[Boatanchors] Need suggestions and question on antenna for DX-100

[Garey Barrell]

Glen -

I think you may be overlooking the fact that the DX-100 final is 
operating Class C, which typically shows 75%  _TUBE_  efficiency.

The RCA Tube Manual shows ICAS ratings of 67.5W max Plate input with an 
"approximately" 52W output, which is a _TUBE_  efficiency of 77%.

Of course this is at a MAX DC Plate voltage of 600 VDC for Class C AM 
operation, but that's another story!

So it looks like Heath merely used RCAs specs, and even allowed 3% loss 
for the Pi-Net!  :-)   100W output carrier is probably a little over 
optimistic, but not all that bad for ICAS service. 

Certainly 6L6s were treated much more harshly in that era!!  I know of 
at least one that was run with 600 VDC on the plate and almost 100 mA of 
plate current for a little over six months.

73, Garey - K4OAH
Atlanta



Glen Zook wrote:
> Looking directly at the Heathkit advertisement for the
> DX-100 it states as follows:
>
> 100 watts RF on phone - 120 watts CW - parallel 6146
> final.
>
> This is from page 53 of the Catalog Section in the
> 1956 ARRL Radio Amateur's Handbook.  
>
> 100 watts output at 135 watts input represents an
> efficiency of 74%.  120 watts output at 180 watts
> input represents an efficiency of 66.67% which is more
> realistic but even then it is optimistic.  A 6146 tube
> is generally in the 60% efficiency range.  A brand new
> one can do around 65% but not for that long.
>
>