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Suitable Antenna

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  • 21-06-2012 11:40am
    #1
    bauderline
    Registered Users Posts: 898 ✭✭✭


    Folks,

    I have purchased an ICOM R71E in order to do some scanning in my spare time. I am complete beginner at this stuff. Any advice on a suitable antenna I could purchase that would get me up an running with this set ?

    Best regards, Peter.


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    #2
    bauderline
    Registered Users Posts: 898 ✭✭✭bauderline


    Another possibly dumb question, can I use CT100 to connect the antenna ? I have a heap of it left over from wiring the house.

    P.


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    #3
    johnayo
    Registered Users Posts: 1,718 ✭✭✭johnayo


    bauderline wrote: »
    Folks,

    I have purchased an ICOM R71E in order to do some scanning in my spare time. I am complete beginner at this stuff. Any advice on a suitable antenna I could purchase that would get me up an running with this set ?

    Best regards, Peter.

    I would assume a long wire antenna is the best bet. Have a look at some of Watty's posts on here. Plenty of advice in them.


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    #4
    watty
    Registered Users Posts: 32,417 ✭✭✭✭watty


    You can use CT100 / TX100 (or 125 better). Nominally Communications Receivers and Scanners and aerials are 50 Ohms and Satellite IF/TV aerial cable is 75 Ohms. But it's not actually going to make much difference.

    Your biggest problem will be attaching connectors. I've used PL529 and a Discone on chimney with PF125 cable. SWR was even acceptable enough to transmit on 29MHz, 50Mhz, 144MHz and 430MHz bands.

    Long wire for 100KHz to 30MHz, 22m works well for 80m to 21m/17m (3.5MHz to 14MHz/18MHz). A tuning/match unit recommended.
    A x2 longer wire much better for 1.8MHz
    A 4m wire or 5/8ths CB whip or 7/8ths CB whip (home base mast) with loading coil removed can be tuned with a matching unit well for 17m (18MHz) to 6m (50MHz)

    For cheap SW Radio about 3m wire is plenty otherwise it overloads!

    Long wires need a matching coil AND a Balun AND a local earth spike at start of "wire" to connect coax.
    Dipoles, G5RVs, Inverted Ls, Vs etc also need matching coils and baluns to connect a coax.
    A Discone, Whip/mast near ground, or on a mast mount of similar height insulated at bottom don't need a Balun or a matching unit.
    A bi-cubical (sort of two discones wired like dipole), Dipole or Yagi need a Balun, but at higher frequencies (> 400MHz) this can be achieved by coiling 4 turns (not too tight) or so at the aerial and then the end of the coax is its own balun.

    Use 1m or more of nylon or other plastic cord/rope to isolate far end(s) of long wire, V, inverted L or G5RV. Multiple "eggs" were for wire supports as in old days rope/cord would have rotted and been conductive when wet.


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