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Antenna Length Formula



 
 
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  #1  
Old April 10th 05, 05:03 PM
Don Forsling
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Posts: n/a
Default Antenna Length Formula

Folks, I'm old, I'm tired, and I'm lazy. I'm also forgetful.

Would someone kindly provide the formula for deterring the length of a
full-wave antenna for a given frequency ( a full-wave whip comes to mind)?
Then, I can do the math. Better yet, I'll give you the frequency and _you_
can do the math. It's 160.890 mHz.

I will never ask this question again. Sorry. Thanks, etc.

Best,
--

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

"Iowa--Gateway to Those Big Rectangular States"


  #2  
Old April 10th 05, 05:43 PM
Ron
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Posts: n/a
Default

Try this.

http://www.crompton.com/wa3dsp/hamradio/antcalc.html


"Don Forsling" wrote in message
...
Folks, I'm old, I'm tired, and I'm lazy. I'm also forgetful.

Would someone kindly provide the formula for deterring the length of a
full-wave antenna for a given frequency ( a full-wave whip comes to mind)?
Then, I can do the math. Better yet, I'll give you the frequency and
_you_ can do the math. It's 160.890 mHz.

I will never ask this question again. Sorry. Thanks, etc.

Best,
--

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

"Iowa--Gateway to Those Big Rectangular States"



  #3  
Old April 11th 05, 01:46 AM
sean
Guest
 
Posts: n/a
Default

234 / frequency in MHz

234/ 160.890 = 1.45 Ft


"Don Forsling" wrote in message
...
Folks, I'm old, I'm tired, and I'm lazy. I'm also forgetful.

Would someone kindly provide the formula for deterring the length of a
full-wave antenna for a given frequency ( a full-wave whip comes to mind)?
Then, I can do the math. Better yet, I'll give you the frequency and

_you_
can do the math. It's 160.890 mHz.

I will never ask this question again. Sorry. Thanks, etc.

Best,
--

--------------------------------------------------------------------------

----
Don Forsling

"Iowa--Gateway to Those Big Rectangular States"




  #4  
Old April 11th 05, 02:06 PM
Dale Parfitt
Guest
 
Posts: n/a
Default


"sean" wrote in message
...
234 / frequency in MHz

234/ 160.890 = 1.45 Ft

He is asking for the length of a full wave whip- so multiply the above X4.
However, bear in mind that full wave whip will:
1. Be more difficult to feed as its end Z is around 1K Ohm or higher.
2. Have less gain than a 1/4 wave antenna at useful elevation angles.

Dale W4OP


  #5  
Old April 30th 05, 03:02 AM
jamoran
Guest
 
Posts: n/a
Default

physsics to the rescue
300/frequency in mhz gives length in meters

the 300 comes form the lv=c calculation

using above a 900mhz frequench has wavelength of .3 meters

I prefer to work in metric because everything is base 10 as in 100
centimeters in a meter but there are not 10 inches in a foot and not
1000 inches in a mile......math is easier in metric

Don Forsling wrote:

Folks, I'm old, I'm tired, and I'm lazy. I'm also forgetful.

Would someone kindly provide the formula for deterring the length of a
full-wave antenna for a given frequency ( a full-wave whip comes to mind)?
Then, I can do the math. Better yet, I'll give you the frequency and _you_
can do the math. It's 160.890 mHz.

I will never ask this question again. Sorry. Thanks, etc.

Best,

  #7  
Old October 6th 05, 05:27 PM
[email protected]
Guest
 
Posts: n/a
Default Antenna Length Formula

2808 divided by the frequency in MHz will give
the length in inches for a 1/4 whip. Roughly
17.5 inches. Times 4 will give you a full wave.

Can't understand why you would want a full wave
whip. The impedence would be very high and
would not match a scanner or two way radio. 1/4,
5/8, or 3/4 in much easier to match.

Jim, K5DIE/9


Al wrote:
(Don Forsling) wrote in
:

Folks, I'm old, I'm tired, and I'm lazy. I'm also forgetful.

Would someone kindly provide the formula for deterring the length of a
full-wave antenna for a given frequency ( a full-wave whip comes to
mind)? Then, I can do the math. Better yet, I'll give you the frequency
and _you_ can do the math. It's 160.890 mHz.

I will never ask this question again. Sorry. Thanks, etc.

Best,


Once upon a time when I was taught physics, I was told that full wave lenght should be
calculated by dividing the speed of a light (299820km/s) with the frequency(in MHz)/1000,
so for full wave dipole it should be 299820*160.89/1000=1.864m, for half-wave dipole
divide the result by two.

Albert


  #9  
Old October 6th 05, 06:34 PM
mikeFNB
Guest
 
Posts: n/a
Default Antenna Length Formula

if it's for RX the imp matters not

mike

wrote in message
ups.com...
2808 divided by the frequency in MHz will give
the length in inches for a 1/4 whip. Roughly
17.5 inches. Times 4 will give you a full wave.

Can't understand why you would want a full wave
whip. The impedence would be very high and
would not match a scanner or two way radio. 1/4,
5/8, or 3/4 in much easier to match.

Jim, K5DIE/9


Al wrote:
(Don Forsling) wrote in
:

Folks, I'm old, I'm tired, and I'm lazy. I'm also forgetful.

Would someone kindly provide the formula for deterring the length of a
full-wave antenna for a given frequency ( a full-wave whip comes to
mind)? Then, I can do the math. Better yet, I'll give you the frequency
and _you_ can do the math. It's 160.890 mHz.

I will never ask this question again. Sorry. Thanks, etc.

Best,


Once upon a time when I was taught physics, I was told that full wave
lenght should be
calculated by dividing the speed of a light (299820km/s) with the
frequency(in MHz)/1000,
so for full wave dipole it should be 299820*160.89/1000=1.864m, for
half-wave dipole
divide the result by two.

Albert




  #10  
Old October 7th 05, 07:33 AM
Al Klein
Guest
 
Posts: n/a
Default Antenna Length Formula

On Thu, 06 Oct 2005 17:34:46 GMT, "mikeFNB"
said in rec.radio.scanner:

if it's for RX the imp matters not


That old nonsense again?

SWR isn't directional. Of course impendence matters, unless you don't
care how much signal you lose between the source and load.
 




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