Hal Murray wrote:
There is another way to compare two frequencies, relevant when they are
very close together. I divide a reference down to 100KHz and use it to clock
a phase detector made of a pair of D flip flops. The unknown (divided to
100KHz) is fed into the circuit and an output
Hi,
the original was built using a HP10811 oscillator and a Garmin 17 GPS
that delivered PPS.
The HP10811 ran a divider by 10 by 10 by 10 down to 1 hz.
I was the servo that adjusted the EFC of the OCXO so that the PPS
matched the 1Hz.
The divider clocked a counter of three decades of BCD,
Brice,
On 26/07/2010, Heathkid heath...@heathkid.com wrote:
Last night, as suggested by several people on this list... I ordered a
Trimble Thunderbolt from Bob Mokia, fluke.l so I should be in pretty good
shape there to get started once it arrives.
Sounds like your starting on the long path
Hi
One issue with the FE's is they often show up as conversions. Various sellers
take the 1 pps version and hack in a 10 MHz output. There is a lot of room for
error in the conversion process.
Bob
On Jul 26, 2010, at 7:06 AM, Steve Rooke sar10...@gmail.com wrote:
Brice,
On
Yes, it's because of the various types that you need to verify exactly
what you have. A number of them are made to customer specifications
with undocumented option numbers but if you have anything like an
option 8 then you have the 1Hz to 20MHz version. Beware that to
program the thing you need to
Hi,
ten years ago not having a super counter I copied the input circuit of
the Austron 2110 that using an XOR gate mixes 5 MHz with 500 Hz getting
5.0005 MHz. It is devided down to 1.0001 Mhz which in turn is mixed in 74 HC 74
D F/F giving 100 Hz, that most counters are able to count at
Sorry Bert, I don't follow the last part about the 100Hz - can you
explain further please? (and is that 100.00 or 100.01 Hz?)
Peter
On 26 July 2010 14:27, ewkeh...@aol.com wrote:
Hi,
ten years ago not having a super counter I copied the input circuit of
the Austron 2110 that using
On 24/07/2010 1:47 PM, Jim Palfreyman wrote:
I picked up an old black bakelite phone in an antique shop and have it
nicely on display on a table. I have wired it through to my workshop
where it is connected to the old Australian speaking clock (sync'ed to
the GPS of course).
So when you pick
I have a now useless 2100 Loran receiver / comparator here, does anyone
have any use for this? Before I recycle it. (Here is southern California.)
Dan
ac6ao
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I have an insane desire to marry up a T'bolt with an E1938 OCXO which I
have here and can't think of a better use for. Does anyone have a
T'bolt with a duff or dead OCXO? TAPR reject pile maybe?
Best wishes
Dan
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Hi
One gotcha on the conversions:
How close did they set the DDS before they shipped it. A few seem to do a
less than perfect job of it.
Bob
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Steve Rooke
Sent: Monday, July 26, 2010
It isn't useless until the Canada chain goes away in November... And then
you might still be able to catch a European chain.
-Chuck Harris
Dan Rae wrote:
I have a now useless 2100 Loran receiver / comparator here, does anyone
have any use for this? Before I recycle it. (Here is southern
Hi
I believe what they do is:
DSB modulate the 5 MHz with 500 Hz to get 5.0005 and 4.9995 MHz
Filter out the 4.9995 MHz with a crystal filter or by using an I/Q modulator
(I believe Austron did the I/Q thing rather than the filter).
Divide the result by 5 to get 1.0001 MHz
Mix the 1.0001 with
Dan Rae wrote:
I have a now useless 2100 Loran receiver / comparator here, does
anyone have any use for this? Before I recycle it. (Here is southern
California.)
The Austron is on it's way to a good home where it may still work.
dr
___
Hal Murray wrote:
There is another way to compare two frequencies, relevant when they
are
very close together. I divide a reference down to 100KHz and use it to
clock
a phase detector made of a pair of D flip flops. The unknown (divided to
100KHz) is fed into the circuit and an output
Glad if found a good home. Good to hear Nov on Can chain.
But they are still usable if you build the simple LORAN C simulator. Single
pic chip/cheap.
You can compare references and offsets just like you do today.
Thats why I designed the simulator so the austrons would have something to
do in
Hi,
Bob since has explained how the 1.0001 MHz are generated. My Austron uses
a Xtal filter. If you want a scan of the circuit contact me direst. The
resulting 100 Hz out of the D F/F results in a high resolution representation.
1 Hz is equal to 1E 6. If you now count the 100Hz with a
In message 4c4daa05.2000...@verizon.net, Dan Rae writes:
I have a now useless 2100 Loran receiver / comparator here, does anyone
have any use for this? Before I recycle it. (Here is southern California.)
Is it the Frequency or the Time version ?
Does it do 4-digit GRI ?
--
Poul-Henning
Hello Dan,
If it is a 2100T I would be glad to adopt that child.
I have already a 2100F currently receiving in Portugal
the European LESSAY 6731 Chain.
Thanks,
Antonio
CT1TE
Quoting Dan Rae dan...@verizon.net:
I have a now useless 2100 Loran receiver / comparator here, does anyone
have any
asma...@fc.up.pt wrote:
Hello Dan,
If it is a 2100T I would be glad to adopt that child.
Antonio, as I thought I said before, it is on it's way to a new home.
Dan
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-Original Message-
There is another way to compare two frequencies, relevant when they
are
very close together...
-
I am trying to measure the frequency of a distant on-air signal, with path
fading, Doppler shift, and maybe even
Hi
Rather than having the 940 in there, why not just build a (simple) direct
conversion receiver?
Feed something like the 3335 or 6061 into one port of a suitable mixer. Feed
the band pass filtered signal from the antenna into another port. Run the IF
output into a preamp / filter and then into
What about using an HP 3586 B or C, locked to a local standard, and GPIB
interface and averaging the data? It goes to 0.1 Hz right out of the box
as I remember.
FWIW,
-John
=
Hi
Rather than having the 940 in there, why not just build a (simple) direct
conversion receiver?
The only way to have that kind of meaningful accuracy with an on-air signal
outside of ground wave range (a.k.a FMT) is to average over a long time (days)
to average out the shift due to variations in propagation. The altitude of the
layer reflecting the signals changes over time, so the
Here's data showing Doppler (and other effects) on WWV as received in
Dayton, OH over several days. I took this by reading an HP 3586C
frequency counter output via GPIB -- which seems to be a good technique
for long-term HF frequency gathering. You need to figure out a way to
remove outliers
Thanks Didier, John, John, Bob, all:
You may have noticed, I came in next to last out of 35 entries in the last
FMT. I was using the power line as an audio reference, but even that
unstable reference was minor considering my 30 Hz lissajou error or 60 Hz
error wrong sideband error! I am taking
I like the 3586 a lot, it's amazing what you can do with it. However, if you
send the audio (beat note) to a computer or other instrument, keep in mind that
the BFOs are not phase locked to the reference, they are just free standing
crystal oscillators, and they may be off by a few Hz. If you
It's a remarkable, and largely unappreciated, instrument. I passed them up
for years, thinking they were only useful for analog multiplex telephony.
It was not until I bought one, almost by accident, at the tail end of a
flea and started to play with it, did its utility became apparent. Thje
Didier Juges wrote:
I like the 3586 a lot, it's amazing what you can do with it. However, if you
send the audio (beat note) to a computer or other instrument, keep in mind that
the BFOs are not phase locked to the reference, they are just free standing
crystal oscillators, and they may be off
You guys are trying to crack a nut with a sledgehammer!
For a start, as Didier says, you can't possibly read the frequency of a
sky-wave signal to 0.01Hz in any short time frame since the Doppler on
the signal can be as much as 1ppm (i.e. 10Hz at 10MHz). You can only
infer it closer than that by
The reason to divide was that the signal from the phase detector
folds back as the phase shift gets to 360*.
At 10Mhz the fold back occurs every 100ns. At 100kHz it is every
10usec. As the fold back (359.9 - 0.1degree) zone may have false
triggering or other noise
it made sense for it to be
I suppose that you could always cheat? Since you know where the
transmitter is going to be, if you could get a timenut near to the
transmitter to give you a beacon to measure 24hrs prior to the event,
you could use the diurnal variations that you observed (observe?) on
the beacon to predict the
...
I use Peter G3PLX's SBSpectrum as the analyser, where you can trim the
sample rate in tiny steps. It also has a frequency resolution of 25mHz,
which is more than adequate for HF. My combination has won FMCs, but I
still can't resolve 0.01Hz off-air.
...
73,
Murray ZL1BPU
You might
Hi
I've used the 6790 for this sort of thing before. It's a good choice since the
whole signal chain is synthesized (if I remember correctly ..). It's still
going to be tough to hit the originally requested accuracy with one.
Bob
On Jul 26, 2010, at 6:34 PM, Murray Greenman wrote:
You
Steve,
I changed the subject line because everything that follows has nothing to do
with the X72. I hope this doesn't confuse anyone but this subject is
probably much better related...
Yes, the FEI 5680A's I got are programmable from 1Hz to 20MHz (SMA output /
currently set to 10MHz) plus
R25 a 10 K resistor only used with the TTL computer interface option, not used
with the RS232 chip, is listed twice as 1% or 5% either will work but you don't
need both.
Stanley
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Understood.
Regards.
Max. K 4 O D S.
Email: m...@maxsmusicplace.com
Transistor site http://www.funwithtransistors.net
Vacuum tube site: http://www.funwithtubes.net
Music site: http://www.maxsmusicplace.com
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