[ARC5] BC453 on 24V - screen voltage

[Kenneth G. Gordon]

On 10 Dec 2019 at 21:07, Hubert Miller wrote:

> I was surprised to read in some National Radio Co. receiver manuals -
> HRO-60 and  others - that the allowance for B+ was -50%. In this
> particular receiver, 270 to 135 volts, without change. If possible, I
> prefer to run at the lowest figure. Less heat, less stress.

I agree.

> Some
> military radios run the B+ quite high, like I think the TRC-10 at 300
> volts. Some few ham radios do too, and I'm thinking those are mostly
> mobile equipment. One thing I have admired about post-WW2 Japanese
> shortwave and ham radios is that they tend to use "calm" B+ voltages,
> like in the 120 - 150 volt range. -Hue

I have mentioned this next before concerning that issue: some time ago, like eons, I read an 
article in, I think, CQ Magazine, wherein the author experimented with reducing the DC 
operating voltage in a Drake 2-B receiver to see what would happen.

He found that the receiver still worked adequately at 12 VDC, although, as expected, audio 
output power was severely reduced.

He commented especially on how little apparent receiver noise there was at lower voltages.

He finally raised that voltage to about 50 VDC and left it there.

As I have mentioned, in my case, I found that with the "ARC-5" receivers, about 170 VDC 
was the "best", since at that voltage audio output power remained "high". Otherwise, it 
dropped off rather drastically.

RF and IF operation did not seem to be effected at all at even lower voltages.

Ken W7EKB