[Collins] Odd symptom and S meter reading

[Gerald Johnson]

Microphone connections? Not necessarily the same as a Drake which uses the same plug. What is the audio like using VOX?

The S-meter reads properly for all settings of the RF gain control. The RF gain control inserts a DC bias into the AGC line to set a threshold for the S-meter.

The S-line has always been considered to have a stingy S-meter. Extra stinginess can come from weak tubes, poor alignment, leaky AGC bypass and time constant capacitors, leaky screen bypass capacitors (and the S-line used several abominable black beauties that are know to be leaky well before age 44), and agc controlled tubes with grid emission.

73, Jerry, K0CQ, Technical Advisor to the CRA
---------- Original Message ----------------------------------
From: Jim Isbell <millenniumfalcon@cableone.net>
Date:  Fri, 21 Nov 2003 21:36:13 -0600

>I have an odd symptom on my 1958 S-Line.
>
>When I key my transmitter using the PTT on the microphone base I get 
>very low level of audio modulation and it is unreliable.  But if I , 
>instead, use the "Function" switch on the station console to switch 
>between "Rec Only" and "Trans Only", the modulation is fine.  I can hear 
>the relay click in both cases, but for some reason the audio is not 
>there if I use the PTT.  Does anyone know what would cause this?
>
>Second question.  I am assuming that the signal strength meter reads 
>properly when the RF gain is full clockwise.  But I find that even with 
>a signal that is very strong, I never see an S9, usually only about S7. 
> When the meter doesn't even come off the pin I can still get loud 
>readable audio.  Is this stingy meter normal?
>
>