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Old 5-Dec-2012, 10:03 PM   #14
rabbit73
Retired A/V Tech
 
Join Date: Aug 2012
Location: S.E. VA
Posts: 2,753
Try just the DB4e alone first to see what it will get.

If the heat in the attic is a problem, this might be a solution: If you have an airconditioned room just below the attic, you could put the preamp there. If the coax from the antenna to the preamp is less than 6 ft, the preamp performance will not be seriously compromised. My coax is 9 ft from the antenna to the preamp, and 50 ft to the power inserter and TV; the preamp makes a big difference.

This is what my tvfool report looks like; my ant is at 5ft---last column. The UHF antenna is a CM4221 4-bay bowtie, and the VHF antenna is a folded dipole of 300 ohm twin lead cut for CH13. The channels are in numerical order to make measurements (not shown here) with my signal level meter:

Code:
Real           tvfool-zip      tvfool-address    tvfool-address, 5 ft
 CH            dBm   path        dBm   path          dBm   path
 
  7  WTPC     -41.9   LOS       -74.0  2Edge        -81.0  2Edge
  9  WSKY     -58.1   LOS       -88.2  2Edge        -95.5  2Edge
 11  WGBS     -73.8   LOS       -98.9  2Edge       -114.6  2Edge
 13  WVEC     -38.6   LOS       -71.1  2Edge        -78.0  2Edge
 16  WHRO     -32.4   LOS       -62.3  2Edge        -72.2  2Edge
 17  WKTD     -50.0   LOS       -87.9  2Edge        -95.4  2Edge
 20  WUND     -93.8   2Edge    -117.9  Tropo       -124.4  Tropo
 22  WRIC     -57.9   LOS       -87.7  2Edge        -94.3  2Edge
 25  WTVR     -60.4   LOS       -90.1  2Edge        -96.5  2Edge
 26  WRLH     -58.5   LOS       -88.5  2Edge        -95.1  2Edge
 29  WVBT     -32.7   LOS       -69.2  2Edge        -77.5  2Edge
 31  WAVY     -32.8   LOS       -66.2  2Edge        -75.6  2Edge
 33  WTVZ     -33.3   LOS       -63.4  2Edge        -73.2  2Edge
 40  WTKR     -33.9   LOS       -64.4  2Edge        -74.0  2Edge
 42  WCVE     -62.1   LOS       -92.6  2Edge        -98.7  2Edge
 45  WNLO     -55.3   LOS       -93.4  2Edge       -101.7  2Edge
 46  WPXV     -35.4   LOS       -67.0  2Edge        -76.4  2Edge
 50  WGNT     -34.8   LOS       -69.6  1Edge        -79.3  1Edge
And this is what my SONY KDL22L5000 gave me on that particular day. The SNR should be at least 16 dB for reception:

Code:
Virtual   Real      Errors       SNR     Signal Strength     Comments
  CH       CH                    dB          

 2.1       20     0 to 6971    13 to 15      58 to 61
 3.1       40         0           25            79
 4.1        9         0           26            78
 6.1       25     0 to 3000    13 to 17         75     Signal from rear of ant
 7.1       11     0 to 3000    13 to 15      67 to 68
 8.1       22         0        17 to 20         76     Signal from rear of ant
10.1       31         0           25            78
13.1       13         0           28            79
15.1       16         0           25            79
21.1        7         0           31            79
27.1       50         0           25            79
33.1       33         0           23            78
35.1       26         0        18 to 19         76     Signal from rear of ant
43.1       29         0           25            79
45.1       45         0        22 to 23         72
49.1       46         0        25 to 26         78
   
23.1       42   Not picked up by scan;                 Signal from rear of ant
                 more comments later

Notice that some SNR numbers below 15 dB are given by the SONY TV.
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Last edited by rabbit73; 5-Dec-2012 at 10:54 PM.
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