FlightAware Discussions

The importance of a good cable

Today i moved my whole setup outside.
I tried two cables, both 5 Meter, both five-times shielded, both with similar dimensions of shield and core.

But one cable with copper/steel core, the other with pure copper core.
The message rate shows the difference, over the time the amount of aircraft in range was similar.

looking at it seem to be that i have to reduce the gain now. The messages > -3dB has been increased with the new wire, even if the amount of aircraft is pretty low currently.

It’s just a coincidence. The 1GHz signal travels only on the surface of the wire anyway (skin effect). The penetration depth of 1GHz is 2 micrometers.

The insulation between the core and the shield makes much more difference (transversal losses).
DC losses are different, but not applicable in your case.
Also, if water gets into the end of the cable, the steel core will rust quickly.

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from the techical details regarding shield both cables are the same (at least documented in the specs)

The RG specs are basically dimension specifications. CCS cables tend to be a cheaper alternative, since steel is much cheaper than copper - they often use an aluminium braid instead of copper as well.

It’s pretty common for CCS cables to not have as good screening as a ‘good’ coax as they have less coverage by the braided screen. A decent copper coax with good braid coverage will likely outperform a cheaper CCS coax.

There might be also some lack of quality control of dimensions and materials.
Manufacturers (of cheap cables made in a certain country) will sometimes claim specs that are just copied from generic ones, but in reality they are really off.

The advantage of copper core cables might be also that the material itself is more expensive and therefore very unlike to be used in that kind of factory, oriented on cheap products with thin profit margins.

I will keep both, but use the pure copper one because the connectors look more reliable.
The other will go to my TV

may I ask - what are these “5-shield cables”?

5 strands of shielding braid!

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It is this one, came with two water resistent compressed connectors.

grafik

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Wow, one step ahead of famous “quad-shielded” coax

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image

As long as it’s working, and mine seem to be :slight_smile:

Without knowing anything else about it, I’d doubt any manufacturer would put that much effort into anything less than a high-spec cable.

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Yeah, that definitely looks like a good cable.

There are some specs, but in german on their website, will post it here later in case you’re interested :smiley:

Thanks - yes, would be very interested.

Copy&Paste, the google translation below.

  • Schirmung: 5-fach geschirmt
  • Schirmungsmaß: 135dB
  • Innenleiter: KUPFER , 1,01 ±0.1mm
  • Außendurchmesser: 7,2 ±0.1 mm
  • Außenmantel: weiß / PVC
  • Mit Metermarkierung
  • Wellenwiderstand: 75 Ohm
  • Verkürzungsfaktor: 0,80 v/c
  • Isolation: 4,7mm Zell-PE 63%
    1. Schirm: AL-Folie, doppelt kaschiert
    1. Schirm: 0,12mm ALU 64 Geflecht
    1. Schirm: AL-Folie, doppelt kaschiert
    1. Schirm: 0,12mm ALU 32 Geflecht
    1. Schirm: AL-Folie, doppelt kaschiert
  • Normen: CE, Rohs, BZT, Class A
>     100 MHz - 5,3 dB
>     200 MHz - 7,1 dB
>     300 MHz – 9,2 dB
>     500 MHz - 12,5 dB
>     800 MHz - 15,9 dB
>     1000 MHz - 18,1 dB
>     1350 MHz - 21,9 dB
>     1750 MHz - 25,0 dB
>     2050 MHz - 28,2 dB
  • Shielding: 5-fold shielded
  • Shielding dimension: 135dB
  • Inner conductor: COPPER, 1.01 ±0.1mm
  • Outer diameter: 7.2 ±0.1 mm
  • Outer sheath: white / PVC
  • With meter marking
  • Characteristic impedance: 75 Ohm
  • Shortening factor: 0.80 v/c
  • Insulation: 4,7mm Cell-PE 63%
  • 1st shield: AL-foil, double laminated
  • 2nd shield: 0,12mm ALU 64 braid
  • 3rd shield: AL-foil, double laminated
  • 4th shield: 0,12mm ALU 32 braiding
  • 5th shield: AL-foil, double laminated
  • Standards: CE, Rohs, BZT, Class A

Is that loss per hundred feet or hundred metres?

/edit - yuck, it’s 75 ohm (but pretend I didn’t say that because it’s a whole can of worms).

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It will trigger a Holy War between supporters of 50Ω/LMR/SMA and 75Ω/RG6/F

In my experience, connected to an LNA output (for reception only), it makes not a big difference.

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