Adapting a Garmin Traffic Receiver to car antenna?
in [Design]
|
Prev: CD4046 Question
Next: Help choose a PIC programmer.
From: DaveC on 23 Feb 2010 15:25 Garmin makes an "integrated" FM traffic info receiver for some models of GPS that allows connection to the car's AM/FM antenna. But not my model (Nuvi 660); I must use only the GTM20, a cigarette-lighter-powered model: <https://buy.garmin.com/shop/shop.do?pID=403> Benefits of using the car's antenna are mostly stealth: the cord-that-is-the-antenna between the cigarette lighter (which will be relocated inside the glove box) and the GPS plug that lays on the dashboard makes for an advertisement to crooks. And the car's antenna would, arguably, work better. What are my options re. adapting the GTM20 to work with the car's antenna? Could this be as simple as splicing in a motorola antenna plug to the cable? Or...? Ideas? Thanks.
From: mpm on 23 Feb 2010 15:40 On Feb 23, 3:25 pm, DaveC <inva...(a)invalid.net> wrote: > Garmin makes an "integrated" FM traffic info receiver for some models of GPS > that allows connection to the car's AM/FM antenna. But not my model (Nuvi > 660); I must use only the GTM20, a cigarette-lighter-powered model: > > <https://buy.garmin.com/shop/shop.do?pID=403> > > Benefits of using the car's antenna are mostly stealth: the > cord-that-is-the-antenna between the cigarette lighter (which will be > relocated inside the glove box) and the GPS plug that lays on the dashboard > makes for an advertisement to crooks. And the car's antenna would, arguably, > work better. > > What are my options re. adapting the GTM20 to work with the car's antenna? > Could this be as simple as splicing in a motorola antenna plug to the cable? > Or...? > > Ideas? > > Thanks. The car's antenna probably won't work better. It is tuned for the FM band, not the GPS band (1.2 or 1.4 GHz, if memory serves...?) Also, many GPS antennas that I've played with have built-in amplifiers, tuned to GPS spectrum, which your car antenna won't have. Not saying it won't work -- but I would expect great performance.
From: DaveC on 23 Feb 2010 15:59 > The car's antenna probably won't work better. > It is tuned for the FM band, not the GPS band (1.2 or 1.4 GHz, if > memory serves...?) > > Also, many GPS antennas that I've played with have built-in > amplifiers, tuned to GPS spectrum, which your car antenna won't have. > > Not saying it won't work -- but I would expect great performance. Maybe I should explain a little... The FM Traffic service is a supplementary broadcast subscription service using some sub-carrier of the FM broadcast band (88-108 MHz). It carries traffic "events" information (accidents, roadwork, etc.). The receiver is located within the cigarette-lighter power adapter, and the antenna is in the 6-foot cable between the adapter and the plug that attaches to the GPS cradle. So we're talking broadcast band here, not GPS band.
From: Rich Webb on 23 Feb 2010 16:01 On Tue, 23 Feb 2010 12:40:25 -0800 (PST), mpm <mpmillard(a)aol.com> wrote: >On Feb 23, 3:25�pm, DaveC <inva...(a)invalid.net> wrote: >> Garmin makes an "integrated" FM traffic info receiver for some models of GPS >> that allows connection to the car's AM/FM antenna. But not my model (Nuvi >> 660); I must use only the GTM20, a cigarette-lighter-powered model: >> >> <https://buy.garmin.com/shop/shop.do?pID=403> >> >> Benefits of using the car's antenna are mostly stealth: the >> cord-that-is-the-antenna between the cigarette lighter (which will be >> relocated inside the glove box) and the GPS plug that lays on the dashboard >> makes for an advertisement to crooks. And the car's antenna would, arguably, >> work better. >> >> What are my options re. adapting the GTM20 to work with the car's antenna? >> Could this be as simple as splicing in a motorola antenna plug to the cable? >> Or...? >> >> Ideas? >> >> Thanks. > >The car's antenna probably won't work better. >It is tuned for the FM band, not the GPS band (1.2 or 1.4 GHz, if >memory serves...?) > >Also, many GPS antennas that I've played with have built-in >amplifiers, tuned to GPS spectrum, which your car antenna won't have. > >Not saying it won't work -- but I would expect great performance. I think he's looking for a solution to the "live traffic update" option and not the GPS signal itself. Traffic info (at least in CONUS) is carried on the FM spectrum as a side channel to one or more local stations. I've got one of these gizmos also (came with the GPS) and from the looks of it I'd hesitate to slice into it. It might be enough to just wrap a few turns of wire around it and connect the free end of the wire to the car's antenna lead. You're only interested in traffic info from local stations, which are probably strong enough to work with this. -- Rich Webb Norfolk, VA
From: ps56k on 23 Feb 2010 16:34
"mpm" <mpmillard(a)aol.com> wrote in message news:8cf11ff0-9d6c-486b-a6d4-fcedd6eb3e6b(a)c5g2000vbh.googlegroups.com... On Feb 23, 3:25 pm, DaveC <inva...(a)invalid.net> wrote: > Garmin makes an "integrated" FM traffic info receiver for some models of > GPS > that allows connection to the car's AM/FM antenna. But not my model (Nuvi > 660); huh ? The "integrated" FM antenna (for traffic info) is located inside the power adapter module, and does not connect to anything else besides the GPS mini-USB. https://buy.garmin.com/shop/shop.do?cID=203 Exactly what product connects to "the car's FM antenna" ? In case you think the GPS receives location info via that FM module, it does not.... it is only for traffic info from the radio stations. If you are looking for using an external GPS antenna - that is a totally different question. > I must use only the GTM20, a cigarette-lighter-powered model: > <https://buy.garmin.com/shop/shop.do?pID=403> > |