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Re: Transmit Output Power (CW) #v5

 

Rob, you might want to try and run the IR510 power transistors from a separate, higher voltage power supply...maybe 18volts or so. I have a V4 that I run the finals at that level and see a big change in output power. I get about 16 watts out on 80, 11w on 40, 16w on 20 and about 7 watts above that. Just a thought :)
Barry
K3bo

On Mon, Mar 30, 2020, 3:24 AM Rob French (KC4UPR) <kc4upr@...> wrote:
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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