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How much do GPS receivers affect the local GPS signal strength?
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Mark F
May 15, 2012, 7:15:06 AM5/15/12
to
How much do GPS receivers affect the local GPS signal strength?
While a receiver doesn't reduce the signal strength much, it
would seem that it has to have some effect.
Perhaps the effect was insignificant with only 1E6 receivers,
but, with GPS in many mobile phone there may now be 1E9 receivers,
1000 times as many. Perhaps in the future when every packaged
item for sale has a GPS receiver in it, or maybe even every piece
of paper in package the satellites will require increased output
in order to keep things working.
While a receiver doesn't reduce the signal strength much, it
would seem that it has to have some effect.
Perhaps the effect was insignificant with only 1E6 receivers,
but, with GPS in many mobile phone there may now be 1E9 receivers,
1000 times as many. Perhaps in the future when every packaged
item for sale has a GPS receiver in it, or maybe even every piece
of paper in package the satellites will require increased output
in order to keep things working.
Peter H. Coffin
May 15, 2012, 8:38:51 AM5/15/12
to
On Tue, 15 May 2012 07:15:06 -0400, Mark F wrote:
> How much do GPS receivers affect the local GPS signal strength?
>
> While a receiver doesn't reduce the signal strength much, it
> would seem that it has to have some effect.
If the other reciever is between yours and the satellite, it might
> How much do GPS receivers affect the local GPS signal strength?
>
> While a receiver doesn't reduce the signal strength much, it
> would seem that it has to have some effect.
affect something. But since there's a whole bunch of satellites and a
lot of redudancy, it's *far* less effect than (for example) being under
a tree.
> Perhaps the effect was insignificant with only 1E6 receivers,
> but, with GPS in many mobile phone there may now be 1E9 receivers,
> 1000 times as many. Perhaps in the future when every packaged
> item for sale has a GPS receiver in it, or maybe even every piece
> of paper in package the satellites will require increased output
> in order to keep things working.
a receiver's there and wants to see them. If you put one radio receiver
in the middle of a field, and it gets signal strength X from an orbital
source, it will still get X strength regardless of whether there's no
others around or there's a thousand other receivers in the same field.
There's no contention for the information in that radio signal either:
the information flows only one way, to all of them, at exactly the same
rate.
--
Any research done on how to efficiently use computers has been long lost
in the mad rush to upgrade systems to do things that aren't needed by
people who don't understand what they are really supposed to do with
them. -- Graham Reed
Sam Wormley
May 15, 2012, 9:03:45 AM5/15/12
to
by each other's LO radiation. I've tested this with Garmin and Trimble
consumer level receivers.
Nicholas
May 15, 2012, 9:23:02 AM5/15/12
to
On Tue, 15 May 2012 08:03:45 -0500, Sam Wormley <swor...@gmail.com>
wrote:
and just for clarification for the OP, LO stands for "local
oscillator"
wrote:
oscillator"
Bert
May 15, 2012, 11:10:03 AM5/15/12
to
In news:slrnjr4jir....@nibelheim.ninehells.com "Peter H. Coffin"
signal to his, but whether some of the signal might be "absorbed" by
other receivers and affect his.
--
be...@iphouse.com St. Paul, MN
<hel...@ninehells.com> wrote:
> Okay, simple thinking check: radio waves don't change direction
> because a receiver's there and wants to see them. If you put one radio
> receiver in the middle of a field, and it gets signal strength X from
> an orbital source, it will still get X strength regardless of whether
> there's no others around or there's a thousand other receivers in the
> same field.
I don't think the OP was thinking about other receivers blocking the
> Okay, simple thinking check: radio waves don't change direction
> because a receiver's there and wants to see them. If you put one radio
> receiver in the middle of a field, and it gets signal strength X from
> an orbital source, it will still get X strength regardless of whether
> there's no others around or there's a thousand other receivers in the
> same field.
signal to his, but whether some of the signal might be "absorbed" by
other receivers and affect his.
--
be...@iphouse.com St. Paul, MN
Alan Browne
May 15, 2012, 2:02:39 PM5/15/12
to
On 2012-05-15 07:15 , Mark F wrote:
> How much do GPS receivers affect the local GPS signal strength?
>
> While a receiver doesn't reduce the signal strength much, it
> would seem that it has to have some effect.
An increasing number of receivers doesn't subtract from the available
> How much do GPS receivers affect the local GPS signal strength?
>
> While a receiver doesn't reduce the signal strength much, it
> would seem that it has to have some effect.
signal.
Two GPS antennas, very close to each other, could affect one another's
fields potentially reducing accuracy and having a minor effect on signal
strength. As Sam says, LO leakage might also affect the other receiver
(I haven't observed this - haven't looked for it either).
If there was a GPS antenna at every point on a grid with 1 m spacing,
there would be no change in received signal strength from if there was
one at every 1000 m.
Most of the GPS signal broadcast ends up hitting the ground unused.
--
"A person with a new idea is a crank until the idea succeeds."
-Samuel Clemens.
Mark F
May 15, 2012, 4:50:29 PM5/15/12
to
On Tue, 15 May 2012 14:02:39 -0400, Alan Browne
<alan....@FreelunchVideotron.ca> wrote:
> On 2012-05-15 07:15 , Mark F wrote:
> > How much do GPS receivers affect the local GPS signal strength?
> >
> > While a receiver doesn't reduce the signal strength much, it
> > would seem that it has to have some effect.
>
> An increasing number of receivers doesn't subtract from the available
> signal.
>
> Two GPS antennas, very close to each other, could affect one another's
> fields potentially reducing accuracy and having a minor effect on signal
> strength. As Sam says, LO leakage might also affect the other receiver
I wasn't concerned about local oscillator interference, but I forgot
<alan....@FreelunchVideotron.ca> wrote:
> On 2012-05-15 07:15 , Mark F wrote:
> > How much do GPS receivers affect the local GPS signal strength?
> >
> > While a receiver doesn't reduce the signal strength much, it
> > would seem that it has to have some effect.
>
> An increasing number of receivers doesn't subtract from the available
> signal.
>
> Two GPS antennas, very close to each other, could affect one another's
> fields potentially reducing accuracy and having a minor effect on signal
> strength. As Sam says, LO leakage might also affect the other receiver
to mention it. I also wasn't concerned about shielding effects,
but I thought that was obvious.
> (I haven't observed this - haven't looked for it either).
>
> If there was a GPS antenna at every point on a grid with 1 m spacing,
> there would be no change in received signal strength from if there was
> one at every 1000 m.
If I suspended the transmitter above the ground
and put 100000 receiving units (bulbs) on my 1 mile circular field,
is each bulb lit slightly less brightly than if it were only bulb
in the middle of the field. (Assume that the receiving antennas are
positioned randomly about equally spaced grid points so that there are
no issues with standing waves or whatever due to the exact positioning
and frequencies.)
Alan Browne
May 15, 2012, 5:05:02 PM5/15/12
to
On 2012-05-15 16:50 , Mark F wrote:
> I was thinking along the lines of a Tesla RF power transmission.
See the last and first sentences of my prior reply.
> I was thinking along the lines of a Tesla RF power transmission.
Peter H. Coffin
May 15, 2012, 6:09:50 PM5/15/12
to
On Tue, 15 May 2012 16:50:29 -0400, Mark F wrote:
> If I suspended the transmitter above the ground
> and put 100000 receiving units (bulbs) on my 1 mile circular field,
> is each bulb lit slightly less brightly than if it were only bulb
> in the middle of the field. (Assume that the receiving antennas are
> positioned randomly about equally spaced grid points so that there are
> no issues with standing waves or whatever due to the exact positioning
> and frequencies.)
That is not the case.
> If I suspended the transmitter above the ground
> and put 100000 receiving units (bulbs) on my 1 mile circular field,
> is each bulb lit slightly less brightly than if it were only bulb
> in the middle of the field. (Assume that the receiving antennas are
> positioned randomly about equally spaced grid points so that there are
> no issues with standing waves or whatever due to the exact positioning
> and frequencies.)
--
"Friendship is born at that moment when one person says to another,
'What! You too? I thought I was the only one!'"
--C.S. Lewis
Message has been deleted
Alan Browne
May 16, 2012, 4:13:26 PM5/16/12
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On 2012-05-16 02:50 , Jeff wrote:
> available field strength, but as the signals are coming from above is is
As I made abundantly clear in the example that you snipped out.
> On 15/05/2012 19:02, Alan Browne wrote:
>> On 2012-05-15 07:15 , Mark F wrote:
>>> How much do GPS receivers affect the local GPS signal strength?
>>>
>>> While a receiver doesn't reduce the signal strength much, it
>>> would seem that it has to have some effect.
>>
>> An increasing number of receivers doesn't subtract from the available
>> signal.
>
> That is not the case, the received signal does indeed subtract from the
>> On 2012-05-15 07:15 , Mark F wrote:
>>> How much do GPS receivers affect the local GPS signal strength?
>>>
>>> While a receiver doesn't reduce the signal strength much, it
>>> would seem that it has to have some effect.
>>
>> An increasing number of receivers doesn't subtract from the available
>> signal.
>
> available field strength, but as the signals are coming from above is is
As I made abundantly clear in the example that you snipped out.
Sam Wormley
May 16, 2012, 6:01:28 PM5/16/12
to
On 5/16/12 1:50 AM, Jeff wrote:
> That is not the case, the received signal does indeed subtract from the
> available field strength, but as the signals are coming from above is is
> unlikely that it would detract from the received signal at another
> That is not the case, the received signal does indeed subtract from the
> available field strength, but as the signals are coming from above is is
> receiver unless the antennas were is exact alignment.
The signals come from all directions in the sky. There essentially
isn't any signal shadowing for the billions gps receivers.
Message has been deleted
Alan Browne
May 17, 2012, 9:30:14 AM5/17/12
to
On 2012-05-17 04:57 , Jeff wrote:
> receivers doesn't subtract from the available signal" which is
> incorrect. I was pointing out the it is the alignment of the receivers
> with respect to the satellites that is important.
In the real world that most of us inhabit such would not normally occur.
If you have a specific circumstance, describe it in detail.
> On 16/05/2012 21:13, Alan Browne wrote:
>> On 2012-05-16 02:50 , Jeff wrote:
>>> On 15/05/2012 19:02, Alan Browne wrote:
>>>> On 2012-05-15 07:15 , Mark F wrote:
>>>>> How much do GPS receivers affect the local GPS signal strength?
>>>>>
>>>>> While a receiver doesn't reduce the signal strength much, it
>>>>> would seem that it has to have some effect.
>>>>
>>>> An increasing number of receivers doesn't subtract from the available
>>>> signal.
>>>
>>> That is not the case, the received signal does indeed subtract from the
>>> available field strength, but as the signals are coming from above is is
>>
>> As I made abundantly clear in the example that you snipped out.
>>
>
> But you still made the above statement, " An increasing number of
>> On 2012-05-16 02:50 , Jeff wrote:
>>> On 15/05/2012 19:02, Alan Browne wrote:
>>>> On 2012-05-15 07:15 , Mark F wrote:
>>>>> How much do GPS receivers affect the local GPS signal strength?
>>>>>
>>>>> While a receiver doesn't reduce the signal strength much, it
>>>>> would seem that it has to have some effect.
>>>>
>>>> An increasing number of receivers doesn't subtract from the available
>>>> signal.
>>>
>>> That is not the case, the received signal does indeed subtract from the
>>> available field strength, but as the signals are coming from above is is
>>
>> As I made abundantly clear in the example that you snipped out.
>>
>
> receivers doesn't subtract from the available signal" which is
> incorrect. I was pointing out the it is the alignment of the receivers
> with respect to the satellites that is important.
In the real world that most of us inhabit such would not normally occur.
If you have a specific circumstance, describe it in detail.
Peter H. Coffin
May 17, 2012, 10:37:43 AM5/17/12
to
On Wed, 16 May 2012 07:50:56 +0100, Jeff wrote:
> On 15/05/2012 19:02, Alan Browne wrote:
> On 15/05/2012 19:02, Alan Browne wrote:
>> On 2012-05-15 07:15 , Mark F wrote:
>>> How much do GPS receivers affect the local GPS signal strength?
>>>
>>> While a receiver doesn't reduce the signal strength much, it
>>> would seem that it has to have some effect.
>>
>> An increasing number of receivers doesn't subtract from the available
>> signal.
>
>>> How much do GPS receivers affect the local GPS signal strength?
>>>
>>> While a receiver doesn't reduce the signal strength much, it
>>> would seem that it has to have some effect.
>>
>> An increasing number of receivers doesn't subtract from the available
>> signal.
>
> That is not the case, the received signal does indeed subtract from the
> available field strength, but as the signals are coming from above is is
> available field strength, but as the signals are coming from above is is
> unlikely that it would detract from the received signal at another
> receiver unless the antennas were is exact alignment.
And they will essentially never BE in exact alignment. There's not just
> receiver unless the antennas were is exact alignment.
one signal, there's usually 8-12, usually scattered all over the sky,
and *they constantly move*.
> There have been cases where people have attempted to extract power from
> high power radio transmitters, and those activities did produce dips in
> the radiated signal in the direction of their activities.
Yeah, let's see you try that with your GPS... (;
--
Don't use this code for realtime control, for weapons systems, or for
anything else that may put life or limb at hazard. It isn't man-rated,
it isn't really thing-rated, and we don't claim that it's worth a good
G*dDamn for anything at all, at all. -- Mike Andrews, on Java compilers
Mark F
May 17, 2012, 5:08:54 PM5/17/12
to
On Thu, 17 May 2012 09:37:43 -0500, "Peter H. Coffin"
<hel...@ninehells.com> wrote:
> On Wed, 16 May 2012 07:50:56 +0100, Jeff wrote:
> > On 15/05/2012 19:02, Alan Browne wrote:
> >> On 2012-05-15 07:15 , Mark F wrote:
> >>> How much do GPS receivers affect the local GPS signal strength?
> >>>
> >>> While a receiver doesn't reduce the signal strength much, it
> >>> would seem that it has to have some effect.
> >>
> >> An increasing number of receivers doesn't subtract from the available
> >> signal.
> >
> > That is not the case, the received signal does indeed subtract from the
> > available field strength, but as the signals are coming from above is is
> > unlikely that it would detract from the received signal at another
> > receiver unless the antennas were is exact alignment.
I wasn't concerned with the alignment of the transmitters (that move
<hel...@ninehells.com> wrote:
> On Wed, 16 May 2012 07:50:56 +0100, Jeff wrote:
> > On 15/05/2012 19:02, Alan Browne wrote:
> >> On 2012-05-15 07:15 , Mark F wrote:
> >>> How much do GPS receivers affect the local GPS signal strength?
> >>>
> >>> While a receiver doesn't reduce the signal strength much, it
> >>> would seem that it has to have some effect.
> >>
> >> An increasing number of receivers doesn't subtract from the available
> >> signal.
> >
> > That is not the case, the received signal does indeed subtract from the
> > available field strength, but as the signals are coming from above is is
> > unlikely that it would detract from the received signal at another
> > receiver unless the antennas were is exact alignment.
relative to each other), but the alignment of the receivers. I wanted
to remove from consideration some special case where the receivers
remained aligned with the signal from one moving satellite.
Alan Browne
May 17, 2012, 5:47:19 PM5/17/12
to
On 2012-05-17 17:08 , Mark F wrote:
> On Thu, 17 May 2012 09:37:43 -0500, "Peter H. Coffin"
> <hel...@ninehells.com> wrote:
>
>> On Wed, 16 May 2012 07:50:56 +0100, Jeff wrote:
>>> On 15/05/2012 19:02, Alan Browne wrote:
>>>> On 2012-05-15 07:15 , Mark F wrote:
>>>>> How much do GPS receivers affect the local GPS signal strength?
>>>>>
>>>>> While a receiver doesn't reduce the signal strength much, it
>>>>> would seem that it has to have some effect.
>>>>
>>>> An increasing number of receivers doesn't subtract from the available
>>>> signal.
>>>
>>> That is not the case, the received signal does indeed subtract from the
>>> available field strength, but as the signals are coming from above is is
>>> unlikely that it would detract from the received signal at another
>>> receiver unless the antennas were is exact alignment.
> I wasn't concerned with the alignment of the transmitters (that move
> relative to each other), but the alignment of the receivers. I wanted
> to remove from consideration some special case where the receivers
> remained aligned with the signal from one moving satellite.
Give us an example of where this concern of yours may occur.
> On Thu, 17 May 2012 09:37:43 -0500, "Peter H. Coffin"
> <hel...@ninehells.com> wrote:
>
>> On Wed, 16 May 2012 07:50:56 +0100, Jeff wrote:
>>> On 15/05/2012 19:02, Alan Browne wrote:
>>>> On 2012-05-15 07:15 , Mark F wrote:
>>>>> How much do GPS receivers affect the local GPS signal strength?
>>>>>
>>>>> While a receiver doesn't reduce the signal strength much, it
>>>>> would seem that it has to have some effect.
>>>>
>>>> An increasing number of receivers doesn't subtract from the available
>>>> signal.
>>>
>>> That is not the case, the received signal does indeed subtract from the
>>> available field strength, but as the signals are coming from above is is
>>> unlikely that it would detract from the received signal at another
>>> receiver unless the antennas were is exact alignment.
> I wasn't concerned with the alignment of the transmitters (that move
> relative to each other), but the alignment of the receivers. I wanted
> to remove from consideration some special case where the receivers
> remained aligned with the signal from one moving satellite.
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