A series of antenna tests conducted on July 1, 2016.
Objective: Compare performance of selected VHF antennas while receiving DFW TV channels
Antennas:
1. Antennas Direct C5
2. Televes Band III Yagi
Antennas Direct C5: Driven element is a loop design (contains two loops, inner and outer) with reflector screen. The balun is ferrite core design.
Televes Band III Yagi: Folded-dipole driven element with reflector and five directors. The balun is sealed in metal can.
Images of antennas shown below:
Antennas Direct ClearStream 5 (C5)
Televes Yagi B-III
Test Location:
Garland, TX, ~30 miles line-of-sight to DFW stations, both VHF channels (8 and 9) located on same transmitting tower.
Test location TVfool info posted earlier:
Compare Preamplifiers - Test Procedure & Configuration
Test Equipment:
Same as previous*, except:
1. Sencore SLM1456CM instead of Sencore SLM1456
2. 3dB attenuator at input of Sencore SLM1456CM
(From antenna perspective, improves coax cable match to 75 Ohms)
*Previous similar test:
Compare Received Signal Strength of 5 UHF Antennas
Test Procedure
1. Calibrate VNWA, with the 40’coax cable (refers measurements to antenna/balun connection).
Starting with Antennas Direct ClearStream 5 antenna:
2. Mount antenna w/coax and ferrites to mast, raise center of antenna to 25 feet
3. Align antenna for peak signal on Channel 8
4. With 1456CM scan DFW VHF stations (Channels 8 & 9) for signal strength and MER.
(repeat scan 9 times while in this configuration, record times).
5. Take at least 2 Photos
6. Turn antenna ~90 degrees, disconnect coax from 1456, connect to VNWA
7. Measure S11 (input impedance, SWR/Return Loss) for the band
8. Lower Mast remove antenna
9. Mount Televes Yagi B-III, repeat steps 2-8
10. Then again, for each antenna, repeat steps 2-9
The test location and setup was similar to that described in previous posts:
Televes DAT-75 vs. Antennas Direct 91XG
Credit:
Thanks to Stuart Sweet of Solid signal for providing the Televes Yagi B-III.
(To be continued)
.