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Where is the best place to locate the GPS antenna?

Tim - W4TMETim - W4TME Administrator, FlexRadio Employee admin
edited February 19 in FLEX-6000 Signature Series
A GPS antenna needs to have a good view of the sky in order to obtain a satellite signal lock. Ideally, a full 360 degree obstructed view of the sky is required. However, in practice GPS antennas can obtain a signal lock with a partially obscured view. Often a good signal lock can be obtained by sitting the antenna on a window sill or ledge provided that the horizon is not too obscured. As a general guide, the better the view of the sky provided the antenna, the better the chance of a good continuous signal lock. A vertical observation of the of the sky with an angle of 65° to an optimum at 85° is recommended. Alternately you can install an outside weatherproof GPS antenna if you have difficulty obtaining a signal lock from your FLEX-6000 operating position. There are many GPS antennas that will work very well with the GPSDO. There are a few considerations if you plan to install an external GPS antenna. One is signal attenuation on the coax. At the 1 GHz frequency range, RG-174 has a 32.0 dB signal loss for every 100 feet of coax. Ideally you want a signal strength of 26 dB at the GPSDO receiver, so you will need to take into account the antenna output gain and coax feedline losses when installing an external antenna. Lower loss feedline may be needed for the GPS antenna installation. Second is the possible antenna preamp overload from a near by HF transmitting antenna. The transmitting HF antenna can monetarily cause the GPSDO to lose signal and unlock. If possible, do not install the external GPS antenna in the near field of the transmitting HF antenna. If the GPS antenna's preamp does overload monetarily it will not effect the frequency stability of the FLEX-6000 as the TCXO will maintain short term accuracy while the GPSDO re-locks. Although if the GPS antenna preamp's front-end is not sufficiently protected it may result in damage of the GPS antenna.
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Answers

  • Bill-W9OLBill-W9OL Member
    edited October 2016
    I was able to get a good GPS signal just by running the antenna out my coax port and hanging the little antenna up about 10 high on a west wall. Can I just get more of that cable with a double male? What is the nomenclature of that small cable and the connector that goes onto the GPS port on the back of the F6.5K? pse & tu de w9ol
  • Tim - W4TMETim - W4TME Administrator, FlexRadio Employee admin
    edited March 2017
    Then GPS antenna connector on the FLEX-6000 is an SMA type connector. You can extend the length of the supplied RG174 coax in order to reach a place for the installation of the GPS antenna where it can receive the satellite signals.
  • RegReg Member ✭✭
    edited March 2017
    Tim: I just noticed that in your post of two months ago you wrote, "Alternately you can install an outside weatherproof GPS antenna...." Is the supplied GPS antenna not waterproof? Should it not be installed outside? Thanks.
  • Tim - W4TMETim - W4TME Administrator, FlexRadio Employee admin
    edited December 2016
    The supplied antenna is not designed for outside use.
  • RegReg Member ✭✭
    edited November 2016
    Can you provide some manufacturers and part numbers for outdoor antennas that will work with the GPSDO? Thanks.
  • Tim - W4TMETim - W4TME Administrator, FlexRadio Employee admin
    edited December 2016
    The info is in the community. Just do a search. Here is the result. http://community.flexradio.com/flexradio/topics/can_i_use_an_different_gps_antenna_with_the_gpsdo_module
  • John WA7UARJohn WA7UAR Member ✭✭
    edited February 19
    Tim, picking up this thread again... you wrote:
    Although if the GPS antenna preamp's front-end is not sufficiently protected it may result in damage of the GPS antenna.
    I've looked in the community here but I've not seen hardware suggestions for protecting the GPS antenna preamp's front-end. Does anyone have a suggestion for this kind of product to install in-line with the GPS antenna? Thanks!
  • HCampbell  WB4IVFHCampbell WB4IVF Member ✭✭
    edited July 2018

    I just maintain sufficient spacing from the tx antenna.  I don’t think any inline products would protect the antenna’s internal pre-amp, but inline surge arrestors would protect the radio from lightning-induced surges. 

    Howard




  • Bill -VA3WTBBill -VA3WTB Member ✭✭✭
    edited July 2018
    I simply stuck my antenna to the inside window and it works really well, I wonder why?
  • edited July 2018
    Interesting. My recent Cell Phone has a good signal to noise ratio for GPS indoors. Beware of phase noise knockoffs :-)

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