[time-nuts] GPS Interference Question

Chuck Forsberg WA7KGX N2469R caf at omen.com
Fri Sep 30 15:20:05 UTC 2011


A wider filter with steep skirts tends to cost more.
Constraints on noise figure, dynamic range, group delay. and flatness 
add more cost
and power consumption.


On 09/30/2011 08:11 AM, Bob Bownes wrote:
> Exactly. The narrower the filter, the more it will cost. In general.
>
>
>
> On Fri, Sep 30, 2011 at 11:10 AM, Tom Holmes<tholmes at woh.rr.com>  wrote:
>> Sticking with the intent to keep this non-political, what good is a filter
>> if the offending signal is within the necessary passband?
>>
>> Tom Holmes, N8ZM
>> Tipp City, OH
>> EM79
>>
>>
>>> -----Original Message-----
>>> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
>>> Behalf Of Chuck Forsberg WA7KGX N2469R
>>> Sent: Friday, September 30, 2011 10:55 AM
>>> To: Discussion of precise time and frequency measurement
>>> Subject: Re: [time-nuts] GPS Interference Question
>>>
>>> If LightSquared deploys their high powered LTE network in the satellite
>> band
>>> the GPS world will become very interesting indeed.  Are LightSquared
>> willing
>>> to spend $20,000 to upgrade the GPS on my Skylane to a new model which
>>> does not yet exist?
>>>
>>> With that many transmitters we may experience areas where RF from multiple
>>> high power transmitters creates hot spots.  In some places pieces of metal
>>> with non Ohmic bonds will create mixing products, some of which may fall
>>> directly within GPS bands.  These effects have not been simulated.
>>>
>>> Who knows who the FCC is listening to - the GPS industry including
>> millions
>>> of current users, or those who appear to have bought under the table
>> favor.
>>> This could make Solyndra look like small change.  Film at 11.
>>>
>>>
>>> On 09/30/2011 07:02 AM, Marco IK1ODO -2 wrote:
>>>> At 15:44 30-09-11, Jason wrote:
>>>>
>>>>> To filter out the L2 signal, would an actual GPS receiver have to be
>>>>> replaced / modified?
>>>>>
>>>>> Or would a more simple and cheaper alternative be to get a new
>>>>> antenna (with fancy filtering) to replace my existing roof-top
>>>>> antenna and expect all my old equipment to be happy?
>>>> I think that a new antenna/filter/amplifier unit would be ok. But the
>>>> problem is the installed base of receivers, including all those costly
>>>> units used for geodesy or navigation, that have embedded antennas.
>>>> Those will be hard to modify.
>>>>
>>>> 73 - Marco IK1ODO
>>>>
>>>>
>>>>
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>>> --
>>> Chuck Forsberg WA7KGX N2469R     caf at omen.com   www.omen.com
>>> Developer of Industrial ZMODEM(Tm) for Embedded Applications
>>>     Omen Technology Inc      "The High Reliability Software"
>>> 10255 NW Old Cornelius Pass Portland OR 97231   503-614-0430
>>>
>>>
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-- 
Chuck Forsberg WA7KGX N2469R     caf at omen.com   www.omen.com
Developer of Industrial ZMODEM(Tm) for Embedded Applications
   Omen Technology Inc      "The High Reliability Software"
10255 NW Old Cornelius Pass Portland OR 97231   503-614-0430




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