From: Joshua B. P. <Joshua.B.Pyke@Dartmouth.EDU> - 2006-05-15 15:02:17
|
Hi all, What are people using as an antenna with the new GPSstix? Is there a good passive antenna out there with an SMA connector (it looks like Sparkfun has only active)? Should I bite the bullet and do the hardware mods to use an active antenna? thanks in advance, Josh |
From: Craig H. <cr...@gu...> - 2006-05-15 17:08:37
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On May 15, 2006, at 8:02 AM, Joshua B. Pyke wrote: > Hi all, > > What are people using as an antenna with the new GPSstix? Is there =20= > a good > passive antenna out there with an SMA connector (it looks like =20 > Sparkfun has only > active)? Should I bite the bullet and do the hardware mods to use =20 > an active > antenna? I have the passive antenna (with H.FL connector) from the sparkfun =20 page, and the SMA<->H.FL patch cable from the same page. =20 Unfortunately the patch cable is the opposite gender at both ends =20 from what is needed -- it's intended to allow an SMA antenna to =20 connect to an H.FL base, rather than the other way around. I think =20 the best/easiest way to go is to make the hardware mod to the GPSstix =20= (I'll post pictures later today), and use the active SMA antenna from =20= sparkfun. I've done a pretty heavy search for passive SMA GPS =20 antennas online, and pretty well struck out. One question I have for people who know stuff about radios: what =20 happens if instead of using a 10=BD resistor between the 2 pins which =20= need connecting (after cutting the line which needs cutting), I =20 instead just short them with a solder ball? That'd leave a nice =20 clean board and remove the problem of the 0603 resistor sticking to =20 my soldering iron... 10=BD seems small enough that it might "just =20 work". Thoughts? C |
From: Aahz. <Eri...@co...> - 2006-05-15 22:44:41
|
I've been following this thread for a while now and from what I understand this is an issue with the current GPSstix and to make it work at all you need to mod it, right? Is this going to stop being a problem in the future? I don't really feel my soldering skills are up to the challenge and I would like to have this functionality. Aahz. |
From: Craig H. <cr...@gu...> - 2006-05-16 00:30:39
Attachments:
GPSStix Modification.jpg
|
On May 15, 2006, at 3:44 PM, Aahz. wrote: > I've been following this thread for a while now and from what I > understand this is an issue with the current GPSstix and to make it > work at all you need to mod it, right? Is this going to stop being > a problem in the future? I don't really feel my soldering skills > are up to the challenge and I would like to have this functionality. No, you don't need to mod it, if you can find a passive GPS antenna, with an SMA connector. But it seems to be that those are hard to find -- passive with SMA connector is what Garmin does, according to a couple folks out there on the 'net, but I can't actually find a garmin antenna for sale anywhere, and Garmin's website is singularly unhelpful. In the future, yes, this will be resolved. Future GPSstix (after some date TBD) will allow active antennas. The soldering job right now is relatively straightforward (it's one cut and then soldering on one resistor) Picture: |
From: Alexandre P. N. <al...@om...> - 2006-05-16 00:59:10
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> [cut] > PS I still haven't heard any opinions on whether a short would work in > place of the 10Ω resistor at the blue line; I guess I'll keep trying > to get the 0603 to stick there... > It probably would work, but this resistor serves as a leak detector, without it and on the event of an antenna leak, the module can get damaged. Alexandre |
From: Jon K. <jo...@65...> - 2006-05-16 04:36:50
|
Doesn't using a passive antenna defeat the whole purpose of having the super sensitive gps module? It seems that many of the features this module offers cant be used because of the way this board was designed. I guess thats what first revisions are for. Just for reference, I found it much easier to solder a small piece of wire to the gps's pad, and then solder the wire to the resister and then the resister to the vcc. I'm by no means an expert solder'er however after this mod I'm much better than I was. All my attempts at soldering the resister straight to the pad only lasted about a day before it broke off, but soldering the wire to the pad has been solid. Heres a picture before the added heat shrink... http://defy.net/balloon/gpstix.jpg -Jon Craig Hughes wrote: > On May 15, 2006, at 3:44 PM, Aahz. wrote: > >> I've been following this thread for a while now and from what I >> understand this is an issue with the current GPSstix and to make it >> work at all you need to mod it, right? Is this going to stop being a >> problem in the future? I don't really feel my soldering skills are up >> to the challenge and I would like to have this functionality. > > No, you don't need to mod it, if you can find a passive GPS antenna, > with an SMA connector. But it seems to be that those are hard to find > -- passive with SMA connector is what Garmin does, according to a > couple folks out there on the 'net, but I can't actually find a garmin > antenna for sale anywhere, and Garmin's website is singularly unhelpful. > > In the future, yes, this will be resolved. Future GPSstix (after some > date TBD) will allow active antennas. The soldering job right now is > relatively straightforward (it's one cut and then soldering on one > resistor) > > |
From: Alexandre P. N. <al...@om...> - 2006-05-16 11:24:45
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Jon Keller escreveu: > Doesn't using a passive antenna defeat the whole purpose of having the > super sensitive gps module? It seems that many of the features this > module offers cant be used because of the way this board was designed. > I guess thats what first revisions are for. > > Just for reference, I found it much easier to solder a small piece of > wire to the gps's pad, and then solder the wire to the resister and > then the resister to the vcc. I'm by no means an expert solder'er > however after this mod I'm much better than I was. All my attempts at > soldering the resister straight to the pad only lasted about a day > before it broke off, but soldering the wire to the pad has been solid. > > Heres a picture before the added heat shrink... > http://defy.net/balloon/gpstix.jpg > > -Jon > The primary goal of an active antenna is to compensate for the loss that happens on the cable. The shorter the cable, the lesser the need for an LNA (low-noise amplifier) on the antenna itself. The module has itself a built-in LNA. The module author's claims that starting with some amount (which I can't remember), any extra amplification from the active antenna's LNA is useless and can even saturate the module's one. It recomends paying special attention by the antenna gain, and warns about many active antenna's suppliers only mentioning the LNA gain, an antenna with a poor gain will not be compensated by a good LNA. Once we have that clear, however, and generally speaking, your chances of success with standard-quality antennas are greater when using a good active antenna, even with a relatively short cable, since if it (the cable) is less than perfect, on low-signal conditions it can be an obstacle as well. But if the cable is very good, the built-in module's LNA can do the job. Under these circusntances, a passive antenna with a good natural gain would be better than a worse antenna with a good built-in LNA. In another words, your mileage may vary. As for the module, I'm with you, with the current design it's quite limited and may be a no-go under some circunstances. I'm quite sure however that the 2nd generation will cover the know flaws. Alexandre |
From: Aahz. <Eri...@co...> - 2006-05-16 06:24:32
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Craig Hughes wrote: > On May 15, 2006, at 3:44 PM, Aahz. wrote: > >> I've been following this thread for a while now and from what I >> understand this is an issue with the current GPSstix and to make it >> work at all you need to mod it, right? Is this going to stop being a >> problem in the future? I don't really feel my soldering skills are >> up to the challenge and I would like to have this functionality. > > > No, you don't need to mod it, if you can find a passive GPS antenna, > with an SMA connector. But it seems to be that those are hard to > find -- passive with SMA connector is what Garmin does, according to > a couple folks out there on the 'net, but I can't actually find a > garmin antenna for sale anywhere, and Garmin's website is singularly > unhelpful. > > In the future, yes, this will be resolved. Future GPSstix (after > some date TBD) will allow active antennas. The soldering job right > now is relatively straightforward (it's one cut and then soldering on > one resistor) Hm, well the descriptoin you and Darren gave are pretty encouraging. I'll give it more thought. I don't mind trying something challenging but the thought of a 130.00 paperweight has me worried ;) Aahz. |
From: Leon H. <leo...@bu...> - 2006-05-16 20:49:34
|
----- Original Message ----- From: "Craig Hughes" <cr...@gu...> To: <gum...@li...> Sent: Monday, May 15, 2006 6:08 PM Subject: Re: [Gumstix-users] GPS antennae On May 15, 2006, at 8:02 AM, Joshua B. Pyke wrote: > Hi all, > > What are people using as an antenna with the new GPSstix? Is there a > good > passive antenna out there with an SMA connector (it looks like Sparkfun > has only > active)? Should I bite the bullet and do the hardware mods to use an > active > antenna? I have the passive antenna (with H.FL connector) from the sparkfun page, and the SMA<->H.FL patch cable from the same page. Unfortunately the patch cable is the opposite gender at both ends from what is needed -- it's intended to allow an SMA antenna to connect to an H.FL base, rather than the other way around. I think the best/easiest way to go is to make the hardware mod to the GPSstix (I'll post pictures later today), and use the active SMA antenna from sparkfun. I've done a pretty heavy search for passive SMA GPS antennas online, and pretty well struck out. One question I have for people who know stuff about radios: what happens if instead of using a 10½ resistor between the 2 pins which need connecting (after cutting the line which needs cutting), I instead just short them with a solder ball? That'd leave a nice clean board and remove the problem of the 0603 resistor sticking to my soldering iron... 10½ seems small enough that it might "just work". Thoughts? u-blox recommends the 10R resistor for short-circuit protection. The receiver can be damaged by a short-circuit on the antenna input if it isn't present. Leon --- [This E-mail has been scanned for viruses but it is your responsibility to maintain up to date anti virus software on the device that you are currently using to read this email. ] |
From: Craig H. <cr...@gu...> - 2006-05-16 21:43:09
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On May 16, 2006, at 1:49 PM, Leon Heller wrote: > u-blox recommends the 10R resistor for short-circuit protection. > The receiver can be damaged by a short-circuit on the antenna input > if it isn't present. Gotcha -- so as long as I'm careful to not short the antenna connector (ie I just connect the active antenna there and glue it down or something), then I don't need the resistor :) Plus, if I blow something, I can just walk over to where the inventory's stored and steal^Wembezzle^Wborrow a new board to "debug" with. C |
From: Marc B. <ma...@ge...> - 2006-05-16 22:50:53
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Well, we just wish it was as easy for us to get a new board you know ... Have you considered my previous post about putting some switch to avoid people having to mess with the board in the future ? Marc |
From: Jon K. <jo...@65...> - 2006-05-16 23:24:32
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The module has a pin for automatic detection of an an active antenna so both types can be used without having to change anything, I guess it turns the voltage on and off. Whoever designed the current gpstix board just decided not to use it. -Jon Marc Bernard wrote: > Well, we just wish it was as easy for us to get a new board you know ... > > Have you considered my previous post about putting some switch to avoid > people having to mess with the board in the future ? > > Marc > > > > ------------------------------------------------------------------------ > > Subject: > Re: [Gumstix-users] GPS antennae > From: > "Craig Hughes" <cr...@gu...> > Date: > Tue, 16 May 2006 17:43:05 -0400 > To: > <gum...@li...> > > To: > <gum...@li...> > > > On May 16, 2006, at 1:49 PM, Leon Heller wrote: > > >> u-blox recommends the 10R resistor for short-circuit protection. >> The receiver can be damaged by a short-circuit on the antenna input >> if it isn't present. >> > > Gotcha -- so as long as I'm careful to not short the antenna > connector (ie I just connect the active antenna there and glue it > down or something), then I don't need the resistor :) > > Plus, if I blow something, I can just walk over to where the > inventory's stored and steal^Wembezzle^Wborrow a new board to "debug" > with. > > C > > > > ------------------------------------------------------- > Using Tomcat but need to do more? Need to support web services, security? > Get stuff done quickly with pre-integrated technology to make your job > easier > Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo > http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 > _______________________________________________ > gumstix-users mailing list > gum...@li... > https://lists.sourceforge.net/lists/listinfo/gumstix-users > |
From: Andrew P. <ap...@gm...> - 2006-05-15 16:11:29
|
Note also that you might be able to hack the antenna-side. Break open an active antenna, find the supply connection, break it and feed DC power directly. It's a cheaper alternative to mod'ing the GPSstix. Haven't done it (yet) myself. Andrew. On 5/15/06, Joshua B. Pyke <Jos...@da...> wrote: > Hi all, > > What are people using as an antenna with the new GPSstix? Is there a goo= d > passive antenna out there with an SMA connector (it looks like Sparkfun h= as only > active)? Should I bite the bullet and do the hardware mods to use an act= ive > antenna? > > thanks in advance, > Josh > > > ------------------------------------------------------- > Using Tomcat but need to do more? Need to support web services, security? > Get stuff done quickly with pre-integrated technology to make your job ea= sier > Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronim= o > http://sel.as-us.falkag.net/sel?cmd=3Dlnk&kid=3D120709&bid=3D263057&dat= =3D121642 > _______________________________________________ > gumstix-users mailing list > gum...@li... > https://lists.sourceforge.net/lists/listinfo/gumstix-users > --=20 If you don't know what to do, do something. Eye: http://www.flickr.com/photos/aplumb/ |
From: Craig H. <cr...@gu...> - 2006-05-16 18:34:20
|
Probably would still be best to cut the trace from the GPS module's =20 antenna power pin to the antenna connector -- probably better to let =20 that pin float rather than grounding it. C On May 15, 2006, at 9:11 AM, Andrew Plumb wrote: > Note also that you might be able to hack the antenna-side. Break open > an active antenna, find the supply connection, break it and feed DC > power directly. It's a cheaper alternative to mod'ing the GPSstix. > > Haven't done it (yet) myself. > > Andrew. > > On 5/15/06, Joshua B. Pyke <Jos...@da...> wrote: >> Hi all, >> >> What are people using as an antenna with the new GPSstix? Is =20 >> there a good >> passive antenna out there with an SMA connector (it looks like =20 >> Sparkfun has only >> active)? Should I bite the bullet and do the hardware mods to use =20= >> an active >> antenna? >> >> thanks in advance, >> Josh >> >> >> ------------------------------------------------------- >> Using Tomcat but need to do more? Need to support web services, =20 >> security? >> Get stuff done quickly with pre-integrated technology to make your =20= >> job easier >> Download IBM WebSphere Application Server v.1.0.1 based on Apache =20 >> Geronimo >> http://sel.as-us.falkag.net/sel?=20 >> cmd=3Dlnk&kid=3D120709&bid=3D263057&dat=3D121642 >> _______________________________________________ >> gumstix-users mailing list >> gum...@li... >> https://lists.sourceforge.net/lists/listinfo/gumstix-users >> > > > --=20 > If you don't know what to do, do something. > > Eye: http://www.flickr.com/photos/aplumb/ > > > ------------------------------------------------------- > Using Tomcat but need to do more? Need to support web services, =20 > security? > Get stuff done quickly with pre-integrated technology to make your =20 > job easier > Download IBM WebSphere Application Server v.1.0.1 based on Apache =20 > Geronimo > http://sel.as-us.falkag.net/sel?cmd=3Dlnk&kid=120709&bid&3057&dat=121642= > _______________________________________________ > gumstix-users mailing list > gum...@li... > https://lists.sourceforge.net/lists/listinfo/gumstix-users |
From: Marc B. <ma...@ge...> - 2006-05-16 18:54:06
|
How about providing some kind of switch or jumper in the future for the gpstix so people wont have to cut the board ? would that be possible ? Marc. |
From: Craig H. <cr...@gu...> - 2006-05-16 19:54:11
|
We'll look at the options, but I suspect most likely we'll connect it =20= the "active" way, given that most passive antennas will deal OK with =20 that setup; and there don't seem to be many passive SMA-connector =20 antennas anyway, which is the basis of the whole problem here :) Of =20 course, that said, we might be switching the honking big SMA =20 connector for something more reasonable in a revised version, like =20 the U.FL or H.FL connector instead. We'll probably avoid using the =20 MMCX connector so people don't plug their bluetooth antenna on the =20 GPS connector and vice-versa. Actually, I think the wifi module =20 we're using has a U.FL connector, so we might use H.FL for the GPS =20 again to avoid accidental cross-plugging of antennae. Gordon's going =20= to love having to have 3 different connectors from a logistical point =20= of view, but I think it'll make things less likely to be confusing =20 for users to have the connector be different. Actually, wifi and =20 bluetooth are both the same wavelength, so maybe it would make sense =20 to switch the bluetooth connector to be U.FL too since cross-=20 connecting those antenna won't actually matter. But then on wifi and =20= bluetooth there are FCC considerations too.... C On May 16, 2006, at 11:53 AM, Marc Bernard wrote: > How about providing some kind of switch or jumper in the future for =20= > the > gpstix so people wont have to cut the board ? would that be possible ? > > =09 > Marc. > > > From: "Craig Hughes" <cr...@gu...> > Date: May 16, 2006 11:34:14 AM PDT > To: <gum...@li...> > Subject: Re: [Gumstix-users] GPS antennae > Reply-To: <gum...@li...> > > > Probably would still be best to cut the trace from the GPS module's > antenna power pin to the antenna connector -- probably better to let > that pin float rather than grounding it. > > C > > On May 15, 2006, at 9:11 AM, Andrew Plumb wrote: > >> Note also that you might be able to hack the antenna-side. Break =20 >> open >> an active antenna, find the supply connection, break it and feed DC >> power directly. It's a cheaper alternative to mod'ing the GPSstix. >> >> Haven't done it (yet) myself. >> >> Andrew. >> >> On 5/15/06, Joshua B. Pyke <Jos...@da...> wrote: >>> Hi all, >>> >>> What are people using as an antenna with the new GPSstix? Is >>> there a good >>> passive antenna out there with an SMA connector (it looks like >>> Sparkfun has only >>> active)? Should I bite the bullet and do the hardware mods to use >>> an active >>> antenna? >>> >>> thanks in advance, >>> Josh >>> >>> >>> ------------------------------------------------------- >>> Using Tomcat but need to do more? Need to support web services, >>> security? >>> Get stuff done quickly with pre-integrated technology to make your >>> job easier >>> Download IBM WebSphere Application Server v.1.0.1 based on Apache >>> Geronimo >>> http://sel.as-us.falkag.net/sel? >>> cmd=3Dlnk&kid=3D120709&bid=3D263057&dat=3D121642 >>> _______________________________________________ >>> gumstix-users mailing list >>> gum...@li... >>> https://lists.sourceforge.net/lists/listinfo/gumstix-users >>> >> >> >> --=20 >> If you don't know what to do, do something. >> >> Eye: http://www.flickr.com/photos/aplumb/ >> >> >> ------------------------------------------------------- >> Using Tomcat but need to do more? Need to support web services, >> security? >> Get stuff done quickly with pre-integrated technology to make your >> job easier >> Download IBM WebSphere Application Server v.1.0.1 based on Apache >> Geronimo >> http://sel.as-us.falkag.net/sel?cmd=3Dlnk&kid=120709&bid&3057&dat=12164= 2 >> _______________________________________________ >> gumstix-users mailing list >> gum...@li... >> https://lists.sourceforge.net/lists/listinfo/gumstix-users > > > > ------------------------------------------------------- > Using Tomcat but need to do more? Need to support web services, =20 > security? > Get stuff done quickly with pre-integrated technology to make your job > easier > Download IBM WebSphere Application Server v.1.0.1 based on Apache =20 > Geronimo > http://sel.as-us.falkag.net/sel?cmd=3Dk&kid=120709&bid&3057&dat=121642 > _______________________________________________ > gumstix-users mailing list > gum...@li... > https://lists.sourceforge.net/lists/listinfo/gumstix-users > > |
From: Chris D. <cg...@co...> - 2006-05-16 20:05:13
|
On 5/16/06, Craig Hughes <cr...@gu...> wrote: > We'll look at the options, but I suspect most likely we'll connect it the > "active" way, given that most passive antennas will deal OK with that set= up; > and there don't seem to be many passive SMA-connector antennas anyway, wh= ich > is the basis of the whole problem here :) Of course, that said, we might= be > switching the honking big SMA connector for something more reasonable in = a > revised version, like the U.FL or H.FL connector instead. We'll probably > avoid using the MMCX connector so people don't plug their bluetooth anten= na > on the GPS connector and vice-versa. Actually, I think the wifi module > we're using has a U.FL connector, so we might use H.FL for the GPS again = to > avoid accidental cross-plugging of antennae. Gordon's going to love havi= ng > to have 3 different connectors from a logistical point of view, but I thi= nk > it'll make things less likely to be confusing for users to have the > connector be different. Actually, wifi and bluetooth are both the same > wavelength, so maybe it would make sense to switch the bluetooth connecto= r > to be U.FL too since cross-connecting those antenna won't actually matter= . > But then on wifi and bluetooth there are FCC considerations too.... Also note that an antenna designed for receive-only (especially, I think, an active antenna) probably will *not* like being transmitted into, at any wavelength. Three different connectors is probably the best way to go, sadly. -chris |
From: David M. <da...@th...> - 2006-05-16 20:31:11
|
I've since forgotten the purpose of the 10=CE=A9 resistor, so what is= it=20 doing and what is the voltage applied and the current through it? Craig Hughes wrote: > On May 15, 2006, at 8:02 AM, Joshua B. Pyke wrote: >=20 >> Hi all, >> >> What are people using as an antenna with the new GPSstix? Is ther= e a=20 >> good >> passive antenna out there with an SMA connector (it looks like = =20 >> Sparkfun has only >> active)? Should I bite the bullet and do the hardware mods to use= an=20 >> active >> antenna? >=20 >=20 > I have the passive antenna (with H.FL connector) from the sparkfun = =20 > page, and the SMA<->H.FL patch cable from the same page. Unfortuna= tely=20 > the patch cable is the opposite gender at both ends from what is n= eeded=20 > -- it's intended to allow an SMA antenna to connect to an H.FL bas= e,=20 > rather than the other way around. I think the best/easiest way to= go=20 > is to make the hardware mod to the GPSstix (I'll post pictures lat= er=20 > today), and use the active SMA antenna from sparkfun. I've done a= =20 > pretty heavy search for passive SMA GPS antennas online, and prett= y=20 > well struck out. >=20 > One question I have for people who know stuff about radios: what = =20 > happens if instead of using a 10=CE=A9 resistor between the 2 pins = which =20 > need connecting (after cutting the line which needs cutting), I in= stead=20 > just short them with a solder ball? That'd leave a nice clean boa= rd=20 > and remove the problem of the 0603 resistor sticking to my solderi= ng=20 > iron... 10=CE=A9 seems small enough that it might "just work". T= houghts? >=20 > C >=20 >=20 >=20 > ------------------------------------------------------- > Using Tomcat but need to do more? Need to support web services, sec= urity? > Get stuff done quickly with pre-integrated technology to make your = job=20 > easier > Download IBM WebSphere Application Server v.1.0.1 based on Apache G= eronimo > http://sel.as-us.falkag.net/sel?cmd=3Dk&kid=120709&bid&3057&dat= =121642 > _______________________________________________ > gumstix-users mailing list > gum...@li... > https://lists.sourceforge.net/lists/listinfo/gumstix-users |