It all depends what part of the HF range it is built for and how many elements it has.I have a Cushcraft A3 tribander beam for 10,15,and 20m.It is a three element yagi and has a 14 foot boom.The longest element is 27 feet long That is almost a standard type of tribander.You can get an 11 element tribander if you want.If you get a log periodic antenna it will be good over a VERY wide range of freqs. but will have LOTS of elements and the overall gain will be lower.Now if you want a REALLY big HF antenna look
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