[ARC5] Voice modulation too loud in headphones on SCR-274

[David Stinson]

From: J Mcvey [mailto:ac2eu at yahoo.com] 

Subject: Re: [ARC5] Voice modulation too loud in headphones on SCR-274

 

Aha! that makes sense. I though that the tel jacks were there for "local operation". However the NOS racks come with these switches capped in the off position , so they were never meant to used at a radio desk?

What size attenuation resistor do you recommend?.

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AAC Tech Order #08-10-50 Feb. ’43, Para. 2-3f, states the modulator supplies sidetone to the aircraft Interphone system.  The jacks on the racks and control box are indeed supplied with both receive audio and sidetone, but were not intended for regular operation (although it certainly was done in some instances).  

 

I haven’t investigated an acceptable attenuator for pin1 on the PL-151.  I just opened the sidetone line.  No reason to leave it open, other than I just haven’t spent the time to determine an answer for it.

 

73 OM DE Dave AB5S


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