[time-nuts] Re: HP Z3801A project update

[Tom Holmes]

HI Ed & Ed...

Thanks for the plot. The dive towards zero just before the spike s surprising; maybe a funky data point?

Anyway, I'm not doubting that the observations are correct, just curious about the timing and source of that power spike. Like maybe the controller decided it wasn't heating fast enough?

Tom Holmes, N8ZM

-----Original Message-----
From: Ed Palmer <ed_palmer at sasktel.net> 
Sent: Saturday, January 29, 2022 11:07 AM
To: time-nuts at lists.febo.com
Subject: [time-nuts] Re: HP Z3801A project update

On 2022-01-29 2:30 AM, "Tom Holmes" <tholmes at woh.rr.com> wrote:
> Ed...
>
> Very good data!
>
> I am curious about one part of the warmup process. At around 7 minutes, the power jumps up radically, which you attribute to
> the outer oven kicking in. It has often been stated on this list that the outer oven was intended for use during really cold
> starts, which I would expect should cause it to kick on almost immediately during a very cold start. I am assuming your start
> was from room temperature. For a room temp start, I wouldn't expect it to kick on at all  if it's purpose was as reported. Or
> do I have the oven functions reversed?
>
> Tom Holmes, N8ZM

I can confirm Ed's tests.  Attached is a similar test that I did on my 
Z3801A.  If it matters, mine is the 24V nominal version.  My test was 
done at 27V.  The power supply was an HP6622A with GPIB.  I wrote a 
program to query the current being drawn each second.  The current value 
was later converted to power.

Ed