The Stanford Standard School for Girls.They wouldn't let me "in" All
kidding aside though,I think Standford is a good College.
cuhulin

David wrote:

On Mon, 11 Apr 2005 17:09:32 GMT, "Michael A. Terrell"
wrote:

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
The wave doesn't travel as fast in a solid conductor and the voltage
reverses sooner (i.e. closer to where it started.)


That's another way to describe propagation delay.

--
Former professional electron wrangler.

Michael A. Terrell
Central Florida

"dxAce" wrote in message
...


Brian Hill wrote:

"David" wrote in message

Jesus ****!! This is goddam kid's stuff from the '50s.


Now that was a terrible thing to say Mr.Meterhertz. I don't think
Stanford.edu would like that kind of talk.

Stanford? Well hell, that sure explains a lot... no wonder he's a scared
little
girl.

dxAce
Michigan
USA



Yep it sure does. He was planted here by the radical leftist elites.

B.H.

Brian Running wrote:

So if I take 10 meters, multiply it times 10 MHz. and I'll get 300?

No, but the 10-Meter band is not 10 MHz, either.

Of course not...

dxAce
Michigan
USA

wrote in message
...
Yeeeeee Hawwwww!,,,, one little simple question the guy asked and so
many different answers.I replaced a couple of eaves boards on my house
not long ago.Now,if a board is too long,I know what to do with it,but if
that damn board is too short,that is a problem.

You need a board stretcher. On the rare occasions that we need one at work,
we send a laborer or a truck driver to either a dedicated rental company or
a lumber yard. (Some of them also rent out tools.) You should try that
option the next time you need one. I recommend the DeWalt brand, myself.

Amazingly, no one has expressed what units these constants 300 and 984, etc.
represent or the fundamental formula:

wavelength = velocity of propagation/frequency
= velocity (units of length per second)/frequency (cycles
per second or Hertz)
= length per cycle
If the velocity is expressed in meters per second, the wavelength is
expressed in meters, if feet per second then in feet.

In free space, velocity of propagation of radio waves is 300 million metres
per second or 984 million feet per second. When divided by frequency in
millions of cycles per second (MegaHertz), we get the length of one cycle or
wavelength in meters or feet, respectively.

In air, the velocity slows down slightly so a wavelength is slightly
shorter. The coefficient of velocity (or velocity factor) expresses the
fraction the speed is relative to that in free space. In air, it is 99.7%.
In denser media, it is slowed more.

Typically, we don't consider velocity of propagation as the reason for the
approx 95% factor for antenna calculations below 30 MHz but as a convenient
way of accommodating the real-world effects of conductor diameter and
capacitance at the ends on the resonant frequency. It is a rule-of-thumb
factor as a starting point for trimming an antenna for resonance at a
certain frequency - not critical for receiving.

Relative velocity of propagation is important in transmission lines, when
used to set the relative phase at each element of an array of driven antenna
elements, and can be as low as 66% that of free space in coaxial cables
using polyethylene insulation between the inner conductor and the shield.

Thus, at 10 MHz, a wavelength is:
- 30 metres, in free space
- 29.91 metres, in air
- ~ 28.5 metres for a 'full wavelength' resonant antenna (varies with end
effects and conductor diameter)
- 19.79 metres in Belden 8241 (RG-59) coaxial cable.

Regards,

Tom
..
"Michael A. Terrell" wrote in message
...
David wrote:

On Mon, 11 Apr 2005 17:09:32 GMT, "Michael A. Terrell"
wrote:

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
The wave doesn't travel as fast in a solid conductor and the voltage
reverses sooner (i.e. closer to where it started.)


That's another way to describe propagation delay.

--
Former professional electron wrangler.

Michael A. Terrell
Central Florida

Didn't read the "inches". Should have been feet. Right numbers, wrong unit.

"CW" wrote in message
...
He's right for a half wave. The guy asked for a full wave though. Just
double it.

"dxAce" wrote in message
...


Brian Hill wrote:

"Don Forsling" wrote in message
...
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).

Your ant would be 2.9088196904717508856983031885139. So about 2 15/16
or
so
inches. I wouldn't recamend a dipole config. LOL!!!

Are you sure about that length? A dipole at 144 MHz is much, much larger
than
that, so something at 160 MHz or so isn't going to be that much smaller.

dxAce
Michigan
USA