[Heath] HP-23 power supplies - an idea and some questions.

[Glen Zook]

Methinks you mean 3 dB instead of 1 dB with an increase from 100-watts to 200-watts.  However, even that increase will not be noted in most situations.


As far as why Heath increased the voltage:  A new power transformer was used in the HP-23A that had dual primary windings for 120 VAC and 240 VAC.  Since a new transformer was being used, Heath went ahead and increased the secondary voltage as well to increase the power on the HW-10X and SB-1XX slightly.  Of course, Heath was never conservative on the power ratings of their transmitters.  Having the slightly higher voltage did allow the equipment to come closer to the power ratings.  However, it has been my experience working on a lot of Heath equipment that to make the power claimed by Heath involved pushing the 6146 final amplifier tubes often to beyond their ratings.


Remember, the original 6146 and 6146A / 8298 were rated at 90-watts for Class "C" operation, 85-watts for AB-1 / AB-2 for SSB, and 67.5-watts for AM (all input ratings).  Heath pushed the tubes very hard for both SSB and AM operation.  Of course, back then, the 6146 was in production and very common.  Therefore, who worried if the tubes did not last as long as possible!

 Glen, K9STH 
Website: http://k9sth.net

      From: Kenneth G. Gordon <kgordon2006 at frontier.com>
 To: Heath at puck.nether.net 
 Sent: Sunday, February 4, 2018 7:35 PM
 Subject: Re: [Heath] HP-23 power supplies - an idea and some questions.
   

You are absolutely correct, of course. 

In fact, in order to increase the signal level at the receiver enough to hear a difference, one 
must double the output power of the transmitter. 100 watts to 200 watts for 1 db difference 
at the receiver.

1 entire S unit (or 6 db, i.e. a power ratio of 4) increase at the receiver requires increasing 
transmitter output power from 100 watts to 400 watts. Then another S unit above that 
requires 1600 watts. No thanks.

I am not concerned about power output here: to my way of thinking, the lower voltage simply 
"isn't right.".

If it was not important, why did Heathkit change the AC voltage from 268 to 282?

Are there deleterious effects due to the lower voltage OTHER THAN power output? I 
suspect so. 

Screen-grid issues come to mind.

But none of the above concerns me.

So, I still have not gotten an opinion or an answer to my question: is it likely that the 410 
VDC across the 12.6 V winding of the added transformer is too much, or is it acceptable?

If no one knows, I believe I'll try it to see. Empirical evidence is always good.


   
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