Cable length

[bigedd9990]

Hi all
Could anyone tell me how far i can run a satellite cable before i would need to amplify it? thinking of installing a Technomate motorized system, but the nearest line of sight 45 east to 45 west.
Buy the time it gets to the receiver it would be about 60 meters away maybe more.
thanks in advance

[Robbo]

Hi
The maximum recommended length for a benchmarked cable such as wf100 is 30 to 40 metres for a total attenuation of approx 13dB.

On that basis, you should be able to get away with up to 60m if you use wf165 instead which only attenuates by 22dB per 100m instead of 32.5dB per 100m for wf100.

If you use an amplifier it should be one that has a frequency response tailored to the cable loss, i.e an equalised slope response.

See here:-

http://www.satcure.co.uk/accs/page1b.htm#amps

Robbo

[satelliteman]

Ditto If your dish was sat on 28.2 only, you could get away with upto 60 Mts of 1mm 'benchmarked' cabling without amplification (We do in the field all the time). Total loss of on cable = 18dB @ 2Ghz for 60Mtrs. We measure satellite signals in dBuV and for example a zone 1 will give you 75dBuV, so on that basis, you would have 57dBuV at the receiver. (52dB to 75dB operating range of receiver)

Given you are on a motor and will have various signal levels being received, an amplifier would be of an advantage in this set up.

Regards

[Robbo]

Originally Posted by satelliteman

Ditto If your dish was sat on 28.2 only, you could get away with upto 60 Mts of 1mm 'benchmarked' cabling without amplification (We do in the field all the time). Total loss of on cable = 18dB @ 2Ghz for 60Mtrs. We measure satellite signals in dBuV and for example a zone 1 will give you 75dBuV, so on that basis, you would have 57dBuV at the receiver. (52dB to 75dB operating range of receiver)

Given you are on a motor and will have various signal levels being received, an amplifier would be of an advantage in this set up.

Regards

Thanks satelliteman, I didn't realise you could get away with 60m of benchmarked type '100'. Having some actual figures is useful too, as I don't have a meter.

So you're saying that a typical minimum signal level at the receiver is 52dBuV and with a zone 1 minidish and 60m of cable you would have 57dBuV, for 28E

I think a motor adds approx 4 dB attenuation, so it would be cutting it a bit fine.

I think I would be tempted to go for wf125 as it's not too expensive and see what happens. If it needs an amp fit one after.

[satelliteman]

Agree Robbo, wf125 in this case.

Yes, the actual DVB-S signal input to a receiver can be a minimum of 52dBuV and a maximum signal of 77dBuV. C/N of 12 to 15 depending on FEC. You can't really determine the levels with out a spec meter and are for info only.

Glad to help out