Garmin External Traffic Signal Antenna Extension Cable / Booster Questions (Nuvi 2460LMT)
  14 years
|
I have a Garmin Nuvi 2460 with a power mount on my dashboard. The GPS sits in the power mount so that I do not need to connect and disconnect the cable each time I use it Essentially, the base connects to the power cable which contains an FM traffic receiver. I live on the outer fringe of the Philly suburbs and find that the FM traffic reception is poor. Garmin suggested an extension cable which does improve the signal somewhat. It appears to be a small 2.5mm mini headphone jack style cable. However, it is annoying to have the wire hanging on the windshield with the suction cups (part of the reason I have the dash mount in the first place). I don't know a lot about FM traffic reception and radio waves, but if a short 18" cable improves the signal, can I just get an audio extension cable to make it even longer and then run the cable up the pillar of my windshield instead? When I tried this, reception seemed to be as bad as without the cable and I cannot understand why. Isn't longer better for an antenna?
The cable is here:
https://buy.garmin.com/shop/shop.do?pID=33370&ra=true
I have something like this plugged into the FM traffic receiver and then put my Garmin cable at the female end of it: http://www.amazon.com/2-5mm-Stereo-Plug-Jack-Cable/dp/B0018M...
there are a couple of things here
There are a couple of things working here. One, the position recommended by Garmin is to elevate the end of the cable to expose as much as possible to the signal from the FM station. That's why they tell you attach it to the windshield. The second thing is the length of the cable. At 18" the cable is approximately 1/4 of the length of the radio waves being transmitted. To work best the length of the cable should be in 9 inch increments. That means the next optimal length would be around 27 inches.
But really, if the coverage map for your area shows it is marginal adding antenna will be of little help.
Illiterate? Write for free help.
Interesting dilemma
The FM traffic information comes in on a subcarrier of an FM broadcast station -- like 99.5 FM, or whatever. Just for interest' sake.
That extension cable is really a cable with an antenna on the end -- the audio cable is simply a cable with no antenna. It also isn't a very good conductor of RF energy -- and that's most likely the reason you don't get very good results with it.
You might investigate the other traffic subscription that is available and see if the transmitting station is any closer to where you drive. Otherwise, you're going to have a hard time fabricating an external antenna with a preamp or else a whip antenna about -- oh -- perhaps 24" might be about right -- to really work with that traffic receiver. In the end, none of it looks good except to a "radio guy".
Hey, I live a hundred miles from the closest transmitting site, and so I only get traffic info when I'm "out of town"! LOL!
7 3
Earl
KD5XB (for 30+ years)
KD5XB in DM84
Interesting. Thanks to you
Interesting. Thanks to you both for the comments.