[Amps] Re: 10dB and propagation

[Jeremy Alexander]

The Dr. is absolutely correct, as he usually is. How can any station on HF
claim anything accurate from what they saw on their S meter. What is the
latency of your meter movement, what is the attack, sustain, hold or decay
time of your AGC, what gives us the notion that just because you see a
momentary 3 dB increase (if you actually could) it was actually anything at
all? I don't even trust a RF Volt meter connected to an antenna well enough
to ever claim such a thing.

Man, this thread is dead.

Why has my request for unsubscription to this reflector not been granted?
How do I get off of here?

Jeremy W7EME




-----Original Message-----
From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com]On
Behalf Of David Kirkby
Sent: Thursday, February 10, 2005 16:58 PM
To: Steven Cook
Cc: amps at contesting.com
Subject: Re: [Amps] Re: 10dB and propagation

Steven Cook wrote:

> Team,
>
> I have seen this many times myself -- however, I don't care nearly
> enough to try and convenience anyone.  If this phenomena is merely the
> result of S-meter calibration/response/accuracy, it is curious that
> the error being reported is seemingly always on the high side.

If a ham has a 100W transmitter and a 1kW linear, and switches in the
linear in and out, it should make a 10dB difference.

If the person receiving the signal says it makes a 13dB (20x)
difference, he will be happy to tell everyone about how good his linear is.

If he is told it makes a 7dB difference, he is far more likely to
attribute the error  to the other persons deaf receiver, or badly
calibrated S-meter. He is not very likely to go telling all his mates
down the local club that his expensive 1kW linear makes only 7dB
difference, which is what you would expect from a 500W linear.

So human nature could distort that, which explains why these effects are
more often seen in one direction than the other.

> For some, seeing is enough.  For other, nothing will do.

There are plenty of optical illusions. The moon often looks bigger when
it is close to the horizon, but it is not actually any bigger or closer.
Measure it *properly* and you will find out that is true. The earth-moon
distance does change a bit during the month and year, but nothing like
as much as the moon would appear to be bigger when its near the horizon.

It is not a case of 'nothing will do' but wanting to be thorough about
something. Thinking about it. That is why it is clear to me any such
amplifier discrepancies are far more likely to be reported when the
linears appear to work better than expected, than when they work worst
than expected.

> If Rich said it, that's enough.

Exactly the sort of thing I would never do. Perhaps that is why I make
my living as a scientist.

--
Dr. David Kirkby,
G8WRB

Please check out http://www.g8wrb.org/
of if you live in Essex http://www.southminster-branch-line.org.uk/



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