Post by thread:[EE] Satellite dish cable together with mains supp

On Wed, May 18, 2011 at 8:06 AM, Gerhard Fiedler <spam_OUTlistsTakeThisOuTconnectionbrazil.com> 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. -- Martin K

On Wed, May 18, 2011 at 4:06 PM, Gerhard Fiedler <.....listsKILLspam@spam@connectionbrazil.com> 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? That shouldn't pose any problems The down converted frequency from the LNB is between 950 - 2150Mhz. Even in the worst case if the shielding doesn't help, only the 18khz - 22khz DiSEqC signal alone is likely to get distorted, but since the diseqc bus is assumed to be a lossy bus -- there are several re-transmissions even in that case. So that also might not pose a threat, other than a sometimes a larger delay in switching from position: A - B., or in some cascade. If you are positioned to a satellite with a faint footprint, then better to have better cabling to avoid signal degradation causing the demodulator not to acquire a Lock. If the signal is pretty much strong, then this shouldn't be an issue. If you don't have a diseqc switch, none of these do matter. But another point to be noted is that some LNB's use the 22k tone to switch between polarizations as well, rather than the usual 13/18v control. Regards, Man

On 18/05/2011 13:13, M.L. wrote: {Quote hidden}> On Wed, May 18, 2011 at 8:06 AM, Gerhard Fiedler > <listsKILLspamconnectionbrazil.com> 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 bottom (950MHz) there is huge gain loss. If in doubt use CT125, or PF125 cable rather than PF100, CT100, TX100. Don't use RG6 unless you know it's a suitable grade as that really only means a size of 75 Ohm cable. There are maybe 100s of different "RG6". if cable isn't in a conduit, then make sure the outer insulation is outdoor type. Note that though the satellite IF is 950Mhz to 2100MHz, there is 900mV approx 22kHz on/off to select above or below 11.7GHz and 13V vs 18V to both power the LNB and do H/V switching. Potentially if there is too much "hum pickup" the Local Oscillator (usually two DROs), LNA, IF amp or H/V switch transistors could be modulated and the BER rise. Maybe need a pretty rubbish design of LNB, but current models don't have a lot inside them and sell for as low as €5 ex works.. 50m is just a bit further than happy distance for regular double screened TX100 (RG6 size) cable, normally 30m. Hence mention of heavier cable. If using a satellite position with widely differing transponder powers esp lower at higher part of band you might need an equaliser (Sky / Freesat in Spain or Italy has dramatically differeing power levels compared to UK/Ireland as there are four satellites with 6 beams and Astra 2D is narrower beam on UK/Ireland, conversely in Donegal and Kerry/South West Cork the Eurobird 28.5 is much lower level, but Astra 2D is much the same as London). there are many good websites that cover this including some I run.

> I have a satellite dish (SKY) and want to connect a small house on the > property to it. > Is this viable, both the length (50 m) and the fact that it is parallel > to the mains supply? You'd want to check the loss of the cable used. Output is often in the 1 GHz - 2 GHz range - bad cable can be very bad at that sort of frequency. Bad cable can definitely do very bad things to signal level over that sort of distance. You may want to add a preamp at the antenna end depending on your LNB output levels. Preamp at start gives you far better result that post-amp at end (as you no doubt realise). I recentlyish bought a 1.2m satellite dish with 4cables run from LNB outputs to house - these were probably around 30 metres each so it shows that some LNBs, some cable, some receivers and some people get acceptable results over this sort of range. I'll probably never get to find out how well that arrangement works - the dish is destined to become a solar mirror. Russel

On Wed, 18 May 2011 09:06 -0300, "Gerhard Fiedler" wrote: > 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? Electronically it should be OK. You could check your local electrical code regarding putting them in the same conduit. My gut tells me it's not allowed, but I'm not an electrician. Carl would probably know. Bob -- http://www.fastmail.fm - Does exactly what it says on the tin

I don't know, but doubt it would be allowable. One of the issues would be 600 volt insulation. Couple of thoughts: 1: What's the money limit? 2: Can the satellite receiver be mounted at the Dish? Our's has RF remotes, but I don't think the RF will go that far. The remote can be remoted either RF, infrared (substitute a laser), or onto the Coax with combiner/splitter. 3: I have seen somewhere TV signal RF remotes, and baluns for running over Cat-5. Might try some of these, I would talk to their tech support: http://www.cablestogo.com/ http://www.mcmelectronics.com/ http://www.bhphotovideo.com/ Unfortunately, my guru, A Directv commercial dealer and did work for the TV stations, passed away before new years at a early age of 53. :( :( On 5/18/2011 11:53 AM, Bob Blick wrote: {Quote hidden}> On Wed, 18 May 2011 09:06 -0300, "Gerhard Fiedler" wrote: > >> 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? >> > Electronically it should be OK. > > You could check your local electrical code regarding putting them in the > same conduit. My gut tells me it's not allowed, but I'm not an > electrician. Carl would probably know. > > Bob > >

Thanks to all who responded. I'm replying here to all, instead of individual replies. Carl Denk wrote: {Quote hidden}> On 5/18/2011 11:53 AM, Bob Blick wrote: >> On Wed, 18 May 2011 09:06 -0300, "Gerhard Fiedler" wrote: >>> 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? >>> >> Electronically it should be OK. >> >> You could check your local electrical code regarding putting them in >> the same conduit. My gut tells me it's not allowed, but I'm not an >> electrician. Carl would probably know. > > I don't know, but doubt it would be allowable. One of the issues > would be 600 volt insulation. Putting them into a separate conduit is not a problem. I've already considered this. (FWIW, this is in Brazil, so US codes wouldn't help :) > Couple of thoughts: > > 1: What's the money limit? I want the most economical solution that works :) > 2: Can the satellite receiver be mounted at the Dish? Our's has RF > remotes, but I don't think the RF will go that far. The remote can be > remoted either RF, infrared (substitute a laser), or onto the Coax > with combiner/splitter. Ours is an infrared remote. > 3: I have seen somewhere TV signal RF remotes, and baluns for running > over Cat-5. AIUI, this and item 2 would point towards mounting the receiver close to the dish, and then carry the TV signal from the receiver's output over the 50 m to the target location. Is that less of a problem than carrying the dish signal directly? > Might try some of these, I would talk to their tech support: > http://www.cablestogo.com/ > http://www.mcmelectronics.com/ > http://www.bhphotovideo.com/ Thanks for the links. I'll check them out, but a simple solution would be my preference (which so far I see as placing the satellite receiver at the target location). Some have mentioned that some satellite receivers use the connection to control the LNB. In this case, I don't think this is the case, or at least it doesn't seem to be a problem. The thing is that we have two receivers. One is currently not in use, but it could be used. I want to connect this second receiver, to a location 50 m away. I figure that if I can connect two receivers to the LNB (AFAIK the cable would simply be split), the receivers can't do any individual configuration of the LNB, or else they could be fighting each other. It seems that there is a consensus that - I should use separate conduits, - I should use heavier cable than normal (CT125 or PF125), - it could/should work :) Thanks, Gerhar

On Wed, 2011-05-18 at 17:53 -0300, Gerhard Fiedler wrote: > Some have mentioned that some satellite receivers use the connection to > control the LNB. In this case, I don't think this is the case, or at > least it doesn't seem to be a problem. The thing is that we have two > receivers. One is currently not in use, but it could be used. I want to > connect this second receiver, to a location 50 m away. I figure that if > I can connect two receivers to the LNB (AFAIK the cable would simply be > split), the receivers can't do any individual configuration of the LNB, > or else they could be fighting each other. I don't know exactly which service you are using, but usually for DBS type service two receivers will require 2 lines to the LNB, no way around that. You cannot "split" the cable. TTYL

Gerhard Fiedler wrote: > Some have mentioned that some satellite receivers use the connection to > control the LNB. In this case, I don't think this is the case, or at > least it doesn't seem to be a problem. The thing is that we have two > receivers. One is currently not in use, but it could be used. I want to > connect this second receiver, to a location 50 m away. I figure that if > I can connect two receivers to the LNB (AFAIK the cable would simply be > split), the receivers can't do any individual configuration of the LNB, > or else they could be fighting each other. If I read you correctly, you want to connect two receivers to one LNB using an RF splitter. That only works if the LNB uses a 'stacked' downconvertor, were the two satellite polarizations (left and right hand) are put into different frequency bands. Cable losses are much higher for the top frequency block. 950-1450 & 1650-2150 MHz typically. You have to use 'DC passing' splitter to ensure the LNB gets power. Most modern LNB's with two outputs have polarity switching built into each port (13v & 18V) so you actually want to run your 2nd receiver directly to the LNB so that it can control polarity switching independently of the other receiver. The quick test is to split the signal next to your current receiver and see if the 2nd receiver can access ALL channels independently. I doubt that it will work fully because whichever IRD is sending out the higher voltage, will control the polarization sent by the LNB. > It seems that there is a consensus that > - I should use separate conduits, > - I should use heavier cable than normal (CT125 or PF125), > - it could/should work :) You should also consider inserting 'in line' signal amplifier to make up for the cable losses. This amplifiers power themselves from the polarity switching voltage. Ideally , half way along the cable, or at the LNB. You only need heavier cable if the LNB draws enough power that the resistive loss in the cable drops the 'high' polarity voltage below 15V (the typical threshold). You can look up the resistance for the cable you use and compute the loss to see if you drop too much voltage to reliably switch. Most LNB's down regulate to 9V so it's only the switching threshold you have to worry about. R

Herbert Graf wrote: {Quote hidden}> On Wed, 2011-05-18 at 17:53 -0300, Gerhard Fiedler wrote: > >>Some have mentioned that some satellite receivers use the connection to >>control the LNB. In this case, I don't think this is the case, or at >>least it doesn't seem to be a problem. The thing is that we have two >>receivers. One is currently not in use, but it could be used. I want to >>connect this second receiver, to a location 50 m away. I figure that if >>I can connect two receivers to the LNB (AFAIK the cable would simply be >>split), the receivers can't do any individual configuration of the LNB, >>or else they could be fighting each other. > > > I don't know exactly which service you are using, but usually for DBS > type service two receivers will require 2 lines to the LNB, no way > around that. You cannot "split" the cable. Or he could build a 'stacked' system using these modules. multimediasystems.co.uk/acatalog/Stacker_De-Stacker.html#aSTACKER_2dD35 Used with their recommended line amplifier, and he can get out to 65M.

On 18/05/2011 22:24, Herbert Graf wrote: > On Wed, 2011-05-18 at 17:53 -0300, Gerhard Fiedler wrote: >> Some have mentioned that some satellite receivers use the connection to >> control the LNB. In this case, I don't think this is the case, or at >> least it doesn't seem to be a problem. The thing is that we have two >> receivers. One is currently not in use, but it could be used. I want to >> connect this second receiver, to a location 50 m away. I figure that if >> I can connect two receivers to the LNB (AFAIK the cable would simply be >> split), the receivers can't do any individual configuration of the LNB, >> or else they could be fighting each other. > I don't know exactly which service you are using, but usually for DBS > type service two receivers will require 2 lines to the LNB, no way > around that. You cannot "split" the cable. > > TTYL > It depends what satellite he is using If Gerhard tells us, then I will know if the cable can be split or not. A Quattro ku LNBF of course uses four cables and then each of those can be split, then you can feed up to 2000 receivers with multiswitches. (my site http://www.techtir.ie/tv-radio/satellite-distribution ) There are satellite services on C-Band. Ku Band and Ka Band that only need one polarisation and one band (C-Band only ever uses one band). The newest Ka-Band service in Europe has 82 spots, but each one is a single band and polarity, so LNB feed can be split for example http://www.techtir.ie/saortv/saorsat-coverage http://www.lyngsat.com you can see quite a few services that can use an LNB feed that can be split. It's certainly generally true that most services you can't split. A Stacker / Destacker needs a Twin or Quad LNB and only works up to about 10m. I recomend against them and that 2nd or more cables are run. A Dual LNB is for H & V separate (usually only on C band or old Ku), most Ku needs Quattro for distribution systems with more than 8 receivers. Twin, Quad and Octo can drive 2, 4 or 8 tuners direct without a Multiswitch.

On Wed, May 18, 2011 at 4:53 PM, Gerhard Fiedler <.....listsKILLspam.....connectionbrazil.com> wrote: > It seems that there is a consensus that > - I should use separate conduits, > - I should use heavier cable than normal (CT125 or PF125), > - it could/should work :) > Back when I worked at a radio station in college, we were putting a 3.7 meter dish on top of the campus center building to receive PRSS. We had also considered putting it on another building and converting the coax feed to fiber, so it could be run about 200 meters to the station. Fortunately for you that's not necessary. The hardware exists though it's expensive. I think we used RG11 for the run that ended up being about 30 meters. The feed signal was probably similar to what you have. I don't recall what it was exactly. -- Martin K

Michael Watterson wrote: > On 18/05/2011 22:24, Herbert Graf wrote: >> On Wed, 2011-05-18 at 17:53 -0300, Gerhard Fiedler wrote: >>> Some have mentioned that some satellite receivers use the connection >>> to control the LNB. In this case, I don't think this is the case, >>> or at least it doesn't seem to be a problem. The thing is that we >>> have two receivers. One is currently not in use, but it could be >>> used. I want to connect this second receiver, to a location 50 m >>> away. I figure that if I can connect two receivers to the LNB >>> (AFAIK the cable would simply be split), the receivers can't do any >>> individual configuration of the LNB, or else they could be fighting >>> each other. >> I don't know exactly which service you are using, but usually for DBS >> type service two receivers will require 2 lines to the LNB, no way >> around that. You cannot "split" the cable. >> > It depends what satellite he is using > > If Gerhard tells us, then I will know if the cable can be split or not. I don't really know what satellite; it was chosen by the guys who installed the antenna. The service is Sky Brazil <http://www.sky.com.br/home/home/default.aspx>, and according to this list <http://pt.wikipedia.org/wiki/SKY_Brasil> the satellites are mostly DirecTV-x and SPACEWAY-x. When I go into the signal test screen, it says that azimuth is 94°, elevation is 85° and "satellite" is 43°. Not sure this helps... I know that there are two independent tuners in the current receiver, each connected with a single coax cable to the antenna. (I can receive two channels at the same time.) I'm also pretty sure (not 100% though) that they connect different receivers in parallel, much like cable TV, but it also could be that they connect the additional receivers directly to the antenna. Thanks, Gerhard

On 5/19/2011 12:12 PM, Gerhard Fiedler wrote: {Quote hidden}> Michael Watterson wrote: > > >> On 18/05/2011 22:24, Herbert Graf wrote: >> >>> On Wed, 2011-05-18 at 17:53 -0300, Gerhard Fiedler wrote: >>> >>>> Some have mentioned that some satellite receivers use the connection >>>> to control the LNB. In this case, I don't think this is the case, >>>> or at least it doesn't seem to be a problem. The thing is that we >>>> have two receivers. One is currently not in use, but it could be >>>> used. I want to connect this second receiver, to a location 50 m >>>> away. I figure that if I can connect two receivers to the LNB >>>> (AFAIK the cable would simply be split), the receivers can't do any >>>> individual configuration of the LNB, or else they could be fighting >>>> each other. >>>> >>> I don't know exactly which service you are using, but usually for DBS >>> type service two receivers will require 2 lines to the LNB, no way >>> around that. You cannot "split" the cable. >>> >>> >> It depends what satellite he is using >> >> If Gerhard tells us, then I will know if the cable can be split or not. >> > I don't really know what satellite; it was chosen by the guys who > installed the antenna. The service is Sky Brazil > <http://www.sky.com.br/home/home/default.aspx>, and according to this > list<http://pt.wikipedia.org/wiki/SKY_Brasil> the satellites are mostly > DirecTV-x and SPACEWAY-x. > > When I go into the signal test screen, it says that azimuth is 94°, > elevation is 85° and "satellite" is 43°. Not sure this helps... > > I know that there are two independent tuners in the current receiver, > each connected with a single coax cable to the antenna. (I can receive > two channels at the same time.) I'm also pretty sure (not 100% though) > that they connect different receivers in parallel, much like cable TV, > but it also could be that they connect the additional receivers directly > to the antenna. > > Thanks, > Gerhard > > Someone mentioned Lyngsat earlier in the thread. Good stuff here: http://www.lyngsat.com/packages/skybrazil.html http://www.lyngsat.com/intel11.html Looks like Ku with linear (H/V) LNB. Another good one: http://www.dishpointer.com

Charles Craft wrote: {Quote hidden}> On 5/19/2011 12:12 PM, Gerhard Fiedler wrote: >> Michael Watterson wrote: >> >> >>> On 18/05/2011 22:24, Herbert Graf wrote: >>> >>>> On Wed, 2011-05-18 at 17:53 -0300, Gerhard Fiedler wrote: >>>> >>>>> Some have mentioned that some satellite receivers use the connection >>>>> to control the LNB. In this case, I don't think this is the case, >>>>> or at least it doesn't seem to be a problem. The thing is that we >>>>> have two receivers. One is currently not in use, but it could be >>>>> used. I want to connect this second receiver, to a location 50 m >>>>> away. I figure that if I can connect two receivers to the LNB >>>>> (AFAIK the cable would simply be split), the receivers can't do any >>>>> individual configuration of the LNB, or else they could be fighting >>>>> each other. >>>>> >>>> I don't know exactly which service you are using, but usually for DBS >>>> type service two receivers will require 2 lines to the LNB, no way >>>> around that. You cannot "split" the cable. >>>> >>>> >>> It depends what satellite he is using >>> >>> If Gerhard tells us, then I will know if the cable can be split or not. >>> >> I don't really know what satellite; it was chosen by the guys who >> installed the antenna. The service is Sky Brazil >> <http://www.sky.com.br/home/home/default.aspx>, and according to this >> list<http://pt.wikipedia.org/wiki/SKY_Brasil> the satellites are mostly >> DirecTV-x and SPACEWAY-x. >> >> When I go into the signal test screen, it says that azimuth is 94°, >> elevation is 85° and "satellite" is 43°. Not sure this helps... >> >> I know that there are two independent tuners in the current receiver, >> each connected with a single coax cable to the antenna. (I can receive >> two channels at the same time.) I'm also pretty sure (not 100% though) >> that they connect different receivers in parallel, much like cable TV, >> but it also could be that they connect the additional receivers directly >> to the antenna. >> >> Thanks, >> Gerhard >> >> > Someone mentioned Lyngsat earlier in the thread. > Good stuff here: > http://www.lyngsat.com/packages/skybrazil.html > > http://www.lyngsat.com/intel11.html > > Looks like Ku with linear (H/V) LNB. > > Another good one: > http://www.dishpointer.com/ Yes, this seems to be the one. Here's another list of what appears to be the same satellite (Intelsat 11) <http://www.exploradoresdesatelites.com/listadecanais/listar.php?sat=3170> Gerhard

On 19/05/2011 17:12, Gerhard Fiedler wrote: > I don't really know what satellite; it was chosen by the guys who > installed the antenna. The service is Sky Brazil Sky in various places are using "unicable" (aka as SCR) LNBFs. Instead of the whole band it responds to a command from the receiver to select part of the band to the IF. Up to 16 receivers / tuners can be served at once. More than that you have to scrap the LNB and replace it with Quattro and Multiswitches. In UK & Ireland Sky use a mix of unicable/SCR, Quad and in apartments fibre connected LNB distribution systems. Sky in Germany seems to favour "unicable"/ SCR. So indeed the two internal tuners can share one connector. Old European Sky Tuners needed two feeds for PVR. Current models will work on ordinary Universal LNBFs and also on unicable/SCR. It reduces install cost and limits the FTA receivers (though some now do support unicable) you can use. http://www.lyngsat.com/intel11.html Sadly unlike Europe's 13E, 19E, 28E etc the Brazil 43W feed has almost no Free to Air. A different LNB and much larger dish is needed to get the C-Band channels (3.7GHz to 4.2GHz). Some can actually be received in Ireland on a 3.7m dish due to very wide beams on C band compared to Ku. Your Sky system will only receive the 10.7GHz to 12.6GHz band (only a small portion occupied). If you did have separate C band dish http://www.lyngsat.com/intel14.html or here is a better place to point it for some free TV. Likely a large mesh dish.

On Wed, 2011-05-18 at 16:01 -0600, Robert Rolf wrote: > You should also consider inserting 'in line' signal amplifier to make up > for the cable losses. This amplifiers power themselves from the polarity > switching voltage. Ideally , half way along the cable, or at the LNB. Perhaps I'm missing some other factor, but a common thing in radio design is that whatever you signal source is, that's where the majority of your amplification should happen. At your signal source is where the highest SNR will be, if you put your amplifier in the middle of the cable then you'll be amplifying a much higher amount of noise, which doesn't help much on the receiver end. Again, this is all based on there not being some other reason making putting the inline amp in the middle of the run a better idea. TTYL

Michael Watterson wrote: > On 19/05/2011 17:12, Gerhard Fiedler wrote: >> I don't really know what satellite; it was chosen by the guys who >> installed the antenna. The service is Sky Brazil > > So indeed the two internal tuners can share one connector. Old > European Sky Tuners needed two feeds for PVR. What I have here needs two cables from the antenna to the receiver for dual-channel reception. {Quote hidden}> A different LNB and much larger dish is needed to get the C-Band > channels (3.7GHz to 4.2GHz). Some can actually be received in Ireland > on a 3.7m dish due to very wide beams on C band compared to Ku. > > Your Sky system will only receive the 10.7GHz to 12.6GHz band (only a > small portion occupied). > > If you did have separate C band dish > http://www.lyngsat.com/intel14.html or here is a better place to > point it for some free TV. > > Likely a large mesh dish. Yes, some people here have the large mesh dishes. I don't think I'll get one any time soon... Thanks, Gerhar

On 19/05/2011 22:22, Gerhard Fiedler wrote: > What I have here needs two cables from the antenna to the receiver for > dual-channel reception. OK, then you have the regular Ku LNBF, a twin or quad. not the newer "unicable" system. There is 13V /18V and 22kHz on/off but your satellite feed is only 10.7 to 11.38, well below the 11.7 needed to switch via 22kHz from 9.750 to 10.6 LO Your cable signal is thus 972MHz to 1632 MHz with only 13V /18V switching. You can't split the cable, so you should run four cables and then you can add two regular receivers or one extra recorder off an Quad LNB. If you ever wanted more feeds, you fit quattro and 1 or more Multiswitches fed by the 4 cables to have 8, 12, 16 or up to 2000 receivers... :) See http://www.techtir.ie/node/1003507#comment-1004343 The multiswitch not only lets you split a Quattro (or a Quad if it's a compatible switch) to 16 or more receiver, but also lets you choose versions with more than one satellite feed in. Sky of course do not enable "satellite position switching" (diseqc) so I have the satellite LNBF needed for Sky as the 1st position because without issuing commands from the receiver the Multiswitch always gives 1st position. Back garden http://www.irishwattystuff.com/amateur/images/dishes-w.png the first dish has four offset feeds to 16 way multiswitch. Sky boxes just work, non-sky boxes and PC receiver can pick any of the 4 satellites. http://www.techtir.ie/blog/watty/mheg5-on-xp (The PC has dual tuner for Digital Terrestrial on USB stick as well as 2x DVB-S2 satellite cards) The 2nd dish is motorised and can get 48E to 56W approx, except there is nothing pointing at Ireland on Ku more east than 42E and more west than 45W (I'm near 8W). It's direct to a separate receiver. the 3rd dish was experiment to see if 1.2m is big enough to get ANYTHING on C band here. It has C band LNBF with adjustable F/D due to sliding scalar rings. A bigger dish is needed. I know where there is nice unused 3.6m mesh..

On 19/05/2011 20:31, Herbert Graf wrote: > Perhaps I'm missing some other factor, but a common thing in radio > design is that whatever you signal source is, that's where the majority > of your amplification should happen. > > At your signal source is where the highest SNR will be, if you put your > amplifier in the middle of the cable then you'll be amplifying a much > higher amount of noise, which doesn't help much on the receiver end. > > Again, this is all based on there not being some other reason making > putting the inline amp in the middle of the run a better idea. You are correct for Professional line drivers. The cheaper ones overload at the LNBF! Really only the professional ones with a switch to set type & length of cable for correct equalisation are any use. The cheap in-line ones with no settings are useless as the 950Mhz may overload when the 2100MHz is amplified enough. Using the heavier cable up to 60m is a simpler solution. (CT125 / PF125, a 1.25mm centre core instead of 1mm, thus overall cable is fatter to keep impedance 75 Ohm. Hydrophobic foam dielectric is more robust than semi-airspaced). Actually may be fine up to 80m on Sky Brazil as only the lower part of IF is used. A bigger dish is best way to get better SNR! Distribution systems always use next size up of dish. Too big a dish creates different problems. Especially in Europe where 4 or more satellite may be "co-located" on a small dish, but separate on a big dish (28.2 Astra 2A, 2B, 2D and 28.5 Eurobird 1)