Re: Transmit Output Power (CW) #v5


Rob French (KC4UPR)
 

Stage 3 - Replaced Q92, Q93, Q96, Q97 with 2N2222A (ended up putting them on the bottom of the board, was easier).  Paralleled R941, R942, R96, and R911 to get 11 ohms each.  Smoke test good!

Definitely see some differences now.  It takes a lot less driver to get the 7.3 W I originally had at 3.5 MHZ.  The output versus frequency is definitely a lot flatter now, though it still goes from ~7W on 80 meters to ~3W on 10 meters.  I am curious about the effects of the output low pass filter characteristics on transmit output power.

Here's the table.
Transmit configuration:              
  Replaced Q90 with BFR106, replaced R81 with 2.7k; replaced Q911+Q912 w/ 2N2222A; replaced drivers, resistors            
  RV1 adjusted to match “Baseline” power output on 80 meters            
  BFO=11,055,935            
Power measurement:              
  ATU N7DDC ATU from Russia; configured for 150W          
  DDL Digital Dummy Load; configured for QRP; calibrated against ATU at 5.3W w/ RS-HFIQ          
               
    CW       2-tone SSB  
Frequency SWR Watts-ATU Watts-DDL   Sideband Watts-ATU Watts-DDL
3500000 1.00 6.70 7.20   LSB 4.60 2.26
4000000 1.00 5.40 5.67   LSB 4.40 2.13
5332000 1.01 4.00 3.96   LSB 4.90 2.52
5405000 1.00 4.10 4.10   LSB 5.10 2.64
7001000 1.00 5.80 5.99   LSB 6.00 3.35
7300000 1.00 4.90 4.95   LSB 6.20 3.65
10100000 1.00 4.90 4.95   USB 4.00 3.11
10150000 1.00 4.50 4.51   USB 3.80 2.78
14000000 1.01 6.40 6.75   USB 3.60 2.21
14350000 1.01 5.80 5.97   USB 3.50 2.02
18068000 1.02 4.30 4.22   USB 3.90 2.27
18168000 1.02 4.30 4.18   USB 3.90 2.28
21000000 1.04 5.40 5.37   USB 3.20 1.98
21450000 1.05 7.80 7.70   USB 4.00 2.43
24890000 1.04 3.50 3.17   USB 2.00 1.17
24990000 1.04 3.40 3.05   USB 2.00 1.17
28000000 1.04 3.10 2.74   USB 2.50 1.30
29700000 1.03 3.50 3.13   USB 1.70 0.99

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