302 not receiving GPS satellites

[Stephen[_3_]]

Hello, if you have or used to have a 302, did it ever quit receiving
GPS satellites? My 302 will not receive and does not display any
satellite bars on the home screen. I have tried a different antenna
and still no joy. I'm thinking it is a send to the factory problem.
Does anyone have comments or suggestions to correct this problem?

Thanks Stephen

[Darryl Ramm]

On Jul 10, 4:58*am, Stephen > wrote:
> Hello, if you have or used to have a 302, did it ever quit receiving
> GPS satellites? My 302 will not receive and does not display any
> satellite bars on the home screen. I have tried a different antenna
> and still no joy. *I'm thinking it is a send to the factory problem.
> Does anyone have comments or suggestions to correct this problem?
>
> *Thanks Stephen

If you've tried to test it with a know good antenna and it does not
work at all (no bars) then you need to send it to the factory. It is
not unheard of to have the GPS board fail or have a physical
connection problem inside the 302. I had one new one DOA like this and
it was just a mechanical connection issue.

Darryl

[Sven[_2_]]

On Jul 10, 6:53*pm, Darryl Ramm > wrote:
> On Jul 10, 4:58*am, Stephen > wrote:
>
> > Hello, if you have or used to have a 302, did it ever quit receiving
> > GPS satellites? My 302 will not receive and does not display any
> > satellite bars on the home screen. I have tried a different antenna
> > and still no joy. *I'm thinking it is a send to the factory problem.
> > Does anyone have comments or suggestions to correct this problem?
>
> > *Thanks Stephen
>
> If you've tried to test it with a know good antenna and it does not
> work at all (no bars) then you need to send it to the factory. It is
> not unheard of to have the GPS board fail or have a physical
> connection problem inside the 302. I had one new one DOA like this and
> it was just a mechanical connection issue.
>
> Darryl

Stephen
I have experienced the same problem in my last two flights - about one
hour into the flight i lose the satelites and satelite bars -
switching off and back on has no effect. After the first failure, and
back on the ground, i tightened the gps antenna connector and voila,
the gps is back on. The next flight, however, one hour into the
flight, i lose everything again. On advice of Paul Bremde and Jeff
Bennett (Cambridge) i have ordered a new antenna (it is on its way to
me). They have both advised that gps antennas should not be placed
close together (mine are not) and that the flarm radio antenna should
also not be close to the 302 gps antenna (which it is - i'll change
that). I shall report back after rectifiying and replacing.
Sven Olivier (Cape Town South Africa)

[Mottley[_2_]]

On Jul 11, 8:35*am, Sven > wrote:
> On Jul 10, 6:53*pm, Darryl Ramm > wrote:
>
>
>
>
>
>
>
>
>
> > On Jul 10, 4:58*am, Stephen > wrote:
>
> > > Hello, if you have or used to have a 302, did it ever quit receiving
> > > GPS satellites? My 302 will not receive and does not display any
> > > satellite bars on the home screen. I have tried a different antenna
> > > and still no joy. *I'm thinking it is a send to the factory problem..
> > > Does anyone have comments or suggestions to correct this problem?
>
> > > *Thanks Stephen
>
> > If you've tried to test it with a know good antenna and it does not
> > work at all (no bars) then you need to send it to the factory. It is
> > not unheard of to have the GPS board fail or have a physical
> > connection problem inside the 302. I had one new one DOA like this and
> > it was just a mechanical connection issue.
>
> > Darryl
>
> Stephen
> I have experienced the same problem in my last two flights - about one
> hour into the flight i lose the satelites and satelite bars -
> switching off and back on has no effect. After the first failure, and
> back on the ground, i tightened the gps antenna connector and voila,
> the gps is back on. The next flight, however, one hour into the
> flight, i lose everything again. On advice of Paul Bremde and Jeff
> Bennett (Cambridge) i have ordered a new antenna (it is on its way to
> me). They have both advised that gps antennas should not be placed
> close together (mine are not) and that the flarm radio antenna should
> also not be close to the 302 gps antenna (which it is - i'll change
> that). I shall report back after rectifiying and replacing.
> Sven Olivier (Cape Town South Africa)



Hi
I had the same problem as Sven on my Duo which had 2 independent
302. The GPS connector at the back of the Unit is suspect. If you
over-
tighten the nut the retention ring on the cable gets damaged and in
some cases is able to slip out. I removed both the retention nuts
and used some tape to hold the cables in place. Another suggestion
was to use Hotmelt glue to do this.
Bruno

[Darryl Ramm]

On Jul 11, 4:52*am, Mottley > wrote:
> On Jul 11, 8:35*am, Sven > wrote:
>
>
>
>
>
>
>
>
>
> > On Jul 10, 6:53*pm, Darryl Ramm > wrote:
>
> > > On Jul 10, 4:58*am, Stephen > wrote:
>
> > > > Hello, if you have or used to have a 302, did it ever quit receiving
> > > > GPS satellites? My 302 will not receive and does not display any
> > > > satellite bars on the home screen. I have tried a different antenna
> > > > and still no joy. *I'm thinking it is a send to the factory problem.
> > > > Does anyone have comments or suggestions to correct this problem?
>
> > > > *Thanks Stephen
>
> > > If you've tried to test it with a know good antenna and it does not
> > > work at all (no bars) then you need to send it to the factory. It is
> > > not unheard of to have the GPS board fail or have a physical
> > > connection problem inside the 302. I had one new one DOA like this and
> > > it was just a mechanical connection issue.
>
> > > Darryl
>
> > Stephen
> > I have experienced the same problem in my last two flights - about one
> > hour into the flight i lose the satelites and satelite bars -
> > switching off and back on has no effect. After the first failure, and
> > back on the ground, i tightened the gps antenna connector and voila,
> > the gps is back on. The next flight, however, one hour into the
> > flight, i lose everything again. On advice of Paul Bremde and Jeff
> > Bennett (Cambridge) i have ordered a new antenna (it is on its way to
> > me). They have both advised that gps antennas should not be placed
> > close together (mine are not) and that the flarm radio antenna should
> > also not be close to the 302 gps antenna (which it is - i'll change
> > that). I shall report back after rectifiying and replacing.
> > Sven Olivier (Cape Town South Africa)
>
> Hi
> I had the same problem as Sven on my Duo which had 2 independent
> 302. The GPS connector at the back of the Unit is suspect. If you
> over-
> tighten the nut the retention ring on the cable gets damaged and in
> some cases is able to slip out. I removed both the retention nuts
> and used some tape to hold the cables in place. Another suggestion
> was to use Hotmelt glue to do this.
> Bruno

Ugh. Hot glue, tape? Why don't you just finger tighten the connector
as it was designed to be used.

All these suggestions are irrelevant if the OP has tried a known good
antenna. He needs to get that C302 back to Cambridge for repair.

Concerns about GPS antennas placed close to each other seem largely a
non-issue. e.g. there is really no local oscillator leakage from these
antennas. More common antenna problem are likely just good sky view/
obstruction issues.

Darryl

[jcarlyle]

I'd be surprised if GPS antennas had oscillators, they're most likely
to be inside the unit itself and signal shouldn't leak out. Some GPS
antennas have preamps, for sure, and of course the only difference
between an amp and an oscillator is feedback. My own experience is
that active GPS antennas close enough to touch one another work
perfectly well. Naturally, keeping a transmitter (like FLARM or a VHF
radio antenna) at a distance from a GPS antenna is a wise idea to
prevent front end overload.

Perhaps a preamp experienced a thermal runaway once, and this led to
the legend of keeping GPS antennas separated? Are there any documented
instances to show that GPS antennas must be separated from one
another?

-John


On Jul 11, 1:31 pm, Darryl Ramm > wrote:
> Concerns about GPS antennas placed close to each other seem largely a
> non-issue. e.g. there is really no local oscillator leakage from these
> antennas. More common antenna problem are likely just good sky view/
> obstruction issues.

[Darryl Ramm]

On Jul 11, 11:44*am, jcarlyle > wrote:
> I'd be surprised if GPS antennas had oscillators, they're most likely
> to be inside the unit itself and signal shouldn't leak out. Some GPS
> antennas have preamps, for sure, and of course the only difference
> between an amp and an oscillator is feedback. My own experience is
> that active GPS antennas close enough to touch one another work
> perfectly well. Naturally, keeping a transmitter (like FLARM or a VHF
> radio antenna) at a distance from a GPS antenna is a wise idea to
> prevent front end overload.
>
> Perhaps a preamp experienced a thermal runaway once, and this led to
> the legend of keeping GPS antennas separated? Are there any documented
> instances to show that GPS antennas must be separated from one
> another?
>
> -John
>
> On Jul 11, 1:31 pm, Darryl Ramm > wrote:
>
>
>
>
>
>
>
> > Concerns about GPS antennas placed close to each other seem largely a
> > non-issue. e.g. there is really no local oscillator leakage from these
> > antennas. More common antenna problem are likely just good sky view/
> > obstruction issues.

Right, I should have been clear. They don't have local oscillators in
the active antennas, just pre-amps. And the good back-isolation means
the local oscillator in the GPS units themselves does not leak back to
the antenna.

Darryl

[Stephen Michalik]

On Jul 11, 2:03*pm, Darryl Ramm > wrote:

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Thanks Darryl and others on your replies...
I spoke to CAE today and they believe it is one of 2 problems and most
likely the GPS board. I'm sending the unit back for repair and will
update the result as I find out.

Stephen

[Stephen[_3_]]

On Jul 11, 5:34*pm, Stephen Michalik
> wrote:
> On Jul 11, 2:03*pm, Darryl Ramm > wrote:
>
>
>
> Thanks Darryl and others on your replies...
> I spoke to CAE today and they believe it is one of 2 problems and most
> likely the GPS board. I'm sending the unit back for repair and will
> update the result as I find out.
>
> Stephen

The GPS engine hardware board in the unit failed. Jeff said likely
from age.

Stephen

[[email protected]]

On Jul 14, 2:48*pm, Stephen > wrote:
> On Jul 11, 5:34*pm, Stephen Michalik
>
> > wrote:
> > On Jul 11, 2:03*pm, Darryl Ramm > wrote:
>
> > Thanks Darryl and others on your replies...
> > I spoke to CAE today and they believe it is one of 2 problems and most
> > likely the GPS board. I'm sending the unit back for repair and will
> > update the result as I find out.
>
> > Stephen
>
> The GPS engine hardware board in the unit failed. Jeff said likely
> from age.
>
> Stephen

I had the same thing happen to me. You will find the new GPS engine
locks in much faster when you turn it on.

Clay

[Darryl Ramm]

On Jul 16, 6:49*am, wrote:
> On Jul 14, 2:48*pm, Stephen > wrote:
>
>
>
>
>
>
>
>
>
> > On Jul 11, 5:34*pm, Stephen Michalik
>
> > > wrote:
> > > On Jul 11, 2:03*pm, Darryl Ramm > wrote:
>
> > > Thanks Darryl and others on your replies...
> > > I spoke to CAE today and they believe it is one of 2 problems and most
> > > likely the GPS board. I'm sending the unit back for repair and will
> > > update the result as I find out.
>
> > > Stephen
>
> > The GPS engine hardware board in the unit failed. Jeff said likely
> > from age.
>
> > Stephen
>
> I had the same thing happen to me. You will find the new GPS engine
> locks in much faster when you turn it on.
>
> Clay

New GPS engine? Huh? The Cambridge 302 IGC approval document describes
a Garmin GPS25-LVC GPS receiver. The manufacturer cannot just change
this themselves and keep IGC approval of the flight recorder.

The actual time to get a GPS fix depends on if it was recently
operated at a different location far enough away and whether it has a
currently valid satellite almanac (and a few more things I'll
ignore). Typically when a GPS receiver like this is returned from a a
repair facility you'll see them need to get a cold fix and therefore
slower than the usual warm fix many people would see before a flight.

The time to get a cold fix times with newer generation GPS receivers
will be a lot faster than the rather old GPS engine used in the C302.

Darryl