Albert Manfredi wrote:
flyback1 wrote:House is 430 ft above mean sea level.7 ft parabolic UHF antenna 28 feet in the air, fwd gain 17 dB, mast mountedpreamp, 40 ft of RG-11 coax. 37 miles from Philly, 52 from Baltimore, inalmost a direct line. Get better [but by no means perfect] reception fromBaltimore than from Philly.But what you miss telling to the uninitiated is that this "direct line" you're talking about is 180 degrees away from Baltimore. Said another way, the parabolic reflector is actually dispersing the Baltimore signal for you, not amplifying it. What you also fail to divulge to the uninitiated is how analog and digital reception of Baltimore channels compare, with this same antenna aimed this way.
No, the stronger signals are coming from Baltimore even though I live15 miles closer to Philadelphia than to Baltimore. That's both stronger digital and analog signals. If I point the antennas at Baltimore, there is little improvement but I lose some of the Philadelphia stations altogether.
I have two antennas up, one for digital [UHF parabolic] and a U/V log antenna about 90 inches long with 48 elements. With both pointed toward Philadelphia, the stronger signals, both analog and digital are coming from Baltimore. This is according to what is displayed on a spectrum analyzer. Must be less dirt in the way.
The 'antenna' on the UHF parabolic is a double bow tie that faces the 7 ft. diameter reflector. I.E. the bow tie antenna IS pointing at Baltimore. The specs for this antenna show that reception off the back side through the reflector to the antenna is about 5 dB less than the front facing gain which is 17 dB. Still the Baltimore signals are all stronger than the Philadelphia UHF digital signals according to the signal meter on any receiver I connect to it.
As for analog, I get very good pictures from most of the Baltimore U/V stations, with extremely low noise at the bottom of the H. sync pulse viewed on a waveform monitor. This is not the case for the Philadelphia U/V analog stations. They are noisy and have occasional hits in them, probably what most would call "Grade B" reception, or maybe worse. This is the way it is year round, not just in winter. The reception has been this way for 5 years, since I installed the antennas.
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