The SWiM signals come from the LNB, so if the LNB's output is low, so will the SWiM.
All signal strength screens including the 1-9 SWiM level one, measure the relative "Bit Error Rate" on a scale of 0-100.gregftlaud said:OK then apparently weather and signal strengths from other sats CAN affect your SWM readings b/c my SWM signal strengths just went back up after the feeder band finally got thru...just like yours NR4P
So looks like a part of that "LNB output" has something to do with signal strenghts the LNB is getting from 101, 103, 99 sats.......and not just dependent if the LNB is working properly or getting enough power.
It might be more likely that they are using a MER or modulation error ratio scheme, which more accurately gives a quantitative approximation of reception/demodulation, and allows that to be modeled on a simulated analog scale more easily that BER, which is simply a baseband count of corrupted bits vs non-corrupted bits. Either will work, but one works better than the other in many cases.HoTat2 said:All signal strength screens including the 1-9 SWiM level one, measure the relative "Bit Error Rate" on a scale of 0-100.
And the BER is dependent upon the C+I/N+I (sometimes abbreviated to C/N if interference is ignored ) ratio at the input of the LNB feedhorn.
Therefore if rain fade, interference, signal blockage, etc. degrade the C+I/N+I ratio so will the numbers on the various SS screens.
However, it has always been of interest to me what specific 8 programming transponders (ignoring the CG one which is obviously 101) are selected for the SWiM level screen. And the fact that you notice them drop out when Ku 101 goes out well after the Ka band goes down makes me wonder if they are not all from 101.
There may be level adjustments due to amplification or attenuation in the distribution from the dish, but the original signals have to come from somewhere, and they all come from the sats. The LNBF definitely amplifies this signal, and there can be amplification elsewhere in the distribution, but if the input signal goes to 0, there is nothing to amplify, meaning that the signal reading will be 0 as well. Signals are converted from band to band but none are actually generated within the antenna or distribution path, other than the return DC.gregftlaud said:Can someone tell me what SWM transponder signal strengths mean and if they also come from the satellites?
Bad weather down here in ft lauderdale even in the heaviest of rains i've never seen my SWM transponder signals go below 95 but tonite it is pouring really bad and my SWM signal strengths are in the 70's (my other sats strengths much worse).
I always thought SWM signal strenghts were determined within your setup but can low satellite readings being affected by heavy rain affect your SWM readings as well?
Possibly;TomCat said:It might be more likely that they are using a MER or modulation error ratio scheme, which more accurately gives a quantitative approximation of reception/demodulation, and allows that to be modeled on a simulated analog scale more easily that BER, which is simply a baseband count of corrupted bits vs non-corrupted bits. Either will work, but one works better than the other in many cases.
MER is probably not expensive to implement here even though a bit more sophisticated, because it can utilize the demodulator already built into the tuner path just like a baseband count of bit errors can. But if MER actually is more expensive to implement, then I would guess that either BER or Eb/No becomes the desired protocol. Eb/No might even be the least expensive since it doesn't need to factor in the bandwidth. ...
Well DIRECTV-4S is not hybrid, but Ku only. DIRECTV-8 and 9S are with both Ku and Ka band payloads.... Technically, they could be all from 101; the "Satellite Transponder Guide" lists DirecTV 4S, 8, and 9S (listed at 101 W) as hybrid Ka/Ku sats, and they can reconfigure any number of transponders to either mode on the fly. My best guess is that they do not illuminate in Ku at all from that location, but that is only a guess based on what channels they provide.
DIRECTV equipment receives signals from 101 which fall into the broadcast ("BSS") or "DBS" portion of the Ku band between 12.2-12.7 GHz and use circular polarization.... Even if they do not, your signal screen could still be seeing Ku signals from the 101 location (which just by nature of them being there could show up on any metering system looking at 101) because SES-1 is also at the 101 location and has 9 Ku transponders illuminated there, at least according to the Sat Guide. DISH metering turns the normally green bar red to weed out signals with a different identifier, but not all methods do that; no telling what DTV does.
Have to dig up the FCC files on SES-1 to know the transmit power levels for sure, but I would assume the 20 watt figure if correct is for the C band payload, whereas the Ku band one is certainly greater.... There are a couple of reasons why the Ku might fade later than Ka; one is that Ku is less susceptible to atmospheric obstacles than Ka, meaning it would naturally drop off later during an increasingly bad weather event. This makes more sense than anything else because SES-1 is a 20-watt bird, while the DirecTV birds are 120 watts, which should mean that the Ku from there would drop off before the Ka from DTV. Not sure why SES-1 is so low in power; it only went up a couple of years ago, and back then it was berthed at 131, so we may not have seen it at 101 for all that long.