Re: [time-nuts] GPS-Attached Equipment Lightning Protection
Hi All, all the comment has been about in-line protectors so far. We in the UK do dot have the ferocity of lightning that is seen in some parts of the USA but surely like all problems "prevention" is better. It is probably not 100% but would it not be better to have a higher metal rod say 6 feet above the GPS antenna spearately grounded as with a building protection system. The GPS antenna should then be placed in the "cone of protection" of this rod. The likelyhood of getting any significant voltage on the centre conductor I would think would be very small. The most likely scenario is for induced voltages/current on the braid due to nearby strikes. This should be grounded in a way that does not allow the whole ground system that it is connected to to to be "pulled up". As has been stated if you do get a direct hit on the GPS antenna nothing will save your kit, but again (I believe I am right here) the vast majority of the current from the strike will flow down the braid (if it doesnt vaporize it), So grounding the braid, preferably outside the premises if a good idea. The size of the antenna is such that the build up of static should not be significantit is not a 200 foot long wire as I use on MSF ! If this is rubbish please say so but it sounds much more sensible way of proceding to me. Cheers Alan G3NYK ___ 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] Coaxial Lightning Arrestors
Hello The Net: At one time the ICE lightning arrestors did not pass DC, so DC on the coax center conductor will be blocked and will not get to the preamplifier, up front at the antenna element. Other lightning arrestors are simply a 50 ohm coaxial line with a gas discharge tube between the center conductor and the outer shield. With an over voltage condition, the gas discharge element conducts and shunts the voltage to ground. When the transient over voltage disappears, the gas discharge element stops conducting and operation is back to normal. For low level rain/precipitation static, the gas discharge tube will not shunt the noise to ground. Lightning can blow up a gas discharge element, So a periodic inspection serves a purpose. These gas discharge elements can be spec'd for RX only, with a lower conduction voltage or much higher to run lotsa RF power, as with a transmitter. Looks like disposal of the gas discharge element is controlled in Germany, as are smoke detectors. But like smoke detectors, here in America, these small radioactive wastes are handled like household trash. Maybe some municipalities have regulations. Be sure to understand if your lightning protector will pass DC or not, and is suitable for your frequency range. Stan, W1LE FN41sr Cape Cod z ___ 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-Attached Equipment Lightning Protection
Forgot to mention, I put that diode and inductor inside my HP GPS Distribution amps retrofitting all of them, it fits quite well. HP uses a similar inductor (but smaller current capacity) to feed antenna power into the Antenna, so the effect of this is negligible. But caveat-emptor: this only protects the center conductor from voltage surges. One still needs to properly ground the antenna cable with a massive ground post to prevent the cable from carrying high voltages to the inside of the house. BTW: these voltages can and often are also be generated by antennae falling into High Voltage power lines. This happens more often than one would think in the US! Another interesting tidbit: in frost areas (Nordig countries, Canada/Alaska etc) the freezing ground turns into a very poor conductor, and any grounding post looses a lot of its current-carrying capacity by becoming high impedance. bye, Said In a message dated 2/29/2008 15:40:19 Pacific Standard Time, SAIDJACK writes: Hi Tom, couple of problems with these gas discharge devices: they need a significant voltage to trip, and usually may only help when the hit is a vicinity hit, not a direct hit. For direct hits, the goal is to prevent human casualties, and fires. I don't think any sensitive RF receiver will survive a direct hit without significant change in performance, or failure. Well, the antenna and cable would likely be vaporized anyways. In my experience, putting a low-voltage TVS surge protector such as the Sision/Panjit 3.0SMCJ24A 3KW diode from RF center to ground (using a 22nH to 33nH high-power (2-3A) inductor to keep the RF away from the diode) helps protect receiver inputs against most proximity hits with minimal effect on the RF signal. This diode will quickly conduct above 24V surges, the Gas tubes need typically 100's of volts to start conducting. I used these in a Satellite receiver that was sold in large volumes across the US after we had a number of receivers returned from the states with active lightning with input failures. A 33nH inductor and 3KW TVS took care of the problem. The impedance of the 33nH inductor at 1.574GHz is high (>300 Ohms) so the transmission loss is << -0.023dB accorcding to AppCad. bye, Said In a message dated 2/29/2008 14:51:00 Pacific Standard Time, [EMAIL PROTECTED] writes: I'd be interested in reports on how well these work for GPS antennas, both in terms of lightning protection and in terms of attenuation, tempco, or phase delay. /tvb Delicious ideas to please the pickiest eaters. _Watch the video on AOL Living._ (http://living.aol.com/video/how-to-please-your-picky-eater/rachel-campos-duffy/2050827?NCID=aolcmp0030002598) **Ideas to please picky eaters. Watch video on AOL Living. (http://living.aol.com/video/how-to-please-your-picky-eater/rachel-campos-duffy/ 2050827?NCID=aolcmp0030002598) ___ 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] SVN23/PRN32 failure...
Hi! So, now the report of GPS failures due to SVN23/PRN32 starts to show up... lots of Swedish Sea-authority had several of their ships "dissapearing" from the AIS system on Wen. They already claim correlationto SVN23/PRN32 set to healthy... http://www.sjofartsverket.se/templates/SFVXNewsPage8738.aspx There's a reference to the US Coast Guard, but I did not see any further info from them. This have already hit the swedish news... Cheers, Magnus ___ 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-Attached Equipment Lightning Protection
Hi Matt, this may not work for you, but the new receivers coming onto the market are amazingly sensitive. I get full signal strength inside our wooden house on a Sirf-based receiver we are evaluating. I also get 8 Sats and more inside a metal building where we don't even get Cell-phone reception. The older Motorola receivers don't see any sats under the same conditions. While hiding the antenna inside the building will degrade the timing performance, it may save your equipment and you from getting zapped. bye, Said In a message dated 2/29/2008 15:43:20 Pacific Standard Time, [EMAIL PROTECTED] writes: Until such time as I can get a permanent antenna system and cabling set up (I don't do roof clambering), I'll leave that side of it and have and insert an optical stage between the receiver and the MAX232 and use fully isolated and independent power. Cheers M **Ideas to please picky eaters. Watch video on AOL Living. (http://living.aol.com/video/how-to-please-your-picky-eater/rachel-campos-duffy/ 2050827?NCID=aolcmp0030002598) ___ 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-Attached Equipment Lightning Protection
Quoth randy warner at 2008-03-01 09:51... ... > Remember, the surge protector will do ABSOLUTELY NOTHING to protect the > antenna. Their sole intent is to prevent large surges from getting into your > electronics, house wiring, fingers, toes, etc. The receiver will be toast > most likely, unless the hit is far away. ... > Turned out the weak point in his system was his computer. Most of the energy > passed through the case, but the serial card was absolute toast. ... And this was the reason for my original query - what I don't want is for anything to get to the computer/LAN. There has been considerable discussion on the 1-Wire Weather list about equipment getting toasted due to strikes on/near anemometers, etc. Until such time as I can get a permanent antenna system and cabling set up (I don't do roof clambering), I'll leave that side of it and have and insert an optical stage between the receiver and the MAX232 and use fully isolated and independent power. Cheers M -- Matthew Smith Smiffytech - Technology Consulting & Web Application Development Business: http://www.smiffytech.com/ Personal: http://www.smiffysplace.com/ LinkedIn: http://www.linkedin.com/in/smiffy ___ 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-Attached Equipment Lightning Protection
Hi Tom, couple of problems with these gas discharge devices: they need a significant voltage to trip, and usually may only help when the hit is a vicinity hit, not a direct hit. For direct hits, the goal is to prevent human casualties, and fires. I don't think any sensitive RF receiver will survive a direct hit without significant change in performance, or failure. Well, the antenna and cable would likely be vaporized anyways. In my experience, putting a low-voltage TVS surge protector such as the Sision/Panjit 3.0SMCJ24A 3KW diode from RF center to ground (using a 22nH to 33nH high-power (2-3A) inductor to keep the RF away from the diode) helps protect receiver inputs against most proximity hits with minimal effect on the RF signal. This diode will quickly conduct above 24V surges, the Gas tubes need typically 100's of volts to start conducting. I used these in a Satellite receiver that was sold in large volumes across the US after we had a number of receivers returned from the states with active lightning with input failures. A 33nH inductor and 3KW TVS took care of the problem. The impedance of the 33nH inductor at 1.574GHz is high (>300 Ohms) so the transmission loss is << -0.023dB accorcding to AppCad. bye, Said In a message dated 2/29/2008 14:51:00 Pacific Standard Time, [EMAIL PROTECTED] writes: I'd be interested in reports on how well these work for GPS antennas, both in terms of lightning protection and in terms of attenuation, tempco, or phase delay. /tvb **Ideas to please picky eaters. Watch video on AOL Living. (http://living.aol.com/video/how-to-please-your-picky-eater/rachel-campos-duffy/ 2050827?NCID=aolcmp0030002598) ___ 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] VP oncore problem
Morris, Are you getting "real" responses, or is the VP just reporting its current settings? If it receives a message it does not recognize due to formatting errors it will just report what its current settings are instead of acting on the command. I'm not sure what would happen if it got a series of commands like this. Message timing - this has tripped up many users. On power up (or after a reset) make sure you wait at least 5-10 seconds before sending any commands. If messages are received before the processor has finished booting, all sorts of bad things can happen (ask me how I know) Normally the receiver will just ignore them, but if the timing is JUST RIGHT you can trash the serial port. Randy -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Morris Odell Sent: Friday, February 29, 2008 3:03 PM To: time-nuts@febo.com Subject: [time-nuts] VP oncore problem Hi all, I wonder if anyone can help me with a problem I'm having with a VP Oncore receiver I am building something which includes one of these receivers and it communicates with the host microcontroller via the VP's serial binary link. The host receives messages from the VP just fine. The problem arises when the host tries to send configuration commands to the VP. When this happens the VP only responds to the first of 4 messages (Total: about 40 bytes). It doesn't matter what order they are sent in a continuous string or whether or not there are time delays up to 5 seconds or dummy characters between them, the VP only acknowledges the first one and is deaf to any more. Once the system is restarted it will receive one more message before going deaf again. The VP manual says the serial receive buffer will store up to 2048 characters and act on them sequentially. This is obviously not happening. Am I missing something here? TIA Morris ___ 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 To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS-Attached Equipment Lightning Protection
TVB Et al, In my experience (horror stories from the field) they have worked well. RF characteristics are pretty good for all. I have used several of the Citel units myself. Remember, the surge protector will do ABSOLUTELY NOTHING to protect the antenna. Their sole intent is to prevent large surges from getting into your electronics, house wiring, fingers, toes, etc. The receiver will be toast most likely, unless the hit is far away. Bear in mind that the front end of the antenna is a little, tiny, low voltage, lo-noise amplifier that really doesn't want to see any more that about a -60dB signal. It doesn't take much energy to pop one of these. Just ask any boat owner who has placed his GPS antenna within the sweep path of his marine radar.. I did have one case several years ago where a customer called to order a new timing antenna. He had no lightning protection and the receiver survived just fine (ya just can't kill a VP - they die when they damn well feel like it..) Turned out the weak point in his system was his computer. Most of the energy passed through the case, but the serial card was absolute toast. Randy -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Tom Van Baak Sent: Friday, February 29, 2008 2:50 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] GPS-Attached Equipment Lightning Protection RF gas-based lightning surge protectors are widely available; look on eBay for items with words like: Huber Suhner Polyphaser EMP surge lightning suppressor protector RGT gas For example, http://search.ebay.com/search/search.dll?satitle=Polyphaser+protector http://search.ebay.com/search/search.dll?satitle=Suhner+lightning http://search.ebay.com/search/search.dll?satitle=EMP+surge I'd be interested in reports on how well these work for GPS antennas, both in terms of lightning protection and in terms of attenuation, tempco, or phase delay. /tvb ___ 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 To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS-Attached Equipment Lightning Protection
ICE Electronics also has a line of surge protectors. Unlike others, they include a resistor to ground to bleed off static build-up. I se these on all my antennas. 73, Dick, W1KSZ -Original Message- >From: Tom Van Baak <[EMAIL PROTECTED]> >Sent: Feb 29, 2008 3:50 PM >To: Discussion of precise time and frequency measurement >Subject: Re: [time-nuts] GPS-Attached Equipment Lightning Protection > >RF gas-based lightning surge protectors are widely available; >look on eBay for items with words like: > Huber Suhner > Polyphaser > EMP surge lightning suppressor protector RGT gas > >For example, > http://search.ebay.com/search/search.dll?satitle=Polyphaser+protector > http://search.ebay.com/search/search.dll?satitle=Suhner+lightning > http://search.ebay.com/search/search.dll?satitle=EMP+surge > >I'd be interested in reports on how well these work for GPS >antennas, both in terms of lightning protection and in terms >of attenuation, tempco, or phase delay. > >/tvb > > >___ >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 To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] VP oncore problem
Hi all, I wonder if anyone can help me with a problem I'm having with a VP Oncore receiver I am building something which includes one of these receivers and it communicates with the host microcontroller via the VP's serial binary link. The host receives messages from the VP just fine. The problem arises when the host tries to send configuration commands to the VP. When this happens the VP only responds to the first of 4 messages (Total: about 40 bytes). It doesn't matter what order they are sent in a continuous string or whether or not there are time delays up to 5 seconds or dummy characters between them, the VP only acknowledges the first one and is deaf to any more. Once the system is restarted it will receive one more message before going deaf again. The VP manual says the serial receive buffer will store up to 2048 characters and act on them sequentially. This is obviously not happening. Am I missing something here? TIA Morris ___ 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-Attached Equipment Lightning Protection
RF gas-based lightning surge protectors are widely available; look on eBay for items with words like: Huber Suhner Polyphaser EMP surge lightning suppressor protector RGT gas For example, http://search.ebay.com/search/search.dll?satitle=Polyphaser+protector http://search.ebay.com/search/search.dll?satitle=Suhner+lightning http://search.ebay.com/search/search.dll?satitle=EMP+surge I'd be interested in reports on how well these work for GPS antennas, both in terms of lightning protection and in terms of attenuation, tempco, or phase delay. /tvb ___ 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-Attached Equipment Lightning Protection
I have lightning protector that uses those gas tubes. I have yet to hook it up though... My GPS antenna is mounted on a metal building so I'm probably a prime candidate for a lightning attractor. The antenna is mounted on a plastic pole giving a little isolation from the building itself though... ___ 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] Antenna problems
Have a pair of HP 58532 GPS antennas mounted four feet apart on an outdoor mast that is below the horizon due to hills. Bought a 100 foot roll of RG-8U, cut it in half and attached N connectors to both ends. Physical distance from radio to antenna is about 40 feet, but I wanted identical lengths. Lost one of them several years ago when lightning struck next door, about 100 feet away. The stroke split a one foot diameter oak and entered the neighbor's house via an outside floodlight. Damage to the house was minimal, but some stuff was fried. Lost another one this year in the Minneapolis cold snaps. At least the 3801 went into holdover and recovered during a brief thaw. But the cold came back and the signal went away again. It hasn't come back (in hold for 700 hours, about 10 seconds off) even though we had another warm spell. Any other lightning or low temp experiences out there? One day, I'll replace the 3801s with Lucent rubidium boxes, (last year's fad) soon as I get a round tuit - and a lot more data on the boxes. 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] GPS-Attached Equipment Lightning Protection
At 04:40 PM 2/28/2008, Matthew Smith wrote... >Is anyone implementing any form of lightning protection for their >GPS-attached equipment? I use an arrestor, something like this: http://www.alphadeltacom.com/tt3g50.html . That's not the brand I have, but it's similar. ___ 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] SVN23/PRN32 useable
My Trimble ACE-III Has been tracking PRN32. Works AOK. Bruce - Original Message - From: "Morris Odell" <[EMAIL PROTECTED]> To: Sent: Friday, February 29, 2008 1:22 AM Subject: Re: [time-nuts] SVN23/PRN32 useable >> Date: Wed, 27 Feb 2008 12:49:40 +0100 (CET) >> From: Magnus Danielson <[EMAIL PROTECTED]> >> Subject: Re: [time-nuts] SVN23/PRN32 useable >> >> The interesting thing would be for really old systems if they are able to >> track >> it or not. Like old 6-channel receivers and such. > > The old Oncore VP in my nixie clock was tracking PRN32 as part of its > timing > solution this morning down here in Melbourne Australia. > > Morris > > > > > ___ > 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. > > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.5.516 / Virus Database: 269.21.1/1302 - Release Date: 2/27/2008 > 4:34 PM > ___ 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-Attached Equipment Lightning Protection
I'm not using any at the moment, but then all my GPS antennae are indoors (long story!). Have been involved with supplying protection to clients over the years, and in the main, have been RF surge suppressor devices such as used by Meinberg http://www.meinberg.de/english/products/cn_ube.htm http://www.meinberg.de/english/products/cn_ube_280.htm and others. For straight RF feeds these are by far the easiest to implement and provide good protection. For GPS systems which utilise "smart antennae" i.e. the antenna also houses the receiver module, and the down cable contains data plus a 1PPS, then opto-isolation or a fibre optic link is the only real way to protect your real estate on the ground. Rob Kimberley (in UK) -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Matthew Smith Sent: 28 February 2008 21:40 To: Time Nuts List Subject: [time-nuts] GPS-Attached Equipment Lightning Protection Hi Folks Is anyone implementing any form of lightning protection for their GPS-attached equipment? If my antenna gets struck or we have a nearby hit (nearest strike to ground since we moved here was about 470m away, IIRC), I would like to limit the damage to the GPS module. My thought was to stick an optoisolator or similar between the serial and PPS pins and the level converter (MAX232 equivalent) and power the GPS module itself with one of those little Meanwell high-isolation DC/DC converters. This is very similar to what I am planning to do with the outside components of my 1-Wire weather system. I'd be interested to know what everyone else is doing in this respect (if anything). Cheers M -- Matthew Smith Smiffytech - Technology Consulting & Web Application Development Business: http://www.smiffytech.com/ Personal: http://www.smiffysplace.com/ LinkedIn: http://www.linkedin.com/in/smiffy ___ 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 To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
