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[AMPS] Setting the record straight--Dick Ehrhorn

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Subject: [AMPS] Setting the record straight--Dick Ehrhorn
From: (2)
Date: Wed, 18 Jul 2001 10:34:20 -0700
>> Dick Ehrhorn clearly has more experience than I do--
>> but I have used (roughly) more than a 1,000 Eimac
>> oxide-coated cathode type tubes without any issues
>> due to VHF parasitics.  Maybe I am just lucky or maybe
>> the design was good.  I'll let you decide.
>> Of course this does not cover any Eimac tubes that have
>> had manufacturing problems--such as the heat dam issue
>> for which the 8877s are notorious.  (Occasionally Eimac
>> has had brain-flatulence issues with which to contend.)
>> John  W0UN
>Everyone else in the world seems to share your and Dick's 
>experience John. 

/\  The excursion on the wide river in the Land of the Pharoahs 

> The only place parasitics cause tube failures is in 
>the mind of the fellow who sells kits that "fix the problem".
/\  Have you seen Figure 24 on my Web site?  Have you seen the photograph 
of the gold-sputtered tube in "Parasitics Revisited" (September/October, 
1990 *QST*?  
>73, Tom W8JI
/\  A low VHF-Rp parasitic suppressor retrofit-kit never absolutely fixes 
the problem.  It lowers VHF amplification in HF applications by c. 60%, 
and it provides glitch protection just in case a parasite ever takes 
place.  So far, we have sold more than 5k low VHF-Rp parasitic suppressor 
retrofit kits.  I keep thinking the market will saturate but it hasn't 
thanks to the AL-1500 and other somewhat less than stable HF amplifiers. 

Cheers, Mr. Rauch

-  R. L. Measures, 805.386.3734,AG6K,  

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