New Truevisions Top Box - Signal Strenght Indication?

[bdenner]

Had a storm and my dish has appeared to have moved.

On the old box there was an easy to find signal strength monitor if read 255 indicated the dish was set correctly.

Question: Where does one find this function on the new box? Been thru the menu items and read the manual it doesn't appear to be there!

Thank you.

[ThaidDown]

Yes, was easier before. Assume Samsung HD box.

Menu > SETUP >System Setup> Signal Setup > Enter Pin (2321) > OK > OK (again) > Should say 'choose Your Transponder' > Entry Point 1 >ok.

Should see Sig Strength on left and Quality on Right with BER bottom Right.

Back out as normal.

If anyone knows a quicker way ie 'hold down ?? key for 7.2 secs, would like to know myself.

[bdenner]

Thank you! Only reading 193 -- extremely small print makes it hard to moniter through a window whilst I'm adjusting!

I must have had the wrong PIN 1232 and couldn't get past that point as well the manual says there's no need to enter the option????

Edited August 16, 2012 by bdenner

[ThaidDown]

PIN 1232 is for 'Parental Control' setting.

[angryfarang]

What sort of signal should you see on a well aligned dish?

Mine says 172.

[ThaidDown]

Should easily make 255 for signal strength.

[angryfarang]

Should easily make 255 for signal strength.

Wow. My dish can't be aligned to well. Time to head out on the roof!....

[Pib]

Be sure to take into consideration any multiswitches/switches/splitters which might be dividing-out the signal, whether feeding the signal to one or more boxes. For example, if the LNB output signal was being fed to a two-way splitter for two boxes, half the signal would be routed in each direction/to each box....but if no splitter was being used the one box would receive the full strength of the LNB signal output. Maybe a poor analogy is when a water hose it split out into multiple water hoses...that water pressure/volume is reduced as it's split out to more hoses.

Seems the newer TrueVisions boxes give out strength readings in a relative numeric valve like 255, 172, etc., as mentioned above...not sure how that relates to an actual signal power level. The old boxes gave readouts in dbm (decibels referenced to one milliwatt). But if a person was using an older box and say a person had an excellent -20dbm (note the minus symbol) signal reading on the one box with no splitters being used, when adding another box and a two-way splitter, each box would then read a -23 dbm. When it comes to power levels, a 3 db drop equates to the power level being cut in half....or a 3db increase (i.e, that -20dbm going to a -17dbm) represents a doubling in power level.

Now, I'm on cable TrueVisions compared to satellite TrueVisions. I have three HD boxes and also have TrueOnline cable internet. The one cable carrying the TV/internet signal enters my house and goes directly to a two-way (a.k.a., 3db) splitter...one output of this splitter goes to my TrueOnline cable internet Wifi router....then the other output of this first two-way splitter goes to "another two-way splitter. One output from this second two-way splitter feeds my master bedroom HD box/TV where I get a 219 strength and 100% quality indication....the other output of that splitter runs up into my attic where it connects to another two-way splitter which feeds my other two HD boxes through different lengths of cabling....on the box with the shortest cabling I get 106 strength and 100% quality indications and on the other box with the longer cabling run I get a 97 strength and 100% quality indications. The standard definition and high definition channels picture quality is identical on all three boxes/TVs although the strength level varies greatly....over 50% lower strength level on two of the boxes/TV due to the splitters/cabling being used to feed the signal around the house.

Now just to mention it again please keep in mind I'm on cable TrueVisions compared to satellite TrueVisions, so I probably have a better signal (rain or shine) and I've never had rainfade since switching to cable, but I think above strength/quality indications serve well as an example of how splitters and cable lengths can make a major difference in strength indications and also shows how quality can remain at a high level as long as the signal strength stays above a certain level.

Now in rainfade situations, just using one satellite box compared to two or more boxes shouldn't help reduce rainfade signal loss since with digital transmission any signal strength arriving at the box input port above a certain level provides a good picture. But when the signal level "exiting the LNB output port(s)" is reduced to a certain low level due to rainfade/thick clouds, the signal reaching the boxes just ain't enough anymore and the box can't display the TV channel anymore as the received satellite signal has dropped down into background noise levels....the LNB can no longer distinguish the satellite signal from everyday background noise.

Also, the satellite reception strength varies somewhat depending on your location in Thailand.

Just be careful in trying to compare one person's signal strength indication against another (whether on satellite or cable), unless they are using the exact same equipment, they are in the same location, and probably most importantly what "devices/splitters/length of cabling/amplifiers/etc." one person may have in his line between the satellite LNB (or cable input point to house) and settop box(es) compared to another person.

For satellite reception, be sure the satellite dish is pointed right at the satellite (versus just being close) and the LNB is mounted properly...ensure no line of sight obstructions between the dish and satellite....just minor movements/tweaks of the satellite dish can make very significant differences in signal strength/quality especially on KU band....ensure the final dish tweaking is done to maximize the signal "quality" indication even if that tweaking might cause the signal "strength" indication to drop a little.

And also be aware that different LNBs will respond differently in response to reduced satellite signal level...one LNB might perform better in a low satellite signal environment (i.e., signal output) compared to the other, while both LNBs might perform equally in a medium-to-high satellite signal environment. And of course, the dish size and alignment reflecting the satellite signal into the LNB makes a big, big difference...much more than whether a LNB is a low or high cost LNB. Without having the whiz bang signal strength/LNB testing equipment the real acid test for dish & LNB gain comes down to times of low signal levels like during rainfade conditions. Good luck.

[angryfarang]

Pib - I wonder what you readings would be with one box plugged directly in to the cable? You're getting 219 after your signal has been split with your modem. You think 400?

[Pib]

I doubt 400 but I really wouldn't want to guess since I don't have a satellite HD box as I'm on the cable system with cable boxes. Hopefully some other folks who have satellite boxes with good signals will respond. Also responded to your PM with other info. Cheers.

[ThaidDown]

Personally on a True Satellite set top box have never seen more than 255 indicated as signal strength. That applies to the current Samsung hd box as well as one previous ( ABS, I think). From a software point of view if holding a value in 1 byte then 0-255 would be the available range, but just guessing.

With another previous box (maybe Humax ?) actual signal values were indicated and a 'blue-sky' figure of -13dBm was normal. Also would doubt if the signal value indication would be linear, eg 3dB down from a signal value of 250 would not be 125.

For me, 255 is easily obtainable (standard True equipment) , after I've got the 255 I then adjust the dish slightly for best signal quality. While getting this best signal quality position the signal level, for me, stays at 255, will not go above, others may have different results of course.

The max signal quality that I have achieved is around 60%. Do not know if that is normal or I there is still some fine adjusting to do. ( note this is a satellite system not cable as pib )

[Pib]

I know that on a C band satellite hookup (which I have also) I can get a 93% quality reading on Channel 7 (probably the strongest channel on Thaicom 5). 60% quality is probably more the norm for most channels, but as a channels get weaker signal strengh-wise getting around 30-40% quality is not uncommon. But even at 30% quality the picture looks as good as a stronger channel with 93% quality. For me, in the 20-25% quality ballpark is when the signal is getting very weak...you start seeing the picture breakup....and usually right around 20% quality the picture is gone....you get the No/Poor Signal Indication. Each person's indictations will vary due to equipment used, cabling, location in Thailand, etc. I'm in Bangkok.

Edit: for final dish alignment I would pick a weak channel. When I was still on satellite TrueVisions there were signficant differences in some channels strengths....can't say for sure that now exist with their new transmissions since I'm now on cable, but it's worth checking the strength/quality levels on various channels just to find a weak channel....then do the final dish alignment to maximinise the quality reading...and don't be surprised if the strength indication changes very little to none although the quality indication can change significantly.

Edited August 24, 2012 by Pib

[Pib]

Personally on a True Satellite set top box have never seen more than 255 indicated as signal strength. That applies to the current Samsung hd box as well as one previous ( ABS, I think). From a software point of view if holding a value in 1 byte then 0-255 would be the available range, but just guessing.

With another previous box (maybe Humax ?) actual signal values were indicated and a 'blue-sky' figure of -13dBm was normal. Also would doubt if the signal value indication would be linear, eg 3dB down from a signal value of 250 would not be 125.

For me, 255 is easily obtainable (standard True equipment) , after I've got the 255 I then adjust the dish slightly for best signal quality. While getting this best signal quality position the signal level, for me, stays at 255, will not go above, others may have different results of course.

The max signal quality that I have achieved is around 60%. Do not know if that is normal or I there is still some fine adjusting to do. ( note this is a satellite system not cable as pib )

It's hard telling what reference the strength indications really represents as it also depends on whether the signal strength circuit is measuring/indicating power or voltage or something else. If measuring power then a 3db increase doubles the power level and a 3db decrease halves the power level. However, if the measuring circuit is using voltage then a 6db increase doubles the voltage level and a 6 db decrease halves the voltage level. Example for Voltage: 0 dbuV (decibels microvolts) equals 1uV...an increase to 6dbuV equals 2uV....so to double the voltage level a 6db gain had to occur. Then the strength indicator is not saying dbuV nor dbm, but just giving a number....a number referenced to what? Power, voltage, etc?

On the Product Specifications page for my cable HD box the Receiver Level specs are in dbuV.....on my old/non-HD satellite TrueVisions box it was in dbm. Whatever the receiver is using (power or voltage but probably voltage) it sure looks like it justs display a number not referenced to anything like voltage or power. Without knowing the actual power/voltage arriving at the box input connector a person just don't know what the indications really mean, especially since I haven't seen any TrueVisions provided info like you really need to get an strength indication of "at least" XYZ. You could be right that a 255 indication means the receiver is receiving all the signal it needs and anything additional is wasted/just overdriving the receiver. Or it could mean the LNB is putting out the max amount it can and any additional signal strength from the satellite is just wasted/overdriving the LNB although the receiver could accept a higher signal level.

Someone might say just add an inline amp like a 20db amp that is commonly used in some setups. I tried that about 6 months ago on the mother in laws C band system to see if it would help with some weak channels. It didn't. Although it increased the signal level X-amount it also decreased the quality indication by approx 10%. I expect this occurred because it was actually distorting the signal a little in the amplification process and also amplying background noise in addition to the signal. While an inline amp can help is some situations/setups, it won't help in others...in fact, it can make things worst.

Just not enough info on what a good signal level is except when we do crossfeed like this, because I just don't think TrueVisions will be forthcoming with posting such info. Like any strength indication below XXX is a low/poor signal level and may result in no picture. When I was still on satellite TrueVisions and a heavy duty thunderstrom would come over I would monitor the strength level dbm reading to see at what level the picture was loss....I can't remember the dbm value right now but the picture sure would disappear at XX dbm and when the signal increased to just 1 db above the signal loss level the picture was back on just as clear as a bell....and as the dbm signal increased as the thunderstorm passed the picture looked no better than at that 1 db above signal loss level. Cheers.

[wayned]

I have the standard True visions hookup with1 set top box. I also have a GMM Grammy unit that has either c band or ku band capability. Can I hookup the GMM Grammy box to the existing installation. If so, how. Through a splitter on the input from the LNB or to the output port on the back of the new HD box. If so. what happens to the loop through cable. I cannot find any explanation of this circuit and when I ask TV all they want to do is sell me a second TV set top box installation.

[Pib]

From looking at lyngsat I see the GMM Grammy KU band channels appear to use Horizontal polarity (i.e., feeding 18V DC power to the KU band LNB) which is what True also uses, so just hooking a two way splitter between the LNB and the two boxes should work...when True hooks up two of their satellite boxes all they do is hooked a two splitter between the LNB and boxes. The LNB output goes to the splitter input and the two splitter outputs go to your boxes.

Edited September 11, 2012 by Pib

[wayned]

Thanks, i was worried about voltage differential if the two boxes were powered at the same time.

[hullupullo]

I have splitter and one cable from that goes to truebox "SAT IN 1" and other to gmm box. In truebox I have loop cable between "LNB OUT" and "SAT 2". Can someone explain me why that loopcable is needed?

And why I can not see some channels in gmm, like thaichannel 9, when both boxes are on? Only when I unplug power from truebox, then every gmm channels work ok. Just turning off truebox is not enough, had to unplug power cord.

Edited September 11, 2012 by hullupullo