Adapting a Garmin Traffic Receiver to car antenna?
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From: RFI-EMI-GUY on 23 Feb 2010 23:53 On 2/23/2010 10:05 PM, ps56k wrote: > "Rich Webb"<bbew.ar(a)mapson.nozirev.ten> wrote in message > news:evo8o5pank0carhhjd8664l8iqm82gclcb(a)4ax.com... >> On Tue, 23 Feb 2010 12:25:39 -0800, DaveC<invalid(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? >> >> Belay my last... It looks like the newer GTM-20 models do in fact have >> a receptacle for a connector to an external antenna. Mic'ing it out, the >> diameter looks like it takes a 1/8" plug (3.5 mm is too large). The >> (fuzzy) picture in the manual shows just a tip/ring configuration >> (reasonable for an antenna) and claims that it's available at the Garmin >> store. Their store search is abysmally bad, though, so if it's even >> there it'll take patience finding it. >> >> -- > > Where is the antenna connector you are talking about ? > > This photo shows the 12v DC tubular connector - with the 12v center pin > contact - > https://buy.garmin.com/shop/alt-image-lg.do?pID=403&img=productImageLarge > and going to the special 18-pin flat connector for the GPS > https://buy.garmin.com/shop/shop.do?pID=403#specsTab > > > > On my Garmin with the GTM-25(?) receiver, there is a boxy looking dongle in the cable and on the side of that box a small almost invisible hole for the antenna. Bear in mind if you try to splice this antenna into the FM/AM antenna on your car, it is very likely the AM sensitivity will go to heck due to impedance mismatch. If you have an XM/Sirius, the satellite might even be muxed onto that cable with DC power for the satellite radio preamplifier. My theory is that the urbanized locations where I am likely to need the RDS traffic receiver, there will be sufficient FM broadcast signal coverage footprint. I am going to do like another poster suggested and route the GTM-25 cable horizontally under the dash pad and install a switched accessory outlet under the dashboard. -- Joe Leikhim K4SAT "The RFI-EMI-GUY"� "Use only Genuine Interocitor Parts" Tom Servo ;-P
From: DaveC on 24 Feb 2010 00:43 > 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" ? <https://buy.garmin.com/shop/shop.do?pID=6395#accessoryTab> The different pigtail connectors (scroll down) adapt the receiver to the car's 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. Yes I know.
From: DaveC on 24 Feb 2010 00:48 > I wired the receiver for my 680 to an accessory jack that's switched > with other stuff; it's hidden, and the cord to the 680 runs under the > dash. Everything works well, with the wiring hidden. My original question is how to tap the FM traffic receiver into the car's radio antenna.
From: DaveC on 24 Feb 2010 00:51 > All of these receivers have the Traffic FM receiver module embedded in the > DC adapter, on inline on the power cable - > > https://buy.garmin.com/shop/shop.do?cID=203 > > AND - as per the manuals - > some DO HAVE a special connector for an external antenna > which in the manual appears to be located directly on the inline module... As far as I could find, only the GTM10 is listed as requiring "professional installation" (ie, having capability of using the car antenna and/or power from other than the cigarette lighter): <https://buy.garmin.com/shop/shop.do?pID=6395#accessoryTab> All others use some kind of cigarette-lighter power adapter and have it's own antenna. > In looking over this list - and actually downloading the manuals, > it's hard to tell the difference between them - > and the "18-pin flat plug" is for those special CRADLE mounts, > while others are for the mini-USB on the GPS itself... It's the cradle-mount FM receiver / power adapter that is unique to the 660 and is found only in the GTM20. > It is a bit confusing - even have the GTM-20 listed twice, > but with different hardware features... In a conversation with Garmin tech support, I learned that there are 2 GTM-20 receivers: pn 010-00544-01 and pn 010-00544-13. The only difference is that the -13 comes with lifetime traffic service and the -01 comes with a trial service (6-months or 10 months -- both were offered).
From: ullim on 24 Feb 2010 07:03
> Where is the antenna connector you are talking about ? Hmm the GTM-25 shipped with my 1490T has a stereo mini-jack plug for antenna cable (included in the package) on the side of the receiver. |