I have acquired one of these double oven oscillators. Seems like a useful
thing. Need info on pin outs, and operating voltages. Also any other useful
information or links to same would be appreciated. Please reply off list with
any files of specs etc to my email - johncr...@aol.com
All help
For the group -
Re: [time-nuts] GPS antenna in silicon/RTV encapsula
I have been reading the comments on this for a few days. Here is the scoop -
Almost every adhesive known to man is absolute bad news when applied to RF
components.
Adhesives are sticky because they consist of polar
The FT-243 holders I revamped in the 1950s and 60s did have the aforementioned
spring. However a close look at the electrode plates that contacted the quartz
resonator had, in every case, a raised boss at each corner that spaced the
center of the electrode a few mills above the center of the
I am so sick and tired of the topic cops. I do not know how many interesting
discussions I was following, that they have killed. In all of my years as an
electrical engineer and engineering VP this group has some of the most
unfriendly and pretentious individuals I have ever encountered.
A good approach to carrier recovery would be the following chain -
1 AGC or limiter amplifier - I would use AGC followed by a limiter to keep the
input to the doubler constant.
2 Analog Frequency Doubler with a bit of Q in the tank tuned to 2X carrier
frequency Digital when it screws up does
Hello All -
I do not believe there is a hard Yes or No answer for this question.
It depends upon the performance specification of the system elements
and the system requirements.
For instance if the leakage of noise and discrete signals from each
receiver out
of the antenna port combined with
Hello All -
The recent discussion on the use / not use of splitters affecting GPS
timing performance may be further informed by this table. It was
extracted from
page 5-8 of the
Thunderbolt Disciplined Clock User Guide
Version 5.0
Part Number: 35326-30
November 2003
Table 5-1 GPS Error
Bob -
Thanks you for your comments below.
As others have reported, a TBolt in a good environment is closer to a
1 or 2
ns one sigma (over 100+ seconds) than to the numbers in the Trimble
manual.
The satellite data on the NIST site shows much better numbers than they
show
for Satellite
Dale -
To your question re BPSK and DPSK. In both modes the phase shift is 180
degrees.
Straight PSK has the issue of determining the 1's from the 0's, at the
receiver as there is
no phase reference.
To avoid this DPSK encodes the the serial data stream prior to the
bi-phase modulator.
As I
Hello All - Just a quick comment from an olde RF engineer.
Bob Camp wrote:
Hi
You might be surprised by the noise floor of an XOR run at 125 KHz. They
are quite good at that low a frequency.
Bob
An XOR, unlike a mixer, does not have a null when the
phases are in quadrature. This is the
Hello all -
People talk about good deals on Thunderbolts but I have
yet to see one. It seems peak Thunderbolt passed before I was
seriously looking.
I would suggest some more serious looking. This guy TRIMBLE GPS
RECEIVER 10MHZ CLOCK THUNDERBOLT currently has more than 10 T-bolts
for sale on
Interesting problem
Re: 10 MHz - 16 MHz clock multiplier
What is low cost?? Serious question.
john k6iql
-Original Message-
From: time-nuts-request time-nuts-requ...@febo.com
To: time-nuts time-nuts@febo.com
Sent: Wed, Jan 2, 2013 9:19 pm
Subject: time-nuts Digest, Vol 102,
Just a few comments on the cable and VSWR business.
The short version is that unless the run is longer than 100 Ft any antenna with
a preamp gain of more than 30 dB will probably do and the VSWR business does
not matter at all unless it is truly terrible.
For example the loss due to mismatch
Hello Hal -
I spent a lot of my RF engineering career in related areas, including radar,
EW, and spread spectrum timing
systems. Since the distance is short and the cost is an issue you may wish to
consider an analog
system solution.
Specifically your master station transmits a RF signal that
I could not agree more, having been burned once or twice.
One batch of 50 Ohm cables was clearly marked 75 Ohms when received. These
used some form of
relatively high resistance foil shield and a drain wire for the outer
conductor. The high resistance permitted
a ground loop with hum on my 10
Re: WWVB Clocks don't sync anymore (revisited) (J. Forster)
As it turns out the batteries in my Radio Shack WWVB alarm clock had died. I
replaced them last night
around midnight and went off to bed. This morning it has synched up fine. I
dissected an identical
one of these a while back.
For those wanting a moisture sealed heat shrink tubing, McMaster-Carr has many
varieties of heat shrink tubing materials, both thick and thin walled. Several
types have an internal adhesive that melts when the heat gun is applied. I have
used this stuff on coax connectors for years and it works
Just a couple of comments from a RF guy and FMT-nut
10 MHz clock distribution for the lab
In the small coax cables one might consider RG-223. This is a 1/4 inch more or
less diameter cable that features two concentric braided shields. Each is a
very dense weave and is silver plated.
The ebay message re this law is probably legit. In any case
the congress IS considering such a law. In essence it forces
all internet sellers to collect the sales tax due in the buyers state. If you
live in a state with a law requiring that sales tax be paid on all out of state
purchases
Re: [time-nuts] S743 Marketplace Fariness Act
And again, this thread has no business being on this list so please make it
go away guys. The only reason I'm saying anything is to encourage people
to just stop!
-Bob
Really Well I am not so sure about that.
In response to a query
For Andy -
It is far easier in terms of bandwidth and power required to distribute sine
waves, and that is the method most used. The sine wave is more easily
transported via coax for long distances with no distortion issues.
I suggest you terminate the output of your oscillator in a nice 6
Re: [time-nuts] OCXO shock protection
Water heaters must be bolted to the wall studs. Other wise they go over.
Several hundred pounds of water is a big mass.
Lived there for 50 years. Generally earthquakes are pretty localized and not a
huge hazard with just a little thought. You do
Attila Kinali
One effective and sure fire way to deal with ground loops is to use
a minature 1:1 50 or 200 ohm (not critical as most instruments are not matched
inputs anyway ) in the line from your distribution amplifier to the driven
device. Coilcraft has these
for both PC and SMT Just
Andy -
Glad to be of some small help. A couple of remarks re your comments
John, thanks for your input, you reminded me that LFP performance often
depends on source impedance. To the MMIC amplifier, you'd be amazed what
you can do with an opamp these days. I was amazed reading the datasheet
Nice topic. I learned at bit. One source of info on the PIC is a course book
and
programming kit, programmer, prototype board and components set up by the ARRL.
www.arrl.org
You get all the stuff you need to get going. Software and a integrated
development environment is provided. All in one
It has been my pleasure to own and operate the VK4GHZ Thunderbolt display for
several months. It works good, does what is should and I am totally pleased
with it. It was easily installed and operated from the get go. If I did not
have one I would have
appreciated being notified of the of such a
At least for the T-bolt moving the antenna to a super-optimal location is a
super waste of effort and money. I suspect this applies to most other GPS DOs.
Unless you can compare the phase of the 10 MHz with a local Rb or Cs (or a good
crystal)
you cannot learn much more or provide better
You might want measure the antenna pattern. Lady Heather has a mode that plots
satellite signal level vs azimuth and elevation. You might want to try that. It
takes a day or so to get a complete plot, but you have some hard data to
compare various choke positions.
-73 john k6iql
Howdy Bob -
Hi John,
I don't have LH here.? I've never looked into it.? Will it work with an NMEA
GPS
receiver?
Bob - AE6RV
My error. The T-bolt and LH combination is so common I just assumed you were
using a T-bolt. As to your receiver, I do not know. Perhaps someone else on the
Tom -
I just had to comment---
Both assume some reasonable limit of mains df/f/dt. You can either
do it with a fancy $100 to $1000 reference signal generator + PLL or FLL + IQ
detector + professional box -- or with a $1 PIC and $0 s/w.
/tvb
You are of course correct. However I would
Tom -
Attached is an example from mains data that Bill just collected with picPET and
that TimeLab plotted.
I really got to get one of these one day. Thanks for the lead.
-john k6iql-
-Original Message-
From: time-nuts-request time-nuts-requ...@febo.com
To: time-nuts
Technique
Message-ID: lt;11440.1385061...@critter.freebsd.dkgt;
Content-Type: text/plain; charset=ISO-8859-1
In message lt;8d0b5020292d91e-cc0-4b...@webmail-vm026.sysops.aol.comgt;,
johncroos@
aol.com writes:
gt; I wish to establish a north south line on my property to an
gt;accuracy of +/- 2
I wish to establish a north south line on my property to an accuracy of +/- 2
degrees.
Could this be done by loading a T-bolt, Antenna, Power source, and laptop into
my
little red wagon? The idea being to find two positions several hundred ft apart
where either LH or T-bolt Mon report the same
Stephen -
[time-nuts] Crude Survey Technique
Thanks for describing your method. I am learning a lot. here is agovt web site
that will give the compass correction for any long and lat. Here in KS the
magnetic pole is about 2.3 degrees to the east.
Once all the ideas are in, I will put
Hello and thanks to all for the great ideas.
Re: [time-nuts] Crude Survey Technique
Some interim comments:
*agree with regard to using pole star. However it is below freezing here and so
I won't be out in the dark with my camera. A good verification technique that
must await warmer
Warren,
Understood. I have a couple more questions. Once the thunderbolt has completed
a survey, does it continue to update its position or are the final numbers at
the end of the survey frozen until a new survey has started.
If it continues to update the logging feature in the thunderbolt
When I asked about Crude Survey Techniques I never expected results much
better than the 10 ft accuracy someone volunteered from the first. In a former
life I ran an engineering department that worked on the old FAA SCAT-1 DGPS
landing project, where I did learn a bit about GPS and its
It is not surprising that one can find little about Alfred Loomis. He was
notoriously publicity shy and never gave interviews. Before his death he had
much of research material disposed of. However the private lab he created at
Tuxedo Park NY. was a gathering place for all of the key scientists
As it turns out Loomis did the original work proving the effect of the moon on
pendelum clocks, eatrhs rotation rate and so. He arranged with Bell Labs to
have their quartz frequency standard transferred by a land line he leased to
his lab. The experiments took several months. The results
Hello All -
I am new to this forum but have read it for a couple of years. The
present fulminations on the WWVB format change should be reconsidered
in the light of prior art. As an old RfFengineer I do not see any issue
with the format and the business about patents is not really applicable
as
To Paul re my receiver thoughts.
You are absolutely correct in some regards and for some
implementations.
The limiter must have very high dynamic range and must not convert
changes in input level to
changes in transmission phase; i.e. No AM to PM conversions. Thus my
specific suggestion of
Various comments -
Hal mentioned SNR for the scheme I suggested. A PLL can be a coherent
demodulator of arbitrary
bandwidth. Thus the PLL at the output of the doubler can have a small
bandwidth since at that point
there is no PSK, it having been removed by the doubler. So given a
stable VCXO
For David - re WWVB carrier recovery.
On squaring vs absolute values for carrier recovery. Never heard of
using absolute value.
As I said in my initial remarks - some perusal of the prior art is
helpful for this problem.
There are 70 years of literature on how to do this for any imaginable
Chris - your solution worked for me - until the grass covered my old PU
truck.
-73 john k6iql
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Hello all -
I Wonder what price the T-Bolts sold for new in single quantities.
Maybe more than $465?
I ran across this some time ago -
Perhaps someone has a better number but the later ones seem to
go for $ 1500 for the kit with the antenna from a distributor. Note that
this is a later
In considering the effect of a simple jammer on a GPS receiver, a
simple link analysis
is insufficient.
What must also be considered is the anti-jam capability of the receiver
which due to spread spectrum processing gain will reject any simple
jamming signal even though is it 10's of dB
Hi Jim -
Thanks for the update on the modern GPS receivers. I was aware that the
modern ones
do not have a classical analog tracking loop, much less a bunch of them.
However it is a useful concept for purposes of explanation that you do
not need the 1 pps to
lock up the 10 MHz VCXO - which
for Jim Lux --
Thanks for the comments -
Yes, if the receiver is linear (e.g. say you do a sliding code
correlator and slide until you get the peak, with the correlator using
a
multiplier)...
That is how the system I did worked. It could defeat an on-frequency
jammer that
was 20 db
I have received permission to distribute copies
of my QEX article on this subject from ARRL. In
addition to the article I will include full size schematics
and color photos of the various assemblies. The
design includes an adjustable 10 MHz output amplifier for driving
50 OHM loads. If
Apparently there is some interest in this technique.
So far I have 35 requests and still counting.
Please if you do want a copy send me an email
OFF LIST to johncr...@aol.com. Requests posted on
list are too hard to find and too hard to make
into a master address list.
In addition to the basic
With all of the discussion of the recent availability of various HP family
GPS DO devices, I was wondering if I should get a couple. Presently I have
a couple of T-bolts that seem to serve me well. What wold be the advantages
gained by going to the HPs. Need 10 MHz output though. Any thoughts?
A further comment on design of pseudo random code
generators. At some point the code may enter the dreaded all
zeros state. This clocks a zero on the input stage through all stages
and the whole thing just stops. So a AND gate looking
at all stages in parallel is used
to detect the all zero
I offer the following for your consideration.
Once upon a time - about 1968 Motorola introduced
4 low noise transistors for audio and low frequency
applications. There were th 2N5086, 5087, 5088 and
5089.
The 5086 and 5087 are PNP and the 5088 and 5089
are NPN. They are almost perfect
Hello Time Nuts -My question is --- both LH and T-Bolt Mon will readout
position during andat the conclusion of a self survey.The readout from LH
provides 2 additional digits of resolution compared to T-bolt Monitor.That is
LH provides 7 digits of Lat or Lon to the right of the decimal point;
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