DataWave RF MaxChannel Antenna Series: The High Gain Single Channel Strategy

MaxChannel Series Single-channel HDTV OTA Antennas by DataWave RF

“A novel strategy for absolutely superlative HDTV Over-The-Air reception”

The MaxChannel Series of single-channel (VHF) and narrow-band (UHF) antennas by DataWave RF are Free Space YAGI designs computer-modeled and highly optimized for a specific channel segment of the HDTV Over-The-Air broadcast spectrum. The MaxChannel Series has been developed to answer the need for the highest performing antennas possible that are essential for reception of extremely weak signals such as Edge Diffraction and Tropospheric propagation modes. Of course, the MaxChannel Series will certainly provide the most rock-solid reception possible for all typically marginal “line-of-sight” signals of 40-80 miles, including aggravated topographies such as hills, valleys, and dense tree covering.

In contrast to “full-band” antenna designs that compromise heavily to provide “some” reception capability over a whole broadcast band, the MaxChannel design is dedicated to zero-compromise for achieving the utmost reception of the weakest signals possible. This extreme reception capability also succeeds in eliminating those occasional signal dropouts from the usually stable signals caused by multi-path cancellation and other temporary interferences.

Gain is meaningless unless the antenna is “impedance matched” to the transmission line.

Impedance Matching 101:

Most wide band antennas, by their nature, suffer wide impedance fluctuations across their band of operation. When the signal encounters an impedance mismatch (something other than 75 ohms, assuming its a 75 ohm system), a percentage of the signal proportional to the mismatch is reflected back to where it came from (the antenna element), and is lost. The specification called “SWR” (Standing Wave Ratio) is a measure that quantifies impedance match. Equivalent measurement expressions of impedance match are “Return Loss” (loss of signal due to return, expressed in dB, the larger the number the better), and Reflection Coefficient (the percentage of signal reflected and lost).

Typically, most consumer-grade antennas have many channels with reflection coefficients between 15%-90%  (.15-.9, lower is better) over their coverage range, especially multi-channel and multi-band antennas. In fact, finding a channel where the reflection coefficient is less than 15% (.15) (SWR: 2.25:1) is uncommon.

In contrast, MaxChannel Series antennas are carefully designed and adjusted to achieve a maximum SWR of just 1.5:1, which is a Reflection Coefficient of less than 4%. The typical MaxChannel Series SWR varies between 1.04:1 and 1.35:1, or between 0.1%-2% (.001-.02) Reflection Coefficient. This precise tuning of the impedance match delivers nearly 100% of the received signal efficiently to the coaxial feed line.

Considering that 12% equates to 0.5dB, the wisdom of having a well impedance-matched antenna is obvious when considering the value of that 0.5dB that sometimes must be obtained through purchasing an exotic Low Noise Amplifier.

Notwithstanding the profusion of attractive gain specs advertised throughout the television antenna industry of late, MaxChannel Gain specs are probably different: they are based upon actual signal analyzer measurements made with comparison to a standard reference dipole antenna having <1.04:1 SWR / .001 Reflection Coefficient, on the same signal. Installing a MaxChannel Series, you can expect a dramatic difference in signal strength with an improvement factor of from 2x to 6x (3dB~8dB), or more,  even from the smallest 10dBi MaxChannel models.

“So, then will I need a separate antenna for every channel I want to receive ?”

Well, MAYBE ! That is, if you are located in an area where every channel that you could receive is a “weak-signal” station that requires the utmost reception measures.

However, for UHF stations (and since the digital channel reassignment, most are), you may be in luck if the channels needed are adjacent. That’s because the 6-MHz channel width is a much smaller percentage of the frequency for UHF channels, so the UHF MaxChannel Series will do an excellent job for adjacent channels including the design frequency/channel, for a total of 5-7 channels covered. Measurement-wise, these 4-6 adjacent channels will still yield an excellent SWR of <1.5:1 .

Another strategy for those in the vast majority that have good signal reception for most stations, but that happen to be scattered around the band, is to employ a high quality wide-band antenna for those nearby strong stations and employ the MaxChannel Series antenna(s) only for channels showing weak or only occasional reception.

The MaxChannel Series antenna will often deliver plenty of signal capture from “line-of-sight” stations (0-80 miles) even though those stations are off the MaxChannel design frequency. Usually as good or better than a “full-band” model. So depending on your particular reception environment, a single MaxChannel antenna will normally provide an array of nearer stations in addition to that challenging 5~7 channel range it was chosen for.

At AbilityHDTV we’re experienced in the selection and deployment of the DataWave RF MaxChannel Series. We welcome your site-specific inquiry for an analysis of what a DataWave RF MaxChannel can do for you.