Re: [time-nuts] apple Xcode
Don-- As others have offered, if you're developing for iOS or OSX, you have little choice. It has a comprehensive suite of tools -- for some, too comprehensive, leading to that old adage about how to eat an elephant -- one bite at a time. The entire Xcode suite has a large learning curve, yet the individual tools are approachable, so you can take it a step at a time. While I'll do stuff at the command line on Linux systems, I'll use the tools Xcode provides for me when I'm on the Mac. 73-- Bob K6RTM ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] time-nuts Digest, Vol 101, Issue 70
Joe-- Thanks for that! A great deal of what makes the Arduino popular, as you've identified, is the ease of use through the IDE. I just finished re-doing code for a portable RF power meter (AD8307, LTC1288), and the Arduino implementation was quick, easy, and provides a lot more capability. I used one of the $20 small form factor Arduino devices, rather than the full-sized board. I looked at the MSP430 when it came out, and it looked interesting, but I wasn't interested in the learning curve of yet another system. This looks like one to check out -- thanks again! 73 de Bob K6RTM -- Message: 1 Date: Sat, 8 Dec 2012 21:30:06 -0700 From: Joseph Gray jg...@zianet.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: [time-nuts] For Arduino lovers and haters Message-ID: caf7opz1fr+c1mf68qwbgk-hlgixb5-apgorhdukufprtent...@mail.gmail.com Content-Type: text/plain; charset=ISO-8859-1 I'm posting this seemingly off topic information, because many times a Time Nut needs to do something with a microcontroller (witness the recent discussion about GPSDO's). Sometimes, you just want to throw something together for a quick test or for a temporary project... I have never used an Arduino, but I see them mentioned all the time, with numerous projects and code posted on the net. A while back, I did pick up a few MSP430 Launchpads, as they were so inexpensive. I started teaching myself C, but kept getting sidetracked with other things. In any event, the simplified C-style of an Arduino program, and the huge quantity of code out there is attractive. What does Arduino have to do with the MSP430 Launchpad? Well, a few guys ported the Arduino IDE to the launchpad. The project is called Energia and is found here: http://energia.nu/ With some minor pin remapping, many Arduino programs (I won't call them sketches) can be run on the Launchpad. Considering that the Launchpad is $4.30 (with free shipping) and an Arduino board is several times that, it makes the Launchpad even more attractive. Of course, you don't have the Arduino addon boards (shields) with the Launchpad, but you may not need all that for a particular project. One item of particular note - the Energia IDE was just updated to include the new TI Stellaris Launchpad. This is a very powerful ARM Cortex board that costs very little. I got two for $5 each with free shipping, on a pre-release special deal. As an example of just getting something done without reinventing the wheel, I just got in one of those AD9851 DDS modules that you find online from China. For now, I just wanted to make sure that the module worked (I have a particular use for it later). I quickly found an Arduino program online that uses the same DDS module. All it took was some pin remapping to make it work with the MSP430 Launchpad and the Energia IDE. I was able to quickly verify that the DDS module works just fine. Sorry for the long winded post, but I thought some here would find this information of use. Eventually, I'll get back to learning C. Right now, the project I'm doing requires me to learn Python :-) Joe Gray W5JG ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] RasberryPi, timing and GPS receivers
I've been looking at the Raspberry Pi for a number of projects as well, and have been running one for a few weeks. My take on the early stability concerns/complaints are that the majority of those are due to poor power supplies, with some assistance from the Raspberry Pi design. Measure what you have for DC at TP1 and TP2; it should be close to 5 volts. The polyswitch self-resetting fuse on the power input introduces series resistance (in the wrong place); on my unit it measures 0.36 ohms (4-wire measurement with my HP33401A). Couple this with a cheepie USB supply that's already below 5 volts, and you're on thin ice. Do anything that spikes power consumption, such as Ethernet, GPU, or plugging in USB devices, and you generate more of an IR drop across the polyswitch which can cause erratic operation or resets. Use a good power supply -- 5 volts at an amp. Adafruit sells one that's 5V/2A for under $10. Or you can bypass some of the protection components and connect your +5 supply to TP1 and TP2. Running mine from a solid power source the only problems I've had are with my own crummy code... Bob K6RTM -- Message: 5 Date: Tue, 16 Oct 2012 15:06:19 -0600 From: x...@darksmile.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: [time-nuts] RasberryPi, timing and GPS receivers Message-ID: 20121016150619.16306sbpxvjy8...@darksmile.net Content-Type: text/plain; charset=ISO-8859-1; DelSp=Yes; format=flowed Hello everyone, I started a new project for myself where I would use the RasperryPi Linux board as a NTP server. My goal is to design a custom board for the Pi and mount a GPS receiver on it. With this combination, I should be able to configure NTP for the Pi and thus have the Pi act as a Stratum 1 NTP server. The new RasberryPI has 512MB memory so it should be fine for running just ntpd. Question: What GPS timing module should I go with? No more Motorola Oncore so what's best right now? Who sell modules? What are the price ranges? Your comments are most welcome. -George, N2FGX ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Symmetricom Presentation -- hijacked to LightSquared
The CSAC presentation from Symmetricom is fabulous -- I'll wait for the $300 version before I start a group buy... Not to scratch yet again at a still festering wound, but also on the agenda was a summary from FAA on Lightsquared: http://scpnt.stanford.edu/pnt/PNT11/2011_presentation_files/09_Bunce-PNT2011.pdf Executive summary: LightSquared breaks GPS in ways that some users can't even design around (Slide 9 on June 2011 NPEF assessments). -- Message: 4 Date: Sun, 04 Dec 2011 19:03:31 -0800 From: gary li...@lazygranch.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: [time-nuts] symetricom presentation Message-ID: 4edc3483.5020...@lazygranch.com Content-Type: text/plain; charset=ISO-8859-1; format=flowed http://scpnt.stanford.edu/pnt/PNT11/2011_presentation_files/18_Lutwak-PNT2011.pdf ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Raven Industries GPS in-line L1 Amplifier
eBay auction for Raven Industries in-line GPS L1 amplifier Item number 370437343397 $25 plus shipping Raven Industries Inline GPS Amplifier Model LA-12-1575-100N http://www.navtechgps.com/Downloads/LA-12-L1L2.pdf Female N Connectors on each end I've ordered one; he's got around ten remaining. 73, Bob K6RTM ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] (OT) Patents...
From a previous (now hijacked) thread-- I wouldnt try to read patents. These are convoluted beasts, written by lawyers for lawyers. If you want to understand the technology, read the papers. Most of them are eithe freely available or for a small fee. If you have a good university nearby you can find them for sure in the physics library. Having read some of the patents I know that they can be quite descriptive. There is a new tradition in patent-writing which you are refering to, but that is rare with older patents. As a patent attorney, I resemble that remark! My undergrad work was physics and computer science. Yes there are plenty of obfuscatory patents out there. However... My job when I write a patent application is to describe the problem and the solution in as clear and concise a manner as possible. U.S. patent applications have two broad requirements, enablement and best-mode. Enablement means someone of average skill in the art should be able to read the patent and go build one without undue experimentation. Best-mode means you're telling people the best way you know how to solve the problem at the time you filed the patent. That's what I want to do -- describe the problem, and then teach someone how to build the solution, to build one that works, keeping things crisp, clear, and concise. As to going and reading the papers... Some times, yes -- but when I worked with Labs (and with Rick) I'd get disclosures from some folks that would start out with a 12 page derivation of PLL stability criteria -- Danny, we don't need that in the patent! Yes, we can cite Gardner's book, but we don't have to teach people how PLLs work when we're trying to patent a particular aspect of PLL operation! Or the disclosures that start out Recall the retarded solution to Maxwell's Equations as shown in... That's not going to make it into the patent application! Clear and concise, that's what I do. I'll be happy to carry on further discussion off-list, and return to trying to figure out if I really want to pick up a used Datum Tymserve 2100... Bob K6RTM ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Efratom FRS manual PDF available
One of the posters to the sci.electronics.design newsgroup (remember newsgroups?) posted a PDF scan of the Efratom FRS manual, including schematics. 3mb, if there is interest in it, someone point me to a place to upload it. bob k6rtm ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Efratom FRS Manual now on ko4bb
I've uploaded the Efratom FRS manual to the Recent_Uploads section of ko4bb's site. bob k6rtm ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP59309A clock
Saying that the HP59309A clock is an HP-IB device is somewhat misleading... It's a very early HP-IB device. No microprocessor control. Not even the complex state-machine of the 8660 series. I'm doing this from memory, but it's like your memory of the dry heaves -- a little fuzzy around the edges, but still intense... You have an HP-IB command to reset the clock. Then you have HP-IB commands to increment different fields. So to set the date to the 13th, you send the increment date command 13 times... I think you get the idea. The resulting code to set the clock is easy enough to write, and once you write it, you never, ever want to look at it again. Well, I guess it is interesting in its own pathological way... 73 bob k6rtm ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Housing LPRO and Thunderbolt together
My two cents, from living with both Thunderbolts and LPROs. They are entirely different kinds of beasts, and aren't suitable for long-term cohabitation without work. Tbolts like thermally stable environments, and are happier (meaning ADEV trending towards zero) when they are powered up in a stable environment for a long time (and with an antenna having a clear view of the sky). LPROs on the other hand, require a heatsink or thermal mass to dump heat and keep the baseplate at a safe operating temperature (if you're running one for more than ten or fifteen minutes at a time). The nature of the rubidium beast is also such that once it's locked, it's not going to vary a whole lot; I also don't tend to run a rubidium all the time, unlike the thunderbolts. I'm looking to package a LPRO in a portable-ish manner with a backup battery good for an hour or so of operation. The idea is to check/trim it with a (non-portable) Thunderbolt and then carry it to where it's needed. Are you proposing to use the rubidium to provide a reference until the tbolt acquires lock? 73 bob k6rtm -- Message: 2 Date: Fri, 22 Apr 2011 16:48:07 +0100 (BST) From: g4...@btopenworld.com To: time-nuts@febo.com Subject: [time-nuts] Housing LPRO and Thunderbolt together Message-ID: 425854.57579...@web86602.mail.ird.yahoo.com Content-Type: text/plain; charset=utf-8 I have a dilemma and wish to access the collective wisdom of the group to advise a solution. I am building a clock generator based on a Thunderbolt. I have an LPRO and would also locate this in the same enclosure. I will also add a distribution amp and a divide chain in due course. The ultimate purpose of the set up is to provide a self contained clock generator set for my other test equipment, and also an experimental workstation for Rubidium and GPS disciplined experiments. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Selecting a used HP sweep/frequency generator
Bob-- For that frequency range, I like the 3314A - 1 to 20 MHz with sweep, bursts, gate, arb, and an easter egg. Lots of modulation capabilities. No easy way to synch it to 10MHz, as it runs off an internal crystal clock (2 MHz?). I've thought about bootlegging it to my house (tbolt) standard, but haven't done that yet. My real RF sweeper is a boat anchor, an old 8660C, which was incredibly cheap by the pound when I got it... I paid around $200 for the 3314A on the usual auction site two or three years ago; the current batch listed seem high. bob k6rtm -- Message: 2 Date: Thu, 14 Apr 2011 11:38:58 -0400 From: Bob Bownes bow...@gmail.com To: Bob Bownes bow...@gmail.com Subject: [time-nuts] Selecting a used HP sweep/frequency generator Message-ID: BANLkTi=upy4x2wumn9rpaw-vreu4yw3...@mail.gmail.com Content-Type: text/plain; charset=ISO-8859-1 Thought I would consult the assembled wisdom here. I'm looking for an HP frequency generator with sweep capability in the 1-20Mhz range. I can live with 1-11, and would really love 1-55, but 1-20 seems to be the most common. Other instruments I already own cover 10 and up. The goal here is to have something complementary to the 8640B, the 8620, and the 10m-20G sweeper. The candidates at present are the 3324 and 3325. The questions are: 1) Of the 3324 and 3325, are there any of the A/B/C/etc variants to favour or avoid? 2) Are there any other candidates to consider? This is for home, not work. Cost is, of course, a consideration. I already have 10mhz standard, so being able to lock to that is a plus. Thanks, Bob -- ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Tbolt temperature question
Maury-- Mine hovers around 36 degrees C +/- about 1.5 degrees C. Given the time, I'm going to start working with LH's active temperature control, and will be looking to settle on something between 34 and 38 degrees C, at least that's my current guess. Over 45 definitely seems warm to me! bob k6rtm in sunny silicon valley -- Message: 6 Date: Mon, 4 Apr 2011 11:50:55 -0500 From: msproul mspr...@suddenlink.net To: time-nuts@febo.com Subject: [time-nuts] Tbolt temperature question Message-ID: p06240800c9bf8833d60d@[192.168.2.100] Content-Type: text/plain; charset=us-ascii ; format=flowed What is the normally expected oven temperature range of the Thunderbolt? Over the past year the temperature of my Tbolt, as reported by Lady Heather, has slowly increased from the low 40s C to the high 40s. The maximum temperature has now crept up to 50 C and is shown today at 50.8 C. At 50 C the LH temperature display changes from white to yellow which suggests a warning. All other parameters appear to be normal. Does the 50.8 C indicate a potential problem? Is something failing? What is the maximum temperature that should be expected? Thanks for any help. Maury -- ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thunderbolt Supply
Larry-- I use a +12 volt linear supply (an open-frame leftover) with a 7805 for the +5 rail. For -12, I use a 2 watt isolated dc-dc converter (leftover from another project). As others have stated, the +12 rail seems to be the noise sensitive one. 73 bob k6rtm in silicon valley -- Message: 4 Date: Thu, 10 Feb 2011 15:16:55 -0800 From: Larry McDavid lmcda...@lmceng.com Subject: [time-nuts] Thunderbolt Supply To: Timenuts time-nuts@febo.com Message-ID: 4d5471e7.4050...@lmceng.com Content-Type: text/plain; charset=ISO-8859-1; format=flowed Greetings! I am a new member of the mail list. I've been using a HP Z3801A GPS-steered standard but have just acquired a Trimble Thunderbolt GPS Disciplined Clock. I'm seeking a recommendation for a power supply for this Thunderbolt receiver. There is much discussion about noise from some switching supplies and the effect on phase noise of the 10 MHz output. The Thunderbolt manual specifies the following supply and loads: +12 vdc 750 mA + 5 vdc 400 mA -12 vdc 10 mA This combination is somewhat unusual in that the highest current is on the 12 volt output rather than the 5 volt output. I'm asking if list members have a favorite power supply for this unit, why and where I can obtain one. -- Best wishes, Larry McDavid W6FUB Anaheim, CA (20 miles southeast of Los Angeles, near Disneyland) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Symmetricom / HP 58538A Lightning Arrestor
Apropos of Chris complaining about possible lightning damage, a chap on *bay is selling a bunch of these at $30 each plus $15 for shipping. No connection with the seller other than being a satisfied customer. --bob k6rtm in sunny silicon valley ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Changes in new LH 3 beta of 5-Jan?
Okay, I'll bite -- what are the changes in the new Lady Heather 3.0 Beta dated 5 Jan? bob k6rtm in silicon valley -- looking for grain of wheat lamps for an hp 8660C ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS Antenna -Receiver Mutual Interference
While you can try and run multiple GPS receivers off a single antenna using an off the shelf mini-circuits splitter, a bias tee, and a handful of dc blocks, you're likely to run into just this kind of problem. It's more than just the normal HP overdesign that has their GPS splitters like the 58535A comprising: an input narrowband (L1) filter feeding a low-noise gain block, the gain block feeding a splitter, and each output leg of the splitter having its own narrow band (L1) filter followed by a pad to improve isolation/return loss. 73 bob k6rtm in not yet raining silicon valley -- Message: 6 Date: Mon, 3 Jan 2011 15:59:24 - From: Rob Kimberley r...@timing-consultants.com Subject: Re: [time-nuts] GPS Antenna -Receiver Mutual Interference... To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com Message-ID: 01cbab5f$319dd060$94d971...@timing-consultants.com Content-Type: text/plain; charset=us-ascii Yes, I've seen this. On installations in the past, when we were putting up dual GPS systems, we always put them at least 10 metres apart. What is actually best practice, is to put one at one end of building and the other one at the other end. Rob Kimberley -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark J. Blair Sent: 03 January 2011 2:19 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] GPS Antenna -Receiver Mutual Interference... On Dec 30, 2010, at 6:53 PM, Burt I. Weiner wrote: Has anyone run into a situation where two GPS Navigation type Antenna/Receivers interfere with each other? It's possible that LO leakage from one is jamming the other. When doing mobile GPS receiver testing at work with a single antenna feeding multiple receivers through a splitter, we sometimes had to insert attenuators in each receiver's antenna feed to keep them from jamming each other. -- Mark J. Blair, NF6X n...@nf6x.net Web page: http://www.nf6x.net/ GnuPG public key available from my web page. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS Antenna
Chris-- The thunderbolt receiver is notably deaf. While a more-or-less standard 24dB antenna will work, you'll get better results with a higher gain antenna, such as one made for this kind of work. eBay may be your friend. The HP/Symmetricom 58532A is 30dB of gain (or a little more). A chap in HK sells them for $40 a pop, $10 shipping, really hard to go wrong. (Don't confuse with the Symmetricom Timing Antenna, which has a GPS receiver built into it and isn't suitable for our type of craziness.) I swapped out an older 24dB active antenna with a 58532A and saw a noticeable improvement in stability at the tbolt outputs. Two GPS receivers from one GPS antenna -- the kicker is providing DC power to the amplifier in the antenna. HP/Symmetricom make a nice bit of kit for doing this, Mini-Circuits has one as well, GPS signal splitters. They have fairly narrow bandpass filters and a low-noise amplifier to overcome the loss in the splitter, and a DC network to supply power to the amplifier and the antenna from the GPS receiver. The HP/Symmetricom unit is the 58535A. N connectors. You can pound nails with it. It's heavier than a thunderbolt, maybe twice as heavy. I use one for driving two thunderbolts off the same antenna. Also available in a 4 port version. If you're good at surface mount rework, you can increase the gain a bit, as the output ports have pads on them (to increase isolation/return loss). There's a MiniCircuits one, the MCL ZAPD-3DB-1575-3 GPS Antenna Amplifier Splitter , on eBay currently for the remarkably low price of $25. Usually these suckers go for $100 or more, as the sellers usually understand that they've got a specialized bit of kit and price it accordingly. Expensive, but if you're going to be driving multiple GPS receivers and comparing them, the alternative (using separate antennas) leads to madness. Of course if you're reading this list, you're well on the path as it is! Watchful waiting on eBay -- I watched a few of the splitters go for $150 or more, and pounced when I saw one for a price I was willing to pay. That MiniCircuits one looks like a good deal... If you want to do lightning protection, Ham Radio Outlet in Anaheim, or one of the other Ham Radio stores can get you a protector with N connectors that's rated for 1 - 2 GHz. Not cheap, but then again, neither is your house. We aren't in Florida, but it only takes one... 73 bob k6rtm in not yet raining silicon valley -- Message: 7 Date: Thu, 30 Dec 2010 15:25:46 -0800 From: Chris Albertson albertson.ch...@gmail.com Subject: [time-nuts] GPS Antenna To: Discussion of precise time and frequency measurement time-nuts@febo.com Message-ID: aanlkti=b3fcbshw7mwyf0dbbnighz_ymnrbqao-cf...@mail.gmail.com Content-Type: text/plain; charset=ISO-8859-1 A few questions about GPS antenna 1) I read the Thunderbolt user manual and did not find any meaningful spec on the antenna except that it is amplified and uses DC power in the coax. What signal level is the Thunderbolt expecting? oes it want a 24dB antenna or more or much less? 2) I want to feed two GPS units with one roof mounted antenna. I figure that splitters are just a transformers and will not pass DC to power the antenna. There must be an easy way around this. 3) Do people really run coax straight from a GPS antenna into their house with no protection from lightening? Maybe a GPS antenna is a small target compared to a 100 foot wire antenna in Florida -- = Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Advice on a freq time standard.
Jerry-- We'll be happy to give you advice, and that advice will be worth every penny you've paid for it! Some of us on the list find a GPSDO (such as a thunderbolt, or Z3801A/58503A) quite adequate for providing time and frequency for racks of test gear. Add a distribution amp (such as the TAPR one) and you can serve 10 MHZ to lots of gear. With something like a tbolt and the Lady Heather program running on a spare PC, you'll have not only disciplined frequency, but a good time standard as well. You didn't say what you wanted to do as far as the ham gear was concerned. If it's providing a frequency standard to gear in the shack, a GPSDO should work well; one caveat being who wins when you transmit on the low bands such as 40 and 20 meters and RF is wandering about the shack. If you're looking for something to stabilize your 10 GHz and higher bricks while on mountain tops, a different answer may be better. I'll call myself a novice-time-nut, and offer my suggestion that a rubidium may be better for that kind of use, as once it warms up it will be on frequency and stay there; that warmup time is on the order of minutes, compared to the half hour or more for a GPSDO to figure things out. You could keep the rubidium trimmed with the shack GPSDO so it's pretty close when you need to haul it. As with ham radio, the price ranges associated with different levels of advice vary substantially. Watching the crazies on eBay can get you a good used rubidium for under $100, and a thunderbolt for about the same, or less if you're lucky. Then again, your own cesium standard might be nice... Don't know how it's going to interact with the Henry 4K in the corner of the room, but that's what makes these hobbies fun, right? 73 bob k6rtm in not yet raining again silicon valley -- Message: 8 Date: Sun, 26 Dec 2010 16:56:33 -0700 From: Jerry jreed...@cox.net Subject: [time-nuts] Advice on a freq time standard. To: time-nuts@febo.com Message-ID: aanlktimqkro7qfo+ef8ibyfdpkg-ht=won8c+nba7...@mail.gmail.com Content-Type: text/plain; charset=ISO-8859-1 I am looking for a time/frequency standard for use with my ham radio and test equipment. There seem to be several surplus units available at inexpensive prices. I bought a Z3801A/58503A which would have meet my needs but had to return it when I found that the firmware would not control the outer oven. I am seeing Z3816A's and Tbird units that seem to be readily available at reasonable prices and I am wondering if I need to continue to look for a Z3801A with the HP 10811 OCXO or if either the Z3816A or the Tbird unit would be a good replacement to generate a 10 MHz signal with a 10 -12 spec locked to the GPS satellites. If either of these two are acceptable which is the best and are there any gotchas to look out for. Reading this group is being very informative and I would appreciate any suggestion. Thanks, Jerry W5RCQ -- ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] (from HP list) Frequency Standards: Basics and Applications
From the HP equipment list, thought it might be of interest here: - Posted by: k6...@aol.com k6...@aol.com k6yaz Sat Dec 11, 2010 8:16 pm (PST) A useful and interesting textbook, Frequency Standards Basics and Applications by Dr. Fritz Riehl, published in 2004, is available on scribd.com for free download. It is 543 pages in length. It is a pure pdf file, not a scanned copy. Stuart Los Angeles, CA - You need a facebook account or a free scribd account to download the pdf. 73 bob k6rtm ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Software defined spectrum analyzer
The Signal Hound is an interesting gadget. It's far more portable than my HP 8594E! And yes, the 10 MHz ref input on the back does help; without an external reference it does tend to wander around. Their website says they've replaced the original model with a rev B which adds a preamp and also temperature compensation. They were saying over the summer they'd have a tracking gen option as well, but I don't see it. The tricks they use (sorry, advanced digital signal processing techniques), such as shifting the LO around and watching what a signal of interest does to determine if it's real or not makes some fundamental assumptions about the signal of interest, such as that it's more or less the same during the multiple passes with different LO values. If the signal of interest doesn't play by those assumptions, all bets are off. The website says that, if you're trying to measure wide bw signals, 20 MHz or wider (such as 802.11g, 802.11n), or hoppers (bluetooth?) you have to throw it into a mode where it only does high-side mixing. 73 bob k6rtm ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] 85630A Manual Available
I have a freshly scanned in manual for the HP 85630A Scalar Transmission/Reflection Test Set. It's a raw PDF, 10.6 MB in size. The 85630A when used with an 859X series spectrum analyzer with tracking generator (option 010) and the 85714A scalar measurements personality card lets you make transmission and reflection measurements from 300 KHz - 2.9 GHz. If you're interested in a copy of the manual, let me know and I'll e-mail it to you. Oh, while Santa and the elves found the 85630A and its manual for me, they haven't had any luck finding the 85714A personality card. Any assistance, or listings of the code (if they exist) would be appreciated. 73 bob k6rtm ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] OT: End of an Era
The last two steerable dishes at Onizuka AFB (The Blue Cube) in Silicon Valley are being disassembled. One of those local landmarks, highway 237 at Mathilda. Did anyone see them listed on eBay? cheers-- Bob Martin K6RTM ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Lady Heather Wish-list
Lady Heather is a tremendous program for working with the Thunderbolt. As I move things to another machine, I find myself struggling with just what options did I whack to get that display? So my wishes for the next (beta) version: --- keep options in a file that I can move to get the same display or -- a command to show what command-line options to use on LH startup to get the current display. Not earthshaking, but would be nice to have. And my continued thanks to all who have contributed to LH, and to this list. cheers-- bob martin k6rtm ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10.23 MHz SC cut 10811 compatible crystals available
Rick-- Sign me up for one. I'll even save you the postage! Bob K6RTM (down the street) -- Message: 2 Date: Sun, 14 Nov 2010 21:25:59 -0800 From: Richard (Rick) Karlquist rich...@karlquist.com Subject: [time-nuts] 10.23 MHz SC cut 10811 compatible crystals available To: Discussion of precise time and frequency measurement time-nuts@febo.com Message-ID: 4ce0c467.4020...@karlquist.com Content-Type: text/plain; charset=ISO-8859-1; format=flowed Someone was asking about SC cut crystals to play with. I have a few dozen 10.23 MHz SC cut crystals that are interchangeable with 10811 10 MHz crystals, except for the frequency difference. They were made for a GPS version of the 10811 that never saw the light of day. Any interest in these? Rick Karlquist N6RK -- ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Determining Time-Nut infection severity.
Dave suggests a wonderful metric for our disease! Of course a single scalar value can't completely cover it. I suggest that it needs an error bound (I hesitate to suggest deviation), perhaps relating to the accuracy of other time devices under common ownership. As an example, in addition to two tbolts, two LPROs, a few 10811's (most of them in instruments, only one running around loose), I have a 100+ year old Seth Thomas mantle clock that has a temperature variation which would make Warren cry. The 40+ year old Regulator-style wind-up clock in a different part of the house runs about five minutes fast. And then there's the other Regulator-style clock that's dead on, twice a day (broken mainspring that still needs replacement)... Then again, some members of this esteemed list should get values assigned based on the contributions they've made. I'm thinking of my neighbor down the street, Rick N6RK, who deserves at least a 16 based on his work, and Warren who has earned a similar number based on helping (and educating) others. respectfully submitted, bob k6rtm in drizzly silicon valley -- Message: 4 Date: Sun, 24 Oct 2010 15:53:37 -0700 From: David Martindale dave.martind...@gmail.com Subject: Re: [time-nuts] Determining Time-Nut infection severity. To: mccor...@ptialaska.net, Discussion of precise time and frequency measurement time-nuts@febo.com Message-ID: aanlktimn4vuylmmsrpm+oaaxq4r1yobfu42boz3-b...@mail.gmail.com Content-Type: text/plain; charset=ISO-8859-1 ... On the other hand, this does suggest a plausible metric for nuttiness: the negative of the base-10 log of the frequency uncertainty of the best reference you own. So the scale for fully qualified nuts starts at 9 and goes upward. Lower numbers are indicative of non-nuts (just owning a quartz watch puts you at about 5, at least if you care about its accuracy). Dave -- ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Cesium standard prices
Awww... Aggravation? Don't you mean challenge? And taming a CS reference is a stepping-stone to your own H maser, right? (I'm still at the tbolt - Rubidium stage of time-nuttiness, and having a lot of fun, thanks to a bunch of folks on this list.) bob K6RTM in sunny silicon valley -- Message: 10 Date: Thu, 21 Oct 2010 20:08:22 -0700 (PDT) From: Perry Sandeen sandee...@yahoo.com Subject: [time-nuts] Cesium standard prices To: time-nuts-requ...@febo.com time-nuts@febo.com Message-ID: 282484.13290...@web38006.mail.mud.yahoo.com Content-Type: text/plain; charset=us-ascii Gents, Talk about ask and ye shall receive! I want to thank all who have contributed answers on and off line. It appears at this time that in the case of a low end CS for me, that the remuneration is not worth the aggravation. I have far many too many projects to complete to be a nanny to what will probably be a quality time black hole. Perhaps after I get more projects finished and have a few more shekels saved up a CS will become feasible. Regards, Perrier ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] antennas
Rather than put up two antennas, why not use one, and pick up a HP/Symmetricom GPS splitter? (Mini-Circuits makes a similar unit). You can find them on eBay for various prices. The Symmetricom one, the 58535A, supports 2 GPS receivers. It has a built-in amplifier and filters, so it provides high isolation between the GPS units. It's powered from the GPS units, and passes power to the antenna. The downsides are that it costs more than a pair of cheap antennas, it's heavy (heavier than the Thunderbolt!), and uses type N connectors. But it's low noise, and you only have one antenna and feedline to worry about. 73 bob k6rtm -- Message: 3 Date: Sun, 26 Sep 2010 15:56:47 -0400 From: Heathkid heath...@heathkid.com Subject: Re: [time-nuts] DS1620 Variants in the Thunderbolt To: Discussion of precise time and frequency measurement time-nuts@febo.com Message-ID: 795f7aa593814ecb9aa24f0b55cad...@d1x25bd10 Content-Type: text/plain; format=flowed; charset=UTF-8; reply-type=original Thanks for all the information on the DS1620. As it turns out, both of the TBolts (remember I got the from two different sellers and appear identical) have the Trimble OCXO, v3.00 firmware, but the DS1620's are marked as follows: DS1620 0415E2 531AD DS1620 0239D1 690AB Interestingly, the first one appears to have been swapped out at some point (flux residue all over the chip / had to clean it off to read the markings). I've already ordered another D1 to swap out the E2 but really need to get them both up and running (still trying to figure out how to mount the antennas!) and see how much difference there really is. 73 Brice KA8MAV ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thunderbolt initial check out?
Go with Lady Heather. Install it using John's files (from http://www.thegleam.com/ke5fx/heather/readme.htm), and use the 3.0 Beta code -- it's far more solid than the production code shipped by a lot of vendors. One of the really great things that happens when you install it is that you get a shortcut to a Tbolt at John's place. You can double-click on that icon and see a working Tbolt! A lot of the parameters are going to look different, but you can get a look at one that's working. If you're serious about this (you'll know in a few hours) I recommend setting up Lady Heather in its client/server mode, even if you think you're only going to be running it for yourself. This is described in the documentation; as mentioned earlier the most complex part may be figuring out which COM port you're on. A big advantage to the server-client setup is that you can ask a Thunderbolt Wizard (such as Warren) to take a look at it, opine on its qualities, and give you insightful and useful suggestions for getting the most out of your particular beast. You can also check in on it remotely. Yes, this requires punching a hole in your firewall. Hopefully you're using a (hardware) stateful firewall such as in a stand-alone router or switch, in addition to the Windows firewall. (a different approach is to allow ssh or other secure tunnel into the box and use a tool such as VNC). Have fun! There's a wealth of information (and opinion) in the archives. 73 Bob K6RTM - Original Message - From: russell rstanph...@austin.rr.com To: time-nuts@febo.com Sent: Sunday, September 19, 2010 4:47:54 PM Subject: [time-nuts] Thunderbolt initial check out? This is my first attempt at having a time reference for my home lab. I have recently ordered a pulled / untested Tbolt (board in box wo/ power supply) from ebay. It has a 5 day right to return if non functional. While waiting to receive the unit, I have been getting things ready here (antenna, power supplies w/ connector, and TboltMon). My question. Is there a check out procedure or list of things that I can test quickly to determine if I have received a functional unit with a decent oscillator? I just want to make sure I have not been sent a dud. Longer term I can read more, learn, monitor and tweak its performance. I am only trying to make sure I have a good platform to start with. Thanks for you advice / comments. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Message: 6 Date: Mon, 20 Sep 2010 12:31:09 +0200 From: francesco messineo francesco.messi...@gmail.com Subject: Re: [time-nuts] Thunderbolt initial check out? To: Discussion of precise time and frequency measurement time-nuts@febo.com Message-ID: aanlktimqjxpyhxrref3xsx03rhg_b35b9qop_efdy...@mail.gmail.com Content-Type: text/plain; charset=ISO-8859-1 Hello, On Mon, Sep 20, 2010 at 12:21 PM, d.sei...@comcast.net wrote: Between Tboltmon and Ladyheather, you'll see that your unit either works or it doesn't. My bet is that it will work just fine, even if the antenna is indoors- and then you won't be able to stop watching it (esp. with lady heather) for at least a few hours... Have fun! well, this is not entirely true. I once witnessed a tbolt that partially worked, it wasn't able to save the position so it needed to do a self survey at each power down and the temperature sensor appeared also not working as it reported always the same (improbable) temperature. It also wouldn't save any parameter different from a factory default. 10 MHz output and pps were present. The vendor sent a replacement unit by the way. Just for the record anyway... best regards Frank -- ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts End of time-nuts Digest, Vol 74, Issue 90 * ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] WG mounting h/w (2)
Another mystery solved! My (late) father-in-law spent most of his career at Varian-Eimac, mostly working on TWTs, BWOs, and the occasional magnetron. In one batch of his goodies, along with the HS SMA torque wrench, was a little box with some tapered metal pins! I've wondered what those were for, and now I know! He was very happy when his daughter brought home someone who knew what vacuum tubes were, even if he did think that the RF work I did as a ham, even the 144 and 440 MHz stuff, was still practically DC... Bob K6RTM -- Message: 2 Date: Mon, 20 Sep 2010 08:19:25 + From: Kit Scally ksca...@bytecan.com.au Subject: [time-nuts] WG mounting h/w (2) To: time-nuts@febo.com time-nuts@febo.com Message-ID: 2ab674d4b0c99d4ca524e8530ba1b87c08dc5...@msg02nsw.bytecan.com.au Content-Type: text/plain; charset=us-ascii Hi, Well, still not strictly, strictly true ! In Ku K band earth stations I've worked in, I've never seen shoulder screws used, although the equipment used was mainnly from the USA. Next to you precision adaptors, SMA torque wrenches etc in your personal goodie box are sets of tapered pins, about 35-40mm long - that fit various diameter WG mounting holes (the old metric vvs Imperial issue again). You insert a pair of pins on diagonal corners then add bog-standard SS hardware to the opposite diagonals tighten. The tapered pins are then removed and replaced with another pair of screws/nuts. This ensures absolute (?) internal WG slot alignment. There are a few variations on this theme if you must have absolutely minimum RL within that section of guide or if one guide face is threaded. Hex-headed bolts are usually used. That may explain why shouldered bolts are seldom seen. Tapered WG pins fall into the 99.% unobtainium class of materials. Kit VK2LL ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Semi-OT: Hardware for WR-90 waveguide sections?
Not completely OT, as stable and accurate timebases are very useful in microwave systems... What's the proper hardware to use for connecting WR-90 (10GHz) waveguide sections? I figure 8-32 brass or stainless, avoiding anything magnetic. Bob K6RTM in Silicon Valley ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] LPRO101 orientation vs lock
I assume you mean Tektronix TM5xx or 5xxx modules. I haven't seen an LPRO plugin, but considered doing one for my TM506 rack. My conclusion was that I couldn't get rid of enough heat without cutting custom fins for the LPRO. Recall that the physics package in the LPRO is the biggest source of heat, and looking at the unit with the connector facing you and on the left, the physics package is along the right side toward the rear of the unit. I decided the way to mount the LPRO if I had to go vertical was with the physics package closest to the top, to minimize the components that got baked. (I welcome recalibration of this opinion from more knowledgeable sources!) If I could cut fins for the new top edge, as well as a good plate for the bottom, and some fans, i might be able to get rid of enough heat to make it work. I considered mounting the LPRO to the rear of the module connectors, in the area containing the linear power supply components. I reconsidered on recalling admonishments in the LPRO docs and on this list that cesiums do not like magnetic fields! Mounting the unit next to large power transformers wouldn't seem to be suck a good idea... You might have better luck running it in a TM5006 rack, as they have much better cooling and airflow (a reason to get rid of that 506 and pick up a 5006!). I've had good results with my LPRO mounted on a half inch plate of T6061 aluminum and an old AMD heatsink+fan mounted above the physics package, held in place with arctic silver heat transfer compound and spring-loaded wire clips going to the plate. I've been meaning to run noise studies to see if the fan causes any problems (vis a vis mag fields). Since I expect to be using the LPRO only occasionally, I've been trying to talk my son into making me a steampunk-themed case, something like rosewood with brass corners and detailing... Cheers and 73 -- Bob K6RTM in sunny silicon valley On Sep 16, 2010, at 2:51 AM, d.sei...@comcast.net wrote: I got one of the ebay LPRO-101s about 6 months ago and played with it for a while, but had problems maintaining a lock. First of all, it has a heat sink bolted to the bottom that is just a little larger than the LPRO itself, including being about 1.25 thick( 1 fins). Typical frequency when locked is 10,000,000.007 on a 5360A clocked by a Z3801A. Both then and now, it takes about 45 seconds to lock from cold, and will stay locked for about 45 minutes. I found that in the position with the heat sink on the bottom will stay locked the longest (up to a few days), but then it becomes intermittent. Other positions will lock for a while, but bottom down always works the longest. For those of you who employed these in TM5xx or similar plugins, did you have lock issues? Is my unit just old? Dave ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts End of time-nuts Digest, Vol 74, Issue 77 * ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] LPRO101 orientation vs lock
Aha! Once again, Google is your friend -- http://www.slack.com/images/TE/EfratomPTB-100.jpg shows the Efratom Rubidium module, and it's a double-width unit. That gives plenty of room to mount the module horizontally, and plenty of room above and below for fins and fans. When I get my time machine working, one of the things I want to go back and stock up on are Tek 5xx prototyping kits. The single-width kits are rare enough these days (and expensive), but the double-width ones are pure unobtanium! Bob K6RTM On Sep 16, 2010, at 2:51 AM, d.sei...@comcast.net wrote: I got one of the ebay LPRO-101s about 6 months ago and played with it for a while, but had problems maintaining a lock. First of all, it has a heat sink bolted to the bottom that is just a little larger than the LPRO itself, including being about 1.25 thick( 1 fins). Typical frequency when locked is 10,000,000.007 on a 5360A clocked by a Z3801A. Both then and now, it takes about 45 seconds to lock from cold, and will stay locked for about 45 minutes. I found that in the position with the heat sink on the bottom will stay locked the longest (up to a few days), but then it becomes intermittent. Other positions will lock for a while, but bottom down always works the longest. For those of you who employed these in TM5xx or similar plugins, did you have lock issues? Is my unit just old? Dave ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Timing Distribution in Mountainous Terrain
Ralph-- As far as getting a signal through mountainous terrain, look at NVIS antennas for HF -- we use them for Field Day for just that kind of communications, 200 - 300 miles in mountainous terrain. Figuring out propagation delays is going to be interesting with NVIS though. 73 de Bob K6RTM -- Message: 3 Date: Thu, 9 Sep 2010 11:37:46 -0400 From: Ralph Smith ra...@ralphsmith.org Subject: [time-nuts] Timing Distribution in Mountainous Terrain To: time-nuts@febo.com Message-ID: a3fa9eac817be681f75c1df76ba2adf5.squir...@ralphsmith.org Content-Type: text/plain;charset=iso-8859-1 We have a requirement for approximately ten radio sites to be synchronized to within 30 ns of each other. Ordinarily you could throw in an appropriate GPSDO and be done with it. However, we also have the reqirement to be able to operate independent of GPS for up to six days. If we were able to have each site within line of sight of another, and could form a network including all sites, we could do differential time measurement between the mutually visible sites and correct in that way. Unfortunately, that is not the case. Absolute time accuracy is not critical, but relative time accuracy is. Does anyone out there have any ideas? Thanks, Ralph AB4RS ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] OT: Weather Stations
Bill-- The first graphic is of a friend and colleague's weather station just down the road. I'd prefer that both graphics were side by side, but Weather Display doesn't give me that flexibility without going to a fully custom web page (something I'm hesitant to do). The remainder is more or less standard WD displays. 73 -- bob K6rtm in Cupertino -- Message: 6 Date: Thu, 02 Sep 2010 23:02:15 -0700 From: WB6BNQ wb6...@cox.net Subject: Re: [time-nuts] OT: weather stations To: Discussion of precise time and frequency measurement time-nuts@febo.com Message-ID: 4c808f67.f3f46...@cox.net Content-Type: text/plain; charset=us-ascii Hi Bob, I went and looked at your weather page and found it quite confusing. I guess you are in Cupertino, yet the first chart states Sunnyvale. I guess after the first two charts is the data for your weather station represented in two different formats of a spreadsheet style and then a data and chart form. Am I reading that right ? Or, which one of the displays is from your weather station ? Thanks for clearing that up for us dummys that don't have a weather station, 73BillWB6BNQ ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Freestanding mast
I've a Symmetricom(HP) 58532A antenna on a six foot mast -- T6061 aluminum schedule 40 pipe. Not as cheap as cast schedule 40 from the home store, but a lot lighter! The previous mast was a length of cheezy Radio Shack antenna mast -- thin wall stuff. The mount for the 58532A wanted larger diameter schedule 40. Oh, that mast also supports a Davis Instruments Vantage Pro2 weather package -- the GPS antenna is on the mast, which is between the rain collector bucket and the anemometer mast. The rain bucket is due south of the GPS antenna, and below the GPS antenna horizon. While the anemometer mast holds the anemometer assembly up a few inches, it's due north, so it's in the region where the GPS birds don't go anyway, and is below the elevation mask angle as well as the angle at which the birds appear. Life is full of compromises... We get very little snow and/or ice here, but usually have storms in the winter with 50+ MPH winds. A 10 foot stick of the cheezy thin wall held up the weather instruments for a number of seasons with no problems. The 58532A doesn't add appreciable cross section in comparison to the rain bucket. I don't anticipate problems with the larger diameter mast, and would expect a 10 foot length to be quite stable. T6061 aluminum is a favourite for antenna construction. (I went with the six foot length as it was available as scrap.) Separate 24 hour antenna surveys with the weather sensors six inches or so below the GPS antenna, and then with the weather sensors at their nominal operating height with respect to the GPS antenna did not show easily observable differences in tbolt operation. 73 de Bob K6RTM in Silicon Valley -- Message: 2 Date: Thu, 02 Sep 2010 20:46:00 -0400 From: Charles P. Steinmetz charles_steinm...@lavabit.com Subject: [time-nuts] Freestanding mast To: Discussion of precise time and frequency measurement time-nuts@febo.com Message-ID: 20100903004603.b222311b...@karen.lavabit.com Content-Type: text/plain; charset=us-ascii; format=flowed I'm curious what the best freestanding mast is for a timing antenna (think Lucent timing antenna or marine mushroom GPS antenna -- light and pretty small). The mast would have its highest support at rooftop or chimney-top level, and could extend from there as far downward as the ground with additional supports as required. Should be able to survive at least Category 2 winds and heavy snow and ice. What reasonably available mast material no more than, say, 3 in maximum cross-section would allow the most vertical extension above the highest support, and how much extension would that be? I'm thinking 10 feet of 2 or so thin-wall steel tube may be OK, but beyond that I don't know. Tubing is probably not the optimum shape, but I assume the availability of other engineering shapes (say, + cross-section) is likely to be limited. Ideas? Thanks, Charles ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] OT: weather stations
Brice-- I'm also running weather display: http://home.comcast.net/~weatherbox/wxsc/wx.html I don't know an easy way to automagically sync the Davis clock with the tbolt other than what WD offers (LH and WD are hosted on the same Windows box, and LH whacks the clock on that box). I make sure the rain gauge is clear a few times a year. I don't have a problem with feathered visitors leaving samples in my rain gauge -- the other antennas on the roof, a discone on one mast and an eggbeater on the other, don't offer comfortable perches. Not as comfortable as the 70 foot tree across the street -- which is mostly in the due North blank spot, or the other large trees nearby. But a two-story house and an elevation mask of at least 20 degrees make those trees not an issue as far as GPS signals are concerned. 73 de Bob K6RTM in Silicon Valley -- Message: 1 Date: Fri, 3 Sep 2010 00:32:15 -0400 From: Heathkid heath...@heathkid.com Subject: Re: [time-nuts] Freestanding mast To: Discussion of precise time and frequency measurement time-nuts@febo.com Message-ID: 1f8f92c02e434600b1354911e0b2d...@d1x25bd10 Content-Type: text/plain; format=flowed; charset=iso-8859-1; reply-type=original Bob, Don't get me started on my Davis Instruments Vantage Pro 2 with BIRDS... and the rain bucket! ;) How many times have you cleaned yours out this year? Spiders and Wasps are the worst. But... unfortunately, my flag pole is now the weather station mount (wireless version) and it's too far away to mount my multiple GPS antennas. I run both Weather Display and VWS (and a LOT of other software for the weather station)... what are you running? Do you know of anyway to sync the timestamps of the weather station to a Thunderbolt? 73 Brice KA8MAV ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Type synch
Date: Sat, 28 Aug 2010 18:31:14 -0500 From: Bill Hawkins b...@iaxs.net Subject: [time-nuts] Does GPS time reception work everywhere all of the time? Bill-- Depending on what you mean by synchronization you may also want to look at IEEE-1588 (Time Synch) and the work done by John Eidson (at HP/Agilent). IEEE-1588 lets you tightly synchronize devices (and data collection) over Ethernet networks. (I worked with John at HP/Agilent.) Cheers-- Bob Martin K6RTM in Silicon Valley To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com Message-ID: 9ef30a464fa04d31b14e6060d19ad...@cyrus Content-Type: text/plain; charset=us-ascii I'm involved with time synchronization of control system computers for multi-national businesses. GPS springs to mind as a way to synchronize time anywhere. Or is it? What about monsoon rains? The Internet is available almost everywhere that control computers are used, but many users prefer to use a data diode between them and the Internet. Control computers are now essential for manufacturing processes. Some of the processes run constantly for years without stopping for any kind of security update. Some of the downtimes cost millions of dollars per day. A GPS time system allows the control systems to be synchronized in time, so that messages sent periodically through the data diodes will have the correct time stamp on various events that occur in the process. But does that work everywhere all of the time? Where can I find answers? Thanks in advance, as we used to say. Bill Hawkins ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Antenna problems
Peter-- Antenna gain and placement make a lot of difference. Yesterday I swapped out my old Trimble active patch antenna (24 - 26 dBc) for an HP/Symmetricom 58532A antenna (30+ dBc). It's on the roof of our two story house, at the end of probably 20 meters of reasonable quality feedline (LMR400). As Warren will attest, my signal levels (which weren't too bad before), are now much better, with 48 dBc readings in the central ring, elevations above 60 degrees, with a relatively clear view of the sky. As the manufacturer's literature suggests, the Thunderbolt was designed for high gain antennas, and is pretty damn deaf in comparison to most modern designs. But then part of being a time-nut is getting equipment considered obsolete by many to outperform its original specifications. I'm still doing signal strength measurements (in Lady Heather, S - A - D, and Z for Zoom if you want to see a larger plot). Over 36 to 48 hours, that will show me if I still have problems with nearby trees. I also use an HP/Symmetricom GPS splitter, the 58535A. The splitter, antenna, and the antenna mount (as well as the thunderbolt) were all sourced from eBay. There are more of the 58532A antennas available from the same seller (in Hong Kong) currently, at a reasonable price. Unfortunately, the folks selling the splitters seem to know what they have, and have priced them accordingly. Putting on my VHF/UHF ham radio hat for a moment, you know that good feedline and good connectors are a must. Sloppy practices and poor quality in feedline and connectors can easily cost you 6dB or more at the relatively low frequency of 1.5 GHz, not tolerable in such weak signal work as GPS. And take Warren's advice -- I think he has quite the sideline tuning up Thunderbolts around the world! He's given me many useful suggestions, and more interesting questions to ponder. Best 73 de Bob K6RTM in Silicon Valley. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Mounting hardware for HP/Symmetricom 58532A GPS antenna?
Just received my well used 58532A GPS antenna; the pipe mount arrived yesterday. I've looked at available documentation on the WWWeb and haven't found an answer -- what size hardware do you use for the antenna? I know that the answer is NOT 10-32! That's what's on the pipe mount, and those are too big. Is this thing metric? I don't have access to a lot of hardware right now to check. If it's possibly metric, I'm better off going to a different hardware store than if it's American sizes. Many thanks! K6RTM Bob in Silicon Valley ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Mounting hardware for HP/Symmetricom 58532A GPS antenna -- M4 x 0.7?
Fleming-- Many thanks! While waiting for a backup to complete, I dug out the traditional box of unsorted hardware each of us probably has. Rummaging through the box turned up four very pretty torx-headed stainless screws the proper size and length. They're not quite captive in the new mount, but the gasket holds them in place. I'm going to dig through the box for more; I'd rather have extras in my kit when I'm up on the roof, as one is certain to try and escape on me! For those looking for the answer later on, the 58532A GPS antenna uses M4 x 0.7 screws. Didier -- I didn't spot that detail in the HP/Symmetricom manuals available on the net. They only show the assemblies. 73 de Bob K6RTM in Silicon Valley -- Message: 3 Date: Thu, 19 Aug 2010 02:07:30 + (GMT) From: Flemming Larsen oz...@yahoo.dk Subject: Re: [time-nuts] Mounting hardware for HP/Symmetricom 58532A GPS antenna? To: did...@cox.net, Discussion of precise time and frequency measurement time-nuts@febo.com Message-ID: 407300.16717...@web24806.mail.ird.yahoo.com Content-Type: text/plain; charset=iso-8859-1 M4 x 0.7 ? -- FL --- Den ons 18/8/10 skrev Didier Juges did...@cox.net: Fra: Didier Juges did...@cox.net Emne: Re: [time-nuts] Mounting hardware for HP/Symmetricom 58532A GPS antenna? Til: Time-Nuts time-nuts@febo.com Dato: onsdag 18. august 2010 17.36 You may want to chec the manual, it's on my web site. Didier KO4BB www.ko4bb.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] buffer amp transformers...
I think I'm a time-nut; as symptoms I include (1) a lot of Mini-Circuits parts on my bench, (2) searches on eBay for Mini-Circuits goodies, and (3) the desire to know how my LPRO, 10811, and Thunderbolt are different, and how much better a Thunderbolt would be with a 10811 double-oven in it... Anyway, here's an eBay auction for 25 T-626 1:1:1 transformers -- item number: 220544907085 http://cgi.ebay.com/25-Mini-Circuits-T-626-RF-Transformers-0-01-10-MHz-/220544907085?cmd=ViewItempt=LH_DefaultDomain_0hash=item335980374d which look like just the thing for this amp... 73 de bob k6rtm in silicon valley - Message: 4 Date: Thu, 05 Aug 2010 10:05:39 +1200 From: Bruce Griffiths bruce.griffi...@xtra.co.nz Subject: Re: [time-nuts] Buffer / distribution amplifier for TCXO To: Discussion of precise time and frequency measurement time-nuts@febo.com Message-ID: 4c59e433.6000...@xtra.co.nz Content-Type: text/plain; charset=iso-8859-1; Format=flowed Bruce Griffiths wrote: In which case a linear distribution amplifier is probably required. With only a ~3V supply available, options for the distribution amplifier topology are somewhat limited. In principle you could use an emitter follower driving 4 other emitter followers with a resistor in series with the emitters of the output devices and the AC coupled loads to match the source to the interconnecting cable impedance to minimise reflections without requiring excessive dissipation in the emitter followers. With the low voltage supply available, using an RF choke is series with the emitter follower's emitter to ground resistor will also be useful in achieving the required dynamic range. Bruce A more efficient buffer amplifier circuit schematic is attached. The series transformer feedback stage has high input impedance and an output impedance matched to the transmission line (yes it works well with long transmission lines as well). However a trifilar wound RF transformer is required. In principle the various GPS receivers could be connected to taps along an end terminated transmission line using feedthrough connections with compensation for the tap shunt capacitance if necessary. A lower impedance line (eg 50 ohms) could also be driven at the expense of a higher collector current. In this case the value of R3 would need to be reduced to around 100 ohms or so. Bruce -- next part -- A non-text attachment was scrubbed... Name: TCXO_BUFFER.gif Type: image/gif Size: 7990 bytes Desc: not available URL: http://www.febo.com/pipermail/time-nuts/attachments/20100805/091e6a74/attachment.gif -- ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts End of time-nuts Digest, Vol 73, Issue 12 * ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Prologix GPIB controllers
Brice-- Wonderful product! Combine it with the EZGPIB software and KE5FX's packages, and you're set. EZGPIB -- http://ulrich-bangert.de/html/downloads.html KE5FX -- http://www.thegleam.com/ke5fx/ Both run under windows (I'm running them under VMWare on OSX, currently with Lady Heather on the secondary display showing how my Thunderbolt is doing with the quieter power supply). EZGPIB lets you get up to speed quickly in dealing with GPIB devices. KE5FX has a number of very useful tools that he's written, as well as pointers to more. One of the great uses for EZGPIB is to go out and enumerate your GPIB (HPIB) devices -- so if someone has changed the default address, it's one call in EZGPIB to scan the address space and let you know what's out there (with the exception of write-only devices like the 59306A relay box). 73 de K6RTM Bob in Silicon Valley k6...@arrl.net (but k6...@comcast.net works too) --- Message: 9 Date: Sun, 1 Aug 2010 20:18:01 -0400 From: Heathkid heath...@heathkid.com Subject: [time-nuts] HP 5335A and HP-IB (GP-IB) To: Discussion of precise time and frequency measurement time-nuts@febo.com Message-ID: bae12857a7b84a4494ffab0bbabbd...@d1x25bd10 Content-Type: text/plain; format=flowed; charset=iso-8859-1; reply-type=original I just purchased a HP 5335A and would like to know the group's opinion on the following: http://www.sparkfun.com/commerce/product_info.php?products_id=549 73 Brice KA8MAV ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
