Teardown of Chinese made eBay GPS antenna.
For those who have been following the saga of the Chinese made, eBay
purchased antenna that failed, I may have an answer as to why it failed.
I had to destructively disassemble it. I just could not get it apart any
other way. I used a Chinese version of a Dremel tool with a metal saw
blade. After making a huge mess with plastic particles everywhere, it
revealed a circular FR4 board with two patch antennas mounted, one atop the
other. I assume the smaller one to be the L1, and the larger to be L2. This
part looks almost identical to the Trimble Microcentered antenna I worked
on recently. On the back side of this is a metal shield about 3 by 3
inches soldered to the circular FR4 board. I switched to a abrasive wheel
and took off some of the solder holding the shield to the board. Then,
using a small screw driver, I went around the shield breaking the solder
loose. The shield off revealed that the coax goes to some capacitors that
couple RF out and through an inductor with some capacitors to ground and
finally to a SOT23-5 package labelled LK33. This appears to be a Micrel
MIC5203 3.3 volt regulator. It is shorted on the input side. I believe that
putting anything over 7.5 volts on the input exceeded the power dissipation
rating and caused it to fail. I plan on wiring up a more robust 3.3 volt
regulator in its place and trying again. It looks like I will be able to re
solder the shield back. The watertight integrity is gone for good. I think
I can find a plastic box I can mount it in so I can at least experiment
with it. I have sent a message to the seller detailing my findings. The
Micrel part lists a 20 volt maximum input voltage, so in theory at least,
this might have worked, and there might be some of these out there that
don't fail.
Chinese made, ... This
part looks almost identical to the Trimble Microcentered antenna I
worked
on recently.
Right. It's Chinese made. 'nuff said.
Don
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Dr. Don Latham
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VOX: 406-626-4304
According to the data sheet, it looks pretty well in spec, and the part has thermal shutdown.
http://ww1.microchip.com/downloads/en/DeviceDoc/mic5203.pdf
ESD hit maybe?
I wish people would lighten up on Chinese goods. Perhaps you are not aware
that China builds for and sells to both the DOD and NASA. Chinese
manufacturers build to the specs they are given. You want cheap crap,
they'll build cheap crap. You want top quality, they'll build top quality.
On Thursday, February 22, 2018, Van Horn, David <
david.vanhorn@backcountryaccess.com> wrote:
According to the data sheet, it looks pretty well in spec, and the part
has thermal shutdown.
http://ww1.microchip.com/downloads/en/DeviceDoc/mic5203.pdf
ESD hit maybe?
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mailman/listinfo/time-nuts
and follow the instructions there.
--
Patriotism is supporting your country all the time, and your government
when it deserves it.
--Mark Twain
We may be surprised at the people we find in heaven. God has a soft spot
for sinners. His standards are quite low.
--Desmond Tutu
I wasn't making any comment about Chinese goods, just the component in question.
-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces+david.vanhorn=backcountryaccess.com@febo.com] On Behalf Of William H. Fite
Sent: Thursday, February 22, 2018 2:40 PM
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Subject: Re: [time-nuts] Teardown of Chinese made eBay GPS antenna.
I wish people would lighten up on Chinese goods. Perhaps you are not aware that China builds for and sells to both the DOD and NASA. Chinese manufacturers build to the specs they are given. You want cheap crap, they'll build cheap crap. You want top quality, they'll build top quality.
On Thursday, February 22, 2018, Van Horn, David < david.vanhorn@backcountryaccess.com> wrote:
According to the data sheet, it looks pretty well in spec, and the
part has thermal shutdown.
http://ww1.microchip.com/downloads/en/DeviceDoc/mic5203.pdf
ESD hit maybe?
time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to
https://www.febo.com/cgi-bin/ mailman/listinfo/time-nuts and follow
the instructions there.
--
Patriotism is supporting your country all the time, and your government when it deserves it.
--Mark Twain
We may be surprised at the people we find in heaven. God has a soft spot for sinners. His standards are quite low.
--Desmond Tutu
time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Hi
As mentioned in another post, the part does claim to have thermal limit
built in. They appear to pulse test them at 150 ma and 16V so there is
indeed something that would suggest operation at 12V would be ok.
I’d guess that the thermal regulation spec applies up to 16V and past that
you are on your own…..
I’d take a look at the bypass caps on the regulator. Looking back at the
original test data, it may have simply gone unstable at the higher voltage.
A 0.1 uf on the input and 0.47 uf on the output seem to be the minimums.
Bob
On Feb 22, 2018, at 2:48 PM, John Green wpxs472@gmail.com wrote:
For those who have been following the saga of the Chinese made, eBay
purchased antenna that failed, I may have an answer as to why it failed.
I had to destructively disassemble it. I just could not get it apart any
other way. I used a Chinese version of a Dremel tool with a metal saw
blade. After making a huge mess with plastic particles everywhere, it
revealed a circular FR4 board with two patch antennas mounted, one atop the
other. I assume the smaller one to be the L1, and the larger to be L2. This
part looks almost identical to the Trimble Microcentered antenna I worked
on recently. On the back side of this is a metal shield about 3 by 3
inches soldered to the circular FR4 board. I switched to a abrasive wheel
and took off some of the solder holding the shield to the board. Then,
using a small screw driver, I went around the shield breaking the solder
loose. The shield off revealed that the coax goes to some capacitors that
couple RF out and through an inductor with some capacitors to ground and
finally to a SOT23-5 package labelled LK33. This appears to be a Micrel
MIC5203 3.3 volt regulator. It is shorted on the input side. I believe that
putting anything over 7.5 volts on the input exceeded the power dissipation
rating and caused it to fail. I plan on wiring up a more robust 3.3 volt
regulator in its place and trying again. It looks like I will be able to re
solder the shield back. The watertight integrity is gone for good. I think
I can find a plastic box I can mount it in so I can at least experiment
with it. I have sent a message to the seller detailing my findings. The
Micrel part lists a 20 volt maximum input voltage, so in theory at least,
this might have worked, and there might be some of these out there that
don't fail.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Some of you are to young to remember when Javanese products were considered junk same storyBert Kehren
Sent from my Galaxy Tab® A
-------- Original message --------From: "Van Horn, David" david.vanhorn@backcountryaccess.com Date: 2/22/18 4:44 PM (GMT-05:00) To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Teardown of Chinese made eBay GPS antenna.
I wasn't making any comment about Chinese goods, just the component in question.
-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces+david.vanhorn=backcountryaccess.com@febo.com] On Behalf Of William H. Fite
Sent: Thursday, February 22, 2018 2:40 PM
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Subject: Re: [time-nuts] Teardown of Chinese made eBay GPS antenna.
I wish people would lighten up on Chinese goods. Perhaps you are not aware that China builds for and sells to both the DOD and NASA. Chinese manufacturers build to the specs they are given. You want cheap crap, they'll build cheap crap. You want top quality, they'll build top quality.
On Thursday, February 22, 2018, Van Horn, David < david.vanhorn@backcountryaccess.com> wrote:
According to the data sheet, it looks pretty well in spec, and the
part has thermal shutdown.
http://ww1.microchip.com/downloads/en/DeviceDoc/mic5203.pdf
ESD hit maybe?
time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to
https://www.febo.com/cgi-bin/ mailman/listinfo/time-nuts and follow
the instructions there.
--
Patriotism is supporting your country all the time, and your government when it deserves it.
--Mark Twain
We may be surprised at the people we find in heaven. God has a soft spot for sinners. His standards are quite low.
--Desmond Tutu
time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
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Fine. The Chinese have no concept of, or ignore, intellectual property
rights. They will cheerfully use 13 year old girls to put together stuff
using counterfeit parts and ripped circuits. There is little or no
quality control. The problem is that these goods drive better goods out
of the market.
On 2018-02-22 14:39, William H. Fite wrote:
I wish people would lighten up on Chinese goods. Perhaps you are not
aware
that China builds for and sells to both the DOD and NASA. Chinese
manufacturers build to the specs they are given. You want cheap crap,
they'll build cheap crap. You want top quality, they'll build top
quality.
On Thursday, February 22, 2018, Van Horn, David <
david.vanhorn@backcountryaccess.com> wrote:
According to the data sheet, it looks pretty well in spec, and the
part
has thermal shutdown.
http://ww1.microchip.com/downloads/en/DeviceDoc/mic5203.pdf
ESD hit maybe?
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/
mailman/listinfo/time-nuts
and follow the instructions there.
--
Dr. Don Latham
PO Box 404, Frenchtown, MT, 59834
VOX: 406-626-4304
Ignore intellectual property rights - yes
Abusive labor practices - yes (I'm a radlib, this bothers me enormously)
Counterfeit parts - sometimes
But...
Little or no quality control - not necessarily
Drive out better goods - only if buyers allow to happen
Because...
The reason that Chinese manufacturers make and sell cheap crap is because
resellers (I'm looking at you, Americans and Europeans) specify the lowest
possible prices so they can make the highest possible profits.
The Chinese economy is strongly supply-side oriented. Simply put, they
build to the market, with little government regulation. If you go to China
and negotiate for top quality designs, parts, manufacturing processes, and
quality controls, they will happily build you products that match similar
items that come from Rohde & Schwarz or other top-notch manufacturers. That
said, if you want cheap, they'll certainly give you cheap.
When we want someone to blame for garbage in the marketplace, a good place
to look is in the mirror. China is not in the charity business; they build
what people want to buy.
On Thursday, February 22, 2018, djl djl@montana.com wrote:
Fine. The Chinese have no concept of, or ignore, intellectual property
rights. They will cheerfully use 13 year old girls to put together stuff
using counterfeit parts and ripped circuits. There is little or no quality
control. The problem is that these goods drive better goods out of the
market.
On 2018-02-22 14:39, William H. Fite wrote:
I wish people would lighten up on Chinese goods. Perhaps you are not aware
that China builds for and sells to both the DOD and NASA. Chinese
manufacturers build to the specs they are given. You want cheap crap,
they'll build cheap crap. You want top quality, they'll build top quality.
On Thursday, February 22, 2018, Van Horn, David <
david.vanhorn@backcountryaccess.com> wrote:
According to the data sheet, it looks pretty well in spec, and the part
has thermal shutdown.
http://ww1.microchip.com/downloads/en/DeviceDoc/mic5203.pdf
ESD hit maybe?
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/
mailman/listinfo/time-nuts
and follow the instructions there.
--
Dr. Don Latham
PO Box 404, Frenchtown, MT, 59834
VOX: 406-626-4304
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/m
ailman/listinfo/time-nuts
and follow the instructions there.
--
Patriotism is supporting your country all the time, and your government
when it deserves it.
--Mark Twain
We may be surprised at the people we find in heaven. God has a soft spot
for sinners. His standards are quite low.
--Desmond Tutu
On Thu, Feb 22, 2018 at 5:48 PM, djl djl@montana.com wrote:
Fine. The Chinese have no concept of, or ignore, intellectual property
rights.
Which is not necessarily perverse---there exist people (most notably
those of the so-called Pirate Party movements worldwide) who deem the
legal theories of the copyright and the patent to be absurd. That is
all that I will say, for I do not wish to excessively deviate from the
topic of discourse.
-Ruslan
--
Ruslan Nabioullin
Wittgenstein Laboratories
rnabioullin@gmail.com
(508) 523-8535
50 Louise Dr.
Hollis, NH 03049