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Re: [Amps] Measuring RF Power

To: <amps@contesting.com>, "Alek Petkovic" <vk6apk@eon.net.au>
Subject: Re: [Amps] Measuring RF Power
From: "Dr. William J. Schmidt, II" <bill@wjschmidt.com>
Reply-to: "Dr. William J. Schmidt, II" <bill@wjschmidt.com>
Date: Mon, 28 Mar 2005 08:39:21 -0600
List-post: <mailto:amps@contesting.com>
I agree....  Lots of good discussion.

Sincerely,

Dr. William J. Schmidt, II  K9HZ
Trustee of the North American QRO - Central Division Club - K9ZC

Email: bill@wjschmidt.com
WebPage: www.wjschmidt.com

"If computers get too powerful, we can organize them into a committee; that 
will do them in."  -- Bradley's Bromide


----- Original Message ----- 
From: "Alek Petkovic" <vk6apk@eon.net.au>
To: <amps@contesting.com>
Sent: Monday, March 28, 2005 6:54 AM
Subject: Re: [Amps] Measuring RF Power


> It is surely the best thread we have seen on this reflector in a long long
> time. Very comprehensive, informative and lots of fun to follow.
>
> Thanks to all,
> Alek. VK6APK
>
> At 08:33 PM 27/03/2005, David Kirkby wrote:
>>John and Mary Powell wrote in a different thread:
>>
>> >Is there a body of opinion out there that considers the above subject
>> has gone on far too long, or got out of hand. To me it appears as if
>> academic intransigence has got in the way of the Reflector dealing with
>> it's core business. I noted an earlier plea for an end to of
>> this  uninteresting topic, which evolved from a simple enquiry as to
>> accuracy of the Bird 43 Wattmeter.
>> >
>> >Cheers
>> >John Powell. ZL1BHQ
>> >_______________________________________________
>> >Amps mailing list
>> >Amps@contesting.com
>> >http://lists.contesting.com/mailman/listinfo/amps
>> >
>> >
>> >
>> >
>>
>>I'm not keen on a thread being split up for no good reason. Someone
>>started this thread with the title 'Measuring RF Power' and so why
>>ZL1BHQ starts a new thread 'MEASURING RF POWER' complaining about the
>>original subject going on too long is beyond me. Most people use mail
>>clients that that are capable of following a thread, and collapsing that
>>down to one line. Most mail clients can be configured to automatically
>>delete something with a particular title.
>>
>>So if you don't like a thread, just collapse it to one line in  your
>>mail client, or do an automatic deletion, so it takes up zero space.
>>Hence I decided to reply under the original thread, not the new one that
>>has been started for no good reason.
>>
>>By starting a new thread, you have of course screwed it up for someone
>>who was choosing to ignore the thread - now they have a second one to
>>ignore. It also means when it is archived, someone interested in the
>>subject will not see all the posts if they follow the thread, since it
>>got split. Hence I'm not replying to the new thread, but under the old 
>>one.
>>
>>Now to address the comments of ZL1BHQ:
>>
>>I think you are right to suggest there is a body of opinion that
>>consider the above subject has gone on for far too long. Those might 
>>include
>>
>>1) People who want just simple things, and don't wish to learn any more.
>>
>>2) People who were wrong, and don't wish to admit it.
>>
>>Sure, the thread is technical in nature, but less so than other threads
>>that have appeared on here before, and with less mystique about it.
>>
>>However, there is also a body of opinion that thinks it is:
>>
>>1) Relevant to amplifiers. They do produce RF power, so measuring it is
>>a pretty good idea.
>>
>>2) There is a 22.5% difference between the mean and RMS values of power,
>>so the replies by some of "who cares anyway" seem odd, when there are
>>quite a few who would care about a 22% difference in power levels.
>>
>>3) Within their grasp to understand.
>>
>>To follow the paper written in Laymens terms
>>http://www.eznec.com/Amateur/RMS_Power.pdf
>>you need the level of maths and electronics any radio ham should be able
>>to handle if they put their mind to it.
>>
>>To understand the formal definition of RMS (using integration) a level
>>of mathematics that I had learnt at school by about the age of 16 will
>>suffice.
>>
>>4) A new topic discussed, and not the same old arguments being used
>>about a topic that comes up again and again, year in and year out.
>>
>>It's also possible the topic has greater implications that some of you
>>think. Someone wrote to me and said
>>
>>"Several years ago I did not realize, like many others, that there was
>>no RMS power calculation that was useful. I ran into problems when
>>looking at tube curves and trying to calculate power levels. Nothing
>>came out quite right. Once I figured out the average power stuff then it
>>all fell into place.  Same thing when trying to figure Peak envelope
>>power. The rms power figure will screw things up. "
>>
>>Should a thread go too far "off topic" then I can see a point in
>>requesting it is dropped, or moved to private email. But this is very
>>relevant to RF amplifiers.
>>
>>--
>>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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>>Amps@contesting.com
>>http://lists.contesting.com/mailman/listinfo/amps
>
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>
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