Antenna & Coax Calculators

1. Dipole and Inverted Vee Antenna Calculator

A dipole antenna will not only work well on the frequency it is cut for, but also at odd multiples of that frequency. For example, a dipole cut for 7.0 Mhz will also work well on 21 Mhz. Keep this in mind, and you may find it possible to make one antenna work on two bands.

To find the antenna length, you just have to make a simple calculation:

468 divided by Frequency in MHz = Dipole Length in Feet

That is the only formula you ever need to know to build a dipole antenna. However, to make it even easier, here is a simple calculator to do the work for you...

Antenna Calculator

Antenna resonant frequency = MHz.

An Inverted Vee is percent shorter.

Dipole total length = feet
Each leg of the dipole = feet

Inverted Vee total length = feet
Each leg of the Inverted Vee = feet

2. Line Loss Calculator

Coax Cable Types

Belden

Belden 8215    (RG-6A)
Belden 8237    (RG-8)
Belden 9913    (RG-8)
Belden 9258    (RG-8X)
Belden 8213    (RG-11)
Belden 8261    (RG-11A)
Belden 8240    (RG-58)
Belden 9201    (RG-58)
Belden 8219    (RG-58A)
Belden 8259    (RG-58C)
Belden 8212    (RG-59)
Belden 8263    (RG-59B)
Belden 9269    (RG-62A)
Belden 83241 (RG-141A)
Belden 8216    (RG-174)
Belden 8267    (RG-213)
Belden 9913F7
Belden 7810A
Belden 7808A

Davis RF

Davis RF Bury-Flex

Times Microwave Systems

TMS LMR-100A
TMS LMR-200
TMS LMR-240
TMS LMR-400
TMS LMR-600
TMS LMR-900

Wireman (coax)

Wireman CQ102 (RG-8)
Wireman CQ106 (RG-8)
Wireman CQ125 (RG-58)
Wireman CQ127 (RG-58C)
Wireman CQ110 (RG-213)

Radio Shack

Tandy Cable RG-8X
Tandy Cable RG-58
Tandy Cable RG-59

Andrew

Andrew Heliax LDF4-50A
Andrew Heliax LDF5-50A
Andrew Heliax LDF6-50A

Wireman (ladder line)

Wireman 551 Ladder Line
Wireman 552 Ladder Line
Wireman 553 Ladder Line
Wireman 554 Ladder Line
Wireman 551 (wet)
Wireman 552 (wet)
Wireman 553 (wet)
Wireman 554 (wet)

Miscellaneous

Generic 300 ohm Tubular
Generic 450 ohm Window
Generic 600 ohm Open
Ideal (lossless) 50 ohm
Ideal (lossless) 75 ohm

The "wet" numbers represent worst case for lines covered with ice or snow.

Quick Line Loss Calculator.
(Note that the simple program used on this web page gives only an approximation of the additional losses due to SWR.)

Enter Parameters Here

Line Type

Line Length Feet Meters

Frequency MHz

Load SWR : 1

Transmitter Power W

Results

Matched Loss dB

SWR Loss dB

Total Loss dB

Power to Antenna W

Last updated April 17, 2017 by KØCF