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Types of Coax Cable and Line Loss Calculator


  • 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.

Here's a quick line loss calculator to use  Note that the simple program used for this web page gives a very close approximation for additional losses due to SWR. 
Set Parameters as Desired
Line Type:
Line Length: Feet Meters
Frequency:  MHz
Load SWR:  : 1
Power In:  W
Matched Loss:  dB
SWR Loss:  dB
Total Loss:  dB
Power Out:  W

Online Coax Cable Loss / Antenna Gain Calculator

Enter dB Loss Of Cable Per 100 Ft. At The Desired Operating Frequency

Enter Length of Cable in Feet

Enter Power into Cable in Watts

Enter Gain of Antenna in dBd

This program is provided "as-is". It is thought to be accurate but it is the responsibility of the user to verify the accuracy of the calculations when using this program.  

Formulas To Design Your Own Dipoles And Inverted Vees

INTRODUCTION-The longwire antenna is a very effective antenna for the listener who wants to cover all of the shortwave bands from 530 KHZ to 30 MHZ. However if you have some favourite frequencies that you listen to on a regular basis you may wish to consider a dipole antenna. This antenna is a fairly easy to construct antenna and will give you better reception on the frequency it is cut for. Think of a dipole as a longwire that has a insulator in the middle.

FREQUENCY-A dipole antenna will not only work well on the frequency it is cut for, but also for the multiples of that frequency. For example if you cut a dipole for 7.0 Mhz will also work well on 14 Mhz, 21 Mhz and 28 Mhz. This way if you can pick and choose your frequency you can make one antenna work on two or three bands.

LENGTH- To find out how long the antenna should be all you have to do is fill in a simple formula:

300 divided by FREQUENCY IN MHZ  = LENGTH IN METERS (wavelength) 

(with end effect calculated in) 

That is the only formula you need ever know to build a dipole antenna.

This page uses the standard formula, 468 / f MHz to calculate dipole lengths. You may change this number if you know of a better number to use as your starting point.
Enter the formula for the antenna calculation

Divided by Freq MHz

Percent smaller for the Inverted Vee

Your dipole's total length is feet or meters
Each leg of the dipole is feet or meters
Your Inverted Vee's total length is feet or meters
Each leg of the Inverted Vee is feet or meters


CONSTRUCTION- Once you have selected a frequency and calculated the length of wire you need add two feet to this length. This is done so you will have six (6) inches of wire at each end to wrap around the insulators. Once you have this extended length of wire cut it in half. This will give you both sides of the dipole.

Attach an end insulator to one end of each piece of wire. You can use the egg shaped insulators sold by many radio supply stores or make your own out of a piece of plastic. This can be done by cutting a piece of heavy plastic or plexi-glass to a size of about six (6) inches in length and about 2-3 inches wide. Drill a small hole one to one and a half inches from each end of the plastic to wrap the wire around. It is best to solder these connections and wrap them in a sealant tape to keep the effects of the weather from harming them.

The other free ends are attached to a center connector which you can buy with a built in coaxial cable connecter, or make your own. This will look similar to the end connectors but you will have to find a way to secure the coax lead wire to the insulator. If you build your own when you attach the coax to the ends of the wires, insure that you solder and wrap the connections. One wire will go to the center of the coax, while the other wire will go to the shielded braid of the coax. This will give you a perfect half wave dipole. You should also wrap the coax fitting of the commercially available center insulator to keep water and other moisture out. Moisture will ruin the connections on any type of insulator and make the antenna less effective or at worst useless.

MULTI-BAND DIPOLES- As was stated above you can use the dipole on the harmonics or multiples of the frequency it is cut for. However if you are short on space you can build a multi-band dipole. This way you will get an antenna that will operate on several frequencies. Instead of using a single strand of wire you can use wire that has several insulated wires in it. These MUST be insulated wires to insure that they do not touch each other. You then cut the top wire to be the longest, the second wire to be the second longest, the third wire to be the third longest etc.. Only the longest wire is attached to the end insulators and all wires are fed to the center insulator to attach to the coax feed line.

INSTALLATION- Once you have the antenna cut all you have to do in put it between two masts. Make sure that you use the free side of the end insulators to attach some rope. Tie this rope from the end insulators to the masts. Leave some slack on the antenna. If you pull too tight the antenna will break in the wind or if snow and or ice should coat the antenna. KEEP AWAY FROM OVERHEAD WIRES!! Keep away from these as should the antenna ever come into contact with an overhead wire you will do permanent damage to your radio if not yourself. All you have to do is feed the coax to your radio and listen to the stations come in. It would be best to install a lightening arrester in the coax feed line to help protect your receiver. These are available from many radio supply stores. Follow the instructions carefully! In areas where thunder storms or snow storms are common a lightening arrester is a must for safety.

You can install them flat or at an angle. If at an angle they will be more directional the direction that they are sloped. You can also install them as an inverted V shape. This dipole has a higher center with lower ends to save on space in smaller back yards. All three versions work well.