Bob and all,
One problem is that you are using '468/fMhz' to compute the length of a
half wavelength. That is the common 'cutting formula' which includes an
end-effect factor of about 5% which reduces the length of a half wave
radiator. An actual half wavelength is longer.
The actual length (in feet) of a wavelength is 983.5712/fMhz which is
considerably longer than that computed using 468/fMhz times 2.
When dealing with a length of transmission line, the use of the '468'
factor should not be used - compute the actual wavelength and then apply
the velocity factor.
For those who work in meters instead of feet, the factor is 299.7925/fMHz.
See any antenna handbook which has essential characteristics of antennas
for validation of my numbers.
73,
Don W3FPR
On 4/1/2020 9:14 AM, Bob McGraw K4TAX wrote:
NOTE: I just noticed that the numbers below are somewhat in error.
468/3.540 = 132.2 which is 1/2 wavelength. Thus 132.2 X 2 = 264 ft
which is 1 wavelength, not 2 wavelengths as stated. I didn't run the
math on the others.
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [email protected]
