Garmin mini USB capacitor to couple traffic antenna

Discussion in 'GPS Technical Discussion' started by David74656, Jul 28, 2017.

  1. David74656

    David74656

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    I see that I need a 18K resistor on pins 4 & 5 for power.
    I think I need a small capacitor on one of the pins to couple the wire for the traffic antenna.
    What value and what pin should be used for Traffic ?
     
    David74656, Jul 28, 2017
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  2. David74656

    Nuvi-Nebie Moderator

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    If you are using the power connector / PSU that was supplied with the Garmin unit then the components that you mention are already in place, so I'm guessing you are trying to use a non Garmin power connector / PSU on your Garmin unit.

    You would have to supply a lot more details about which Garmin unit you have and what you intend to acheive by adding these components, the 18K resistor is used to pursuade some Nuvi models to charge at a higher rate.

    Satnavs that receive traffic information via the USB connector use a special power lead that has a radio receiver half way down the cable, if you don't have the Garmin supplied cable, you won't get Traffic info. working by adding a capacitor to any of the USB pins
     
    Nuvi-Nebie, Jul 28, 2017
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  3. David74656

    David74656

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    Thank-you !
    I have 2559 LTD so the traffic receiver is "supposed" to be in the unit and not on the wire like my NUVI 765.
    I have had wires run up to my mirror and the stock Garmin power has too much wire to keep tucked away. My plan is to run with the USB only. One link said that 1000ma was needed to navigate and charge. I expect that I need 470 ?pf capacitor from a data line to 5 volts to conduct the RF frequencies of the traffic to the DC supply. I just didn't want to cut open my new garmin cable to find out for myself.
     
    David74656, Jul 28, 2017
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  4. David74656

    Nuvi-Nebie Moderator

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    I wasn't aware that any Nuvis had built-in radio receivers for traffic, the info. for the 2559 suggests it uses Smartlink (via bluetooth) for traffic, however it also says one of it's accessories is the FMI 25 cable which has a traffic receiver in the cable.

    If your Nuvi can receive traffic info. (without Bluetooth), with the supplied cable, I would try it with your replacement cable to see if it still works, my guess is that if it simply needed a capacitor on 2 of the USB pins this could have been done inside the unit

    As far as the resistor goes, you can monitor if the Nuvi is 'seeing' the correct cable in a secret menu, If you touch and hold the battery icon on the main screen for 3 seconds, you will see a page that displays lots of data about the Nuvi, check the "USB Device" and the "I limit USB" data, it will change from "No cable detected" and "Suspend" to 500mA or 1300mA and Power Cable depending on the power output of the PSU and in some models the 'resistor' arrangenent

    My Nuvi56 does not require the resistor in the cable, and will display '1300mA' and 'Power Cable' when connected to a 2Amp PSU, however if the same cable is plugged into a 300mA PSU, it goes into computer comms. mode and can't be used for navigation
     
    Nuvi-Nebie, Jul 29, 2017
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  5. David74656

    David74656

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    My 2559 came with Ta10. I took it apart and it's a very well designed 12v to 5v switching converter. No radio.
    There are only 2 wires going to the mini USB so I will try the 2559 from a 5 volt source in the glove box !
     

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    David74656, Jul 31, 2017
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  6. David74656

    Nuvi-Nebie Moderator

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    O.K., yes it looks like these models have built-in traffic receivers
    • 55LMT 56LMT
    • 65LMT 66LMT
    • 2457LMT 2497LMT
    • 2557LMT 2577LT 2597LMT
    I'm not sure if your intention was to cut down the existing cable, or to use an alternative (shorter), one, although there are only two wires terminating in the PSU, there could be another aerial wire that runs the lenght of the cable but stops before getting to the PSU.

    Remember that if you reduce the length of the cable you will be reducing the aerial's affectiveness, If you use an alternative PSU cable, you can check that the unit it goes into navigation mode correctly (also use the secret menu), and see if the traffic info. still works
     
    Nuvi-Nebie, Aug 1, 2017
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