[ARC5] Grid Blocked Keying an ARC-5

[Bill Cromwell]

On 01/13/2014 09:55 PM, Kenneth G. Gordon wrote:
> Sounds good, Doug. Let us know your results. However, one thing I left 
> out of the previous discussion: be sure to ground the + (plus) sides 
> of the full-wave bridge rectifier and the electrolytic caps, leaving 
> the - (negative) sides completely UN-grounded and hard-wired 
> "through", so you get a NEGATIVE 120VDC out of your supply. In such a 
> supply, the negative side is the "hot" side. Connect your resistor in 
> the "hot" side, between the two negative leads of the caps. It will 
> look "funny" to you, since the electrolytics will look like they are 
> "upside down"...but they ain't. If you are using a tube-rectifier like 
> a 5Y3, you ground one side of the filament, and use the center-tap of 
> the transfomer as your negative voltage output. The filter is the same 
> as the SS version: + (positive) sides of the caps grounded, - 
> (negative) sides connected "through" with the resistor (or choke) 
> between them. If your 120 VDC is positive, you will blow up your 
> tubes. Kenneth G. Gordon W7EKB "Courage is being scared to death but 
> saddling up anyway."--- John Wayne

Grid blocking gets even better. It can be used to also control the 
receiver shifting from receive to "standby" and setup to allow the 
receiver to hear your transmitter instead of using an artificial 
sidetone. Electronic T-R antenna switches block use transmitted RF to 
block the grid (or gate) of the switch tube (or FET), too. Are you ready 
for more fun?

73,

Bill  KU8H