Posted: 9/15/2012 1:02:40 PM EDT
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I’m a newb (  ) and recently acquired a HF radio with an internaltuner - I need an antenna. I 'm a little bewildered with all the issues to consider. I’m looking for multiband from 6-40 meters mainly, and a 40 meter horizontal loop or a ZS6BKW dipole both look like good options. I have a trapezoid shaped yard and a few trees that I can use to get the antenna up.  1) I can just fit a 92’ long ZS6BKW dipole across my property, and I can get it about 35’ up at one end (South or lower left) and about 20’(North or upper right) on the other. The middle would initially not be supported, but it may be possible support it up to 35’ later. The north leg of the antenna would need to go over my one story house. My shack is at the NE corner of the house, so I’ll need to run a feeder to the antenna lead. This antenna would have a due north/south orientation and slope facing the north. The ZS6BKW is fed by 40’ of ladder. I’ll need to run coax (or more ladder?) to bring it to my shack entry point leading to my tuner. I plan to use a short (10’-15’) coax stub leading outside to the entry point. Questions: One mfg suggests using a min of 70’ of coax to attach to the ladder feed (forming a matching network) thus eliminating the need for an external tuner. Would using a longer run of more efficient ladder instead with the coax stub routed to an external radio tuner inside my shack be a better choice? As long as the ladder is not close to metal flashing/standpipes, can it touch or lay on my roof and or trees? If I use a 10’-15’ coax stub to run from my tuner inside, and I use more than 40’ of ladder, will a 4/1 current balun at the end of the coax stub be appropriate? 2) If I go with the 40 meter loop, the South (lower left) corner can be up to 35’ but the others would be at about 20’. I can position the antenna feed point almost directly above my shack entrance. Questions: Does the length of ladder matter with the loop? Do I use a 4/1 current balun for this also? As long as I use coated wire to build the loop, no need to worry about brushing against leaves & limbs, etc? I have read that this arrangement will probably not be good for DX due to the horizontal orientation. Is this correct? Am I likely to get outside the CONUS? Any thoughts about what I might expect from each would be welcome. Of the two, which might work the best? Suggestions? School me.... Thanks!!! -KF5NZE |
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I'm sure someone who knows more about antennas will be along shortly.
Now, I'll tell you how I got on the air. Thanks to SCWolverine I put up a 75' end fed wire. One end goes to a tree and the other end goes to a 4:1 balun. I then ran a wire down to a grounding rod and I attached a counterpoise that I laid on the ground under the antenna. The RG-8X coax runs from the balun into a window to my external turner. With this setup, I've been able to work into Europa, Asia, North, Central and South America.  Not too bad for something that I just threw up in less that 30 minutes.
Vulcan94 |
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I would suggest a "fan" dipole. Essentially three dipoles spread out at angles... 40m (will also work on 15), 20m and 10m.
Kinda like this except 40, 20, and 10 instead of the bands mentioned. 
There is a "system" where you use specific distances between the elements which allows the element lengths to be more accurately predicted, but I found when you get enough angle between the elements that it's pretty predictable as well. For 6m I would suggest a rigid dipole that's rotatable, or else put up a pair at right angles. I have a couple homebrewed from parts from broken TV antennas. A little 3 element yagi would be good if you have a rotator. |