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

[Kenneth G. Gordon]

Excellent, Glenn, and thank you.

As for the 6293, I found out long ago what a really good tube that was. I installed one in my 
original DX-35 in about 1960. It is too bad there were so few of them made.

They are getting almost impossible to find any more.

On 5 Feb 2018 at 16:12, Glen Zook wrote:

> 
> An increase of power, times 2, which going from 100-watts to 200-watts 
> represents, is a 3 dB increase.  The formula for a dB is 10(log).  The logarithm for 
> 2 (twice the power) is 0.30103.  Therefore, twice the power is 3 dB.  However, at 
> the receiver, the voltage increase is not 2.  It takes a 6 dB increase in voltage for 
> twice the voltage.  For a 2-times increase in power, the voltage, at the receiver 
> will increase by 1.414.
> 
> Here is an article, from my website, that explains why this happens:
> 
>  http://nebula.wsimg.com/87fa72d0e2a5447f6496b4a6476ef1df?AccessKeyId=D1
> 250C433DB440D6B60D&disposition=0&alloworigin=1
> 
> As for using the 8032 in place of the 6146A / 8298, I do that all the time in 
> equipment that utilizes a pair of 6146 tubes with the heaters ("filaments") wired in 
> series for 12-volt operation.  You can also use the 6883 which is the 12-volt 
> equivalent of the original 6146.  The 6883A / 8032 is exactly the same as the 
> 6146A / 8298 except for the heater voltage.  The 6293 is the pulse modulator 
> version of the 6146A / 8298 (has a 1000-watt pulse input rating) and those tubes, 
> when run at the same level as the 6146, can last up to 10-times longer, certainly 
> at least 5-times longer.
> 
> Here is the article on the 6146 family of tubes that has appeared in 73 Magazine, 
> Electric Radio, Collins Signal, and several European amateur radio publications:
> 
> http://nebula.wsimg.com/e7364f5298b88b460a668216b4be5946?AccessKeyId=D
> 1250C433DB440D6B60D&disposition=0&alloworigin=1
> 
> Having an input, for a pair of 6146 or 6146A / 8298 tubes for CW, of 180-watts is 
> within the maximum ICAS ratings (RCA ratings).  However, for AM operation the 
> maximum rating, again for a pair of those tubes, is only 135-watts.  The Johnson 
> Viking II is the only popular transmitter that was rated at 135-watts input for 
> phone operation.
> 
> The Heath DX-100 was rated at 125-watts OUTPUT for phone.  Assuming an 
> efficiency of 70%, that means an input of right at 180-watts.  This exceeds the 
> ratings by 45-watts or 33.333%.  The rating for CW is 140-watts output which, at 
> 70% efficiency means an input of 200-watts.  That is a bit better because it is only 
> 20-watts over the maximum ICAS ratings or about 11%.
> 
> Heath, for the TX-1 Apache, got the ratings a lot closer but still a bit too much for 
> phone.  The Apache did not have a power output rating.  Instead, the Apache 
> was rated at 180-watts input for CW and 150-watts input for AM.  The AM rating 
> is still over the maximum rating by 15-watts which, again, represents about a 11% 
> margin.
> 
> The maximum plate dissipation for the 6146 and 6146A / 8298 is 25-watts.  
> Technically, Heath only exceeds this by 5-watts per tube or 20%.  However, 20% 
> is a lot and, in the real world, 70% efficiency is not going to happen as the tubes 
> "age".  The efficiency will drop, over time, and that means when the same power 
> is run, the actual plate dissipation will increase because the input power has to be 
> increased to get the same output power.
> 
> Collins rated the 32S-1, 32S-2, 32S-3, 32S-3A, KWM-2, and KWM-2A at 
> 100-watts output for 80, 40, and 20-meters, 90-watts output for 15-meters, and 
> 80-watts output on 10-meters.  
> 
> Reducing the power 10% from the maximum ratings generally will increase the 
> life of the tubes by a factor of about 3 and reducing the power 20% from the 
> maximum generally will increase the life of the tubes by a factor of 10.  Even a 
> 20% reduction will almost never be even noticed by the operator on the "other" 
> end of the QSO.  However, the tubes will definitely know the difference!  
> Considering the fact that the tubes are becoming less, and less, available, at 
> least to me, doing whatever possible to increase the lifespan is certainly a good 
> thing.
> 
> Since today's equipment ratings are in power output, many operators do not 
> realize that, for many "boat anchor" transmitters, the power rating is for input, 
> those operators try to get the rated input power as output power and that causes 
> all sorts of problems!
>  
> Glen, K9STH 
> 
> Website: http://k9sth.net

Ken W7EKB

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