[time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy)

[Bruce Griffiths]

Didier

As jammers those devices are extremely inefficient.
They may well rely on the inefficient generation and radiation of a very 
high order harmonic of the clock of an unshielded legal device.

A commercial GPS receiver may require a signal as small as 60dB (depends 
on the operating mode, and receiver design) above the GPS signal at the 
receiver input.
An ERP of a few microwatts should suffice to achieve the claimed range.

Bruce

Didier Juges wrote:
> The commercial jammers referred to in an earlier post advertise 10 to 45m or
> so range, with significant power levels and battery life measured in a few
> hours. Considering that these devices are illegal to begin with, I have to
> assume that these figures are probably optimistic (optimistic advertisement
> is probably the least of their concern.)
>
> If I were a pilot, I would probably be more worried about the kid playing
> with his Nintendo in 15A (or his father trying to retrieve his email with
> his GSM smart phone) during approach than a jammer on the ground.
>
> Didier
>
>    
>> -----Original Message-----
>> From: time-nuts-bounces at febo.com
>> [mailto:time-nuts-bounces at febo.com] On Behalf Of J. Forster
>> Sent: Sunday, November 15, 2009 6:38 PM
>> To: Discussion of precise time and frequency measurement
>> Subject: Re: [time-nuts] The Demise of LORAN (was Re:
>> Reference oscillator accuracy)
>>
>> Even 10 KM is pretty useful. If the thing were solar powered
>> with a supercap "battery" it could easly transmit for say 2
>> minutes per hour w/ significant power. It'd be hard to find
>> if the on times were generated by a multiple fedback CMOS
>> shift register.
>>
>> -John
>>
>>      
>
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