[Amps] Re: 10dB and propagation

[R.Measures]

On Feb 10, 2005, at 7:56 PM, Jeremy Alexander wrote:

> 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.
>
Do you trust HP 355 attenuator sets?

> Man, this thread is dead.

So why try to ride a dead horse?

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

Filter it, and stop kvetching.
>
> 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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>

Richard L. Measures, AG6K, 805.386.3734.  www.somis.org