[AMPS] ClippertonL Help

[measures]

>
>Recently picked up a well used Clipperton. Has 4 new 811A's that I plan on
>using with the lower plate voltage. 

With a rated diss. of only 65w, 811s do better when tuned with a tuning 
pulser.  However, if you have a free supply of new tubes, you needn't 
bother.  

>Have some questions that hopefully can
>be answered here.
>1. I assume the 9.1 Zener is used for idling plate current via the relay on
>TX.

correct

>2. Also assume the 47k resistor via the relay is for cutoff bias on RX also
>via the relay.

yes - but a g-g amp will work fine business without one.  

>3. I used a 47ohm/220pf combination on each grid to ground as did Collins in
>the 30L1. That should get 4.7 volts bias on each grid with the thought that
>with about 1700 volts on the plates some bias would be needed.
>4. Why no filament center tap. If I need to, can I use a 22 ohm resistor
>from each side of the secondary to make one ??

not enough conductivity.  A pair of 2.5-ohmers in series make a better 
semi-CT. 

>5. What is the recommended safety for spikes? I used 10 ohms in the B+ line,
>are back to back diodes still the cure on the B- ??

For limiting the drop across the grid-current meter shunt R, 3A diodes 
work fairly well.   1a diodes are prone to fail.   

>6. Tuned input, can anyone send me the values needed for 10-160 especially
>160 as the HB has 10-80 that I guess would be OK.
>7. Can a parallel tuned circuit be used on the input rather than a pi. or is
>the bandwidth too narrow without a pi?
>
 pi  networks with a Q of 2 is what works best.  

cheers, Ed.  

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


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