PennyWhistle - 20 Watt Power Amplifier
PennyWhistle is a compact RF power amplifier stage that can be used with Penelope and Alex to make a complete 16 to 20 Watt transmitter. Since any higher power HPSDR amplifier does not appear to be close in time, this amplifier can quickly and inexpensively be used to get an HPSDR on the air, either barefoot, or as a driver for a larger linear. It covers the same 160 Meter through 6 Meter bands as the rest of HPSDR.
It is 10 cm by 8 cm (half Euro-board size.)
The output stage is a single stage amplifier that uses a pair of TO-220 "16 Watt" Mitsubishi RD16HFF1 parts in push pull and has approximately 19 dB gain, depending where you bias it, so it will deliver 16 to 20 watts output with 1/4 watt drive.
The photographs and data are from the first alpha-1 unit built. Additional kits are already in the hands of Phil, VK6APH, Bill KD5TFD, and Dick K9IVB.
I would expect this could be sold as a bare PC build-it-yourself kit. It uses surface mount, but would be easy to build. Easily wound transformers. Scotty won't have time for more factory build boards for some time to come. As a pure kit, hopefully it could be offered in the same time frame as ALEX, and let people get on the air.
It will fit in a Euro-Card housing, if the heat extraction problem can be addressed. We need to extract about 30 watts of heat when transmitting. Dissipation in standby is negligible. The circuit is capable of continuous duty, provided that the heatsink is big enough to hold a reasonable temperature.
The project leader for PennyWhistle is Graham, KE9H, with testing help from Phil VK6APH, Bill, KD5TFD, and Dick, K9IVB.
Link to Wiki
Our HPSDR Wiki will contain the latest news, links, files, etc. for PennyWhistle. Here is the direct link to the HPSDR Wiki: PENNYWHISTLE
Link to Documents
Here is the direct link to the PennyWhistle Documents: