TIP: How to increase the voltage to the OTA antenna

[Ilya]

I've found an easy way to increase the voltage supplied by the STB to the built-in signal amplifier in your OTA antenna from 13 to 18 Volts.

If you have an amplified OTA antenna (like Winegard Sensar II S2000A) that takes power from the VOOM STB via diplexer, and if you have reasons to believe that the amplifier does not get sufficient voltage (e.g. due to excessive voltage loss in a very long cable run), you can try the following trick:

1. Switch your STB to channel 261 or 301.
2. Switch to one of the OTA channels by directly entering the channel number on the remote (do not use ChUp/Down buttons).​

This increases the voltage supplied by the STB from 13 Volts to 18 Volts! You can now use ChUp/Down button to switch between OTA channels, just don't switch to any satellite channel, or the voltage will drop back to 13 Volts.

Explanation.

Amplified OTA antennas require a source of power. For example, amplified Winegard Sensar II (S2000A) requires 12-18 Volts for its built-in amplifier. This voltage is normally delivered over the coax cable itself, so no additional wiring is required.

If you have a separate coax cable going from the antenna to the STB (no diplexers), you must use an additional power source, like Winegard's recommended PS-9370 (an 18-Volt power supply). The above trick does not apply in this case.

If you are using diplexers to combine OTA and satellite cables into a single coax cable, the antenna will share the power supplied by the STB to the LNB module in your dish. The voltage supplied to the LNB depends on the polarity of the satellite channel. Most channels on VOOM use "Right_Ve" polarity, so the STB sends 13 Volts in most cases. Some channels (e.g. 261, 301) use "Left_Horiz" polarity and the STB sends 18 Volts for those channels.

When you switch from one of those 18-Volt channels to an OTA channel, the STB continues sending 18 Volts (I have verified that with a voltmeter).

Under normal conditions the difference between 13 Volts and 18 Volts should not affect the OTA amplifier as it is designed to work with this voltage range. However, a long cable run (above 100-200 feet), old cables and other factors may cause an excessive voltage loss, so the effective voltage at the OTA antenna may be much less than the expected 12-13 Volts. In such cases the above procedure of boosting the STB-supplied voltage from 13 to 18 Volts could come helpful. Perhaps, not as a permanent solution, but as a trouble-shooting tip.

 

[occammd]

Great INFO!

So if you get to the OTA channel by using the channel up/down you still get 13? Are they fixing this in the firmware?

 

[Ilya]

So if you get to the OTA channel by using the channel up/down you still get 13?

Yes. I believe it all depends on the last satellite channel you tune to. So, if you get to the OTA range by doing ChDown, the last satellite channel you pass is 100 (a 13-Volt channel).

 

[sat4me]

I've found an easy way to increase the voltage supplied by the STB to the built-in signal amplifier in your OTA antenna from 13 to 18 Volts.

If you have an amplified OTA antenna (like Winegard Sensar II S2000A) that takes power from the VOOM STB via diplexer, and if you have reasons to believe that the amplifier does not get sufficient voltage (e.g. due to excessive voltage loss in a very long cable run), you can try the following trick:

1. Switch your STB to channel 261 or 301.
2. Switch to one of the OTA channels by directly entering the channel number on the remote (do not use ChUp/Down buttons).​

This increases the voltage supplied by the STB from 13 Volts to 18 Volts! You can now use ChUp/Down button to switch between OTA channels, just don't switch to any satellite channel, or the voltage will drop back to 13 Volts.

Explanation.

Amplified OTA antennas require a source of power. For example, amplified Winegard Sensar II (S2000A) requires 12-18 Volts for its built-in amplifier. This voltage is normally delivered over the coax cable itself, so no additional wiring is required.

If you have a separate coax cable going from the antenna to the STB (no diplexers), you must use an additional power source, like Winegard's recommended PS-9370 (an 18-Volt power supply). The above trick does not apply in this case.

If you are using diplexers to combine OTA and satellite cables into a single coax cable, the antenna will share the power supplied by the STB to the LNB module in your dish. The voltage supplied to the LNB depends on the polarity of the satellite channel. Most channels on VOOM use "Right_Ve" polarity, so the STB sends 13 Volts in most cases. Some channels (e.g. 261, 301) use "Left_Horiz" polarity and the STB sends 18 Volts for those channels.

When you switch from one of those 18-Volt channels to an OTA channel, the STB continues sending 18 Volts (I have verified that with a voltmeter).

Under normal conditions the difference between 13 Volts and 18 Volts should not affect the OTA amplifier as it is designed to work with this voltage range. However, a long cable run (above 100-200 feet), old cables and other factors may cause an excessive voltage loss, so the effective voltage at the OTA antenna may be much less than the expected 12-13 Volts. In such cases the above procedure of boosting the STB-supplied voltage from 13 to 18 Volts could come helpful. Perhaps, not as a permanent solution, but as a trouble-shooting tip.

Iyla,
Your post is totally correct. However, what did you actually gain by doing this? Did more channels appear? Did the signal of the OTA jump?

I'm not being contradictory, just not sure what the logic is, other than on excessive long runs and other conditions you mention that can affect the voltage drop off.

In theory, if you have that much voltage line loss, that also will affect the LNB and it's switching of the 13v polarization. Are you having that problem as well?

If you're having voltage drop of that affects your LNB and OTA power, then the "cure" is to install a LNB power supply/inserter (not and in-line amp, those will do nothing for voltage).
If the length of cable run exceeds 200+ feet then this MAY be necessary.

Just curious as to what you found with your "trick". I've never tried it myself so I'm no expert as to what it may actually improve.

Thanks for the post, very interesting

 

[Ilya]

Are you having that problem as well?

No, I am not having any problems. I am not using diplexers in my setup, so this doesn't apply to me at all. Just wanted to share this new information with others, perhaps someone will find it helpful...

 

[Ricknau]

Ilya,

What a great forum! This is my first post. I have a couple of questions regarding using OTA amplifiers.

I have a Radio Shack amp which consists of a pre-amp up the mast that drives another amp down below. The lower amp supplies the DC power for the upper pre-amp. The lower amp output normally would go directly to the TV. But the installer has it routed up to the Voom dish where it combines with the sat signal and comes into the STB via a single coax. If I read your post correctly this means the second stage of my amplification is having 13-18 volts DC driven into its output. This can't be good.

I need to connect my amplified antenna to the STB without going through the diplexor but I don't see any other input on the back of the STB for an OTA. The coax from the dish connects through what looks like a "snap-on" module. Is the OTA connection behind that?

Another option for me might be to eliminate the second stage amplifier and let the diplexor feed power to the pre-amp. The pre-amp has 10-15db gain and I've wondered if this might not be enough to feed the TV. One less stage of amplification is one less stage of possible distortion. I do have "issues" with bringing in a few OTA stations where it seems like it got better when I turned the gain down on the second stage.

Does bypassing the diplexor affect the interaction with the OTA, like the viewing signal strength, seeing OTA program info, etc?

Any enlightenment would be appreciated.

 

[Ilya]

I need to connect my amplified antenna to the STB without going through the diplexor but I don't see any other input on the back of the STB for an OTA. The coax from the dish connects through what looks like a "snap-on" module. Is the OTA connection behind that?

Yes, just unlock it first (rotate the plastic pin to the unlock position)) and then remove it.

Another option for me might be to eliminate the second stage amplifier...

Are you sure it is a second stage amplifier? Could be just a power inserter.

Does bypassing the diplexor affect the interaction with the OTA, like the viewing signal strength, seeing OTA program info, etc?

Not at all!

Welcome to the forum!

 

[Ricknau]

You won't beleive what just happened! Within one minute of my clicking "submit reply" my door bell rang. It was a Voom technician saying he was responding to a service call at my address! These Voom guys are fantastic. They respond with tech support before you even ask!

Actually he was responding to an old call that was already taken care of. They just didn't log it as completed. But... since he was here I pinged him with my questions. He showed me how the module comes off the back to reveal two F connectors. The OTA connector under the cover supplies the DC power. The other antenna F connector on the back (not covered by snap-on mudule) is for analog OTA and doesn't supply DC volts.

So this give me some things to play with.

Yes, I'm sure of the 2 stage scheme. Each supplies gain with the second stage being variable ( approx 5 -15 db) via a pot.

Thanks for the quick reply.

 

[Ricknau]

Ilya,

Actually, as I ponder what that technician said I realize that it conflicts with what you are saying. (Or maybe I misunderstood him.) I thought he said the DC volts comes out of the OTA F connector (under the snap-on diplexor) that looks for a DTV signal. I think you are saying that this connector does not supply DC volts, that the DC comes out of the SAT F connector under the snap-on. I'm going to go with your assesment. You say you measured it. These technicians, though most are fairly knowledgeable in basic electroncs, work on so many different things that it can be real hard to know the intimate details about all the things they encounter in a day. Especially Voom stuff because it is so new to them.

 

[Ilya]

Ilya,

Actually, as I ponder what that technician said I realize that it conflicts with what you are saying. (Or maybe I misunderstood him.) I thought he said the DC volts comes out of the OTA F connector (under the snap-on diplexor)

I don't think this is the case, but I will double-check when I get home. If you have a volt-meter around you can check for yourself.

 

[SeattleGuy]

I'm having VOOM installed on Saturday (8/14) and want the OTA antenna to have a separate cable run to the STB. Since it won't be on a diplexor, I'll need to buy a separate power inserter to drive the OTA antenna that VOOM supplies- right?

Does Radio Shack sell something similar to the Winegard PS-9370 described earlier in these posts? I looked at the RS on-line catalog and only found "matched sets" of an antenna-mounted pre-amp together with an indoor amplifier. Would one of these work?

 

[Ilya]

I'm having VOOM installed on Saturday (8/14) and want the OTA antenna to have a separate cable run to the STB. Since it won't be on a diplexor, I'll need to buy a separate power inserter to drive the OTA antenna that VOOM supplies- right?

Does Radio Shack sell something similar to the Winegard PS-9370 described earlier in these posts? I looked at the RS on-line catalog and only found "matched sets" of an antenna-mounted pre-amp together with an indoor amplifier. Would one of these work?

It all depends on what kind of antenna they will provide. VOOM supplies several types of OTA antennas. Some of them come with power supplies/inserters, some don't. Talk to your installer about that.

Welcome to the forum, SeattleGuy!

 

[SeattleGuy]

I'd love to talk to my installer about the OTA antenna and other issues related to the upcoming install, but he/she/they won't return my calls. I saw somewhere else on this forum that the Stealth antennas came with a power inserter, but the Winegard did not. Guess I just have to be surprised by what appears on Saturday! ... and then hope that, if an amplifier is needed, I can rush over to Radio Shack and get the part while the installer is on site.

Based on several comments I've seen in the VOOM forums, I concluded that it was best to avoid the diplexor connection. Or should I just go with whatever the standard installation is, and then deal with any problems that may arise later?

 

[Ilya]

I'd love to talk to my installer about the OTA antenna and other issues related to the upcoming install, but he/she/they won't return my calls.

If they don't return your calls there is no guarantee that they will show up. I would keep calling!

I saw somewhere else on this forum that the Stealth antennas came with a power inserter, but the Winegard did not.

Correct. But there are other brands too.

Based on several comments I've seen in the VOOM forums, I concluded that it was best to avoid the diplexor connection. Or should I just go with whatever the standard installation is, and then deal with any problems that may arise later?

It depends. In some cases, running a separate OTA cable can make things easier to troubleshoot, and, at least in certain cases, may potentially improve your reception. But then again, there is an issue with the power supply, and an extra cable run to deal with. Most likely, either way will be fine as long as the installer knows what he is doing. If you leave it up to the installer, at least he won't have an excuse to blame any problems on your non-standard installation request.

 

[Ilya]

...he said the DC volts comes out of the OTA F connector (under the snap-on diplexor) that looks for a DTV signal. I think you are saying that this connector does not supply DC volts, that the DC comes out of the SAT F connector under the snap-on.

I checked the voltage again. I can confirm that there is no voltage supplied by the OTA input on the STB. Only the SAT input supplies the voltage. It is used by the LNB and with a diplexer installed, can also be shared by the antenna pre-amp in some cases.

 

[lakewoodvoomer]

Amplifying OTA signal

Ilya,

Would the "voltage increase" trick allow me to amplify certain low OTA signals that produce a pixelated picture? I receive most of the OTA signals just fine. However, I have had pixelation issues with the Public TV station here in Dallas for the last 2 weeks.

If the above won't work, what should I try?

 

[Ilya]

Probably not (though it's easy enough to try). The "voltage increase" can only help if you are not getting sufficient voltage (due to a long cable run to the antenna, etc.) Increasing the voltage to the pre-amp will not increase amplification: most of the pre-amps have voltage stabilization, so extra few volts won't matter: the pre-amp either works or it doesn't.

Maybe you should try rotating your antenna?

 

[lakewoodvoomer]

Thanks, Ilya. I am afraid to move the antenna in case I lose the remaining OTAs, which I have no problem with.