[TenTec] Herc II Power Source Redux

[Michael Melland]

I don't mean to whip a dead horse but I think a reasonable 
power source besides batteries might interest a few on the 
list besides me.... if my email is any indication.  Here 
is what I have found regarding power supplies as of now...


I had been advised that possibly placing two Astron power 
supplies in parallel was an option to provide power to the 
Herc II.  I had called Astron and they stated that this 
could be done and "generally" it would work fine.  I 
didn't really get an answer when I asked what "generally" 
meant.

One of the engineering professors here at the college 
where I work tells me (as did Astron) that it is critical 
that both supplies provide the same voltage.  Astron tells 
me that you just adjust one supply to within 50 ma of the 
other prior to hooking them up.  The good professor tells 
me that this might not be a good idea 'cause the amps will 
differ their respective output under load and if not 
closely matched under load may self destruct.  He tells me 
that laboratory supplies apparently have some way to track 
one another so this doesn't cause problems. Astron tells 
me that there supplies do not track. Anyone ever have a 
problem with this ?

My other option (besides what appears to be the most 
popular power source... batteries) is to utilize one of 
the new generation of switching supplies.  The supplies 
being considered are made by IOTA and are available in 75 
and 90 amp versions.  On paper they look pretty good and 
the mfg tells me they are purchased for use in 
communications installations by Harris and others and are 
generally considered to be RFI free in the ham bands. They 
are allegedly filtered and bypassed for RFI.  The IOTA 
supplies are also sold to OEM's and re-badged and sold 
under the names "Duracom" and "CAE" (cascade audio 
engineering) among others. 

The new IOTA 90 amp continuous switcher weighs 7.8 lbs and 
draws a maximum of 21 amps @ full load at 108 volts (worse 
case scenario) so if RFI free is quite the option for the 
Herc.... especially at the $360 shipped price it can be 
found at compared to the cheapest Astron dual supply price 
of $560 shipped.

I found a third supply that is a linear supply and very 
inexpensive at under $300.  It's advertised as an 80 amp 
supply and marketed by Okura USA under the name Nippon 
America.  However... it's instructions caution that the 
amp is designed for "light duty" and one should be careful 
using it at close to it's maximum ratings.... so much for 
that one <grin>.

Is anyone using a IOTA, Duracom or CAE switcher on the 
list that can comment on RFI?

Mike, W9WIS 



--
Michael Melland, W9WIS
Winneconne, WI USA