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Re: [Amps] 10 DB increase

To: Amplificadores Lineales <amps@contesting.com>
Subject: Re: [Amps] 10 DB increase
From: GGLL <nagato@arnet.com.ar>
Date: Sat, 05 Feb 2005 11:29:55 -0300
List-post: <mailto:amps@contesting.com>
Ken, IMHO it's non linear (a simpler, bad design) or unadjusted metering system. In older receivers with S-meters calibrated in microvolts, a 10 dB power increase reflects as a 20 Db input change.
Concerning S-meter systems, the best I have seen were mainly Kenwood's with needle instruments (TS 430, 440) and a few Icoms (three adjustment pots!, and you see the result). In those Kenwoods, during the adjustment process you also tweak for "mis-alignment" one of the IF-unit's tuned can. I guess this way they achieve the accurate readings.
I also believe that what's in the "middle" of both antennas should affect equally both signal power levels, don't they? (a linear propagation media).
But as said in another e-mail in the case of fast changing condx, several tests should average readings.


Best regards
Guillermo - LU8EYW.

kenw2dtc escribió:
"Many years ago, an old timer (W6SDM) told me that to make a noticable
difference on HF SSB, it took +10db."

While on the subject of DB. Many times when someone adds 10db to the transmit side, in an A/B test, almost no one on the receiver side shows a 10 db 'S' meter increase, many times the receiver readings show a 20 or 25 db increase. Is the major reason due to liberal non-linear metering or are other factors such as antenna, location of both stations, propagation etc, the greater of the factors?

73,
Ken W2DTC


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