Originally Posted By: HerrStig
Originally Posted By: sleddriver
Originally Posted By: Hokiefyd
Originally Posted By: yesthatsteve
Nice placement of the antenna.
Maybe.
It worked like a charm the other night after I installed it. I came home last night and turned the TV on and most of the farther-away channels were very pixelated and would come in and out. I found this odd as there was no wind yesterday and no storms. The only thing different, environmentally, was the temperature. It was HOT. And it's HOT today (about 100*F outside), so I'll see if it's also screwey tonight.
As near as I could tell, there is no operating temperature range associated with this antenna; it's completely passive and there is no amplifier. It simply plugs into the television. I may consider shortening the coax cable in the attic (I have a coax connector toolset, so I can do this easily), but that's all I could do short of moving the antenna. But I'm not sure why the reception seems (at least so far) to be dependent on temperature. There is a very small plastic box on the antenna where the coax connection is; the very basic instructions that came with the antenna call this a "transformer". I suppose something in there could be sensitive to temperature, but again, there is no maximum operating temperature associated with this model. If reception is poor again this evening, I will contact the antenna manufacturer to see if they have any ideas.
Edit: this is the model I purchased; the description specifically mentions using it in an attic space.
http://www.antennasdirect.com/store/DB4e-extended-long-range-outdoor-dtv-antenna.html
What you've got there is a bowtie. Nice UHF antenna. Next time you're up in the attic, I'd reroute the coax behind instead of in front of the antenna.
Also check the signal strength on each of your channels and make a chart over time. I sincerely doubt heat has anything to do with it.
A range of 65 miles sounds too-good-to-be-true for the antenna, so count me skeptical. Unless it's high enough to be line-of-sight to the transmitter. Height always helps antennas. Mine is mounted about 16' up a pole on top of the roof. The UHF section is a small corner reflector. But I can see the transmitter towers from the roof!
If you're 50 mi. to the transmitter, you may need an amp, bigger antenna, or more height to get a consistently strong signal.
You didn't metion the type of coax you're using, but it should be RG-6QS for best performance. Be sure it's properly terminated with none of the shield exposed.
Welcome to the world of UHF propagation. Bending of the signal takes place at the intersection of layers of air at different temps. A preamp might help by compensating for the loss in the RG6. You can also buy larger, .405 diameter cable with lower loss and type "F" connectors which will fit it. Preamps have a weakness in that they tend to overload when a strong local signal is present, and the overloading masks the weaker, more distant signal you want. The problem with digital is there is no graduation in observed signal strength, its' either there or gone. The signal "meters" in the TV software are next to useless for anything other than aiming an antenna on a rotator. It's interesting that to make these new HD TV's work we are going back to what was needed in the good old days when " living out in the woods" meant you needed a high gain antenna, a rotor, low loss feedline, and a preamp. The service maps for stations moving to UHF for HD almost always show a coverage loss, and the FCC has been pressed to allow some stations to retain their VHF allocation so coverage - which directly affects market share. If you really want to take advantage of what's out there in UHF TV, you need a higher gain antenna, mounted outside, better feedline, and unless EVERYTHING is in the same direction, a rotor. There's no free lunch with antenna gain, when it "hears" better in one direction it is at the expense of "hearing off the back and sides.
Ah yes, the short lamda domain....where hardline rules but doesn't bend.
The "meters" are what most people have to use as proper aiming is critical.
I've used nothing but antennas for nearly 30 yrs. No cable/satellite/$$$$$ (bills). I don't have a rotor though...it would be interesting to see if I could receive signals from San Antonio to the S about 65mi, Houston to the SE about 185mi. and Frt. Worth to the N about the same as I currently tune about 8 channels of the 15 or so I'm capable of receiving (
no habla espanol).
It's amazing some receive 40+ stations...but of what? I prefer to watch movies or via internet as broadcast TV (that I receive) is aimed at a much younger audience.