[TowerTalk] Dumb Question

[Jim Lux]

At 08:22 PM 11/20/2006, D. Scott MacKenzie wrote:
>I am trying to set up a set of 2 phased verticals in a similar fashion to
>this:
>
>http://home.comcast.net/~kb0fhp/80M_Vertical/80M_Vertical.htm
>
>With the limited space I have available, I have decided to use 1/8 wave
>spacing, with 135 degree phasing - it should give me about 3-4 db gain over
>my existing set up.  The question I have, is what is the free space length
>of 1/8 wave at 3.8 Mhz?  Can I use 125.625/f (from the loop equation l =
>1005/f)?  Or is there something else I should use?

The dipole and loop equations are estimates of the length for a 
resonant doublet or loop, and take into account the fact that a 
resonant dipole is 3-5% shorter than a half wavelength long dipole.

For free space:
299.8/f in MHz gives you wavelength in meters in free space.  Or, 
just use 300.. it's close enough.
(78.89 m for 3.8 MHz)

Multiply meters by 3.28 to get feet. (258.8 ft for a whole 
wavelength, 32.35 ft for 1/8th wavelength)

How were you planning on doing the phasing?  A tuned LC 
network?  There's a fair amount of coupling between two antennas 
1/8th wavelength apart.



>Sorry for the dumb question....I appreciate your help in advance.
>
>Scott