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shorten gps antenna cable

Old 07-17-2005, 03:42 PM
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Default shorten gps antenna cable

garmin voids warranty if antenna cable is shortened. has any one done this without problems. i'd like to shorten mine I hate having extra length stowed in cc. any help greatly appreciated.

peace @ port & sea
grouperface
Old 07-17-2005, 03:48 PM
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Default Re: shorten gps antenna cable

voids your warranty on what? the antenna? so what? I sent my 2010C back without the antenna or cable for work and they did not void my warranty...I went ahead and shortened mine - no problem if you hook it up right - get a junction box from consumer marine.com and do it yourself....too many people worry about the "warranty police" in my opin....
Old 07-17-2005, 03:50 PM
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Default RE: shorten gps antenna cable

First....I know of no one who ever sends their antenna back to Garmin if there is a problem with their GPS....so the fact that they void the warranty is somewhat meaningless.

Second...depending on the antenna, the lead is either coax or a multi wire cable. In the case of the multiwire cable, all of the processing is done in the head itself and the link between the antenna and the GPS is digital. The other two wires are power to the antenna. This type of antenna can be shortened, but you do have to connect all of the wires together correctly.

For Coax antennas, it's generally recommended that you just coil the loop in your dash. If you don't want to do that, then you probably can shorten it, however still leave about 6' of looped cable. If the cable is too short, you will run into problems.
Old 07-17-2005, 04:04 PM
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Default Re: shorten gps antenna cable

i believe i have a coax cable for 188c antenna model ga29. it is a bnc rg 58 connector. also why would their be a problem with cable less than 6ft. thanks for the quick response

peace on and offshore
grouperface
Old 07-17-2005, 04:19 PM
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Default Re: shorten gps antenna cable

You will most likely not have any problems if you shorten your antenna a few feet, but it will affect the antenna gain. Again, you will should be be ok if its only a few feet, but if the gain is too far out of spec from shortening it, you may run into VSWR issues. (voltage standing wave ratio). I have seen this with VHF antennas, not GPS, but anything is possible. You may be better off just looping the antenna cable hiding it under the console and forgetting about it. The GPS is designed to put out a specific voltage/current taking into account the losses due to cable sixe and length, changing the length may affect the expect return to the gps fro the antenna.
Old 07-18-2005, 11:13 AM
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Default Re: shorten gps antenna cable

Glen E is correct. If the GPS "antenna" is where the signal processing occurs, all you need do is cut and splice. Either by use of a junction box or simply splicing and re-shielding. The wires themselves only carry digital data and power.

If your antenna is connected via coax, it takes a bit more technical experience, but shortening it actually improves the signal level when it reaches the receiver. Coax is extremely lossy at 2 Ghz and above, and anything you can do to decrease the loss can only improve the signal.
Old 07-20-2005, 11:13 AM
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Default Re: shorten gps antenna cable

GPS is using 1.575GHz, I believe.


jky

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