Unicable LNB and inline amplifier.

[goral]

Hi.
Can I use inline amplifier with Unicable LNB?
I have more then 30 meters cable with Unicable LNB. I try boost my signal, and connect inline amplifier around 1 meter from LNB. But no success.
Signal stay same. No improvement not worse signal.
Also can anybody recommend inline amplifier, from own expirence?
Thanks.

[adm]

Hi.
Can I use inline amplifier with Unicable LNB?
I have more then 30 meters cable with Unicable LNB. I try boost my signal, and connect inline amplifier around 1 meter from LNB. But no success.
Signal stay same. No improvement not worse signal.
Also can anybody recommend inline amplifier, from own expirence?
Thanks.

What do you mean by the signal staying the same? How are you measuring it?
Have you got a meter suitable of measuring signal strength for a unicable LNB?

30 metres of good quality WF100 or WF125 should only give an attenuation of 7 to 8.5dB towards the higher frequencies.


What is the problem you are trying to solve?

[goral]

What do you mean by the signal staying the same? How are you measuring it?
Have you got a meter suitable of measuring signal strength for a unicable LNB?

30 metres of good quality WF100 or WF125 should only give an attenuation of 7 to 8.5dB towards the higher frequencies.


What is the problem you are trying to solve?

Hi. Thanks for reply!
I use signal meter in box (VU+ Uno 4k SE) and I look for SNR and dB.
Cable is RG6 (JCRG6100MBLB) Cable lenght from LNB to receiver is roughly no more then 35 meters (more like 30-32).
I have also 90cm dish and Inverto IDLB-QUDL42-UNI2L-1PP LNB.
And on 13e transponder 11258 pol. H I can't get more then SNR 60%; ~9 dB
same satellite 13e transponder 10911 pol. V I can't get more then SNR 70%; 11 dB
13 e transponder 12284 pol. H maks. SNR 73%; ~12 dB

So, I just get inline amplifier and connect around 1 meter from LNB - no effect, nothing, no boost, no worst. It looks like will be nothing between LNB and receiver.
I try boost signal at least to 13-14 dB.
So, inline amplifier will working with unicable LNB?

[ronand]

RG6 is barely sufficient for short runs. Replace it with decent coax as previously advised.

[Joe_90]

A bigger dish will get you better SNR. RG6 can be pretty crap depending on supplier (usually aluminium core/braid with a light coating of copper).

[Huevos]

So, I just get inline amplifier and connect around 1 meter from LNB - no effect, nothing, no boost, no worst. It looks like will be nothing between LNB and receiver.
I try boost signal at least to 13-14 dB.
So, inline amplifier will working with unicable LNB?

So an inline amp boosts the signal and boosts the noise.

So if you start with 40 dB of signal at the receiver and 32 dB of noise, the SNR at the receiver will be 8 dB.

Now add 14 dB with the amp...

Now you will have 54 dB signal and 46 dB of noise, giving an SNR of 8dB.

This is why you are seeing no difference.

The only time a booster will help is if signal at the receiver is less than about 30dB.

And to be of maximum benefit the booster must be exactly at the halfway point along the cable.

But anyway, for any decent regular satellite cable a 30m run is nothing.

Most likely if you test directly at the LNB the SNR will be the same as over the 30m run.

[adm]

Hi. Thanks for reply!
I use signal meter in box (VU+ Uno 4k SE) and I look for SNR and dB.

SNR = Signal to noise ratio. The level of the signal above noise. If you put an amplifier in the line you amplify the signal AND you amplify the noise by the same amount. The SNR value therefore stays the same. In real life the amplifier may/will add a bit of noise of its own and the SNR value may actually fall but in most cases not be enough to bother about.

What you may/should see is a difference in the AGC (Automatic Gain Control) figure. Higher level of input signal = lower value of AGC.

Cable is RG6 (JCRG6100MBLB) Cable lenght from LNB to receiver is roughly no more then 35 meters (more like 30-32).

Do you have the specification sheet for that cable? Some RG6 is specified for satellite use and has the same attenuation as CT/WF100 type cable, some RG6 is only specified for use up to 1GHz with poor attenuation figures to match and some RG6 cable falls in the middle of these two.

I have also 90cm dish and Inverto IDLB-QUDL42-UNI2L-1PP LNB.
And on 13e transponder 11258 pol. H I can't get more then SNR 60%; ~9 dB
same satellite 13e transponder 10911 pol. V I can't get more then SNR 70%; 11 dB
13 e transponder 12284 pol. H maks. SNR 73%; ~12 dB

Are you comparing like with like by using the same single tuner or are these readings from different tuners.

Again, you are looking at the signal to noise value and not the signal level value.

So, I just get inline amplifier and connect around 1 meter from LNB - no effect, nothing, no boost, no worst. It looks like will be nothing between LNB and receiver.
I try boost signal at least to 13-14 dB.
So, inline amplifier will working with unicable LNB?

Your amplifier may be working - you may/are interpreting the results incorrectly.

A poor SNR may indicate that the dish is not aligned correctly.

Going back to one of my original questions what really is the problem?
No reception from some satellites?
Picture breakup?
Something else?

[goral]

SNR = Signal to noise ratio. The level of the signal above noise. If you put an amplifier in the line you amplify the signal AND you amplify the noise by the same amount. The SNR value therefore stays the same. In real life the amplifier may/will add a bit of noise of its own and the SNR value may actually fall but in most cases not be enough to bother about.

What you may/should see is a difference in the AGC (Automatic Gain Control) figure. Higher level of input signal = lower value of AGC.

I don't get it, so bigger number in % worst signal?
If I have on Astra1 19e, transponder 11913 H. SNR: 88%, dB: 14.20, ACG: 93%, but on HotBird 13e, transponder 11158 V. SNR 67%, dB: ~10, ACG: 89%
So different between 19e and 13e is just 4% but 19e is on 80cm dish and 13e 90cm dish. But in bad weather I have problem with reception from 13e not from 19e.

Do you have the specification sheet for that cable? Some RG6 is specified for satellite use and has the same attenuation as CT/WF100 type cable, some RG6 is only specified for use up to 1GHz with poor attenuation figures to match and some RG6 cable falls in the middle of these two.

On the label: RG6UCCA

Are you comparing like with like by using the same single tuner or are these readings from different tuners.

No, Is same tuner.

Again, you are looking at the signal to noise value and not the signal level value.

So, where I can find signal value?

Your amplifier may be working - you may/are interpreting the results incorrectly.

How can I reed results correctly?

A poor SNR may indicate that the dish is not aligned correctly.

Going back to one of my original questions what really is the problem?
No reception from some satellites?
Picture breakup?
Something else?

In bad weather condition (heavy cloud) Is no reception from some channels, also picture is breakup.
I position the antenna as accurately as I can.
And I cant get better readings. Moving vertically I loos signal so is in middle of the strongest signal, then horizontal same as vertically.

Maybe is something wit satellite dish? Like LNB is not aimed exactly at the center of the antenna - I don't know. I just end of ideas.
When I use WS-6933 sat meter, reading are even worst on meter. But they same on LNB and on other end of cable 35m long.

[Huevos]

I don't get it, so bigger number in % worst signal?
If I have on Astra1 19e, transponder 11913 H. SNR: 88%, dB: 14.20, ACG: 93%, but on HotBird 13e, transponder 11158 V. SNR 67%, dB: ~10, ACG: 89%
So different between 19e and 13e is just 4% but 19e is on 80cm dish and 13e 90cm dish. But in bad weather I have problem with reception from 13e not from 19e.

You are not taking the modulation or error correction into account.

11913 H on 19.2E requires an SNR greater than 6.4 dB for the picture to show.
11158 V on 13.0E requires an SNR greater than 7.9 dB.

[Joe_90]

I don't get it, so bigger number in % worst signal?
If I have on Astra1 19e, transponder 11913 H. SNR: 88%, dB: 14.20, ACG: 93%, but on HotBird 13e, transponder 11158 V. SNR 67%, dB: ~10, ACG: 89%
So different between 19e and 13e is just 4% but 19e is on 80cm dish and 13e 90cm dish. But in bad weather I have problem with reception from 13e not from 19e.

Where are you getting your figure of 4% difference between 19E and 13E? If you compare 10dB SNR with 14dB SNR, then that is more than twice. A 3dB difference is exactly twice as "good" (dB is a logarithmic scale). If you are getting worse reception on 13E than on 19E, then it is because either the signal from the transponder is weaker or your dish is not pointing properly at 13E. An amplifier (booster) will only help if the cable is causing degradation of the signal between the LNB and the receiver. If the SNR is bad at the LNB, then a booster will not improve matters. You need a bigger dish or better pointing at the satellite.

[goral]

You are not taking the modulation or error correction into account.

11913 H on 19.2E requires an SNR greater than 6.4 dB for the picture to show.
11158 V on 13.0E requires an SNR greater than 7.9 dB.

Where you get this data?

[goral]

Where are you getting your figure of 4% difference between 19E and 13E?

ACG at 19e 93%
ACG at 13e 89%

If you compare 10dB SNR with 14dB SNR, then that is more than twice. A 3dB difference is exactly twice as "good" (dB is a logarithmic scale). If you are getting worse reception on 13E than on 19E, then it is because either the signal from the transponder is weaker or your dish is not pointing properly at 13E. An amplifier (booster) will only help if the cable is causing degradation of the signal between the LNB and the receiver. If the SNR is bad at the LNB, then a booster will not improve matters. You need a bigger dish or better pointing at the satellite.

I know dB is logarithmic, but [%] is linear.

[adm]

Where are you getting your figure of 4% difference between 19E and 13E? If you compare 10dB SNR with 14dB SNR, then that is more than twice. A 3dB difference is exactly twice as "good" (dB is a logarithmic scale). If you are getting worse reception on 13E than on 19E, then it is because either the signal from the transponder is weaker or your dish is not pointing properly at 13E. An amplifier (booster) will only help if the cable is causing degradation of the signal between the LNB and the receiver. If the SNR is bad at the LNB, then a booster will not improve matters. You need a bigger dish or better pointing at the satellite.

goral has already said that using the same test equipment the SNR at the output of the LNB is exactly the same as the SNR figure at the end of his 32 metres of cable. If the SNR ratio is inadequate for reliable reception then probably nothing done after the LNB will improve it. What he hasn't said is did the amplifier make any difference to his reception or did he erroneously assume that because the SNR ratio didn't change that the amplifier wasn't working.

While not the best cable in the world RG6U should be more than adequate being specified to >2.2GHz. The problem is unlikely to be the cable.

A question for goral - what are the BER figures during good and bad weather for the problem satellites/transponders.

[Huevos]

Where you get this data?

It is right there on the infobar. One is QPSK. The other is 8PSK.

[adm]

ACG at 19e 93%
ACG at 13e 89%



I know dB is logarithmic, but [%] is linear.

Don't get too hung up on AGC figures. they are likely to be arbitrary values referenced to no common standard and may be different for different tuners and different boxes.