On 18/05/2011 13:13, M.L. wrote: > On Wed, May 18, 2011 at 8:06 AM, Gerhard Fiedler > wrote: >> Hello, >> >> I have a satellite dish (SKY) and want to connect a small house on the >> property to it. The distance is about 50 m cable length. It would be >> convenient to route the satellite dish coax next to the mains supply, >> whether in the same conduit or a separate one (but that one would still >> be routed very close to the mains conduit). >> >> Is this viable, both the length (50 m) and the fact that it is parallel >> to the mains supply? >> >> Thanks, >> Gerhard > It should work. The coax is generally pretty well shielded. The mains > supply is probably twisted together. > > The satellite feed is probably close to 900 MHz (or at least several > hundred MHz) so the 50/60 Hz interference shouldn't be a problem. > I'd still put it in a different conduit if possible anyway. > Modern LNBs give a high output. At top of band (2100MHz) compared with=20 bottom (950MHz) there is huge gain loss. If in doubt use CT125, or PF125=20 cable rather than PF100, CT100, TX100. Don't use RG6 unless you know=20 it's a suitable grade as that really only means a size of 75 Ohm cable.=20 There are maybe 100s of different "RG6". if cable isn't in a conduit, then make sure the outer insulation is=20 outdoor type. Note that though the satellite IF is 950Mhz to 2100MHz,=20 there is 900mV approx 22kHz on/off to select above or below 11.7GHz and=20 13V vs 18V to both power the LNB and do H/V switching. Potentially if=20 there is too much "hum pickup" the Local Oscillator (usually two DROs),=20 LNA, IF amp or H/V switch transistors could be modulated and the BER=20 rise. Maybe need a pretty rubbish design of LNB, but current models=20 don't have a lot inside them and sell for as low as =805 ex works.. 50m is just a bit further than happy distance for regular double=20 screened TX100 (RG6 size) cable, normally 30m. Hence mention of heavier=20 cable. If using a satellite position with widely differing transponder powers=20 esp lower at higher part of band you might need an equaliser (Sky /=20 Freesat in Spain or Italy has dramatically differeing power levels=20 compared to UK/Ireland as there are four satellites with 6 beams and=20 Astra 2D is narrower beam on UK/Ireland, conversely in Donegal and=20 Kerry/South West Cork the Eurobird 28.5 is much lower level, but Astra=20 2D is much the same as London). there are many good websites that cover this including some I run. --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .