Quote:
Originally Posted by cmihai
... I calculated my losses at 17 db (3 db preamp, 6 db 100 ft coax cable, 8 db 4 way splitter), reason I opted for a 19 db gain preamp. Does the built-in TV tuner introduce signal loss too? Should I go with Winegard AP-8275 / 4800 (28 db gain)?
TV Fool Analysis Results
http://www.tvfool.com/?option=com_wr...03d944daf69fe2
Antenna Setup: Antennas Direct DB8, Winegard AP-8700 Preamp, approx 80 ft RG6 coax cable to the 4-way splitter, Sony Bravia with built-in tuner |
Quote:
Originally Posted by cmihai
Two of the splitter outputs are connected (to one TV each), one has a coax F terminator and the last output is currently wide open (I realize this is not the ideal situation). Later on I'd need to connect it to the third TV in the basement.
The highest (first in line) pre-amp gain is at about 28 db on UHF. The second (in line) comes at about 19 db UHF. I red that the pre-amp is supposed to compensate for cable loss and should not provide much more than the actual cable loss, otherwise it might burn out the TV tuner (if I'm not mistaken). As mentioned in the first thread, my cable loss is at about 17 db that is why I decided to go with a 19 db pre-amp gain. I was afraid that 28 db would be too much of a good thing  |
I don't understand why you attribute 3 dB of loss to a preamp. If you are considering the noise figure, it is not attenuation and can not be overcome with amplification (it's unwanted noise generated by the amplifier added to the desired signal).
You indicate 80' of RG-6 and a 4-way split. My calculation says you are facing a total of 13 dB of loss due to cable and splitters.
There is no reason to be using two amplifiers in the system you describe. The long list of strong local signals indicates against use of any amplifier with low to moderate input capability. A second amplifier in-line will most certainly be overloaded even if the first amplifier is not.
Either the Winegard HDP-269 (which I think JC recommended) or an Antennas Direct CPA-19 would be all the amplifier I could recommend. My inclination is toward the CPA-19. Both amplifiers are resistant to overloading, the CPA-19 has a better noise figure.
Per your TVFR, WUTV-FOX, real channel 14 arrives at your location with an available NM of 8.5 DB (signal level of -82.3 dBm). The DB-8 is not known for peak gain at the bottom of the UHF band.
IF if has 10 dBd gain at CH-14, that can be added to the NM of 8.5 dB providing a NM of 18.5 dB (signal level of -72.3) to the preamp input. The CPA-19 has a NF of about 2 dB which will subtract from the NM ant the preamp input, now we have a NM of 16.5 (signal level of -72.3 + 17 dB amplifier gain = -55.3 dBm at the amplifier output.) After that signal passes through 13 dB of cable and splitter attenuation the signal level at the tuner input would be -68.3 dBm, not the strongest signal in the world, but sufficient for a decent tuner to work with...
IF there is no significant external interference problem,
AND, the TVFR prediction is accurate.
There are better antennas for reception of real channel 14. The Antennas Direct XG-91 for example. If the 2-edge path for WUTV is introducing unpredicted loss or multipath or, there is external interference, you may never see reliable signal from WUTV. As a test, you can remove the splitter and check to see if you can see WUTV, if you see it, you may be lucky and simply be facing lower than predicted signal levels.