Odd Question regarding the Garmin 35-HVS Receiver Antennae

Discussion in 'Garmin GPS' started by proton32060, May 10, 2020.

  1. proton32060

    Nuvi-Nebie Moderator

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    I was just thinking if the cable removal and re-installation was the biggest problem, it might be a good idea to keep the cable that is currently in place and make a cut somewhere near the 35HVS that is in the dry and then connect the replacement unit to the cut with some sort of multi way connector

    Something like this :-
    2020-06-17_23.23.35.jpg 2020-06-17_23.30.43.jpg
     
    Nuvi-Nebie, Jun 17, 2020
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  2. proton32060

    proton32060

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    Nuvi,

    I think we may have a winner here.
    As I said, I charged the three good ones for three days weekend before last, reprogrammed them again, and let them sit for the last 6 days.

    I tried one of them today and it is still holding the update so I think this will work. We have never had a power outage for more than 2-3 days in the 30 years I have been here so odds are this will work.

    As far as the other two, I did not check them today to see if they still retained the update. We have had a very long hard day and I am too tired to test the other two today.
    But I will check them tomorrow.

    As far as doing a quick disconnect on the GPS units, it just isn’t possible to have the quick disconnect outside where the unit is.
    But I do have another idea which may be just as effective.
    It would involve using the same type of tie bar you pictured but instead of having it outside, it would be inside the mechanical room where the GPS wire enters the building.

    I would have one long cable going through the conduit from the mechanical room to the clock controller and the connector between the cable going through the conduit and the wire from GPS would be connected using a tie bar like in your picture but it would be inside the mechanical room instead of outside.
    it is hard to describe but it would work exactly like your picture, only it would be inside so it would not require a water proof housing.

    With that setup the GPS unit could be swapped for a new one in less than an hour.

    Or an easier way may be if it ever does lose the update and as long as the battery is still good in the GPS I could run the update again from inside the office using the controller as a power source.
    It would just mean running the white and blue wires about ten feet from the controller to the laptop so I could re-run the update from inside the office.

    As long as I never lose the update software, the instructions, and my old laptop I think I will be fine. Assuming of course the GPS batteries never die for good.

    Thanks for all your help.
    I will check the other two tomorrow to see if they held the update and let you know.
    I will recharge all three again this coming weekend.

    I will try to reinstall the GPS to the clock controller next week and will let you know how it went.

    Again, I want to thank you for all the time and trouble you have gone to on my behalf. I was ready to give up but it looks like your perseverance may have paid off and the clock will have a GPS unit again after all.

    Thanks, and I will keep you posted.
     
    proton32060, Jun 22, 2020
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  3. proton32060

    Nuvi-Nebie Moderator

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    Well I would say that the unit that held it's charge for 6 days is a winner and the other 2 units will probably be the same, so that is looking good, I think if it is not too much trouble to re-fit the cable to somewhere indoors before the 'cut' that is a better idea and as you say it will allow to you reprogram the unit while it is in place if that is needed (hopefully that won't be needed), you would need to connect 3 wires to your laptop because the black (common) is also be needed, also if you can get a 5 way terminal strip it might be useful to extend the Yellow wire as well as this would be needed if you wanted to use a battery back-up (hopefully that won't be needed either). All the wires can be connected to both the controller and the laptop at the same time apart from the white wire which needs to be disconnected from the controller before it is connected to the laptop
    junc.jpg
     
    Nuvi-Nebie, Jun 23, 2020
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  4. proton32060

    proton32060

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    I will send you pictures of how it was installed and the tie strip as far as where it is and how I decided to connect it.

    You have mentioned the yellow wire as the "standby" and in your diagram you have it connected to the Controller. But I am really not sure how it should be connected or used.
    I have looked at the Controller manual wiring diagram and can not see how it could be used. I am including a copy of the manual.
    If you have any ideas how to use it I would like to know.
    It would be nice to rig up an independent backup power supply for the GPS but I have no idea how to use the yellow wire to do it.
     

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    proton32060, Jun 23, 2020
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  5. proton32060

    Nuvi-Nebie Moderator

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    The yellow wire can't be used at present, if it is wired to the Red terminal at the controller the 35 HVS will still be powered but it will be in standby drawing less than 1mA instead of 140mA when working, however it would require some extra circuitry to be fitted in between the controller and the 35 HVS like this :-

    bat-backup.jpg
     
    Nuvi-Nebie, Jun 23, 2020
    #45
  6. proton32060

    proton32060

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    Nuvi,

    I can read a schematic ( in a fashion) and know the symbols.
    You have three resistors
    Two diodes
    One Zenar diode
    One Transistor
    and a 7.2 volt Lithium Battery.

    The question is would the circuit charge the battery and what mAh battery capacity would you recommend?

    I can probably build it using a blank circuit Board and wiring the components on the back of the board and putting it all in a project box.
    What I don't know is the values of the various components.

    Would you happen to have that information?

    Or even better, from your experience would this even be worthwhile under the circumstances?

    The units are well over a decade old so I know they have a lifespan and since the units are well over 13 years old and two would not charge or accept the update they have to be reaching the end of their useful lifespan.

    I just wish I could get to the batteries inside of them.
    But Garmin did a good job of ensuring that getting to the batteries results in destroying the units at the same time.
     
    Last edited: Jun 23, 2020
    proton32060, Jun 23, 2020
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  7. proton32060

    Nuvi-Nebie Moderator

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    I don't think the battery back-up will be required, I just designed the circuit for amusement, I can supply more details if required but do you have a multi-meter with which you can take some measurments?, I would need to know the voltage across Red and Black on the controller

    The battery is charged via R1 and Z1, the charge rate is set by R1 and the zener diode (Z1), limits the maximum value that the battery is charged to

    A 1.2Ah battery would keep the 35HVS in standby for 50 days
     
    Nuvi-Nebie, Jun 23, 2020
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  8. proton32060

    proton32060

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    Yes,
    I do have a multi-meter and will provide you the voltages.
    But if you don't really think it is necessary I will trust your judgement on the matter.
    But I will give you the voltage at the Controller if I can find 5 minutes to sit down and take a breath.
    We are still working long hours trying to catch up from the lock down.
     
    proton32060, Jun 23, 2020
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  9. proton32060

    Nuvi-Nebie Moderator

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    Understood, there's no hurry for it
     
    Nuvi-Nebie, Jun 23, 2020
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  10. proton32060

    proton32060

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    Nuvi,
    I got around to testing the other two to see if they held the update and only one of the other two held it. The other one lost it but would accept the update again.
    That is only two of the three that held the charge for two weeks.

    The last thing I need right now is another project and granted two of the three did hold the update for two weeks but the older these units get the older the batteries are going to get as well.

    I wish they hadn’t built this stupid receiver where the only way you can get to the battery involves destroying the whole unit. Or better still if they had used non-volatile memory instead of what apparently is akin to computer ram.

    I guess a reasonable question would be if once the battery goes completely dead in one of these units will they accept the update again or is that the end of the road anyway?

    And could that possibly be the reason why only three of the five would update even though they had all been charged for three days.

    If that is the case I am wondering if it is worth building a backup circuit at all.
    Because one day the remaining two will have the battery finally die for good and since the unit I install will probably last for years what would be the point if the batteries in the remaining two have completely died by then and would not accept the update at that point anyway?

    Have you ever gotten the feeling after messing with something for weeks that the end result your looking for is probably more trouble than it is worth?

    That is the way I am starting to feel about this.

    Probably what I should do is just install one of the working units and let it last as long as it will last and be done with it.
    When it finally dies then I will just let the internal clock take over.

    After all it had been running that way for years without me even realizing it and I never noticed and nobody cared anyway.

    Besides who knows if I will even be here five years from now?
    I don’t know what it is like in England but every time my wife and I go out we see throngs of idiots not wearing masks or even trying to keep their distance from each other.

    Every time my wife and I go into the room to work on a patient we now feel like we are playing a game of Russian Roulette.

    Dental Offices were never meant or designed to be isolation wards and there is no way we can make ours into one. We take all the precautions but there is no way to protect ourselves if a Covid-19 patient comes into the office.

    You know where our office is and that it is in a small town.
    Last week there was a Funereal at the Funereal Home across the street.
    We watched over 150 people coming in and out and all talking and hugging in large groups without a mask in sight.

    I told my wife, “Look carefully, those are the kind of morons that are going to be responsible for us eventually catching this mess”.

    I know you people in England think Americans are crazy and you are probably right.
    But we didn’t start out that way.

    We are watching our cities being looted and burned to the ground without people uprising or saying “enough!!!”.
    But when it comes to masks they think their rights are being violated and will not comply.

    I think I am just going to put the good unit in and be done with it.
    At least if the GPS lasts longer than I do people will at least get to my Funereal on time since they will have an accurate clock to check right across the street.

    And by the way, your Country makes much better Documentaries than we do.
    The best Documentaries I have ever seen came from your Country.

    I will let you know when it is finally installed for good.


    ______________________________________________________________________________________________________________________________________________________________'

    Nuvi,

    After writing the above Post I finally decided I have had enough of this clock, the GPS, and messing with the whole thing.

    I hooked it back up and it works and it will work until it doesn't and after that it can use its own clock to tell time. I finally reached my limit with this thing.

    But I do have one last question:

    In the settings on the controller there is a menu for Daylight Savings Time.

    The options are:

    1) Table
    2) Rule
    3) off

    I know the US changed when DST starts and ends after the clock was installed but it will not let me into "Rule" mode with the GPS hooked up.
    Since it knows what time it is right now it must have some way of knowing when the time changes from the satellites.

    Is that right?

    I figure the satellites must have that kind of data built into them or all the GPS's would get confused if they arbitrarily changed DST as they did a few years ago without some means of letting the various units out there know when it was.
     
    Last edited: Jun 30, 2020
    proton32060, Jun 30, 2020
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  11. proton32060

    Nuvi-Nebie Moderator

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    I think even this unit will accept a date update, but I guess the battery won't hold up as well as the rest

    I suppose a completely dead battery could stop the unit working even when powered externally, but there are other possibilities, did the two that would not accept a date update manage to get a satellite fix?, you may have already answered this qusetion but I couldn't find it, If they don't get a satellite fix either, they may have other problems apart from the rollover problem
    The problem with an external battery is if you try to power the unit in normal running mode the back-up battery will only last a day or so and if you add the yellow wire circuitry it is not clear from the data sheet whether the internal battery is kept alive, I would think it would be BUT, the 35HVS spec says that in low power standby the internal power regulators are powered off and this could include the regulator that feeds the internal battery
    If the 35HVS fails there are other options, you could get the same NMEA sentence from another GPS unit that does not have the rollover problem, but that's for another day / year?
    I you don't already do this, you could take patient's temperature with a non contact infrared thermometer, the kind that you point at a forehead to get a reading, this is just a suggestion, I certainly wouldn't try to tell you how to do your job
    So is your clock getting time (and date) from one of your replacement 35HVS units, if that's great news
    No the satellites have no idea about DST, (but the GPS may have a time zone selection), I did see something in the Clock user guide (Page 18), about a DST change that was fixed with a software update for the clock controller, I think if the controller is stopping you going into 'Rule' option it is a error as the GPS can't supply this info via the NMEA sentences, a way around this would be to disconnect the White wire to the controller so it doesn't get any data from the GPS then set 'Rule' and re-connect the GPS after 'Rule' has been set and selected as an option, but I am guessing you would only need to do this if the current DST switch over days change
     
    Nuvi-Nebie, Jun 30, 2020
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  12. proton32060

    proton32060

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    Nuvi,

    It is working perfectly off the GPS and showing the right date and time.
    As far as DST, I called the company and they programmed the new dates right before the unit was sent so as long as they don't change them again I should be okay.

    But with the GPS working the controller will only read its pre-programmed table.
    It is not possible to change the dates using the Rule option.
    But since it does have the right dates programmed and as long as they don't change them again it should be fine for years to come.

    Nuvi, I think we have reached the end of this long road.
    I want to thank you again for all your help and patience assisting me to get this to work again.
    You will never know how much I appreciate your help and the time and trouble you went to on my behalf.
    If you were not on a different Continent I would take you out for the best dinner you have ever had.
    I think it is time for me to ride off into the sunset on this one but I will never forget how much time you spent helping me.
    I hate to admit it but I am going to kind of miss you.
    You're a good man.
     
    proton32060, Jun 30, 2020
    #52
  13. proton32060

    Nuvi-Nebie Moderator

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    I'm glad the clock is working at present and hopefully will continue for some years, If you do get another problem please don't hesitate to contact the forum.
    (See conversations page)
     
    Nuvi-Nebie, Jul 1, 2020
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