,
Each chain of transmitters has a Group Repition Interval (GRI)
Middletown, CA station is one of the slave transmitters in the
a GRI of 9940 (i.e. the period of the group is 99.4 mS).
when one of these pulses falls exactly on top of a UTC 1 second
can be computed if you know the current time to better than 99.4
my case and you know how the total number of leap seconds since
patent widens the 99.4 mS time window by looking
different chains since the Time Of Concidence for both chains
much larger than for a single chain.
Open front panel and set toggle switch to 1, 10 or 5 (left to
frequency. (if this is not done the Tracking LED may blink Red
Green). Then connect to:
Key in the desired GRI (in my case
99400) and press "GRI".
Key in 1 and press Master.
Now the Acquire red LED turns on for awhile, then the Settle red
for awhile, then the green Tracking LED is on.
At this point pressing "Track Data 8" will show "--E-----"
that the TOC has not yet been set.
Note the receiver is now tracking the master station for the
At this point I set the time constant to the longest possible
Track Data 6) which is 3200 GRIs.
15 Feb 2005 - With the Time Constant set to 3200 GRIs I changed
Field on the FTS4060 from 525 to 580, maybe a change of 5.5E-13
1.1E-12 and the Tracking LED started blinking alternately Red
Green. Pressing <1> <SECOND>ary relocked the
to Middletown in about 8 minutes.
Now by entering the Total Emission Delay for the salve station
(Middletown in my case is 28000 us) and pressing SEC TD to set
value, then key in 1 and press SECONDary to lock to that
my case it took 8 minutes to lock up. After the
Tracking LED lights the display is showing the actual emmission
in my case 27072. This can be brought back by pressing the
SECONDary key. Doing the slave lock also disables TOC
tracking so it needs to be re synchronized.
If the receiver is tracking a secondary station and you
MASTER button the display will show "--------", and when you
SECONDary the display will show the total emission delay, in my
This LED is green when tracking a station. It slow blinks
green when the receiver can not track the local reference or it
seen a signal strength change of 10 or more dB. This
will happen if there is no local reference connected or if the
reference is drifting too fast for the Time Constant that has
For a signal strength change the Red-Green can be reset to
by pressing 0 then Track Data then 8.
Ref Freq Offset
TOC lock in photo at left the stability is shown as E10 1.7.
The offset of the local reference can be displayed by using
4 which now is E12 9.4. 8 minutes later the display is E12
and it appears to be working it's way to lower numbers.
minimum delta time interval measured for the Track Data 4
display is 0.01 uS (see this by pressing O/FS). Thus to
would take 1E6 seconds or about 11.57 days. This is where
with a 1 PPS accuracy on the order of tens of nanoseconds has a
The next morning (about 18 hours running time) the Track Data 4
E13 3.7 but waiting more days the best it gets is in the 3E-13
maybe that's as good as the FTS4060 is set?
By pressing <0>, <Track Data>, <7> the O/FS
will be reset to zero. Only zero can be set, not other
This is a good thing to do when adjusting a frequency standard,
Cesium, when a
setting has been made.
LORAN-C may be as good as GPS
precision time transfer, and may have advantages over GPS.
There seems to be a limit of 1.0E-13 in the 2100T. It may
never gets any better,
think that's not the case. For example the stability
into and out of the 1E-14 area, but the 2100T never shows
better than 1.0E-13. If you have seen better numbers let
In order to set the internal clock
external 1 PPS input in needed that's within one GRI (and ahead
second tick). Or the slewable 1 PPS output can be
the EXT 1 PPS input, which I did for convenience. Then the
TOC is keyed in and First TOC pressed to load it. Then 1
in and Begin TOC pressed. At this point the TOC LED will
alternatly flash red nad green and when the TOC time occurs if
well the TOC LED turns solid green.
Once the TOC has been set, the second prior to a new TOC the TOC
turns red then if the internal 1 PPS edge is aligned with the
TOC the LED turns green again.
At power up the green 1PPS LED will have a random timing.
of this it's impossible to set the UTC to within one GRI.
when an external 1PPS is input to the 2100T and an attempt is
set the TOC, although the TOC setting fails, the green 1PPS LED
synchronized to the external 1PPS thus allowing the UTC to be
set. The next TOC setting procedure will then work.
22 Apr 2005 - When using an external 1 PPS that's good, like
from a GPS
receiver, if you set a random time for First TOC and try to
will NOT sync. I tried this to get the 1 PPS in sync, but
didn't work, so now need to use an actual TOC to resync after a
Once the receiver has the TOC locked it automatically computes
next TOC will occur. You can see it by pressing FIRST TOC
(without first pressing 1). One second prior to a TOC the
will turn red then at the TOC back to green.
Pressing <Track Data> <n> will display the Track
Pressing <some number(s)> <Track Data> <n>
the Track Data Value.
Sometimes only zero is a valid input number.
4 = 9 dB
28 = 0 dB
224 = -12 dB
3584 = -21 dB
being tracked (S.B. 3.0)
0 = 3200 GRIs
1 = 1600 GRIs
2 = 800 GRIs
3 = 400 GRIs
4 = 200 GRIs
shift (same as O/FS)
MSB to LSB
E = acquisition Mode
E = TOC LED red
E = No TOC Sync
E = loss for reference
E = LORAN-C Blinking
E= tracking cycle more than 0.5 from 3.0
E= gain change > 10 dB
E = not tracking
Internal fixed - External 1 PPS
Pressing O/FS (Offset) causes
to show the difference between the local reference and the
derived 1 PPS. This receiver was designed for use with
crystal oscillators and so the display can go to thousands of
microseconds with a LSD of 10 nano seconds. The minus
sign is all
the way to the left of the display and so can easily be missed
display is something like 0.03.
Both of these receivers have the IEEE-488 option.
Two 2100T receivers arrived in the
jiffy box from a Government Liquidation auction. They were
as condition code A1 (new) units and included a couple of
manuals. One unit had the left front handle bent inward
prevented the front panel from hinging down and is missing the
side panel attachment captured screw (since replaced with part
RAF). It was
DOA. The other
unit looks nice on the outside.
After reseating the LCD module in the bent handle unit and
the front panel ribbon cable the unit operates properly.
looking unit still has some type of electrical problem.
7 Feb 2005- Board swap troubleshooting
Moving the microprocessor board from the bad receiver into the
receiver causes the good receiver to show the same power up
not end up in time mode) as the bad receiver. This means
there's something wrong with the microprocessor board.
the microprocessor board from the good receiver to ge bad
receiver also has the same power up error. Why?
mystery since there was a bad IC on the microprocessor board,
the loose screw & washer were causing a problem.
A short 2-56 screw and a #2 lock washer were found loose in the
receiver. Came from front panel PCB.
The large PCBs have edge connectors with 43x2 contacts.
front panel facing you looking down on a PCB the contacts are
/Y to A (left to right) The letters are: ABCDEFHJKLMNPRSTUVWXYZ
then again except with a bar over the letter
like /A /B.../Y (no /Z). The contact directly below A is 1
below /Y is 43.
The manual uses signature analysis as a trouble shooting method,
have an HP 5004
Signature Analyzer and will be shortly testing the non working
1 March 2005 - Replaced U4 (74LS244) that the 5004 identified as
and now the receiver powers up properly ending in the time
2 March 2005 - the repaired receiver is working just like the
one. The HP 5004
pointed out the bad IC. If you have an Austron 2100F or
any equipment documented to use it) the Signature Analyzer is a
Some other possible front panel related problems from Chuck
- The 1 uF tantalum caps (C2 and C5) on the front panel PCB
need to be replaced if each key press is causing bounces.
- The LCD may have a poor connection between the pins and
frame. But first try reseating it. This should
be a stock
part, but need to find it.
- If the +5 supply regulator is bad and the voltage gets to
5.5 V the LCD will become erratic.
large PCBs plug into a bus and any one of them can be moved to
top or bottom position to get easy service access without using
The 2 RF amplifiers (small PCBs) also are on a bus so one of
be moved to the top for alignment. The bottom small PCB
card) is always in the bottom slot.
The LORAN-C frequency of 100 kHz is
surrounded by high power military digital radio stations. By
filtering out these stations the interference they cause can be
reduced. There is also a Sferics
panel. Filter #2 (they are numbered right to left when
the front panel) has a "peak" function. The idea is to tune
filter #2 for the maximum interfering signal and then tune one of
other filters to be on that frequency.
The A.C. power input connector looks like a standard american 3
plug recessed in a cylinder, so a special line cord is needed for
power. Made from an extension cord by cutting off a small
Here is a 0 to 200 kHz spectrum
with the output from both the DA-100 and the AMRAD active whip
antennas. You can see that there are a number of adjacent
stronger than my local LORAN-C station.
After using the HP 4395A in both spectrum and network analyzer
filters were set and a comparison spectrum plot from 60 to 160 kHz
made. The upper trace is w/o the filters set using rear
switch. The lower trace is with all filters set except
The Loran-c "triangle" has a peak (-80 dBm) that's maybe 50 dB
floor (-130 dBm) becasue the Middletwon station is very close to
RTTY station at 132.625 has been depressed by about 30 dB.
When testing in N.A. mode any power level higher than -24 dBm
the Sferics lamp to turn on, so N.A. testing was done at -30dBm.
The station at the very left side (60 kHz) is WWVB-C.
I'm using the 2084 as an antenna multicoupler driving a couple of
receivers with the filters turned on. I've noticed that the
Sferics white lamp flashes every
now and then.
I notice that the green 1 PPS LEDs on the two receivers are not
flashing at the same time, need to figure out how to synchronize
i.e. get them correct. This has been done, see TOC above for
Friday 22 April 2005 4 pm PDT N. Calif.- It's been high overcast
of the day and the
Sferics lamp has been flashing and sometimes double flash.
2100T receivers went into alternate red-green TRACK mode.
Pressing 0 - <Track Data> 8 cured the top 2100T, but the
receiver (has the top receiver's output as it's input) lost lock
would wasn't fixed by 0 - <Track Data> 8. These
are almost certainly being caused by Sferies. Sometimes the
Sferies lamp is flashing within seconds of a prior flash.
there's going to be a lighting storm? The forecast is for
tonight and maybe thunder storms tomorrow. So there's
thunderstorm going on now that causing the Sferics. The
indication was that the gain had changed by more than 10.
very close the the 99400 station at Middletown (normal gain 40)
the sferic must have been very strong to cause the gain (88) to
This appears to simulate a master
station and two salve stations. Although it has a whip
transmitting antenna the signal strength must be very feeble, only
enough to drive a very nearby receiver. Thumbwheel switches
set the GRI and emission delay for each slave.
info wanted for the 2042.
1290A 24 Volt
This is a battery backup supply for
volt timing instruments. And for many years they have been
Lorchron LORAN-C Timing
with MGRS -
held with military MGRS cooridnates
PSN-6 - attaches to PRC-25
or PRC-77 military
LORAN-C Spectral Lines
If you tune in the 135.7 - 137.8 kHz
range you will find spectral lines coming from LORAN-C
The lines depend on the GRI of the station and have been complied
Visible in North America
For my local station at
Middletown, CA 9940 they are:
135,699.195, 135,704.225, 135,709.256, 135,714.286, 135,719.316,
135,724.346, 135,729.376, 135,734.406, 135,739.437, 135,744.467,
135,749.497, 135,754.527, and many more.
Here is a 4395A Spectrum Analyzer plot
of 135.7 -
kHz showing maybe 36 loran-c spurs. This is using the AMRAD LF active whip antenna
The marker peak serach finds the largest one at 137.6005 kHz and
list shows one at 137,600.604
Next peak search finds 136.8445 kHz at -122.56 dBm, but they are
about the same magnitude and so the peak jumps around. The
floor between peaks is about -139.45dBm/root Hz.
Pickard & Burns Model 601 Loran-C
This receiver, as is typical of LORAN-C receivers, has no frequency
conversion circuitry. The RF is filtered and amplified and
out the output separated from adjacent signals centered at 100
kHz. The functional boxes are:
The Preamp did not come with the receiver and power supply.
are two options:
- Preamplifier 601-10 for 102" whip
- Receiver 601-20
- Power Supply
The manual was included that has schematics and parts lists.
- Use my existing AMRAD active whip
This has the advantage of simplicity
- build the P&B amplifier and use with a 102" CB type whip
This may be a better solution for a LORAN-C only receiver since
contains some filtering.
My interest is in looking at the new 9th pulse that
data. This would make a nice front end for a micro controller
based data decoder. Maybe not as nice as the Austron 2000
front end, but better than some others.
LeapSecond.com - Museum - Austron
Loran-C Timing Receiver - Austron
procedure - Loran-C
oscilloscope (unfinished) - 9940 TOC
DF6NM - Listening to all the worlds LORAN-C stations from
A CD-ROM with the following
manuals is available. For ordering information see the product
1120 Oscillator (octal tube base)
brochure & drawing 3 pg
1210D Clock stiched, rotated, cleaned. 130 pg (prior to
more like >200 pg
1250 Frequency Standard. 33 pg
1250A Frequency Standard. 52 pg
1250B Frequency Standard. 51 pg
1290A Power Supply 57 pg
2000C Analog Loran-C receiver. Good overview of Loran-C and
receiver works. 253 pg
2010B Disciplined Oscillator - locks to an external reference 105
2042 Simulator - a Master and two Slave stations make up a chain
and antenna outputs 67 pg
2084 Filter & Multicoupler - also has Sferics lamp, great for
feeding multiple Loran-C receivers 54 pg
2100F Loran-C Frequency Monitor uP based- includes Signature
data 166 pg
2100R Loran-C Frequency Monitor 168 pg
2100T Loran-C Timing Receiver uP based includes locking to Time of
Coincidence, S.A. test data 225 pg
Brochure of Austron Products 8 pg
5220333 Method and apparatus for determining universal
time from Loran-C Transmissions,
Bruce M. Penrod, Jun 15, 1993,
4839613 Temperature compensation for a disciplined frequency
of atomic frequency standards, Barnes; James, Rodrigo;
Enrico, April 26, 1988, 331/3 ; 331/94.1,
4314378 Antenna low-noise Q
W. Fowler, Bruce
M. Penrod (Tractor,
Inc.), Feb 2, 1982, 455/291, 455/292 -
An input coupling circuit for detuning the Q of a high-Q
ferrite rod antenna is disclosed. A high-impedence low-noise
amplifier is used to amplify the output signal from the LC
resonant tank of the rod antenna. A portion of the amplified
signal is fed back directly into the magnetic circuit of the
antenna tank. This negative feedback reduces the losses produced
in the magnetic circuit due to the presence of nearby conductors.
As a result of this reduction, an increase in the antenna
sensitivity and a decrease in the cross-feed from other nearby
antenna is produced.
||Short wave receiver
antenna and system
||Emerson Radio &
||Automatic gain and band
width control for transistor circuits
||Constant band-width input
stage with high q antenna
||Avco Mfg Corp
and automatic gain control circuit
||Key Lee P
||High gain radio receiver
||Attenuation circuit using
a tuned amplifier whose q is varied by shunting resistors
||Zenith Radio Corp
||Variable q i.f. amplifier
circuit for a television receiver
||Electronic switch using a
series string of two diodes,one zener and one
conventional,and a capacitor in parallel with a resonant
circuit as a q spoiler
||Gen Dynamics Corp
networks and control circuits for the tuners of signal
||U.S. Philips Corporation
||Bang & Olufsen A/S
||Antenna circuit of the
negative impedance type
||Ma John Y
||Atlantic Richfield Company
||Method and apparatus for
cancelling powerline noise in geophysical electromagnetic
||Adjustable beamwidth and
azimuth scanning antenna with dipole elements
beamwidth and variable azimuth scanning antenna
||Damping circuit for the
antenna resonance circuit of a radio transmitter-receiver
||Roke Manor Research
||Reduced Q low frequency
||Radio receiving circuits
||Antenna quality factor
Table of US LORAN-C Stations
Patents related to Disciplined
USCG - LORAN-C
Specification - just U.S. LORAN-C - History
U.S. Naval Observatory - Time
Service Department - LORAN-C
Timing Operations - LORAN
Times of Coincidence on line computation
International Loran Association
Radio navigation Systems by Jerry Proc VE3FAB
SDR in action: The last
LORAN-C receiver -
Locus - modern "All In View" (i.e. 40 stations) Loran-C receivers -
SDR in action: The last
LORAN-C receiver - A
LF Loop antenna -
From a Quarter Nautical Mile Down to Meter-Level
e-LORAN by the UK
All these have extensive bookmarks and the instrument manuals have
supplement with color photographs including inside.
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