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I just got an HDTV set, and my sat installer -- who was supposed to install an attic antenna (a winegard something or other?) told me we can't get enough signal strength for it to work.


(He claimed that they need about 10-20dB of signal, and mine was at -20db. Here in Simi Valley)


I'm wondering if there are any in-room antennae I can buy cheaply to try things out. Otherwise, I'm screwed. http://www.avsforum.com/ubb/frown.gif


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-- jas
 

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No reason to panic.


Try the Silver Sensor indoor antenna (about $40), and get a good preamp. The Channel Master Titan 2 #7775 UHF-only preamp ($69.95) works very well. I use this preamp to watch DTV stations from 25 miles distant, inside my basement, on channels 26, 42, 46, 55, 62, and 64.


I have also used this preamp with a 6" home-built antenna, made from hardware store parts, to watch indoor DTV over a 25-mile path.


KC
 

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An indoor antenna from Simi Valley is asking alot. 'probably need to go outdoors. A low-noise preamp would also be a help; at least you don't need to worry about signal overload out where you are. The CM7775 should work well.


--Barry (former LA-area resident)
 

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I am surprised your installer would claim that signals in the 10 - 20 dB range would be required. That's a lot of signal. I have locked up signals as low as -12 dBmV (about -59 dBm) on Panasonic and Samsung tuners. I can consistently hold any signal in the 0 dBmV to -6 dBmV range (about -47 dBm to -53 dBm).


Try a better UHF antenna and a preamp. If you can attic mount an antenna, try the Channel Master 3021 (also known as 4221) and their companion #7775 UHF-only preamp, as the previous post suggests. I use that combo with a great deal of success.


KC
 

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What is the 10 to 20 dB figure relative to? Doing a back of the envelope calculation for a 6 MHz BW, 10 dB noise figure, and a 14 dB SNR, I come up with -82.2 dBm, -33.6 dBmV, and 26.5 dBuV. I guess the closest thing 10 to 20 dB comes to is dBuV, but even then you're below threshold by 6.5 dB minimum. It seems to me that for 10 dB margin you'd want something like 40 dBuV minimum.


Even more important is the fact that none of these measurements mean anything if there is a preamp in front of the receiver. All that matters is the ultimate SNR, and the amount of ripple in the passband.


What kind of instrument were they using to decide they needed 10 to 20 dB for proper operation??


Bob Smith
 
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