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Old 2-Apr-2013, 6:25 PM   #1
tripelo
Senior Member
 
Join Date: Jan 2010
Location: Dallas, TX
Posts: 127
Some Antenna Photos and Tests

Tests were conducted in 2011 to evaluate performance of some TV antennas.

The tests involved a signal source feeding a CM-4228 at ~45 ft AGL radiating to antenna under test located ~150 feet distant at ~level height to source antenna.

The signal source was a homebrew signal synthesizer, remotely controlled at the receiving location by a notebook PC.

Received signals from the test antenna were measured using a homebrew wideband power meter with digital readout and logged into an Excel spreadsheet.

The test frequencies were chosen to represent channels that might be of personal interest.

This location is rural, the only UHF strong signal is at Channel 14; the frequency band was omitted from the tests.

The last image below shows results from comparing four antennas:

- Channel Master 4228 (the most common of the older versions)
- Channel Master 4251
- Antennacraft P7
- Antennacraft SuperG 1483 (the stacked Hooverman version)







The decibel scale is relative for a comparison between the units.

Caveats:

Each antenna was installed at the test mast for a few days while several preamps were individually tested with that particular antenna. So, each antenna was measured days apart from others.

There may be some SWR effects in the antenna gain patterns, affecting each antenna differently.

Comments:

In general, testing against distant weak TV signals was consistent with the measured results. CM-4251 was best on upper UHF. P7 performed well on mid UHF channels. SuperG 1483 was comparably good on mid-20 range channels.

Attachment 496
Attached Images
File Type: gif Antenna Compare.gif (13.3 KB, 21787 views)
File Type: jpg Antennas.JPG (79.9 KB, 25176 views)
File Type: jpg Test Range & P7.jpg (110.8 KB, 21818 views)
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