[ARC5] "Curing Chirp in Command Transmitters"

[Glen Zook via ARC5]

Whether or not the heaters run from AC or DC doesn't really matter.  The tubes have indirectly heated cathodes which are independent of the heater voltage source.
 
Glen, K9STH 

Website:  http://k9sth.net


On Sunday, October 5, 2014 6:13 PM, AKLDGUY . <neilb0627 at gmail.com> wrote:
 


> The justification is that airplanes of that time had DC power @24/28V!

Well gee, I knew that back in 1965 when I first started playing with
Command sets.
Yes, 1965. Maybe before you were born, lol.

Lately I've come to question the need to modify the VFO wiring when
using AC for
the heaters.

The typical mod back then was to disconnect the 1626's heater pins from the
VFO
circuitry and connect them directly to heater line and ground.

On re-appraising the circuit recently, I think there's no justification for
doing that.

73 de Neil ZL1ANM

On Mon, Oct 6, 2014 at 11:56 AM, Francesco Ledda <frledda at att.net> wrote:

> The justification is that airplanes of that time had DC power @24/28V!
>
> Sent from my iPhone
>
> > On Oct 5, 2014, at 17:49, "AKLDGUY ." <neilb0627 at gmail.com> wrote:
> >
> > Yes but what is the technical justification?
> >
> > 73 de Neil ZL1ANM
> >
> > On Mon, Oct 6, 2014 at 11:26 AM, Kenneth G. Gordon <
> kgordon2006 at frontier.com
> >> wrote:
> >
> >>> On 6 Oct 2014 at 11:17, AKLDGUY . wrote:
> >>>
> >>> I can't think of a good reason to run the heaters on DC.
> >>> Can anyone suggest one?
> >>
> >> Yes. Because the transmitters (and receivers) were designed for DC, not
> AC.
> >>
> >> Ken W7EKB
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