Mobil Screwdriver Ant.

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by N0CIC, Aug 2, 2011.

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  1. N0CIC

    N0CIC Ham Member

    When using a mobile screwdriver ant. can a person use a external tuner to fine tune the ant. before transmitting ?
     
  2. KJ3N

    KJ3N Ham Member

    A properly installed screwdriver antenna will be able to tune to 1:1. There is no need for an external tuner.

    My HS-1800 has no problem tuning to 1:1, even on 75m.
     
  3. K0BG

    K0BG Platinum Subscriber

    You really don't need a tuner, but any decent quality screwdriver will require some matching. The HS1800 mentioned, as do many other, has a factory supplied shunt matching coil. This is the preferred method, as once adjusted, no further adjustment is needed over the range of the antenna.

    This said, screwdrivers which cover 160 meter, usually don't need matching on 160 do to the much higher losses in the coil (several times that of an 80 meter coil).

    Built in and external tuners will extend the bandwidth of a monoband antenna, which on 160, 80, and 40 is nice to have. However, using one on a screwdriver, and forgetting to retune the antenna before switching on the tuner, can result in damaging the antenna.
     
  4. N5MOA

    N5MOA Subscriber

    You can, but why? Kinda defeats the point of having a remote tuned antenna.

    A good remote tuned antenna, properly installed, can be matched very well with a shunt coil. They are pretty easy to make, and once adjusted, you don't have to fool with them anymore.

    If your antenna covers 160m, you will need a larger shunt coil to get a good match. I made my shunt coil for 160m, and tapped it for 80/40m and up.

    Operating 160m is a simple matter of unplugging the tap.
     
  5. N7HWI

    N7HWI Ham Member

    What type of screw driver do you plan to use? I have used a Tarheel, a Serria, a BB3 and do to going
    160m, I now have a Larry's (KJ7U 160-6) and I have NEVER used or had to use, a external turner. I have used 4 differant radios in the vehicle. I have gone to a memerizer that once the antenna is turned will
    remember that tuning location. I connect my radio coax from radio to swr mtr to memerizer to antenna and just hit the pwr switch on the radio and good to go. Try the W4RT.com and check them out.
     
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