Improving reception in Lancaster, PA

spivonious · 3-Sep-2013, 2:24 PM

http://www.tvfool.com/?option=com_wr...46ae1f27ccf8b8

Comcast is going to encrypt our locals starting next month, so we decided to switch to OTA. I built mclapp's 4-bay bowtie design using 10" whiskers with a 9.5" spacing with no reflector. I used steel coat hangers for the whiskers, and some 6awg bare copper for the phasing lines. They're all mounted to a piece of scrap wood I had and placed in our attic, roughly 25 feet above ground level on the western side of the house. The antenna is pointing at a plywood wall with a side vent approximately 2'x1' covered with a metal screen. The antenna is about 3 feet away from the wall. It is above the neighbor's roof, but not above their tree (which is full of leaves this time of year).

With the help of my wonderful wife, I managed to get the antenna aimed at the best spot for the channels we watch the most (WGAL, WPMT, WHP, and WITF). It turned out to be parallel to the wall of the house, which I estimate at about 275 degrees (I couldn't find my compass).

The signal is split twice before the TV. I put an old Radio Shack 10dB booster that I had in the line before the first split. Due to no electric in the attic, the booster is after approximately 40' of cable. All cable in the house is RG6.

Average signal levels right now are (according to my TV):
WPMT (RF47): 87%
WLYH (RF23): 76%
WGAL (RF8): 100%
WHP (RF21): 86%
WITF (RF36): 76%
WGCB (RF30): 63%
WHTM (RF10): 47%

It seems that with my TV, anything over 55% comes in fine with no glitches. Below that and I start getting intermittent blocking and anything under 50% just won't tune at all.

The problem is that WHTM is just too weak for the TV to pick up reliably, even when the antenna is aimed right at the tower (got an average signal level of 50%). I'd also like to be able to pick up the Baltimore PBS just to see what's on, but that's not as important as WHTM, and I'm doubtful I can do it without a separate antenna aimed south.

Would a reflector help? Should I get a dedicated VHF-high antenna (such as the AntennaCraft Y5-7-13) and a diplexer? Am I stuck with mounting outside of the attic? I'd prefer to avoid putting an antenna on the roof for cosmetic reasons (and that I'm picking up most channels fine inside the attic). Would I see any benefit from replacing the coat hangers with something like the AntennaCraft U4000?

GroundUrMast · 3-Sep-2013, 4:26 PM

If you enjoy building your own antenna, take a look at the GH2n and similar designs... http://clients.teksavvy.com/~nickm/g..._5V7_12u8.html The Gray-Hoverman with NARODs have morphed the basic antenna from being a UHF only antenna into a remarkably good UHF/High-VHF combo... And it's quite compact.

A conventional store bought option would be an Antennacraft HBU series antenna. Or, as you have proposed, just add a Y5713 or Y10713 to your existing system. A simple UHF/VHF combiner could do the trick.

Another option is to toss the 10 dB amp... it's probably adding nearly the same amount of noise as gain (if it's like most of those I've seen). Replace it with a Channel Master CM-3410 adjacent to the antenna. With a PCTMPI1G power inserter, you can locate the power supply separate of the amplifier. http://www.channelmasterstore.com/Am...p/pctmpi1g.htm

In some cases, placing an amplifier close to an antenna will isolate the effects of poor SWR, resulting in better performance. In this case, I suspect the SWR of the home made bow-tie antenna is quite high in the VHF band. Also, the CM-3410 has more gain with far less noise than the typical 10 dB 'boosters'.

spivonious · 3-Sep-2013, 8:44 PM

Thanks for the reply. I did not know that something like that power inserter existed; that's good to know about.

Do you think adding a reflector would help boost the channel 10 signal enough?

While I enjoyed the end result, the actual assembling of the antenna was a bit frustrating (had to dig through my workbench to find washers that were big enough, kept breaking hangers when bending them). While it would be fun to build that Hoverman antenna, I don't think I have the materials at hand, and it's tough to argue with the low cost of AntennaCraft antennas.

Would the HBU series be too directional? My stations have quite a wide spread, which is why I stayed away from the yagi designs.

GroundUrMast · 4-Sep-2013, 3:17 AM

I would certainly expect a reflector to make the antenna more directional and improve the UHF gain to the front. The only way to know for sure whether adding a reflector might help H-VHF reception is to try.

An Antennacraft HBU-11 or HBU-22 is not very directional, The H-VHF forward beam-width of the HBU-22 is spec'd at 62.5° and the UHF spec is 46.8°. If needed, roof mounting a small antenna like that can be pretty in-obtrusive.

I know I've stood on the soap box already, but I doubt that RS amp is helping enough to overcome it's own internally generated noise.