Re: Transmit Output Power (CW) #v5


Rob French (KC4UPR)
 

Stage 1 - Replace Q90 with BFR106, replaced R81 with 2.7k.  Here are the results.  I just did the 2-tone test, because the 300/3000 Hz are tapered down so far by the crystal filter.   I just used those to help me pick a good BFO frequency.  

As an aside, removing that teensy SMD 2N3904 and replacing it with the likewise teensy BFR106, was one of the more tedious things I have done... I could handle not doing that again...

Summary:  Honestly, I don't see tons of change.  I started with RV1 set for minimum drive, and slowly increased it until the 80 meter (3.5 MHz) CW output power on my digital dummy load was equal to the output power that I saw in the baseline configuration.  Then I ran the rest of the numbers.  Power output went up in some cases, down in other cases.  In CW especially, it really didn't look like the output power "flattened out" across the bands.  I will say that in SSB, it does look like there were more power increases than decreases, with the result that the SSB output power level looks "flatter".

Hopefully this is useful to someone??? I'll keep posting as I run through each stage.

Transmit configuration:              
  Replaced Q90 with BFR106, replaced R81 with 2.7k            
  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 7.30 7.63   LSB 5.10 2.68
4000000 1.00 6.00 6.45   LSB 5.20 2.65
5332000 1.01 4.10 4.15   LSB 4.90 2.54
5405000 1.00 4.30 4.32   LSB 5.00 2.72
7001000 1.00 5.30 5.47   LSB 5.50 3.14
7300000 1.00 4.60 4.62   LSB 5.50 3.31
10100000 1.00 4.50 4.53   USB 3.70 2.67
10150000 1.00 4.10 4.10   USB 3.40 2.42
14000000 1.01 5.40 5.51   USB 3.30 2.02
14350000 1.01 4.90 5.01   USB 3.20 1.90
18068000 1.02 3.80 3.62   USB 3.50 2.09
18168000 1.02 3.60 3.44   USB 3.40 2.00
21000000 1.04 4.30 4.18   USB 2.80 1.75
21450000 1.05 5.80 5.81   USB 3.50 2.27
24890000 1.04 3.10 2.82   USB 2.00 1.24
24990000 1.04 3.10 2.78   USB 1.90 1.23
28000000 1.04 2.80 2.44   USB 2.50 1.37
29700000 1.03 2.90 2.49   USB 1.70 1.06

Join BITX20@groups.io to automatically receive all group messages.