936, or 1005/f...?

[ve6pg]

...hi from tim..doing some more antenna werk here...for years, all of us have known the old 234/f, 468/f etc formula.   ok, i know some guys use 936/f for a full wave, whereas others us 1005/f.
  if a guy wants to build a loop for say, 1900kc, the difference in wire length is quite a bit.
  comparing the two results, the difference is 36 ft.   what do you prefer, and why?...in 30 yrs ive done both, with gud results...sk...

[KF1Z]

468/F  is ONLY to give an electrical 1/2 wave ONLY for ONE 1/2 wave wire..... (a dipole)
Takes into account "end effect" etc.....

if the wire is any longer than one 1/2 wave 468 (936) is a useless number....

984/F   would be much closer, BUT  1005 is used for a full-wave because of again, the end effect, but now the ends are close together so instead of a shorter wire, it needs to be a bit longer......


Go with 1005/F   and, if needed trim to fit.....

[k4kyv]

Another consideration is the velocity factor, particularly of a feedline.  Coax and ribbon type twin lead have a greater velocity factor than open wire feeders or antenna wire.

The velocity factor is to be  considered only when there is a voltage differential between the conductors in the feedline.  For example, when using ribbon type twin-lead to make a folded dipole, the rf voltage in each conductor is the same (the two conductors are effectively in parallel), so the resonant length will not be affected by the velocity factor, but when using the same feedline as a transmission line, the velocity factor must be considered.

Insulated wire may have a very slight velocity factor, but usually it is so slight that it can be neglected.

[ve6pg]

...gud point don....i'm gonna use h/brew 600 ohm ladder line, to the loop...tim....sk...