Thread: Rca ant751
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Old 21-May-2017, 2:24 AM   #46
rabbit73
Retired A/V Tech
 
Join Date: Aug 2012
Location: S.E. VA
Posts: 2,551
The next test that I did was to compare the GE PRO, ANT 751R, and the ANT 7511.

Code:
Relative Gain Comparison of three Antennas

Channel  GE PRO     RCA       RCA
          29884   ANT751R   ANT7511
          dBmV     dBmV      dBmV

15       -10.2    -12.5     -15.6
28       -10.4    -11.6     -13.4
39       -12.0    -12.3     -16.3

Equipment Used:
Antennas Direct DB2E source antenna
3 antennas to be compared
Blonder Tongue HAVM-1UA Agile Modulator
20 dB attenuator to reduce HAVM output
Sadelco DisplayMax 800 Signal Level Meter

Test Conditions:
Indoor Test Range; ground floor, carpet over concrete slab
Antennas 10 wavelengths apart
Antennas elevated on Table-Mate tables
Signal Level Meter measuring analog video carrier
Conclusions:

The GE PRO 29884 antenna is the best of the 3 antennas for my indoor location. The RCA ANT 751R is a close second. The RCA ANT 7511 is third. The RCA design change has sacrificed considerable UHF gain.

I have a little more confidence in these measurements, but there are reflections that will introduce errors. I miss my outdoor range with stable LOS signals.

Quote:
I'm fascinated by your test equipment!
So am I. Making antenna measurements is one of my favorite things.

You don't need a lot of expensive equipment. With just a variable attenuator and a TV, you can measure margin to dropout of the signal. The simplified form is shown in my signature link.

__________________
If you can not measure it, you can not improve it.
Lord Kelvin, 1883
http://www.megalithia.com/elect/aeri...ttpoorman.html

Last edited by rabbit73; 21-May-2017 at 3:03 AM.
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