Maker Pro
Maker Pro

Adapting a Garmin Traffic Receiver to car antenna?

D

DaveC

Jan 1, 1970
0
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.
 
D

DaveC

Jan 1, 1970
0
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.
 
R

Rich Webb

Jan 1, 1970
0
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.
 
P

ps56k

Jan 1, 1970
0
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.
 
R

Rich Webb

Jan 1, 1970
0
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.
 
P

ps56k

Jan 1, 1970
0
Rich Webb said:
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
 
P

ps56k

Jan 1, 1970
0
DaveC said:
Garmin makes an "integrated" FM traffic info receiver for some models of
GPS
that allows connection to the car's AM/FM antenna.

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...

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 is a bit confusing - even have the GTM-20 listed twice,
but with different hardware features...
 
D

DaveC

Jan 1, 1970
0
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.
 
D

DaveC

Jan 1, 1970
0
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.
 
D

DaveC

Jan 1, 1970
0
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).
 
U

ullim

Jan 1, 1970
0
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.
 
R

Rich Webb

Jan 1, 1970
0
It's the cradle-mount FM receiver / power adapter that is unique to the 660
and is found only in the GTM20.


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 what I can tell, the two parts that are labeled GTM-20 are also
physically different. The original, with the 6/10 month trial, had a
uniform cord between the 12 V plug and the GPS-side connector. The newer
one, with the lifetime subscription, has a molded section near the GPS
terminus which includes the receptacle for an external antenna
connector.
 
T

Thibaud Taudin Chabot

Jan 1, 1970
0
DaveC schreef:
My original question is how to tap the FM traffic receiver into the car's
radio antenna.
Is the VIB11 from Garmin the solution for you? It uses the carantenna
for receiving the traffic messages.
Thibaud
 
S

Steve Stone

Jan 1, 1970
0
A few days ago I picked up a Garmin NUVI 285WT for $100 from Amazon.com
I was configuring it indoors and trying to activate the MSN traffic
service 9 month trail.
I could not get a good enough signal indoors so I connected a piece of
coax to the wall jack leading to our outdoor TV antenna, put a jumper
wire with an alligator clip on the inner wire of the coax and wrapped
the jumper wire around the NUVI power cord (which includes the traffic
receiver) and the signal strength increased to 100 percent, all bars lit
green, allowing me to activate the traffic software. I wonder if a
similar technique would work with a car radio antenna?

Steve
 
G

Gene E. Bloch

Jan 1, 1970
0
What is so goddamned difficult about simply buying a GPS antenna, which
BTW, you retarded, overtly cross-posting twit, makes the device properly
accurate?

Because that's not what they are talking about. As stated in the posts
and in the subject line, they are talking about the traffic receiver,
which uses FM radio signals.
 
K

krw

Jan 1, 1970
0
Because that's not what they are talking about. As stated in the posts
and in the subject line, they are talking about the traffic receiver,
which uses FM radio signals.

You have to understand AlwaysWrong. He's *always* wrong.
 
G

Gene E. Bloch

Jan 1, 1970
0
You have to understand AlwaysWrong. He's *always* wrong.

He posted a reply to my post about the same time you did. I am beginning to
see what you mean.

Also, I hadn't looked at his headers before - a serious misstep on my
part...
 
S

Steve Stone

Jan 1, 1970
0
Bart! said:
What is so goddamned difficult about simply buying a GPS antenna, which
BTW, you retarded, overtly cross-posting twit, makes the device properly
accurate?

Bart, you old fart.....

This is not a GPS frequency.
Traffic data is piggy backed on broadcast band FM frequencies.
An external GPS antenna won't do squat to fix this issue.

You need more fiber in your diet.
Have a nice day!
 
S

Steve Stone

Jan 1, 1970
0
Bart! said:
Then, the device should have a separate antenna port.

It should but it does not.
It plugs into the USB port on the back of the GPS.
The USB port is used to data signal and power to recharge the built in
battery.

the cable is wired like this

12 VDC power plug,

A couple of inches of DC power cord to an approx. 2 inch oblong FM receiver

From the FM receiver 2 cables go to the GPS USB port, one is data/power,
the other is used as a broadcast band FM antenna , hanging inside your car.

Hacking the assembly would require cracking open the sealed FM receiver
without damaging the device, figuring out where the antenna wire input
is located, and soldering in an antenna input jack and an A/B switch ,
sealing up the unit (voiding any warranty).

Do you suggest I put the device in my shop vice,
apply pressure till it cracks open or turns to shrapnel, or dig out the
dremel tool?

I prefer inductive coupling to hacking a device still under warranty.

Steve
73 de N2UBP
 
R

Rich Webb

Jan 1, 1970
0
Bart, you old fart.....

This is not a GPS frequency.
Traffic data is piggy backed on broadcast band FM frequencies.
An external GPS antenna won't do squat to fix this issue.

You need more fiber in your diet.
Have a nice day!

You must be new here. This month the kill-file log shows that he is
using the following aliases, sorted by number of entries. Better to just
ignore him. Don't feed the trolls and all that...


1: CellShocked <[email protected]>
1: VioletaPachydermata
<[email protected]>
2: Abbey Somebody <[email protected]>
2: SoothSayer <[email protected]>
2: TralfamadoranJetPilot
<[email protected]>
3: "[email protected]"
<[email protected]>
4: Bungalow Bill <[email protected]>
4: Pieyed Piper <[email protected]>
6: UltimatePatriot <[email protected]>
8: Lil Red Riding In The Hood
<[email protected]>
8: TheJoker
<[email protected]>
11: Son of a Sea Cook <[email protected]>
15: Mycelium <[email protected]>
17: AwlSome Auger <[email protected]>
17: Bart! <B@rt_The_Sheriff_Is_A_Nig***!.org>
21: "Herbert John \"Jackie\" Gleason"
<[email protected]>
21: Capt. Cave Man <[email protected]>
25: StickThatInYourPipeAndSmokeIt <[email protected]>
34: Archimedes' Lever <[email protected]>
40: FatBytestard <[email protected]>
413: life imitates life <[email protected]>
 
Top