[AMPS] AL-80 / SB-1000 circuit improvements

[measures]

To owners of SB-1000s and AL-80s:  :

The B+ to gnd bypass cap. (C-23 in SB1000) at the base of the HV RFC 
(RFC-3) is 1000pF.  At  1.8MHz, 1000pF has -j88 ohms of reactance.  It is 
my opinion that 88 ohms is not a sufficient bypass.   My unsolicited 
advise is to:

1.   parallel more C with C23 to keep RF away from PS components during 
160m and 80m operation.  
2.   add a glitch protection resistor in the B+ lead. 
3.  add 200a-pk glitch diodes to protect the meter movements.  
4.  disregard the users' manual's ok of more than 500mA of anode current. 
 No 3-500Z/8008 manufacturer has Ever rated this tube at more than 400mA. 
 
Might not the designer improve his credibility if he corrected his 
misstatement?.  

good luck.  

-  Rich..., 805.386.3734, www.vcnet.com/measures.  
end


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