[1000mp] Mark V PA failure. Need source for devices

[Adam Farson]

Hi Rob,

In 2004, I did a brief analysis of Class-A exciter operation, and wrote a
brief article on the subject. Here is the link:

http://www.ab4oj.com/icom/pro_notes.html#imd

Cheers for now, 73,
Adam VA7OJ/AB4OJ
 

-----Original Message-----
From: 1000mp-bounces at mailman.qth.net [mailto:1000mp-bounces at mailman.qth.net]
On Behalf Of Rob Atkinson
Sent: Monday, August 06, 2007 20:34
To: All about Yaesu 1000mp
Subject: Re: [1000mp] Mark V PA failure. Need source for devices

Hi Martin,

the pa gets fried running class A because the operator usually does not
understand that in class A the rig has to dissipate _more_ heat running 
low power than it does at the rated maximum.   so owners turn down the 
PA collector current pot (usually labeled drive or power) thinking they 
are saving the PA when in fact they are doing more damage.  anyway,   
class A is  supposed to put out a low 3rd order IM product compared to class
AB but when you get it fixed I'd forget about class A, make sure the heat
sink fan is working and limit it to a pep of 175 w. on ssb and save the PA.

73

rob / k5uj




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