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Re: [Amps] How to read the 3-500Z spec sheet?

To: Jeff Blaine AC0C <>
Subject: Re: [Amps] How to read the 3-500Z spec sheet?
From: Martin Flynn <>
Date: Sun, 23 May 2010 20:03:00 -0400
List-post: <">>
No insult intended -  It was a legit question based on what I had been 
exposed to so far.  

As a side note, I  am looking for a service monitor.    I also need some 
sort of two-tone source & if the sound card is good enough for a 
beginner, thats what I am going to use.

73 de Martin       

Jeff Blaine AC0C wrote:
> Martin,
> There are 2 ways to look at this.  If you look at it from a "is this 
> the official lab-standard proper way" standpoint, it comes up a 
> loser.  I'm not suggesting it is.
> And If you look at it from a "is it a step in the right direction" and 
> "can it be done by average joe ham for a few bucks" and get somewhat 
> interesting results - the answer is yes.
> If guys want to keep peppering me with the details of proper IMD 
> measurement, we can do that - but it's a sidebar to my key point.  I 
> get it. This is not a proper Grandberg setup.  So for all those guys 
> who are reading this or are sending me little off line mail about "IMD 
> measurements 101," give me a break.  You are missing the point.
> Better the guy use a ruler to measure things than none at all.  If one 
> headlight burns out in my car, I don't turn them both off because "if 
> it's not perfect, then it's not worth doing."  There is no point to 
> debate that a ruler is not as good as a caliper and my mailbox is 
> filled with guys making that comment.  Even if the ruler is a gross 
> approximation, the simple effort of looking at it raises awareness in 
> an area of the hobby that as far as I can tell, gets damn near zero 
> attention.  Well unless someone mentions certain down-under amp 
> suppliers, anyway.
> Is better to have some newbie cranking away on his amp or his rig 
> without any thought at all to the stuff going out his pipe - than it 
> is to have him use less than perfect test setups?  Not here, at least 
> here in the fly over country of KS.
> But then again, I've got a lot of inbox nonsense suggesting I don't 
> know what I'm talking about.  Maybe that is the case...
> 73/jeff/ac0c
> --------------------------------------------------
> From: "Martin Flynn" <>
> Sent: Sunday, May 23, 2010 3:06 PM
> To: "Jeff Blaine AC0C" <>
> Cc: <>
> Subject: Re: [Amps] How to read the 3-500Z spec sheet?
>> Jeff,
>> Is using a sound card good enough?  One of my elmers <sk>  had a 
>> dedicated two channel audio generator for testing.
>> Motorola published a white paper by  Helge Granberg  on IMD 
>> measurements:
>> Martin
>> Jeff Blaine AC0C wrote:
>>> Of course, a real IMD test requires a 2 -tone source and you can 
>>> download those applications on the web free of charge.  A good quick 
>>> and dirty solution is to switch your digi mode application over to 
>>> PSK.  In fact, if it were up to me, it would be a legal requirement 
>>> for all PSK ops to have station monitors of this type when running 
>>> PSK.  Lot of misinformation and nonsense in that community among the 
>>> rookie ops.

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