[time-nuts] GPS simulator,

[Luis Cupido]

Hi,

The fact they refer that atmospheric s/n degradation and dropouts etc 
being replayed precisely lead me to think this is just a spectrum 
rec/play machine (no mod/demod of any kind)
like the ham-oriented "time machine" but for GPS.
http://www.expandedspectrumsystems.com/prod2.html

Luis Cupido.
ct1dmk.



Bob Camp wrote:
> Hi
> 
> It's not real clear that they do anything more than sample the RX and play it back for the TX. 
> 
> Bob
> 
> Sent from my iPhone
> 
> On Nov 25, 2010, at 9:39 AM, "J. Forster" <jfor at quik.com> wrote:
> 
>> Agreed. The trick is to properly partition what is done in hardware ane
>> what is done in software. This could eliminate a lot of logic hardware.
>>
>> Clearly, the RF stuff and modulator are hardware.
>> Ditto PR code generation.
>> Everything else in SW, I think.
>>
>> FWIW,
>>
>> -John
>>
>> ===============
>>
>>
>>> Hi
>>>
>>> One bit serial at 16 MHz isn't all that fancy any more. Sounds like a
>>> shift register feeding a couple filters.
>>>
>>> The money must be in the receive side.
>>>
>>> Bob
>>>
>>> On Nov 24, 2010, at 5:14 PM, ernieperes at aol.com wrote:
>>>
>>>>
>>>>
>>>> Hi,
>>>>
>>>>  found an interesting unit. I think it is not for the usual pocket
>>>> money for a time-nuts.
>>>>  have a look...
>>>>
>>>>      http://www.chronos.co.uk/pdfs/rac/labsat.pdf
>>>>
>>>> Rgds Ernie.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> -----Original Message-----
>>>> From: John Green <wpxs472 at gmail.com>
>>>> To: time-nuts at febo.com
>>>> Sent: Mon, Nov 22, 2010 6:43 pm
>>>> Subject: [time-nuts] GPS jamming susceptibility
>>>>
>>>>
>>>> Given that this is an extremely sensitive topic and completely illegal
>>>> lso, let me just state at the outset that I have no interest in
>>>> amming anyone's GPS. A while back, I was looking at one of those
>>>> hinese discount electronics websites, I'm sure we all have, and
>>>> oticed a GPS jammer for sale. I had been wanting to do some jamming
>>>> usceptibility testing for quite some time but had never got around to
>>>> uilding a generator to test with. The thing was cheap so I ordered
>>>> t. After it arrived, I opened it up, first thing, to see how it was
>>>> ade. It has a dual 555 oscillator, a couple of analog switches, a 1.9
>>>> Hz VCO, a single amplifier. It doesn't look capable of putting out
>>>> ore than 50 milliwatts or so into a 2 inch antenna. I was somewhat
>>>> ubious that it would do anything, so I took it to the bench where the
>>>> 3801 lives and turned it on. Within 2 seconds, the holdover LED lit.
>>>> immediately turned it off and within a few more seconds, the
>>>> oldover LED was back off. The GPS antenna is perhaps 35 feet away
>>>> ith a cinder block wall, a brick wall, and a metal roof in between. I
>>>> lso put a 15 Db attenuator between it and the antenna with almost the
>>>> ame result. I am going to do more testing with it wired into the GPS
>>>> ownfeed an an adjustable attenuator in line just to see how much
>>>> ignal it takes. That way, there will be little danger of messing with
>>>> nyone's reception. It is just a simple sweeper so it must do its job
>>>> y brute force. I am amazed that it took so little to shut my Z3801
>>>> own. Has anyone here had any actual experience testing GPS receivers
>>>> or susceptibility?
>>>> _______________________________________________
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>>>>
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>>>
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>>
>>
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