Is it posiible to increase LNB voltage, specifically the 18V? They state more than 19V outpout without load for H polarization however I only measure approx. 18.4 with or without LNB connected. This is a bit too low in my case and H palarization doesn't kick on, possibly because of long cable. Tried with an external supply and H works perfectly with 20V. BH image 2.0.6.3. There is an Increase Voltage option in the LNB menu but it changes nothing.
LNB voltage
- Thread starter cipsas
- Start date
Eragon
Vu+ User+++
LNB specifications state that polarization voltages are 13V and 18V, so your box is perfectly working.
What is probably defective is your cables or your LNB, so check the cabling and eventually replace the LNB.
There is nothing else to do within the box if the increase option (if available) can't help..
http://en.wikipedia.org/wiki/Low-noise_block_downconverter
What is probably defective is your cables or your LNB, so check the cabling and eventually replace the LNB.
There is nothing else to do within the box if the increase option (if available) can't help..
http://en.wikipedia.org/wiki/Low-noise_block_downconverter
Sure the box is OK. However the LNB has worked perfectly with all my previous receivers, it also works with higher voltage now, so it should be OK too. Most probably it's the long cable... Checking the voltage at LNB side is a bit troublesome at this moment as it's nasty weather and also weat snow on the roof 
That's why I am looking for some solution within the receiver, some SW setting, script or possibly a HW jumper on the PCB inside.
That's why I am looking for some solution within the receiver, some SW setting, script or possibly a HW jumper on the PCB inside.
el bandido
Vu+ User
Howe long is the cable? What is the size of the cable? What is the make and model of the lnb? Are any other receivers connected to the lnb?
Are any switches, ground blocks, or anything else installed between the receiver and the lnb?
Are any switches, ground blocks, or anything else installed between the receiver and the lnb?
It's some 50 meters of RG6U, I haven't measured, not the best quality available. No other devices in the path. Weather permitting I will try to check what do I have at the LNB side. Anyway, I understand voltage drops / loads etc. myself. The only thing that I am searching for here is the possibility to adjust the H voltage within the receiver in order to avoid HW changes which are costly and time consuming.
Can anyone comment how shall the setting "Increase Voltage" in the LNB menu work? Currently I see no effect on the LNB voltage whatsoever. Is it something else? Shall it work at all with BH image?
Can anyone comment how shall the setting "Increase Voltage" in the LNB menu work? Currently I see no effect on the LNB voltage whatsoever. Is it something else? Shall it work at all with BH image?
el bandido
Vu+ User
My understanding of the "increase Voltage" setting only allows a motor to operate at 18 volts when moving between satellites. I do not use this setting and it should not have any positive effect on H V lnb switching.
How many receivers are connected to this lnb? What is the make/model of the lnb? How old is the lnb?
50 Meters of RG6 should not cause H V switching problems because most lnbs will easily switch between voltage controlled polarities with 80 meters of RG6 between the lnb and receiver.
The specs on most lnbs show that only 16 volts is needed to switch between polarities.
Control Signal Ca (Vertical Polarization) 11.0 ~ 14.0 V
Control Signal Cb (Horizontal Polarization) 16.0 ~ 20.0 V
How many receivers are connected to this lnb? What is the make/model of the lnb? How old is the lnb?
50 Meters of RG6 should not cause H V switching problems because most lnbs will easily switch between voltage controlled polarities with 80 meters of RG6 between the lnb and receiver.
The specs on most lnbs show that only 16 volts is needed to switch between polarities.
Control Signal Ca (Vertical Polarization) 11.0 ~ 14.0 V
Control Signal Cb (Horizontal Polarization) 16.0 ~ 20.0 V
Just a single receiver is connected.
The LNB is quite old, but so what? I can't fetch the make unless I get to the roof... Anyway, I have already checked (using an old analog receiver with a possibility to adjust LNB voltage) that the LNB works OK with a bit higher H voltage (18V was too little and 20V was OK, couldn't check in between as this was the step). So it's only voltage that I need. Alternatively I have to look for an LNB with a flange which is not so easy to get (I guess not so cheap neither) as I've got a parabolic antenna, not offset.
The LNB is quite old, but so what? I can't fetch the make unless I get to the roof... Anyway, I have already checked (using an old analog receiver with a possibility to adjust LNB voltage) that the LNB works OK with a bit higher H voltage (18V was too little and 20V was OK, couldn't check in between as this was the step). So it's only voltage that I need. Alternatively I have to look for an LNB with a flange which is not so easy to get (I guess not so cheap neither) as I've got a parabolic antenna, not offset.
el bandido
Vu+ User
Flange lnbs are available. I have two that are about two years old. One of these lnbs is on an offset dish, while the other is on a prime focus. These two lnbs have the C120 flange type which is pretty common.
Lnbs can deteriorate with age. The same could be said with the cable feeding the lnb. My guess would be that you will need to replace the lnb or possibly the cable. It would be wonderful to check the voltage at the dish, but I understand that is not really an option right now. Also, I would expect you to have over 16 volts DC at the lnb using 50 meters of RG6. However, we do not know what the exact voltage switching requirements are supposed to be for your lnb.
As for the receiver itself, I do not know how to increase the Horizontal voltage unless you made adjustments or modifications to the power supply in the receiver.
Lnbs can deteriorate with age. The same could be said with the cable feeding the lnb. My guess would be that you will need to replace the lnb or possibly the cable. It would be wonderful to check the voltage at the dish, but I understand that is not really an option right now. Also, I would expect you to have over 16 volts DC at the lnb using 50 meters of RG6. However, we do not know what the exact voltage switching requirements are supposed to be for your lnb.
As for the receiver itself, I do not know how to increase the Horizontal voltage unless you made adjustments or modifications to the power supply in the receiver.
OK, figured it out finally 
There was a piece (a couple of meters) of extension cable connected at the LNB side. It appears that this specific piece was not weather-proof. That is, the entire central wire (steel galvanized with copper) was black, and that was the reason of too much voltage drop. I cut it in several places, and it was the same everywhere. Initially I thought that it was just moisture inside the connectors but apparently is was not; the remaining cable is nice and shiny. Throughing that bad piece out solved everything. Hope this info might help others sometime.
Thanks everyone who replied.
There was a piece (a couple of meters) of extension cable connected at the LNB side. It appears that this specific piece was not weather-proof. That is, the entire central wire (steel galvanized with copper) was black, and that was the reason of too much voltage drop. I cut it in several places, and it was the same everywhere. Initially I thought that it was just moisture inside the connectors but apparently is was not; the remaining cable is nice and shiny. Throughing that bad piece out solved everything. Hope this info might help others sometime.
Thanks everyone who replied.