[Milsurplus] RE: GB> ART-13

[Mike Hanz]

I'll agree with Meir, but for a slightly different reason.  The cooling 
of this transmitter was exquisitely engineered (and fine-tuned 
empirically) for the heat load presented by the system of tube heat 
radiation and other resistive losses within it.  If you provide the 
requisite inch or so of clearance between the bottom of the transmitter 
and the shelf it sits on, then it will have a long and happy life.  
Start fiddling with voltages and you will destroy that heat balance in a 
hurry.  Yup, hams have done it for a long time...I have heard, perhaps 
apocryphally, of 500 watt ART-13s using blowers on the back in an 
attempt to cool the thing.  Makes no sense to me when you can just build 
an amplifier, but then some folks always like to push the envelope. :-)

73,  Mike  KC4TOS

wf2u at ws19ops.com wrote:

> It's not that the 813 can't take a higher voltage, but the ART-13 was  
> designed to run on around 1100 V on the 813. This is the way the  
> resonant circuit was designed to match the 813 impedance at this 
> plate  voltage/current. Some of the components may be rated at a 
> higher  voltage, but why mess with a good design and long 
> tube/component life  for a few more watts?
> The modulation transformer is a design marvel, as it is physically  
> small for its rating. I heard some people running it with double the  
> audio power it was designed for, but again - what for?
> I'll never use my ART-13's with anything but the voltages it was 
> designed for.
>
> 73, Meir WF2U
>
>
> Quoting Hue Miller <kargo_cult at msn.com>:
>
>>
>>
>> What B+ are people using on the 813 ? I think the original
>> dyno supply was 1100v, which is a bit on the low side for
>> an 813, but possibly the modulation transformer will not
>> stand a higher power level ?  -Hue Miller
>
>
>
> ______________________________________________________________
> Milsurplus mailing list
> Home: http://mailman.qth.net/mailman/listinfo/milsurplus
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Milsurplus at mailman.qth.net
>
>