[ARC5] "Curing Chirp in Command Transmitters"

Brian brianclarke01 at optusnet.com.au
Mon Oct 6 02:37:54 EDT 2014


Hello Ken,
I wondered about that heating effect, too. Already the insides of the Tx get 
heated from the proximity of the 1625s, 1626 and 1629. That heat flow is 
from the tubes to the osc coil. But in un-pressurised aircraft - prevalent 
in WWII - the Tx could get quite cool. Perhaps this small amount of heating, 
in a totally enclosed chamber provided some stability?
Having discovered how operations and maintenance manuals get generated, I'm 
always a little sceptical of explanations of theory of operation in them. I 
take them as interesting opinions.
73 de Brian, VK2GCE.

On Monday, October 06, 2014 4:44 PM , Ken said to Neil:

On 6 Oct 2014 at 13:34, AKLDGUY . wrote:

> Pins 7 and 8 are connected to a tap on the VFO coil (it's a type of 
> Hartley
> oscillator). Now, obviously the cathode and heater currents flow through 
> part of
> the VFO coil, from the tap to ground.

Yes. And is this current NOT likely to cause localized heating of that 
portion
of the VFO coil, and thereby contribute to drift?

Ken W7EKB 



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