[OKDXA] 20m yagi ez files

[dan edwards]

jeff, how many eznec files for 20m yagis would you like to see? < grin >
jim lawson, w2pv, was right; there is no magic, yagi gain is largely defined by boom length. roughly, double the boom length, pick up 2 dB..
kim, n5op, is also right; a 40' 4 el version was fairly successful, and klm, now m^2, still makes one.
later on, it was found that adding elements in the right places could improve the pattern and / or match across a broader range of frequencies..thus, the 'OWA' arrays found favor ( optimized wide-band array ). Asymmetric element spacing makes the things tend to 'wind vane' when the breeze picks up.
So, w6nl, in 'Physical Design of Yagi Antennas' described a way to add vestigial elements ( like pvc ) to torque balance the things..
but to me, more elements = more cost, weight, wind loading...usually, i'm looking for best bang for the buck, rather than unlimited budget, anyway.. and, w5dc, also sk, convinced me 'dont use a gamma match'..insulated driven element feed, slightly shortened from resonance, and matched with shunt inductance, is efficient and foolproof..
as always, JM2C...73, dsw, w5xz, dan
the last model was what we put up at w5wmu, fixed on europe..the 'death ray', ha! even komrad veektor, n8oo, said 'dan, this i like'..