[Heathkit] Heath AT-1 info

[Bwana Bob]

My recollection is that 7-8 W is about what a 6L6 will do. Heath 
probably put the meter in the cathode circuit, so what you are measuring 
is the plate current plus the screen current.


					73,


					Bob WB2VUF

Van K7VS wrote:
> Interesting:  I don't know if anyone else has actually spent any time 
> using one but I have discovered the following:  Mine has 485 volts DC 
> under load, key down and 535V DC key up.  Original iron vane meter shows 
> 58 ma. into a 52 ohm dummy load.  That amounts to 28 watts input.  
> Heathkit says in the older catalogs approximately 25 to 30 watts input.  
> However, one would think that you should see minimumly  50% effeciency.  
> Not even close!!  Using a 50 watt slug thru my bird wattmeter I see 8 
> watts output.  I see 7 watts output thru my Waters Dummy load/wattmeter 
> so will assume that the power is about 8 watts out.  Now that is looking 
> at minimum dip  of 58 mills into the dummy load.
> 
> What gives???  I have tried several 6L6 tubes and still see the same 
> output. Have replaced all the old postage stamp mica's with new brown 
> silver mica units and checked for loose grounds, tightened screws around 
> the plate circuit where appropriate and so forth. And have plenty of 
> grid drive using a PR crystal on 3650 Khz.
> 
> Still 7 to 8 watts output.  Does that sound right.  Has anyone else 
> checked the output (not with a lightbulb!!) but with a reasonably well 
> calibrated wattmeter?  Should I not get at least 12-15 watts output??
> 
> When I was a kid (14) and a novice I built one of these as was my second 
> novice transmitter.  Admittedly, I lived in W1 Land (MASS) and worked 
> stations all over New England and south in Virginia and West back around 
> Indiana and Ohio so I know it worked pretty well.  But maybe I was one 
> of the first QRPers!  Or anyone running an AT-1 back then was as well.  
> HI HI. Any comments about the output I am seeing would be appreciated.  
> Thanks. Van. K7VS (first licensed as WN1ZLK in 1953)
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