Signal Levels on 125W (AMC 21) (1 Viewer)

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chapelrun

Thread Starter
SatelliteGuys Pro
Pub Member / Supporter
Feb 12, 2008
962
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Berryville, VA
Since my fixed dish for 125W fell during the recent snow storm - - - I pointed my 90 cm dish at 125W today.

I was interested in the signal levels of the PBS TP's.

12178 V 30000 S75 Q90
12138 V 30000 S75 Q45
12165 H 4444 S71 Q33
12149 H 14028 S71 Q30

If you are pointed to 125W could you also post your Signal and Quality numbers for these 4 locations?

TIA
 

AcWxRadar

SatelliteGuys Pro
Apr 26, 2006
4,575
4
40 miles NW of Omaha. Omaha?
Chapelrun,

It is difficult to compare signal levels and quality readings if you are not utilizing the identical equipment. The receiver make and model, the LNBF, the antenna make, model and size as well as your location and your dish and motor alignment all effect the readings you detect.

The only accurate way to test and compare this is to have a neighbor with the identical equipment. Otherwise, there are simply too many variables that affect the readings. Therefore, you cannot discern any accurate hypotheses regarding your system health and its setup precision.

With the above disclaimer being presented, I will list what I can detect using my SuperBuddy meter and my AZBox Premium and Coolsat 5000 receivers with a 1.2M GeoSAT Pro antenna and an Invacom QPH-031 LNBF.


125°W AMC 21

...TP.......POL........SR.........dBm....IRD%......C/N.......AZBox Q%.....COOLSAT Q%

12140.....V........30000.....-57.6.....95.........13.0..........76...................76

12150.....H........14029.....-63.8.....80..........9.8...........59...................71

12163.....H..........4444.....-64.1.....92.........12.4..........75...................81

12169.....H..........4444.....-63.6.....87.........11.6..........70...................78

12175.....H..........4444.....-64.0.....91.........12.0..........73...................75(??)

12180.....V........30000.....-59.1.....96.........13.8..........79...................78

Please do not utilize this data for anything more than just a training excercise. As you can see right off, the quality readings between the two different receivers and the SuperBuddy's IRD reading do not match, even with identical external components.

The only values that I trust here are the dBm readings and the C/N ratio readings that I obtain from the SuperBuddy meter, since it is a calibrated instrument.

I wish that all FTA receivers would adopt a meter style that displayed dBm readings and C/N ratios opposed to Q% readings. Even if they were not precisely calibrated and were just a rough reading with 10% or better accuracy, it would end a great deal of confusion for the end users.

We could then actually check each receiver's meter accuracy with a calibrated instrument and better judge the receiver's design quality from such. As it is currently, the signal level and quality level meters really mean very little unless you are comparing a Coolsat 5000 to Coolsat 5000 or an AZBox to an AZBox, etc. And then, you have to be sure that the firmware is matched as well!

LOL... I have 76 apples, how many oranges do you have?

RADAR
 

AcWxRadar

SatelliteGuys Pro
Apr 26, 2006
4,575
4
40 miles NW of Omaha. Omaha?
Chaperun,

You might notice that the frequencies of our transponders may differ. That does not mean that either your receiver or mine is inaccurate. This variance often exists. I can even blind scan with two identical receivers and result with two slightly different TP frequencies. As long as they are accurate within a +/- 2 to 3 MHz window, (possibly even more) this should usually be acceptable.

Don't be overly concerned with these differences unless someone informs you to the contrary or if you have troubles scanning in channels on a specific TP that you know that should be there.

RADAR
 

chapelrun

Thread Starter
SatelliteGuys Pro
Pub Member / Supporter
Feb 12, 2008
962
12
Berryville, VA
WOW - - thanks for the detailed explaination

Two questions

1. What is C/N ratio?
2. Has the expense of a SuperBuddy been worth it to you?

I've been considering getting an cheap sat finder but find it difficult to justify the cost of something like a SuperBuddy.

Thanks again for the great reply!
 

AcWxRadar

SatelliteGuys Pro
Apr 26, 2006
4,575
4
40 miles NW of Omaha. Omaha?
Two questions

1. What is C/N ratio?
2. Has the expense of a SuperBuddy been worth it to you?

I've been considering getting an cheap sat finder but find it difficult to justify the cost of something like a SuperBuddy.

Thanks again for the great reply!

Chapelrun,

C/N ratio is the "carrier to noise" ratio. The greater this value is means that the carrier signal is that much further above the general background noise and therefore more detectable and a "cleaner" signal.

The expense of the SuperBuddy meter is difficult to justify if you are just setting up your own FTA system at home for your own use. There is no need for a meter like this in such a case. I had a special purpose in mind when I purchased my SuperBuddy meter and that was to install WildBlue satellite Internet systems, not FTA. However, since I was also into FTA it seemed even more reasonable to me.

Unless you are going into business installing satellites for TV and for internet, you don't need this or any other meter. It just isn't justified. Heck, if you are setting up your own dish at home, you don't even require a meter at all. I set up many without even using those little freebie meters that you sometimes get with a receiver purchase. In fact, I threw them all away. They were nothing more to me than a cheap prize at the bottom of a CrackerJack box. I had no use for them.

Whatever receiver you have will be sufficient to judge the signal with. You just have to have some sort of notion of what you are doing in the first place, any external meter is useless. It is just a gadget with no purpose.

Nothing beats having your receiver and a small, portable TV out on the install site. The receiver that you are using has the final say in how good the signal quality is anyway, so as long as the signal quality meter on the receiver is fairly good (response wise) that is all you need.

A SuperBuddy meter is excellent for a business operation, when time is money. Those little crackerjack prize meters you can just toss because they are not worth anything to anyone. Simply knowing what you are doing as you set up your dish is plenty suffient. If you don't know how to do this from scratch, no meter is going to help you.

Other than setting up WildBlue internet antennas, I don't require my SuperBuddy for anything else. FTA installs I can do so easily now. Fixed point systems I can almost set up without a receiver. The trick to this is understanding your territory and the landscape and the landmarks. If you were to install enough dishes in your home town, you would get accustomed to this practice, too. I basically have developed a "calibrated" eye and can set up a dish without a compass and without a meter. It eventually just becomes familiar territory.

I think that this is why I like this hobby so much. It is something that I can do so well that I can enjoy it. Just like fishing or home brewin beer. I just have a knack for these hobbies without thinking about them. I think that if anyone works at it enough, they will be able to do it just the same, too.

Good luck and have fun!

RADAR
 

B.J.

SatelliteGuys Pro
Oct 15, 2008
2,029
1
Western Maine
Chapelrun,

It is difficult to compare signal levels and quality readings .....
......

......

125°W AMC 21

...TP.......POL........SR.........dBm....IRD%......C/N.......AZBox Q%.....COOLSAT Q%

12140.....V........30000.....-57.6.....95.........13.0..........76...................76

12150.....H........14029.....-63.8.....80..........9.8...........59...................71

12163.....H..........4444.....-64.1.....92.........12.4..........75...................81

12169.....H..........4444.....-63.6.....87.........11.6..........70...................78

12175.....H..........4444.....-64.0.....91.........12.0..........73...................75(??)

12180.....V........30000.....-59.1.....96.........13.8..........79...................78

Please do not utilize this data for anything more than just a training excercise. ....
....

I wish that all FTA receivers would adopt a meter style that displayed dBm readings and C/N ratios opposed to Q% readings. Even if they were not precisely calibrated and were just a rough reading with 10% or better accuracy, it would end a great deal of confusion for the end users.

We could then actually check each receiver's meter accuracy with a calibrated instrument and better judge the receiver's design quality from such. As it is currently, the signal level and quality level meters really mean very little unless you are comparing a Coolsat 5000 to Coolsat 5000 or an AZBox to an AZBox, etc. And then, you have to be sure that the firmware is matched as well!
.....

I agree that the S/Q reading comparisons between receivers are virtually meaningless. I would also suggest that the S/N or C/N figures from different meters, regardless of whether calibrated or not, would not be too meaningful either because I'm pretty sure that these readings are affected by the bandwidth of the particular receiver/instrument in question.

However, I was interested in your chart, mainly because over the past year or so, since AMC-21 became operational, I have been interested in why in general I have much more trouble with horizontal transponders than vertical, on this satellite, although it isn't always the case. Usually, there isn't too much difference, but the past two days, the 12150 transponder has been WAY down in quality relative to the vertical transponders. I noticed that it was a bit lower on your chart too, although not as much as I've been seeing, which is more like 80 for 12180, and 49 for 12150.
So I decided to do a comparison similar to yours, just for fun, but also thinking that my Twinhan results would be funny, since a STRONG signal is usually around 30 on it. Today though, the Twinhan was giving high readings for some reason. Oh well. Anyway MY CHART

Freq... Diamond ..Twinhan..Azbox.. Genpix-S/N ...TT-3200-S/N ...BL-1030-S/N


12140 .... 73 ...... 34 ........ 60 ........ 10.2 ............. 10.1 ........... 4.4
12150 .... 62 ...... 37 ........ 55 ........ 9.2 ................. 8.7 ........... 3.8
12163 .... 72 ...... 38 ........ 59 ........ 8.7 ................. 9.6 ........... 5.8
12169 .... 72 ...... 37 ........ 62 ........ 9 .................. 10.3 ........... 6.8
12175 .... 69 ...... 33 ........ 54 ........ 8.1 ................. 8.7 ........... 4.5
12180 .... 80 ...... 54 ........ 76 ........ 11.9 .............. 11.3 ........... 6.5


As you see the first three are quality readings, the last 3 are S/N readings.

But anyway, these reading are all over the place, when comparing receiver to receiver, but I'm mainly interested in the comparison between 12150, and the 2 vertical transponders. Turns out that today, it's all over the place even comparing different transponders on the same receiver. However, overall, as usual, the horizontal transponders seem to be generally worse than the vertical transponders for some reason.
I've long been confused about why horizontal just doesn't work as well on this sat for some reason. I've observed this with 4 different LNBs. I think once I even turned the LNBF 90 deg to see if it was a voltage issue (ie picking up V as H and visa-versa). Only thing I could figure is that since AMC-21 is fairly low in the sky for me, that perhaps the two polarities propagate differently when low in the sky. But now, seeing that 12150 is low for you too, perhaps it's just that 12150 is really just a bit less powerful?

But one more aspect of this. You really cannot make ANY sense out of comparisons of those 4444 SR transponders, even with the same receiver, because those 3 signals come from different places at different times. I've seen them be coming in very strong, then the signal will go off completely, then come back from a different uplink site, and be very weak, then go off, and come back up from a 3rd uplink site, and be moderately strong, then come back to the original uplink and be strong again. So you pretty much have to be looking at these 4444 signals at the same time to compare them, because even 5 minutes difference in time can mean a big difference. I'm starting to think that the same might be true of the 12150 signal as well, as I think that can be uplinked from different sites, whereas the 12140 and 12180 signals are always from the same place.

BTW, all readings are from my 3' Primestar fixed, with QPH-031 through a 4x1 diseqC switch, through an SG2100 motor, through more than 250' of RG6, with several barrel connector splices. The BL1030 values are additionally through a splitter, since it can't control a diseqC switch so I had to slave it, however I generally don't see much difference in S/N readings though a splitter, since it attenuates both.

I'm also curious relative to where your SuperBuddy readings were taken, because I've generally found that satellite meters only work well when close to the dish relative to close to the receiver. Just curious.
 

John Popper

SatelliteGuys Pro
Dec 11, 2009
788
5
Central Mexico
I hate the fact that I miss this bird's beam by a frog's hair



red dot is where I live :mad:
 

AcWxRadar

SatelliteGuys Pro
Apr 26, 2006
4,575
4
40 miles NW of Omaha. Omaha?
B.J.

I will have to take some time to digest everything that you have said. Currently, I am getting prepared to head to work and can't afoord too much time. I should leave a little eary because we had a mini-blizzard yesterday and I don't know what the roads are like.

However, I think we have a similar setup. Although my dish is smaller (I have the 1.2M GeoSAT pro). But, I also have the QPH-031 and route the signal through my DG-380 motor and then a 4x1 DiSEqC switch (which is only there to select between the circular and the linear signals. Then I have a run of about 290 feet or more of RG-11 cable up near to the house. Then there is about 40 feet of RG-6 cable to route it into the house and to my living room.

I took the readings with my SuperBuddy meter directly at the receiver, so at the very end of the cable where my receivers were connected. I took those readings at this point in order to obtain the most similar readings between the SuperBuddy and the two receivers in an attempt to make all things as equal as possible.

I agree that the S/Q reading comparisons between receivers are virtually meaningless. I would also suggest that the S/N or C/N figures from different meters, regardless of whether calibrated or not, would not be too meaningful either because I'm pretty sure that these readings are affected by the bandwidth of the particular receiver/instrument in question.

Regarding the above quotation, it is necessary for me to note that the SuperBuddy meter has its own power supply to drive the LNBF and thus doesn't need to slave through the tuner. So I can elliminate any signal degradation caused by the receiver or the tuner module that they are using within. This is a really swell thing about the SuperBuddy meter, as it can be used as a stand alone instrument in the field when setting up a dish, without requiring a receiver to power the LNBF.

I wouldn't want to talk you into spending $700 for a toy like this, but I do think that you would be impressed with the SuperBuddy. It is almost more fun for me to play with than it is for me to set up and watch FTA TV. However, like I stated earlier, it isn't a necessary piece of equipment... It is more of an expensive toy than anything else.

Well, I am sorry, but I got to run and get to work now. Catch you later. I'll try to check back in later if I can. Take care.

RADAR
 

B.J.

SatelliteGuys Pro
Oct 15, 2008
2,029
1
Western Maine
...

However, I think we have a similar setup. Although my dish is smaller (I have the 1.2M GeoSAT pro).
? typo ? 1.2M is about 4' which is a foot bigger than my 3' Primestar.
I took the readings with my SuperBuddy meter directly at the receiver, so at the very end of the cable where my receivers were connected.
Interesting. I'll have to try that again with my cheap meters. Last time I tried taking a meter reading close to the receivers, it gave meaningless results. Couldn't even tell that I was on a sat. This was with one of those SF95 or whatever they're called. I once used my Channel Master near the receiver, but wasn't looking at the signal readings, I was only checking the current draw.
Anyway, I just assumed that meters wouldn't work well near the receiver.
 

AcWxRadar

SatelliteGuys Pro
Apr 26, 2006
4,575
4
40 miles NW of Omaha. Omaha?
? typo ? 1.2M is about 4' which is a foot bigger than my 3' Primestar.

Nawh, I just read you wrong. I was thinking you had a 3 'meter' dish not 3 foot. My error.

Interesting. I'll have to try that again with my cheap meters. Last time I tried taking a meter reading close to the receivers, it gave meaningless results. Couldn't even tell that I was on a sat. This was with one of those SF95 or whatever they're called. I once used my Channel Master near the receiver, but wasn't looking at the signal readings, I was only checking the current draw.
Anyway, I just assumed that meters wouldn't work well near the receiver.

I think the reason my SuperBuddy does well here is because it provides its own power to drive the LNBF. It does have a lot of "UUMPH".

I guess I need to explain why I am not at work by now. I tried, but I cannot get out because of the 2" or so of snow. Sounds odd, but because of the wind, we have drifts over all the roads. I got stuck at the end of my driveway at the mailbox. I made it out of that, but had no where to go beyond. I am stuck here. I cannot make it down the pass to the highway as that is closed. The road to the north is totally impassable for certain and the road to my east has a 5-7 foot deep drift about 50 yards long. I cannot punch throught that even with my 4WD. So I am stuck here at home until the plows make it through the pass.

This is now the third time this year that I have not been able to get out and nobody can make it in, until they clear the pass. With snow on the ground in all 50 states and setting records for length of time of snow on the ground here in Nebraska, you can tell Al Gore that he can shove that global warming idea up his mule! :rant:

RADAR :D
 
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