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RF Modulator

Discussion in 'Miscellaneous Equipment' started by jimstick, Nov 4, 2010.

  1. Nov 4, 2010 #1 of 15
    jimstick

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    I had a Directv R10 hooked up through a splitter to two older SD tv's via RF. The picture quality was quite acceptable to me on both. I decided to upgrade the R10 to a HR20-700, which does not have RF output, so I bought an RF modulator and hooked it up to both TV's. The picture quality is now considerably worse on both TV's. I can hook one up to composite, and it's fine, but the other is in the bedroom 30' away. I tried checking all the connections, and even took the RF modulator back and bought another, and it's the same. It is a cheap phillips brand. I tried two different models of the same brand. Do you get what you pay for with these things, or am I expecting to much?
     
  2. Nov 4, 2010 #2 of 15
    fluffybear

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    Peachtree...
    The RF signal coming off many modulators was not designed to be split. You could try adding a distribution amp in the mix and see if that fixes things or maybe look at adding a second RF modulator (using the second set of composite outputs) specifically for the other TV.
    I had a similar set-up several years back and it did not matter if I was using a cheap $19.95 RF Modulator or $299 one.
     
  3. Nov 4, 2010 #3 of 15
    BattleZone

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    Those cheap "DVD" modulators have a very low signal output, as they are designed to feed a single TV with a very short run of cable. You do indeed need a small amp (5-7 db or so) to solve the problem.
     
  4. Nov 5, 2010 #4 of 15
    jimstick

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    Even with only one TV hooked up it is still not very good. It doesn't really seem much different than two. If I run it to the TV next to it, I get wavy lines in the picture, if I run it to the bedroom, there is some snow in the picture, but it is a long run of cable to there. I tried switching outputs from the HR20, and using another cable (composite and coax). Both modulators I tried had the same wavy lines and snowy picture. I will try an amp and see if that helps. Thanks.
     
  5. Nov 5, 2010 #5 of 15
    fluffybear

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    Peachtree...
    Do you have a gain adjustment on your modulator? If so, try adjusting it and see if your picture improves.

    Can you adjust the channel which the modulator outputs on? If so, you will want to find a channel where there is at least 2 or 3 channel separation on both sides (if at all possible). Additionally, avoid channel 37 is (or was the last time I looked) for Radio Astronomy and could cause some issues.
     
  6. Nov 5, 2010 #6 of 15
    fluffybear

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    Peachtree...
    It might help if we can have a little more information on your modulator. If the modulator has the ability for different inputs, which are you using.

    Also do you have any other devices connected to these TV's and if so, how?
     
  7. Nov 5, 2010 #7 of 15
    jimstick

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    I happened across a post in another thread that turned the light bulb on in the dark space I call my head that reminded me that a VCR is a wonderful RF modulator, so I hooked it up and VOILA! Perfect! Don't waste your money on an RF modulator if you have a VCR with composite inputs. It works SOOOOOO much better. I ran the composite from the HR20 to the VCR and the coax from there to my splitter, then out to both TV's and...amazing! No more wavy lines, no more snowy picture, I don't have to buy an amp, I just have to leave the VCR on and all is well. Took the RF modulators back to the store. Thanks everybody for your suggestions.
     
  8. Nov 5, 2010 #8 of 15
    fluffybear

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    Peachtree...
    Glad to hear you were able to come up with a solution.
     
  9. Nov 6, 2010 #9 of 15
    Yoda-DBSguy

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    A Galaxy...
    It wasn't the fact that you were using a modulator that caused the "wavy lines" you described; it was the fact that you were using a "CHEAP" one that caused the issue.

    The benefit of using a modulator in lue of going the vcr route as you did is multi-fold:

    1. The modulator is always on; thus the modulated picture will always be there even after power is restored from an outage. A VCR would have to be turned back on and placed back on the correct "line input" in order to restore picture.

    2. Most modulators are designed to mix antenna or cable in with the modulated station thus giving you an option for an independant viewing selection at each and every connected tv location. The VCR connection method you descrbed doesn't do that as it is only capable of outputing the "line in" connected picture to each location simultaneously.

    3. Some of the better modulators on the market have an adjustoible gain amplifier buit in. This allows for attinuation and gain adjustments to accomidate you specific system needs based on length of runs, splitters in use and minimum tuner requirements to allow for the best picture possible. Again a VCR doesn't do this independantly without the addition of an external amplifier to do the same job.
     
  10. jimstick

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    So you disagree with fluffybear's comment? Do you have any recommendations for a "better" modulator?
     
  11. fluffybear

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    Peachtree...

    Channel Master is considered by many to be a top of the line but with it comes a top of the line price. RF Dayton is also considered to be a good unit but chances are you will not get either unit locally.

    Let me ask you a couple of questions

    What's your budget?
    Do you want your channel output limited to channel 3 or 4 or will any unused UHF do?
     
  12. Yoda-DBSguy

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    A Galaxy...
    The exact model to fit your needs depends on factors as I mentioned like:
    How many TVs you want to run off the modulated signal, the longest drop run length, if you want to add MATV or CATV signal into the mix, etc.

    I use a variety of units including Channel Master, Channel Vision, Pico, Net Media, depending on the particular application.

    Hit me in a PM (Private Message) if you need further assistance...
     
  13. jimstick

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  14. fluffybear

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    Peachtree...
    Jim, I am a true believer in "If it is not broken, why fix it". If you have something that is working right now and at the right cost then why change anything?

    I know of a couple of good Channel Master modulators which would handle two inputs and allow to distribute to 5 TV's but those outputs would be on unused UHF or CATV channels. The cost for a system such as this is somewhere between $80 to $100.
     
  15. jimstick

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    I tend to agree.
     

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