Winegard vs. Jack antenna (again)
This is my second attempt to do a Winegard vs. Jack antenna comparison. Here's my test setup: Antennas: Winegard Sensar III with Wingman attachment and King Controls Jack antenna head unit. T...
Forum Discussion
Mark: Mine was done in Valencia in North LA County that has a clear shot to Mt. Wilson, and is shaded prettymuch on all sides by mtns. But that's also why I did the angular tests. It's a single point source for everything from channel 7, all the way to the top of the UHF band.
Tom: You cannot do 'real world' antenna gain tests with a consumer receiver and have definitive numbers. All you can do is see how the receiver reacts to different antennas, and the AGC is the main reason why. When I said that the numbers are off, they are off in relation to the two antennas which the AGC obviously influences, and not necessarily the same. It it possible for the Jack to not have enough gain to hit the AGC threshold, and also possible that the Winegard to have just enough gain to get into AGC threshold to force the receiver to roll back a little. You also don't know if your sample metering is pre or post the AGC circuit. See the problem? (Edit) And thirdly you may actually have a problem with the Batwing. But how do you know.. ? That's why I went to the trouble of bringing the big hardware home for the measurements. You can see by the setup on the screen what the setup is, and the analyzer cannot be fooled by internal automatics because it has a none. And because I have a calibrated receiver (the analyzer) that cannot be fooled when I did those, and known good antennas, I said if anyone says the Jack performs better, the Batwing is broken. The problem is that your comparisons look correct on VHF, but the UHF is definitely not what I'd expect to see. So...... ??
As for measuring the actual gain of each antenna, it's impossible unless you can shut off all of the receiver automatics. You also don't have a calibrated antenna reference that you can say this is my unity gain antenna and all other measurements are referenced to this zero (unity) gain source. And if you really want to do it right, then you measure the antennas against the reference without preamps. I wasn't interested in cutting antennas open, nor have any experience with calibrated antennas. Maybe our resident antenna design engineer can comment on that?
Tom: You cannot do 'real world' antenna gain tests with a consumer receiver and have definitive numbers. All you can do is see how the receiver reacts to different antennas, and the AGC is the main reason why. When I said that the numbers are off, they are off in relation to the two antennas which the AGC obviously influences, and not necessarily the same. It it possible for the Jack to not have enough gain to hit the AGC threshold, and also possible that the Winegard to have just enough gain to get into AGC threshold to force the receiver to roll back a little. You also don't know if your sample metering is pre or post the AGC circuit. See the problem? (Edit) And thirdly you may actually have a problem with the Batwing. But how do you know.. ? That's why I went to the trouble of bringing the big hardware home for the measurements. You can see by the setup on the screen what the setup is, and the analyzer cannot be fooled by internal automatics because it has a none. And because I have a calibrated receiver (the analyzer) that cannot be fooled when I did those, and known good antennas, I said if anyone says the Jack performs better, the Batwing is broken. The problem is that your comparisons look correct on VHF, but the UHF is definitely not what I'd expect to see. So...... ??
As for measuring the actual gain of each antenna, it's impossible unless you can shut off all of the receiver automatics. You also don't have a calibrated antenna reference that you can say this is my unity gain antenna and all other measurements are referenced to this zero (unity) gain source. And if you really want to do it right, then you measure the antennas against the reference without preamps. I wasn't interested in cutting antennas open, nor have any experience with calibrated antennas. Maybe our resident antenna design engineer can comment on that?
