EEVblog #721 - Globalstar Satellite Phone Teardown

[EEVblog]

What's inside a 2000 vintage Globalstar GSP1600 Tri-Band Satellite Phone?
Behold the Erectile Antenna, a helical designed extending antenna.
Thanks to: Electronics Responsible Recyclers: http://er2.com/

DSP: http://www.analog.com/media/en/technical-documentation/data-sheets/ADSP-2185.pdf

Intel 386EX Embedded Processor:
http://pdf.datasheetcatalog.com/datasheets2/78/784732_1.pdf

[Stonent]

I remember seeing the GlobalStar commercials when it first came out.  I remember one where it showed someone climbing a mountain and it shows him standing on top. There was a voice-over that said something like "Out of phone range? Out of cell range?  Now entering GlobalStar range." and then it shows him talking on the phone.

I'm still watching the video but if it works when you're done taking it apart, try dialing 611 on it.  That's customer service for most US mobile phones.  If the phone isn't activated it will usually just offer start a new line of service.

Since it has ESN numbers on the back it's probably a CDMA phone.  It would probably roam onto Verizon or Sprint in the US.

Yup, I was right:

https://www.globalstar.com/shop/index.php?main_page=product_info&products_id=99

Talk Time/Standby Time
In Globalstar satellite mode, the phone will sustain normal operation for 3.75 hours of talk time, 19 hours of standby time.
In CDMA (IS-95) mode, the phone will sustain normal operation for 4.7 hours of talk time or 75 hours of standby time.
In AMPS (IS-41) mode, the phone will sustain normal operation for 2.8 hours of talk time or 15 hours of standby time.

GSM didn't really catch on in the US until the early 2000s.  Before that it was Analog (AMPS), CDMA (IS-95), iDEN (Motorola) and TDMA (IS-136). 

AT&T and SouthWestern Bell (aka SBC) provided AMPS/TDMA service in my area.
PrimeCo, GTE (later known as Verizon) and Sprint were the major AMPS/CDMA carriers.
Nextel and SouthernLinc were iDEN carriers.
VoiceStream was the first national GSM carrier in the US, but shortly after it started, it was bought by Deutsche Telekom AG and renamed T-Mobile USA.

[nitro2k01]

The instruction on the right of the sticker further lends itself well for bad jokes.

[miguelvp]

The instruction on the right of the sticker further lends itself well for bad jokes.

Like what? Do not pull or push or it might become permanently erect or suffer ED? 

[Stonent]

The instruction on the right of the sticker further lends itself well for bad jokes.

Perhaps the designer is related to the engineer who designed the Dallas/Fort Worth highway system. (And no, I didn't purposely darken those lines.  Every map is like that )

[austinhmfic]

Answering Dave's erectile antenna patent challenge -- traced back from Qualcomm US patent#6,720,929 which references a number of previous revisions starting from the early/mid 1990's with the idea of " A novel antenna assembly is created wherein the radiating portion is elevated above the handset by combining a half wavelength sleeve dipole antenna with a coaxial line section followed by a quarter wavelength choke "  originating from AT&T on patent #5,440,317

[PinheadBE]

Dave, you did it again.....
I already told you: don't drink and blog...

So, tell me again: where's your left hand and where's your right hand ?  (4:08 and on) 

And, yeah... that's it: "Ethyl RF", as in "Ethylic" perhaps ?

[nitro2k01]

So, tell me again: where's your left hand and where's your right hand ?  (4:08 and on) 

Hmm, same mistake as Bush did. Though is it really a mistake? Perhaps when you're facing a camera as a professional, you're subconsciously imagining the viewer's left and right.



Also, I'm noticing, a Seppy cameo in the previous blog, a Seppy cameo in the latest EEVBlog2 video, but no cameo in this video, unless I missed it...

[Fungus]

Weird that there's very little coverage over the sea, that most voice coverage is concentrated where regular cellphone coverage is good.

I would have thought a major market for these 'phones would be people with boats.

[Fungus]

"Ethel" (the girl's name) doesn't have a 'y': http://en.wikipedia.org/wiki/Ethel

"Ethyl" is something to do with chemistry: http://en.wikipedia.org/w/index.php?title=Ethyl

[Howardlong]

Weird that there's very little coverage over the sea, that most voice coverage is concentrated where regular cellphone coverage is good.

I would have thought a major market for these 'phones would be people with boats.

I would imagine that the coverage limitation is due to location of and co-visibilty with groundstation base stations bearing in mind the altitude of the orbit, limiting the satellites' footprints.

Using LEO means the path loss is limited and the handsets can be small, ie you don't need large antennas with high gain and/or high power RF amplifiers.

[Stonent]

"Ethel" (the girl's name) doesn't have a 'y': http://en.wikipedia.org/wiki/Ethel

"Ethyl" is something to do with chemistry: http://en.wikipedia.org/w/index.php?title=Ethyl

In the US years ago Ethyl was a term used for Gasoline with Tetra Ethyl Lead in it.

Also the Ethyl Corporation was a company that manufactured that chemical. http://en.m.wikipedia.org/wiki/Ethyl_Corporation

[Tek_TDS220]

I was fascinated by the helical receive/transmit antenna with integrated balun. Very cool engineering and physics!

Also, I was surprised by the i386 processor.  There must be a story behind that.  It appears that Qualcomm didn't get into the processor business until 2008 when they introduced their first ARM processor.

Finally, when my first daughter was born, I proposed to my wife to name her Ethyl.  The second girl would be Methyl.  My wife didn't think this was a good idea.

[N2IXK]

Finally, when my first daughter was born, I proposed to my wife to name her Ethyl.  The second girl would be Methyl.  My wife didn't think this was a good idea.

But Methyl should be the first (CH3), followed by Ethyl (C2H5), then Propyl (C3H7).

[German_EE]

I have always wondered with those RF assemblies, do they design the PCB then order shielding cans to fit or do they purchase standard size shielding cans then design the PCB sections to fit inside them?

[SeanB]

The multipin connector is there to support a full RS232 data link, along with having a proper voice channel with separate transmit and receive audio links as well. There is a very common use of these phones in remote oil fields ( which also explains the coverage map, covering all major oil production areas) and in remote mining areas, where they are used for data links.

Permanent ones ( or at least in a big heavy steel cabinet with batteries, the ruggedised computer and sensor arrays) also have an antenna that plugs in in place of the extensible circularly polarised antenna unit, providing the phone with a better antenna that is mounted on the roof of the container, where you can have a higher gain on the transmit antenna and a bigger receive antenna and LNB.

Almost all older industrial computers still have RS232, and with the phone capable of emulating a proper Hayes modem, including having ring detect to wake up the remote site on command, you can do a lot over the 2400baud link of the phone.  There are still remote sites using this to get basic voice comms, and text only email so they can stay in touch with a head office and send exploration data back fast, and more importantly securely, instead of having to drive to a town somewhere with basic phone or internet connectivity. some models were capable of having both voice and data connectivity at the same time.

You pay for the service ( and boy do you pay per month for the basic service) and then you pay again for calls and data. One person I know was saying he had a similar phone, and after a call of about 20 minutes from somebody wanting him to come immediately, he replied that there was no way he could do it, seeing as he was at that time in Siberia, and 3 days travel from an airport. Then the question was " how much is this call costing" to which the answer was "$30 per minute", followed by a click. He was there with the phone, having rented it for the trip as there was otherwise no communications in that area.

[nixfu]

Weird that there's very little coverage over the sea, that most voice coverage is concentrated where regular cellphone coverage is good.

I would have thought a major market for these 'phones would be people with boats.

Inmarsat has the global coverage market, including maritime and aircraft usage. They use much higher satellites which I think are in geosync orbit.  It provides pretty much entire planet coverage with three satellites. 

http://www.inmarsat.com/service/isatphone2/

[SeanB]

I have always wondered with those RF assemblies, do they design the PCB then order shielding cans to fit or do they purchase standard size shielding cans then design the PCB sections to fit inside them?

You design the PCB to fit in the area to form a rectangle, then you go and have the dies made for the shields, and they get pressed out of tinned sheet steel. If you are only doing a few you can use premade shields, but there you are constrained by the shield. The roll your own allows you to have custom leadout slots in the shield for traces, and to have custom sizes and also have the option of having those shorting straps across the shield, or to have custom contacts to allow a press fit cooling clip for power devices.

Off the shelf is cheap in low quantity, but the custom parts allow you to have smaller assemblies. The die costs though are pretty high, you are looking at $10k per set or so for each unit, comprising of a set of press plates, cutting dies and punches that form all the edges and holes in the unit, along with the clips to hold it together in a single set.

[ornea]

Spot on Dave, those connectors have proven to be a massive fail especially with the heavy fisted users.

[f4eru]

one of the chip you didn't find (first line was the datecode)

http://pdf1.alldatasheet.com/datasheet-pdf/view/152301/QUALCOMM/Q5500.html

Qualcomm of course !

[RupertGo]

The coverage map will be dictated by the downlinks to the earth stations. The Globalstar system uses (I think as mentioned in Mailbag) a very simple system where the satellites just act as bent-pipe analogue repeaters in space. LEO satellites have quite a restricted footprint, so you'll only get service if you and the ground station are within the footprint of whatever satellite you're using. (Hence the lack of coverage over the oceans.) You'll still get signals to and from the satellites if you're out of coverage range, but there'll be nobody to talk to.

Higher satellites have a bigger footprint so need fewer ground stations to cover a wider area, and satellite-satellite relays are another option. All more expensive and complex, though.

 

[ConKbot]

Permanent ones ( or at least in a big heavy steel cabinet with batteries, the ruggedised computer and sensor arrays) also have an antenna that plugs in in place of the extensible circularly polarised antenna unit, providing the phone with a better antenna that is mounted on the roof of the container, where you can have a higher gain on the transmit antenna and a bigger receive antenna and LNB.

Good post  One minor thing is that on stuff in L and even S band, it will probably use an LNA (just an low noise amplifier) instead of an LNB (low noise block downconverter) as cable loss wouldnt be huge like it would be in the K/Ka/Ku range.  I always wondered how they shrunk a LNB down to the tiny puck used for Sirius/XM antennas, then I learned it was 2.x GHz.

The antenna in the teardown is really interesting, with the patterning inside and out, along with the different elements. And I like how the telescoping bit goes far enough to clear the users head to make for a good omni pattern. 

[Smokey]

So Hugoneus (Shahriar Shahramian from the Signal Path)......

Does it make you insane watching Dave talk about RF circuitry?

[necessaryevil]

I have always wondered with those RF assemblies, do they design the PCB then order shielding cans to fit or do they purchase standard size shielding cans then design the PCB sections to fit inside them?

I guess the first one since the construction of those cans is quite simple. (I didn't say the design). It's also possible that they will do iterations.

[Monittosan]

So Hugoneus (Shahriar Shahramian from the Signal Path)......

Does it make you insane watching Dave talk about RF circuitry?

LOLL!