[TowerTalk] determining db gain

[Ken Hirschberg]

Hi Tom - Yes, the closely-held-belief effect is definitly there in humans,
especially those who own antennas.   Just like the deer whistle experiment
on your wife's car.  Summed up by one of the best bumper-stickers I've seen:
"BELIEVING IS SEEING"
Ken

Tom Rauch wrote:

> > Recently on 75 meters while calling the same station, I was reported
> > as 2 s units better than another station. I was using my rain gutters
> > for an antenna, the other station was using a rhombic. Since an s unit
> > is typically 6 db, I have therefore determined that my rain gutters
> > have 12db gain over a rhombic.
>
> Years ago, after being involved in some double-blind medical device
> testing, I did a test on 75 meters where I compared a G5RV and a
> "something" (I think it was a "full-size dipole" or "loop").
>
> Quite a few operators reported the G5RV weaker during A-B tests,
> sometimes the difference was significant even if I repeated the test
> several times to "factor out" QSB. On two or three occasions
> operators would say the G5RV had "less audio" or "poorer audio"
> even though it was just as strong!!!!
>
> (I remember one guy saying "you won't believe this but your audio
> is actually better on the xxxx")
>
> The most amazing part of this test is I wasn't changing anything at
> all! I was tapping the PPT switch and making a click, and then
> saying the fictitious name of the new antenna.
>
> After that, whenever I changed antennas in a real test, I never told
> anyone what they actually were. If they found out, I occasionally
> would swap antenna positions between A and B.
>
> I did that in several hundred A-B comparisons of a dipole at 300
> feet and a 200 foot vertical on 160 meters, where the VK's and ZL's
> would learn what antenna A and B were. Once they never knew
> which was which, the reports were more "honest".
>
> The dipole at 300 feet was statistically improved (but not enough to
> be a winner) if people knew or suspected when I was using it.
> When they didn't know which was which, the vertical was an even
> bigger winner!!!
>
> Weird, but absolutely true!
> 73, Tom W8JI
> w8ji@contesting.com
>
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