5W Amp PA-100 Home Construction Project
Use as a SDR Pre-Amp to remove heat and RF out of the computer box. Drive the HF SuperPackerPro Amplifier to 100W
160-10 Meters; Post Filter required
3-8W typical output
3.7x2.4x1.4 inch; 3oz
8.5-15VDC; 30mA standby
RF In: 100 mW (500 mw max)
PTT, RF Switched, Bypass control
Fan required; 5 CFM sufficient
Intermittent SSB Service
Spurious –40dB (ext filter required)
Harmonics –45dB (ext filter required)
Medium Skill Level
I am a happy user of your SDR 5W AMP and I would like to thank you for designing and making the kit available.
I use the SDR AMP in my all band SDR project, with the following modules:
1. Tony's Softrock RxTx v6.3
2. Dave Brainerd's Si570 board
3. Dave Brainerd's 12-24V converter
4. My "Motherboard" switched BPF and PA
5. An Ex-commercial 7 band relay switched LPF
6. UBW uController for PC USB communications (Emulating the AVR USB-i2c interface), Si570 freq control and BPF/LPF switching
I made the following mods on the SDR 5W AMP:
1. increased drain voltage to 24v
2. changed the Battery Reservoir Electrolytic Cap to a +50V cap
3. cut the Battery trace to the +5v bias regulator and supply the bias regulator from my SWR protection circuitry
4. replaced the RxTx switch relay and circuitry with SDS RF relays and my relay driver circuitry
5. added a small fan over the heat sink and output transformer area.
When the AMP is driven with 1W output from the Motherboard, the output level reaches 50W on the low bands, 30W on 20m, 25W on 15m, and 12W on 10m (the drive level from my prototype Motherboard may have been lower on 10m). Mindful of the limits of heat dissipation, I run the AMP for SSB QSO at 30W PEP or lower. I have had a number of Dx QSO's so far with good reports on the audio.
The compact size of the AMP allows me to package the project comfortably (see photos in the Yahoo Softrock40 Forum, PHOTOS->9V1AL).
73's
Alex
9V1AL
