468/Freq in Mhz.

Don Forsling wrote:
Yes, I'm iold, tired, lazy and forgetful. That said, can someone remind me
of the formula for calculating the length of a full-wave antenna wire if the
frequency is known (think whip and a frequency of 160.890 mhz).

Sorry to ask about such simple stuff, but your help will be appreciated.'

Thanks,

Don

-----------------------------------------------------------------------------
Don Forsling

"Iowa--Gateway to Those Big Rectangular States"

Anders Henriksen wrote:

wavelength [m] = 285/f[MHz] = wavelength = 285/160.89 = 1,771 m

A dipole should normally be half of this lenght: 1,771/2 = 0,886 m, that
would be 2.91 feet. Each leg of the dipole should be 44.3 cm or 1.45 feet.

I am not sure I remember the factor between metres and feet correctly,
but the picture should be clear to all.


HA HA! Didn't take me long to show off my 'tardism... "," should be
replaced by "."

Regards,
Anders Henriksen
oz7ahr, Denmark

RHF wrote:

DF,
.
And the 'original' Question Is (Was) :
" formula for calculating the length of a full-wave antenna wire "
.
"How Do I" ? Calculate the Length of Wire I need to build a Wire
Antenna ?
http://groups.yahoo.com/group/Shortw...a/message/2884
.
This webpage does a very good job of providing an answer.
- - - How Do I Find the WaveLength of a Frequency ? - - -
.
GoTo= http://www.radiomods.co.nz/radiomath.html
.
IN THEORY - The Numbers Are :
Meters = 300 Divided by Frequency in MHz
Feet = 984 Divided by Frequency in MHz
Inches = 11,811 Divided by Frequency in MHz.


Not "In theory" but in free space.


IN PRACTICE - {The-Real-World} - The Numbers Are :
Meters = 285 Divided by Frequency in MHz
Feet = 936 Divided by Frequency in MHz
Inches = 11,235 Divided by Frequency in MHz.


This is caused by the propagation delay in the conductor the antenna
is made of. In other words, the wire is measurably slower that free
space. This is speced as the "Propagation Delay" and is stated as a
percentage. Look at the data on Coaxial cable for examples.


Other Questions - Asked-and-Answered :
* How do I find the frequency of a wave length ?
* How do I Calculate the Length of Wire I need to build a Wire
Antenna. ?
[ You must use the following Math to Correctly Cut an Antenna. ]
- One {Full} Wave Length (WL)
- Three-Quarter Wave Length (3/4 WL)
- Five-Eighths Wave Length (5/8 WL)
- One-Half Wave Length (1/2 WL)
- One-Quarter Wave Length (1/4 WL)
- One-Eighth Wave Length (1/8 WL)
.
FULL WAVE LENGTH WIRE (WL) ANTENNA
IN FEET = 936 DIVIDED BY FREQUENCY
.
Plus the Age Old - How Do I Convert :
* Meters-to-Feet ?
* Feet-to-Meters ?
.
.
iane ~ RHF


--
Former professional electron wrangler.

Michael A. Terrell
Central Florida

Nawww,Cmd Buzz Corey,,, I do things the right way.Measure twice (but in
my case,I measure a bunch of times and even then,once in a great while,I
mess up :{) and cut once.I am not perfect,but almost so.
cuhulin