[time-nuts] Best location for a GPS antenna...?

[Bob Camp]

Hi

If the antenna is no higher than your house, it's no more likely to get hit than the house. If it's higher than the house by a few feet, the increase in hit probability is vanishingly small. Provided the antenna is grounded as well as your house power (as in *very* poorly) it's no more a hazard than any other conductor in your home. Run it down to ground level and through a proper protector and it's less of a hazard than the rest of the conductors in the house.

Food for thought: do you have metal downspouts on the gutters? A metal lining in the chimney? Metal heating ducts ? Any bets on how they are grounded...

Bob

On Apr 11, 2012, at 5:34 PM, Tom Knox wrote:

> 
> This is a great discussion. I have been trying to decide the best compromise between optimal reception and safety.  Here in Boulder afternoon thunder stormers are often a daily occurrence.
> I cannot afford to learn from my mistakes on this one.
> Thomas Knox
> 
> 
> 
>> Date: Wed, 11 Apr 2012 22:37:06 +0200
>> From: attila at kinali.ch
>> To: time-nuts at febo.com
>> Subject: Re: [time-nuts] Best location for a GPS antenna...?
>> 
>> On Wed, 11 Apr 2012 22:06:06 +0200
>> "Andrea Baldoni" <erm1eaae7 at ermione.com> wrote:
>> 
>>> On Wed, Apr 11, 2012 at 10:19:40AM -0400, Bob Bownes wrote:
>>> 
>>>> I do like the optical isolation suggestion. While less than optimal,
>>>> perhaps the easiest solution is not to put the isolation between the t'bolt
>>>> and the antenna, but to put the isolation between the t'bolt and the
>>>> distribution amplifier.
>>> 
>>> By the way, would it be possible to retransmit the GPS signal to isolate it?
>>> 
>>> I mean, rx external antenna -> preamp -> tx directional internal antenna -> big
>>> air gap -> rx directional internal antenna -> receiver.
>>> The preamp would not be so power hungry as the full thunderbolt and maybe
>>> it could be powered via a magnetic link (or a little solar panel with a
>>> lamp illuminating it).
>> 
>> Yes it would be. What you basically would need is to have a LNA,
>> a bandpass filter and something that converts the voltage into
>> light with very little noise. I think it would be easiest to down
>> mix it first to 100MHz or so, then modulate a laser diode. In the
>> house you'd have to mix it up to 1.5GHz again, of course.
>> 
>> I have no clue whether that is feasible from the noise this whole
>> circuitry will add or whether it would add so much noise that the
>> receiver would have no chance...
>> 
>> 				Attila Kinali
>> -- 
>> Why does it take years to find the answers to
>> the questions one should have asked long ago?
>> 
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