[Milsurplus] BC-342 N Question

[Glen Zook]

Some background "hiss" is going to be present in every tube-type receiver that I know of when the audio gain is wide open.  Basically, every tube has a noise figure.  Even solid-state equipment is going to have some background noise with volume at maximum.

Mixer stages often contribute more to the noise than other stages.  But, both the r.f. stages and the i.f. stages are going to contribute to noise as well.

My particular BC-312M has had most of the components, except for the frequency dependent capacitors in the shielded portions, replaced with new components.  There is still a fair amount of noise when the antenna is disconnected and the audio gain and r.f gain run at the maximum.  

http://k9sth.com/uploads/Restoration_of_BC.pdf

 
Glen, K9STH


Website:  http://k9sth.com


________________________________
 From: Laura and Jim <mcenfalz at humboldt1.com>
To: milsurplus at mailman.qth.net 
Sent: Tuesday, April 2, 2013 7:30 PM
Subject: [Milsurplus] BC-342 N Question
 
Triggers a memory - I have a BC-312-M and there's always a background hiss then in dead air, 200V B+, and the volume is turned all the way up. I seem to recall discussion of "noisy mixer tubes" but can't place where it took place. Any ideas?