JerseyShor said:
Would upgrading from a UHF antenna with 11.4dB of gain to one with 13.7dB of gain have any significant effect?
A 2.3 db gain is approximately a 30% increase in signal voltage gathering capability.
http://www.muzique.com/schem/gain.htm
If we had more information we could specifically address your situation. How far from the transmitter site(s), height of antenna, etc. There are several options to consider.
That small increase in gain alone is usually not really worth the expense and the work involved if your existing antenna and feedline is in good condition. Are you using a signal amplifier? (provided that you are not located too close to the stations in your area - less than say, 20-25 miles - then you might overload your tuner) Using a signal amplifier may be an option to help receive that particular station. You could also use a signal attenuator with your signal amplifier if the amplifier does not have a built-in adjustable signal gain control. For example, I am 40 miles from the transmitters and using a signal amplifier definitely makes a difference. A few of the stations are strong enough without amplification, but the stations that are not high enough in signal strength or are "borderline" in signal strength, say between 60 - 70%, will either cut out completely or pixelate when the signal strength fluctuates a bit lower due to atmospheric conditions such as rain, foliage, etc. With the amplifier the minimum signal is more like 85%+ and the strongest stations are now 96-98% signal strength, and of course, none of the signals cut out completely or pixellate at those levels.
Gain is one of several factors to consider when trying to improve reception. There's the terrain between your antenna setup and
the TV station's transmitting site, the quality of components used in your installation: the cable, the antenna, the connectors, the height of your antenna, whether it's attic mounted or mounted outdoors, possibly the signal sensitivity of the tuner or converter box you're using etc., the power of the (H)DTV station - the station that you're trying to receive may not be operating at it's maximum licensed power yet - and may increase power on June 12 by a sufficient amount making a replacement antenna unnecessary because (a) nearby analog station(s) on the same frequency may shut off their analog channel then. It may be best to wait and see in June if you know for a fact that the station may be increasing its power. Check FCC database at:
http://www.fcc.gov/mb/video/tvq.html to see if the station has a construction permit to increase power, increase antenna height, etc...
Also, it depends on the design of the antenna, what frequency you are trying to receive, etc. Many manufacturers provide "polar" charts that show what the gain of an antenna is in a 360 degree pattern, and also provide some gain figures at least at the low, middle and high end of the UHF band. The gain may be sufficient enough for your situation if the antenna has adequate gain for the desired channel. Most UHF TV receive antennas cannot by design have exactly the same gain across the entire UHF band, that is rather difficult to do even with a large number of elements and the fact that the antenna is trying to receive signals over a span of about 230 MHz!
Check out these websites for additional ideas and/or ask questions there as well:
http://www.hdtvantennalabs.com/
http://www.antennaweb.org/
http://www.satelliteguys.us/hd-over-air-ota/
or use your search engine of choice using words such as: DTV antenna questions
If the manufacturer does not provide the technical information there may be some independent testers of antennas on the web.
http://www.avsforum.com/avs-vb/showthread.php?t=1037779
http://www.hdtvexpert.com/pages/8vsb.htm
http://www.kyes.com/antenna/antennadex.html
Good luck and let us know what happens!