Who has a meter and can measure...

[veryoldschool]

I was wondering if anybody with a meter could make some measurements of the levels:
Coming out of the dish,
Coming out of the multi-switch,
Cable lengths,
At the receiver,
Either in dBm or dBmV and SAT/TPs.

Sonora has a pdf that seems to show 25 dB is all the system loss there should be, and I'm wanting some "other" measurements to validate some of this pdf info.

"My system loss" is about 24 dB, but would bet there are [many] other systems out there with more loss.

Thanks for your time, if you can do this and post them. :)

[Mertzen]

I can but not untill early next month. I think a birdog 2.5 can do this. If not you might need to find one with a superbuddy.

[veryoldschool]

I can but not untill early next month. I think a birdog 2.5 can do this. If not you might need to find one with a superbuddy.
Well, if no one else "steps up", would you bookmark this thread, or send me a PM?

[Mertzen]

I'll make a mental note..

[netraa]

I was wondering if anybody with a meter could make some measurements of the levels:
Coming out of the dish,
Coming out of the multi-switch,
Cable lengths,
At the receiver,
Either in dBm or dBmV and SAT/TPs.

Sonora has a pdf that seems to show 25 dB is all the system loss there should be, and I'm wanting some "other" measurements to validate some of this pdf info.

"My system loss" is about 24 dB, but would bet there are [many] other systems out there with more loss.

Thanks for your time, if you can do this and post them. :)

give me a couple days and i'll get you some data on this when i'm out in the field.

[doctor j]

VOS:
I have a superbuddy and some time.
I unfortunately am not certain what you want measured, and why.
My regular setup is complex as per my sig. but can put up temp dish if needed.
??
Doctor j

[veryoldschool]

VOS:
I have a superbuddy and some time.
I unfortunately am not certain what you want measured, and why.
My regular setup is complex as per my sig. but can put up temp dish if needed.
??
Doctor j
I'm trying to validate a Sonora pdf.
Cable loss is basically a no brainner, and the LNB output "they say" is -30 dBm.
"They also say" the receiver needs -55 dBm input.
Zinwell doesn't spec the loss through their WB68.

I'm getting a feeling there are some systems out there that may have more rainfade than others due to overall system losses not being realized/addressed.
"Or" maybe Sonora is in the business of selling amps. :lol:

[MrShowtime]

The loss at the LNB that I normally see is -19 to -30 depending on the type of LNB and the manufacturer of the lnb. The best performing LNBs seem to be the WNC Slimline 3 LNBs where they max out right around -19 dbs of loss on the 101 sat. I have a system thats been up for over 3 years, 18" dish w/ 4x8. All parts original, never changed. My super buddy is in my room charging right now (and its dark out) but I'll see if I have time to get you some other numbers tomorrow, but here are the numbers @ the IRD in my room:

-40.4 DB
98% signal strength

Funny thing is I've never tested my system and DB loss is alot higher than I see on most customers houses I leave, but I very rarely lose signal due to rain.

[pressureman0]

I too have a super buddy but in Florida:(

[veryoldschool]

The loss at the LNB that I normally see is -19 to -30 depending on the type of LNB and the manufacturer of the lnb. The best performing LNBs seem to be the WNC Slimline 3 LNBs where they max out right around -19 dbs of loss on the 101 sat. I have a system thats been up for over 3 years, 18" dish w/ 4x8. All parts original, never changed. My super buddy is in my room charging right now (and its dark out) but I'll see if I have time to get you some other numbers tomorrow, but here are the numbers @ the IRD in my room:

-40.4 DB
98% signal strength

Funny thing is I've never tested my system and DB loss is alot higher than I see on most customers houses I leave, but I very rarely lose signal due to rain.
"dBs"?
can you relate that to either dBm or dBmV?

[MrShowtime]

sorry meant to type dBm

was a long day

[veryoldschool]

sorry meant to type dBm

was a long day
N/P, dBs wasn't something I knew.

-19 dBm, or 30 dBmV, or 90 dBuV, seems like a pretty "hot" LNB.

Sonora is using -30 dBm, 19 dBmV, 79 dBuV for their pdf.

Broadcom is listing their chip at -25 dBm to -75 dBm, so this "hot LNB" needs to have some cable loss to not overdrive the receiver.

Sure hope someone can measure the loss through a WB68.

[netraa]

prior to testing this, can someone throw up the list of spots on 101 real quick.

thanks!

[veryoldschool]

prior to testing this, can someone throw up the list of spots on 101 real quick.

thanks!
There was nothing "real quick" about this, but scanning through about half the locals & TP from here: http://www.dbstalk.com/showthread.php?t=166768
TP: 4,12,18,20,21,24,26,28,30,31 seems to be the spots.

[carl6]

The last list of spot beams I saw showed 4, 12, 18, 20, 26 and 28 for 101.
For 119 they should be 23, 25, 29 and 31.

[doctor j]

OK here's what a quick check found:
Measuring at 1) inside house 50 ft from AT-9 Dish(self installed late 10/2005 i might add) : 2) after PI-6S NAS power locker and 3-way Hi Freq splitter, just prior to WB68 : and 3) at WB68 output.
Measuring in -dBm by older SuperBuddy on A) 101 TP#1 ; B) 101 TP#2 ; C) 119 TP27 and D) SW-1 KA HI TP #1 i get:


A B C D
1) 29 28.2 23 21.5

2) 36.1 34.1 32 33.3

3) 37.5 36.8 32 33.6



Virtually no loss thru WB68
Not powered but almost unity with 8 way split says it has to be amping from line voltage.

Hope this helps

Doctor j

[veryoldschool]

Virtually no loss thru WB68
Not powered but almost unity with 8 way split says it has to be amping from line voltage.

Hope this helps

Doctor j
If it doesn't "help", it sure gives food for thought. :lol:
A & B show "some loss", where C & D show none.

"I wonder" if there would be a change in output of the WB68 as more receivers are switched/tuned to the same channel/TP?

[doctor j]

maybe some operator error? :lol:

With power locker and trying to match up odd/even/22hz lines some error's likely.
101 easiest to follow and suggests little loss by PI-6S, expected 6 or so dB loss of 3 way and only 1 or 2 dB loss by WB68.

Somewhere way back I think I reviewed the specs on the WB68 and remember "minimal loss".

Doctor j

[veryoldschool]

maybe some operator error? :lol:

With power locker and trying to match up odd/even/22hz lines some error's likely.
101 easiest to follow and suggests little loss by PI-6S, expected 6 or so dB loss of 3 way and only 1 or 2 dB loss by WB68.

Somewhere way back I think I reviewed the specs on the WB68 and remember "minimal loss".

Doctor j
It sure would be nice to get hold of those "specs". [just ask Zinwell for them]
How many milliamps do they draw [if they have an amp]?
Spaun spec's their gain, but Zinwell ?????
What we [I] don't know is whether they use a [8-way] splitter to feed the switches with an amp to offset the loss, or whether they "simply" switch the inputs to the outputs "as needed".

[AntAltMike]

Powered switches that I have previously checked were all virtual lossless, ranging from no more than 1dB of gain to no more than 2 dB of loss. Some unpowered 3x4 switches lost 4 to 5 dB, meaning they had a little Ku band amplification, whereas a few other unpowered ones were close to unity.

I used to use a lot of Holland 3x4 switches because the diplexed off-air signal path was unamplified, losing typically 12 to 14 dB. I liked it because it was most practical for me to manage that loss independently, without it contributing to intermodulation distortion in the Ku amplification.

In the late 1990s, hardware manufacturer's all used the same arbitrary receiver window margins of -30dBm to -60 dBm. Sonora tested a bunch of Sony receivers and found that there was no decrease in "signal strength" percentage numbers until the input level got down to -66 dBm. Remarkably, if a satellite signal gets down to -70 dBm or even a little lower, it can be restored to sufficiency by gently amplifying it just before it goes into the satellite receiver, indicating that the satellite receivers have really crappy noise figures.

The old LNB's specs all used to say "Gain: 50 to 62dB", but whenever I swapped from one to another, I never measured any variation in output level. I think that most of that documentation was just copied from other similar products, just as the antenna gain figures on most cheap mesh dishes is copied rather than measured.

[veryoldschool]

Sonora tested a bunch of Sony receivers and found that there was no decrease in "signal strength" percentage numbers until the input level got down to -66 dBm. Remarkably, if a satellite signal gets down to -70 dBm or even a little lower, it can be restored to sufficiency by gently amplifying it just before it goes into the satellite receiver, indicating that the satellite receivers have really crappy noise figures.
This seems to match with the Broadcom LNA chip on the input, with a -75 dBm minimum.
I'm not sure "the satellite receivers have really crappy noise figures", as noise figure is pretty much "nailed" by the NF of the first amp in the system.
http://www.microwaves101.com/encyclopedia/images/Noise%20figure/NF_equation1.jpg

[netraa]

ok, here we go.

all measurements are TP 1, 2, and 20(my LIL) on 101 and are in dBm
dish-slimeline with a 2 year old eagle aspen kaku5

2 feet from the dish
-27.0 -32.7 -24.5
50-60 feet of CCS rg6 quad 60% braid WB6X8 13 no tone lead with 1 inline blue f81
-29.0 -36.4 -26.7
behind the WB6X8
-31.7 -37.2 -29.6
another 60ish feet of CCS rg6 quad...... with 3 inline barrels (2 blue, 1 white) and 1 B-band converter
-37.2 -42.5 -27.9


Because the 18 with tone line was easier to access at first i measured off that one and got this... this would be pre-switch
-29.6 -36.6 -27.9

TP readings at IRD
95 95 100

[veryoldschool]

Thanks for the numbers.
Once Zinwell comes up with their specs, I hope to put together some "optimum" system losses.

[AntAltMike]

It might be more useful for people to sample transponers 1 and 32 because quality switches might have a little slope compensation in them.

[veryoldschool]

It might be more useful for people to samle transponers 1 and 32 because quality switches might have a little slope compensation in them.
Spaun & now Sonora offer slope compensation products.

[AntAltMike]

This seems to match with the Broadcom LNA chip on the input, with a -75 dBm minimum.
I'm not sure "the satellite receivers have really crappy noise figures", as noise figure is pretty much "nailed" by the NF of the first amp in the system.
http://www.microwaves101.com/encyclopedia/images/Noise%20figure/NF_equation1.jpg

But it only stays "nailed" as long as the level by the time it gets to the receiver is still well above the noise floor. The noise floor comes back into play at the receiver if the input and S/N ratio drop to near the receiver's published input threshold.

[veryoldschool]

But it only stays "nailed" as long as the level by the time it gets to the receiver is still well above the noise floor. The noise floor comes back into play at the receiver if the input and S/N ratio drop to near the receiver's published input threshold.
"True", my point was more that you can add amps downstream to overcome losses without adversely affecting the noise figure [and the receiver has a low noise amp on it's input].

[RobertE]

Only got two sets of readings. This is with 18" dish, Zinwell dual LNB. No switches involved. Approx 25 feet from dish to groundblock Reading 1 is right at LNB, reading 2 is at ground block

Transponder | RF Level dBuV | C/N dB | MER dB | QBER | VBER
DTV Ka/Ku&3G 101 | 76.2 | 12.6 | | 9.79E-05 | 0.00E+00
DTV Ka/Ku&3G 101 | 74.2 | 12.4 | | 2.03E-04 | 0.00E+00

RF is reported in dB micrvolts. :)

Didn't get a chance to take a reading inside, boss was being...well a boss. :p

[RobertE]

You'll find these a bit interesting. Zinwell dual LNB, 18" basic dish, Eagle Aspen 3.4 switch, lightly overcast. Cable mix of SCC & CCS. :grin:

Transponder | RF Level dBuV | C/N dB | QBER | Reading Location | Approx Cable Length
DTV Ka/Ku&3G 101 | 78.7 | 12.0 | 2.66E-04 | LNB | 0
DTV Ka/Ku&3G 101 | 76.8 | 11.8 | 4.01E-04 | Ground Block | 15
DTV Ka/Ku&3G 101 | 80.0 | 11.7 | 4.24E-04 | Switch | +1
DTV Ka/Ku&3G 101 | 76.2 | 11.0 | 7.15E-04 | Bedroom 1 | +25
DTV Ka/Ku&3G 101 | 71.4 | 11.7 | 4.28E-04 | Bedroom 2 | +60

It appears that even the basic 3x4 does a little amping.

[veryoldschool]

You'll find these a bit interesting. Zinwell dual LNB, 18" basic dish, Eagle Aspen 3.4 switch, lightly overcast. Cable mix of SCC & CCS. :grin:

Transponder | RF Level dBuV | C/N dB | QBER | Reading Location | Approx Cable Length
DTV Ka/Ku&3G 101 | 78.7 | 12.0 | 2.66E-04 | LNB | 0
DTV Ka/Ku&3G 101 | 76.8 | 11.8 | 4.01E-04 | Ground Block | 15
DTV Ka/Ku&3G 101 | 80.0 | 11.7 | 4.24E-04 | Switch | +1
DTV Ka/Ku&3G 101 | 76.2 | 11.0 | 7.15E-04 | Bedroom 1 | +25
DTV Ka/Ku&3G 101 | 71.4 | 11.7 | 4.28E-04 | Bedroom 2 | +60

It appears that even the basic 3x4 does a little amping.
C/N is becoming [to me] even more interesting. 12.0/11.8/11.7 shows "nominal" [to be expected] drops, but Bedroom 1 with 11.0 has more noise on that line, where bedroom 2 looks to have no added noise and simply a drop in overall power.

[AntAltMike]

It appears that even the basic 3x4 does a little amping.

It would have to do at least 10 dB of amping just to make up for the internal, 4-way splitter and diplexer losses.

[AntAltMike]

C/N is becoming [to me] even more interesting. 12.0/11.8/11.7 shows "nominal" [to be expected] drops, but Bedroom 1 with 11.0 has more noise on that line, where bedroom 2 looks to have no added noise and simply a drop in overall power.

I take decimal differential broadcast signal field strength readings with a grain of salt. These readings were taken at different times when the sky was "overcast", and the bedroom measurements are being taken from two different multiswitch ports.

I remember that Sonora claimed that the DBS receivers needed an S/N ratio of 8dB to reliably lock. That was back in the day of QPSK and MPEG2. Are they now on 8PSK for the Ka band? If so, that alone would warrant a higher S/N threshold.