[AMRadio] HRO question for the day

Larry Szendrei ne1s at securespeed.us
Sat Dec 19 14:01:12 EST 2009

Bernie Doran wrote:
> National decided in the HRO50 design to use a 4.3 Ohm resister in series 
> with the fil of both 6H6  dual diodes, ( noise blanker and detector) 
> dropping the fil to about 5 v.   In the Hro 50-1 the noise blanker 6h6 
> operates at normal Volts and the detector still at reduced voltage. I see no 
> reason for this and the tube data sheets do not address lower volt 
> operation. only effect I notice is that it takes several minutes for the 
> detector to warm up and produce audio. It can not be for life as when this 
> was designed and built 6h6s were cheap, still are.  certainly not to save 
> energy or battery operation.  perhaps it fools the detector into something 
> other that a square law detector due to low emission.  tube life would be 
> extended, but so what, this is not a transmitting valve and the only one I 
> have seen where reduced voltage is recommended for standby is the 813, data 
> recommends 8 volt when on standby and I have never done that or seen one 
> used that way.  So does anyone KNOW why national did this?    I have never 
> seen this in Collins so it must be wrong!!!! HI   Bernie W8RPW 

Hi Bernie,

This has nothing to do with your excellent question, but I thought I'd 
let you know I'm pretty sure I heard you last Thursday night down on 80M 
(not 75M) AM talking to a VE3. Let me know if that was you.

I was just casually scanning for an AM QSO, on an old Sky Buddy, to 
listen to while I stoked up the coal stove for the evening, and came 
across you (if that was in fact you). Nice signal into Maine. You sound 
younger on the air than you do on the reflector :-)


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