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Thread: Basic FTA Amplifier Questions

  1. #1
    Senior Member RHCP's Avatar
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    Default Basic FTA Amplifier Questions

    My father wants to add FTA to an additional room at his property for a total of 3 TVs. An RG11 cable is already present from an old sat install. As it stands now, there is 2-way splitter/booster (distribution amp) in use. I can't provide specifics on it, as he lives a few hours away.
    The FTA channels are all in the UHF band ~600 MHz.

    I was planning on replacing the current 2-way splitter/amplifier with either:

    1. . One in One amplifier + 3 way passive splitter
    2. (with unused leg terminated)


    Questions:
    1. With regards to option 1, am I correct in assuming that this can be adjusted to provide between 10 - 20 dB UHF gain? And therefore assuming a 6.5 DB loss on the 3-way splitter, each splitter output leg will have a net gain of 3.5 to 13.5 dB (depending on the gain adjustment of the amp)? Hence this will allow me to tune the gain as required.
    2. With Option 2, the splitter has gain of 16 dB. Does this means that each output leg will have a +4 dB gain?

    Many thanks, RHCP.
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  • #2
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    I appreciate you don't have details of the existing amp/setup, but I'm sure you'll appreciate I can't give you a definitive answer without more info.

    I'm not familiar with the KDA20 amp, but the specs suggest it has a variable output.

    It's wideband, so the specified gain figures are a guide only, as it's likely gain is different at different frequencies, but yes, typically from 10-20dB gain.

    Of the two options, that would be my pick, with a 3-way passive splitter. Naturally, signal at the amp input, length and type of cable to the 3 outlets will vary the result.

    Depending on how much signal output there is on the existing 2-outlet amp, just adding a passive 2-way splitter to one leg may be sufficient, especially with RG11 cable.

    Personally, I would go with a UHF-only 20dB distribution amp at the antenna and use a 3-way splitter.

    That way, you are rejecting unwanted signals which can interfere/reduce signal performance because wideband amps have to be de-rated as they amplify everything in the bands they cover.

    Option 2 powered splitter has higher UHF gain then VHF, but from memory, they have a high noise level, which isn't provided in the specs.

    It basically will provide a slight boost to each leg to compensate for the insertion loss.

    Again, without accurate signal measurements, it's a very general suggestion.

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    Any update on this?

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    I'm unsure of the specifics of your setup, suburb, signal level and quality.

    Yes you can use the SA164F if you prefer, it might appear you have the 2 output version currently there from what you are saying.

    In regards to your questions. If you are using a passive splitter (e.g not one with an amplifier in it), the legs always have a loss. That loss does not change regardless if you use an amp or not strictly speaking, the incoming signal to that splitter varies depending on which amp is used before it, it's gain setting etc. As an example you can increase the signal level by raising the antenna higher, the passive splitter still has the same loss through it

    I can only speak for the SA162F (two output), which I have tested has a 15db gain on VHF (Tested on 226.50mhz) at the output, and 17db on UHF (Tested on 683.50mhz).
    So I would assume the 4 way version has similar figures when the gain knob is turned up all the way, something which the twin output version doesn't have
    Last edited by Z2TT; 29-11-20 at 04:05 AM.

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    In regards to option two, the stated gain of 16db would be for all legs, not 4db for each leg. I'm wondering why there is existing RG11 cable, is it a really long run?

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    OP was in June of this year, so it's probably been sorted by now.
    Never stand under a shadow that's getting bigger

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