[ARC5] Smart People: Multi-Set Current Corn-fusion

[Mike Feher]

Dave -

 

That must have been a pretty dim bulb, HI, as that answer is obvious. You
could try using a sig gen that has tone modulation Use it individually,
resetting frequency and making sure each set puts out the same audio. 73 -
Mike

 

Mike B. Feher, N4FS

89 Arnold Blvd.

Howell NJ 07731

848-245-9115

 

From: arc5-bounces at mailman.qth.net [mailto:arc5-bounces at mailman.qth.net] On
Behalf Of David Stinson
Sent: Sunday, December 3, 2017 9:47 AM
To: 'Mike Feher' <n4fs at eozinc.com>; 'ARC-5' <arc5 at mailman.qth.net>;
milsurplus at mailman.qth.net
Subject: Re: [ARC5] Smart People: Multi-Set Current Corn-fusion

 

 

From: Mike Feher [mailto:n4fs at eozinc.com] 

When you have just one set on, did you include the off current of the other
sets. How were the measurements made? 73 - Mike 

----------

 

Have them all on a common B+ buss, fed from a regulated, current-limited
supply.  Individually, when off, the sets should draw about 4 mA each
(screen dividers).  Current is measure both at the supply and via a Fluke
bench meter in the Negative lead.  Individual set current measurements do,
therefore, include the currents from the two "off" sets, but that should
amount to no more than 8 or 9 mA additional.  With all three sets playing at
identical levels, we seem to have 34 mA missing here.

 

A dim bulb just went off in my head.

The DC current isn't constant; the current varies with the receiver output,
especially the Audio PA output.  Bench meters "average" the current over
time.  Since the three receivers are outputting different waveforms if
plotted over time, the average of the currents will not be a straight sum of
the individual currents, but rather an *averaged* sum of all three over
time.  i.e. At any one instance in time, Set 1 may be at full output and
pulling 50 mills, while set 3 is silent pulling 5 mills and set 3 is in
between, pulling 20 mills.   Total at that time: 75 mills.  Take an average
over a long enough time and 83 mills is probably right.  What do you think?
Somewhere close?

73 Dave AB5S

 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/arc5/attachments/20171203/76e079ec/attachment.html>