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Elecraft K2 # 21,  with two TFR Paddles by W4ED.

My first TFR paddle was a dual.   For Pictures of  the original

TFR paddle and construction pictorial  click here.

Closer look at a new Tuning KNOB,

skirt was removed using a Dremel & cutter wheel.

Click to expand



Here's my (and N0RC) measured total XMT current draw vs three
non-mod T4 units at 5 watts, per band.  VDC IN is accross battery.
 
 
RF_Out 0.1 W  1 W   2 W   5 W   5 W  5 W  5 W  5 W   Watts@
T4mod T4mod T4mod T4mod T4mod 2 Amps
K2 (by) W4ED W4ED W4ED W4ED N0RC K1JD NOSS KW1ND  W4ED Xmt
VDC IN 13.4 13.4  13.4  13.4 13.2 13.4 13.5 13.98 13.4 Eff. 
  MHZ
 3.56 0.50 0.68 0.84 1.24   1.82 1.90 1.60  6.0 22%
 7.04 0.54 0.68 0.82 1.18 1.38 1.68 1.70 1.55  9.5 35%
10.10 0.56 0.70 0.82 1.20   1.70 1.75 1.60  6.6 22%
14.06 0.54 0.70 0.80 1.12 1.44 1.78 1.60 1.60 10.2 38%
18.08 0.56 0.70 0.92 1.26   1.84 1.58 1.75  9.8 37%
21.06 0.56 0.76 0.98 1.36 1.52 1.80 1.82 1.70  9.1 34%
24.90 0.56 0.78 1.00 1.40   1.80 1.76 1.85  8.0 * 33%
28.06 0.56 0.84 1.06 1.56   1.74 2.14 1.80  8.2 * 34%
Ave.  Amps 1.29 1.44 1.77 1.72 1.47
8.4 W Ave.
Xmt  Eff.  29%   26%   21%   22%   24%

* watts output max reached at ~ 1.8 A

 Right most column was established by turning the power level
 up until 2.0 amps registered on K2 display then read K2
 power out.  Also, I understand this power compression does
 nasty things to SSB, probably reducing useful PEP power
 even more than for CW.  I'm not interested in SSB, but am
 very interested in getting the last 1/2 hour of FYBO, BUBBA,
 QRPTTF, FD, or ARS/BB out of a battery pack !!