Re: [time-nuts] Surge Arresters
On 26 November 2012 15:44, Peter G. Viscarola pete...@osr.com wrote: Hi TimeNuts, What are people using for surge arresters between your GPS receiver and the antenna, at the entrance to your house? Several years ago there was lightning near my house, which I think went on the telephone lines, as it destroyed the ADSL modem, and destroyed the ethernet ports on everything connected to it. Luckily my instance company paid for this, although it was a battle with their computer experts, who clearly got very lost when coming to Sun workstations, despite me warning the insurers before that these were not ordinary computers. I once worked for a defunt company Belling Lee Intec who built Electromagnetic Pulse (EMP) protection systems for customers. 95% were military, but the BBC were also a big customer. These systems used to consist of 3 components. 1) Spark gap 2) Voltage dependant resistor 3) Low pass filter. You could take a similar approach, but with a band-pass filter. A VDR is not going to be any use at 1.6 GHz, so you could forget that part. But that method is not going to be foolproof, as a direct hit would destroy the capacitors in your BPF. If I was reallly concerned, then I'd look at using an optical interace. Use a battery to power the GPS antenna, modulate a laser and detect the RF on a photodiode connected by a metre of so of optical fibre. Whilst nothing can be considered 100% relieble, an optical interface is probably the best you can do. One might consider this OTT, but I don't see any other method can be very certain to work. Having had the problem with the ADSL modem on the telphone line, I did promise myself I'd build such an optical interface, which is much easy at ADSL frequencies. But I never did! 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] Surge Arresters
On 27 November 2012 09:15, David Kirkby david.kir...@onetel.net wrote: If I was reallly concerned, then I'd look at using an optical interace. Use a battery to power the GPS antenna, modulate a laser and detect the RF on a photodiode connected by a metre of so of optical fibre. Of course, I mean detect the RF modulated light on a photodiode. An optical interface is I believe the best you can do. I would certainly not trust surge protectors on this sort of thing. But a band-pass filter would do a pretty decent job, as there will be very little RF at those frequencies from lightning. I did once used to know the frequency range of EMP and ligthning, and whilst I can't remember them now, it is well below 1.6 GHz where there is significant energy. 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] Surge Arresters
You really can't protect yourself from a direct strike. But that is rare. More common is a close strike. You first line of defense is to ground the metal mast (pipe). Place a ground clamp on the pipe and run a large ground write by the most direct route to a ground rod driven into the soil. This rod needs to be tied into the the building ground. You must use mechanical clamp type connections at each end.This ground system is direct almost all the energy away. If the coax wire is inside the mast it will be well protected. I owned a sail boat for years. On the ocean my 65 foot aluminum mast was the tallest conductor for many miles. But it was securely conected to a 8,000 pound lead keel that was in saltwater. Any lightening strike the energy would go mostly to the water. Then inside the atto you have a lighten/surge protector mounted on some kind of metal bulkhead. (A common electrical box works for this and is cheap. As long as you don't like in Orlando FL you should be fine -- 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.
[time-nuts] Surge Arresters
Hi TimeNuts, What are people using for surge arresters between your GPS receiver and the antenna, at the entrance to your house? I've got an entrance panel set up for HF, with copper ribbon to two ground rods. I'd like to add a connection for my GPSDO. I know the frequency is about 1.6GHz, and the active antennas use 5V or less... is that correct? What are the parameters I should consider when selecting an arrester? An associated question, also, if I may: Does it matter if I use different types of cable between the antenna and the entrance panel and then entrance panel and the GPS receiver? Thanks for your guidance, Peter K1PGV ___ 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] Surge Arresters
Hi Commercial units designed for cell tower use often show up on eBay for sub $20 prices. Since they are set up for the frequency (1.5 GHz), the levels (RX, so no power), and the purpose there isn't a lot of need for anything else. Last time I bought some, they came as part of a kit that also included the ground strapping and various other useful bits and pieces. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Peter G. Viscarola Sent: Monday, November 26, 2012 10:45 AM To: time-nuts@febo.com Subject: [time-nuts] Surge Arresters Hi TimeNuts, What are people using for surge arresters between your GPS receiver and the antenna, at the entrance to your house? I've got an entrance panel set up for HF, with copper ribbon to two ground rods. I'd like to add a connection for my GPSDO. I know the frequency is about 1.6GHz, and the active antennas use 5V or less... is that correct? What are the parameters I should consider when selecting an arrester? An associated question, also, if I may: Does it matter if I use different types of cable between the antenna and the entrance panel and then entrance panel and the GPS receiver? Thanks for your guidance, Peter K1PGV ___ 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] Surge Arresters
There really isn't anything that will protect your receiver if the antenna takes a strike. But, if you pass the coax into your house using a well grounded bulkhead connector, you can protect your house. I got one GPS antenna that had an EMP protector attached to it (came from NSA)... since the EMP protector was right at the base of the antenna, I suspect they were trying to protect the antenna from induced coax currents from nearby lightning strikes. The antenna was dead, of course. -Chuck Harris Peter G. Viscarola wrote: Hi TimeNuts, What are people using for surge arresters between your GPS receiver and the antenna, at the entrance to your house? I've got an entrance panel set up for HF, with copper ribbon to two ground rods. I'd like to add a connection for my GPSDO. I know the frequency is about 1.6GHz, and the active antennas use 5V or less... is that correct? What are the parameters I should consider when selecting an arrester? An associated question, also, if I may: Does it matter if I use different types of cable between the antenna and the entrance panel and then entrance panel and the GPS receiver? Thanks for your guidance, Peter K1PGV ___ 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] Surge Arresters
I don't use one on my gpsdo feed line. The shield of the feed line is grounded prior to it entering the house and I don't live in a lightning prone area. The gps antenna I use apparently has diode protection to provide some immunity to near by lightning strikes. Most of my radio antennas are dc grounded. I also had a dedicated roof top ground system installed during some prior home renovations that the coax shields of my roof top antenna(s) are connected to. This ground system is in turn connected to the electrical service ground out side of the house. I'm hopeful the roof top ground will be a more attractive path to ground for lightning than the shields of the feed lines that run into the house that are connected to gpsdo's and radios that are in turn grounded via the electrical system in the house. If I see a surge suppressor for a decent price on eBay I might re consider getting one, but I'm unsure if it would make much difference in my circumstances in the event of a direct hit. I'm primarily interested in protecting the house and it's occupants. The survival of the radios is a fairly low priority to me. I hope I never get to find out what happens if my roof top antennas get hit by lightning. Regards Mark Spencer Sent from my iPad ___ 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] Surge Arresters
I have a box-full of GPS protectors that were built by a company called ZapTech. They are just coaxial gas tubes that seem to have a strike voltage around 60-90 volts. We replaced them with (MUCH) more expensive PolyPhaser units. I use the ZapTechs on all of my long (600-800 ft) low-freq receiving wire antennas, and they seem to be doing the job but, as with all surge suppression schemes, you can never really be sure. 73, geo - n4ua On Mon, Nov 26, 2012 at 11:42 AM, Chuck Harris cfhar...@erols.com wrote: There really isn't anything that will protect your receiver if the antenna takes a strike. But, if you pass the coax into your house using a well grounded bulkhead connector, you can protect your house. I got one GPS antenna that had an EMP protector attached to it (came from NSA)... since the EMP protector was right at the base of the antenna, I suspect they were trying to protect the antenna from induced coax currents from nearby lightning strikes. The antenna was dead, of course. -Chuck Harris Peter G. Viscarola wrote: Hi TimeNuts, What are people using for surge arresters between your GPS receiver and the antenna, at the entrance to your house? I've got an entrance panel set up for HF, with copper ribbon to two ground rods. I'd like to add a connection for my GPSDO. I know the frequency is about 1.6GHz, and the active antennas use 5V or less... is that correct? What are the parameters I should consider when selecting an arrester? An associated question, also, if I may: Does it matter if I use different types of cable between the antenna and the entrance panel and then entrance panel and the GPS receiver? Thanks for your guidance, Peter K1PGV __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/**mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nutsand 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-nutshttps://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] Surge Arresters
There's not much in this world that is able to reliably protect a radios input from a direct lightning hit (maybe a block of copper instead of the antenna...). But a surge protector (sometimes called EMP protector or surge arrester) can increase the probability that a nearby lightning strike won't induce to high a voltage surge on your receivers input. Since the input itself may have protection diodes the surge arrester has to eliminate the part of energy, that would blow the diodes. If you have a look here http://precision.hubersuhner.com/co-rub/mozilla/products/hs-p-rf/hs-rf-lightning-protectors/hs-p-rf-lp-pg/hs-p-rf-lp-pg-fp.htm you'll find types, that are able to handle up to 30kA. If you could get a GPS receiver protector for, say, 15 or 20 Dollars, I would apply it. It should be designed to particularly protect receivers, since transmitter protectors have higher ignition voltages. Cheers Volker - DF9PL Am 26.11.2012 19:18, schrieb Mark Spencer: I don't use one on my gpsdo feed line. The shield of the feed line is grounded prior to it entering the house and I don't live in a lightning prone area. The gps antenna I use apparently has diode protection to provide some immunity to near by lightning strikes. Most of my radio antennas are dc grounded. I also had a dedicated roof top ground system installed during some prior home renovations that the coax shields of my roof top antenna(s) are connected to. This ground system is in turn connected to the electrical service ground out side of the house. I'm hopeful the roof top ground will be a more attractive path to ground for lightning than the shields of the feed lines that run into the house that are connected to gpsdo's and radios that are in turn grounded via the electrical system in the house. If I see a surge suppressor for a decent price on eBay I might re consider getting one, but I'm unsure if it would make much difference in my circumstances in the event of a direct hit. I'm primarily interested in protecting the house and it's occupants. The survival of the radios is a fairly low priority to me. I hope I never get to find out what happens if my roof top antennas get hit by lightning. Regards Mark Spencer Sent from my iPad ___ 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] Surge Arresters
Cable question: I assume that won't be the problem. I use my 26dB Trimble timing antenna with RG-213 because of the low loss (and the low cost). Before that I had 15 m (45 feet) of RG-58 combined with a car roof magnetic patch antenna in use without any problem. Any 50 Ohm cable can be used, just mind the attenuation. Any combination of those cables will do. Some of the time nuts even recommend cable-TV cable (75 Ohms) due to low loss and good shielding capabilities. I'd rather take care with the connectors since this can be a great source of trouble, so avoid too much connectors on the signals way down to your shack and use appropriate and well-assembled quality connectors. The slightly higher cost will pay off. After decades of using and assembling every type and brand of connector I can assure you, this is the main thing. Volker Am 26.11.2012 16:44, schrieb Peter G. Viscarola: Hi TimeNuts, What are people using for surge arresters between your GPS receiver and the antenna, at the entrance to your house? I've got an entrance panel set up for HF, with copper ribbon to two ground rods. I'd like to add a connection for my GPSDO. I know the frequency is about 1.6GHz, and the active antennas use 5V or less... is that correct? What are the parameters I should consider when selecting an arrester? An associated question, also, if I may: Does it matter if I use different types of cable between the antenna and the entrance panel and then entrance panel and the GPS receiver? Thanks for your guidance, Peter K1PGV ___ 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] Surge Arresters
Hi RG-6 quad shield satellite TV cable is pretty much the low cost / low loss way to go for feed line. The TBolts are set up to use it by default. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Volker Esper Sent: Monday, November 26, 2012 2:38 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Surge Arresters Cable question: I assume that won't be the problem. I use my 26dB Trimble timing antenna with RG-213 because of the low loss (and the low cost). Before that I had 15 m (45 feet) of RG-58 combined with a car roof magnetic patch antenna in use without any problem. Any 50 Ohm cable can be used, just mind the attenuation. Any combination of those cables will do. Some of the time nuts even recommend cable-TV cable (75 Ohms) due to low loss and good shielding capabilities. I'd rather take care with the connectors since this can be a great source of trouble, so avoid too much connectors on the signals way down to your shack and use appropriate and well-assembled quality connectors. The slightly higher cost will pay off. After decades of using and assembling every type and brand of connector I can assure you, this is the main thing. Volker Am 26.11.2012 16:44, schrieb Peter G. Viscarola: Hi TimeNuts, What are people using for surge arresters between your GPS receiver and the antenna, at the entrance to your house? I've got an entrance panel set up for HF, with copper ribbon to two ground rods. I'd like to add a connection for my GPSDO. I know the frequency is about 1.6GHz, and the active antennas use 5V or less... is that correct? What are the parameters I should consider when selecting an arrester? An associated question, also, if I may: Does it matter if I use different types of cable between the antenna and the entrance panel and then entrance panel and the GPS receiver? Thanks for your guidance, Peter K1PGV ___ 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 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] Surge Arresters
Unfortunately, many of the surge arresters available on ebay do not pass DC or have a DC shunt to ground internally. This means they won't work with an amplified antenna. Make sure any suppressor you get will pass the DC current to the antenna. Al, K9SI, retired ___ 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.
