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Thread: Receiving from versus transmitting to repeater in mountains

  1. #1

    Default Receiving from versus transmitting to repeater in mountains

    I'm a new ham. My house is in a cove mostly surrounded by mountains in the Southern Appalachians. I can hear transmissions from several repeaters in the area but can't be heard. I was able to be heard (but not too well) at the top of the ridge behind the house but that is a hike. So I have two questions: (1) If I can hear transmissions just fine, is my problem just lack of power and the proper antenna? (2) Is there line-of-sight mapping software available I could run to find out if I actually do or don't have line-of-sight? Thanks!

  2. #2

    Join Date
    Oct 2009
    Location
    Oulu, Finland
    Posts
    475

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    Yes, you can often hear better than you can transmit: Just recently, the coax dropped out of thr connector of my 2m aerial. I could clearly hear the local repeater which is less than 20 km away, but I couldn't access it. Even the SWR meter showed just under 1,5 to 1 giving the impression of a good connection.

    I suggest you try getting or making a small beam aerial, just three or four elements should be enough to get you to the repeater and get it up as high as possible.

    I don't know about mapping software, but a regular map with contour lines should help youvwork out if you have line of site. But even if you don't, if you're not too close to the basse of a hill which is in the way, the signal can still be defracted downwards towards you.

  3. #3

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    Due to a lack of information, it is difficult, if not impossible to answer your question.

    Since there is a definite lack of good Elmers' out there, the best I can do is guess and make assumptions.

    The laws of physic's says that all effective communications is line of sight.

    Anything you put between the transmit and receive antenna's will block line of sight.

    A walkie talkie is a portable device that is designed for local communications.

    Local being - almost visual line of sight. The space station / when it is overhead, might be a couple of hundred miles above the earth, and yet is visual line of sight.

    But take that same walkie talkie and expect it to transmit more than a couple of miles and you will quickly discover that it won't.

    The amount of power is irrelevant, Once you reach the 50w threshold, you will either have reception or you won't. My advice is to buy a base station antenna, good low loss coax - Belden 9913 or LMR 400.
    Invest in a good 50w mobile. Get the antenna at least 10 higher then everything else in the neighborhood.

    30' - 50' off the ground is a good starting point.

    Even where I live, in the heart of Appalachia, it still gets me 20 - 50 miles of coverage, depending upon which direction the signal is in and what is between the repeater and me.

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