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.