Cable types and losses

[JohnE]

been meaning to put this out there for a while,since I have had a few conversations about this w/various members.
first pics,cables from L-R w/associated N male connectors.
RG8/213 LMR400 type, 1/2Inch superflex, 1/2inch hard line also known as Heliax, 7/8inch hard line.

 

 
[ MyGMRS STAFF EDIT:  3 Photos no longer available from linked source.]
 

 

now lets talk about the losses in Db and how much power that is.
Cable type                                  loss at 100Mc                          400Mc


RG8/213                                      2.0dB/100'                              4.7dB/100'
LMR400                                       1.2                                         2.5

Hardline type                                       150Mc                              450Mc

1/2" superflex                                    1.3dB/100'                         2.3dB/100'
LMR600                                             1.0                                   1.7
1/2" Heliax                                         0.85                                  1.5
7/8" Heliax                                         0.44                                  0.8
1-1/4" Heliax                                      0.3                                    0.6

dB loss            power loss in %
0.5                        10                        100W in 90W out
1.0                        20
1.5                        30
2.0                        37
2.5                        44
3.0                        50
3.5                        56
4.0                        60

all of the above loss specs are manufacture specs, I strongly suggest that you measure your line loss w/watt meter if possible to know exactly what you are getting at the antenna.
IME most of the book specs are on the money for hard line ,RG8/213 can be a crap shoot depending on manufacturer. I've had some really bad and some pretty good.
LMR I've had a love/hate relationship w/, good cable but seems to be prone to moisture issues. wish I had pic of the 7yr old cable that pretty much self destructed.
hope this is of some help to those looking to put up a machine or control station in the future.
JE

***EDIT***

found this very useful

http://www.arrg.us/pages/Loss-Calc.htm

Edited March 12, 2022 by JohnE

[BoxCar]

No. Perfection is the enemy of good enough. 

[SteveShannon]

7 hours ago, LeoG said:

is it really worth the 0.3dB?

Probably not.  I wouldn’t change it out.

[LeoG]

Well at the shop I have 50' of LMR400 and I need to get coax for the house.  So it looks like I can get away with the Airborne 10.  Plus it's a higher wattage transmitter than an HT.  It claims 20 watts out but I've measured it at an average of 25 watts when it's a 14 volt input in my truck.  Right around 18 watts when the voltage is at 12.0

Kinda what I figured when it's only going to be .3dB

[SteveShannon]

2 hours ago, LeoG said:

Well at the shop I have 50' of LMR400 and I need to get coax for the house.  So it looks like I can get away with the Airborne 10.  Plus it's a higher wattage transmitter than an HT.  It claims 20 watts out but I've measured it at an average of 25 watts when it's a 14 volt input in my truck.  Right around 18 watts when the voltage is at 12.0

Kinda what I figured when it's only going to be .3dB

-0.3 db means 6.67% of the signal is attenuated. 93.333% gets through.

[LeoG]

That's the difference between the 2 cables.  1.6dB loss over 65' for the for the Airborne10 and 1.3db loss for the Hyperflex13.

 

The gain of .3dB comes at the double the cost of the cable.  I think my distance isn't great enough to jump up to the better cable.  If it was a 1-1.5dB I wouldn't even be asking.