QRP Frontend 02

QRP Frontend 02

Final test with the Arduino Mega controlling the i2C buss(select Filter and set attenuator Tx/Rx, turn Rx amplifier on/off.

QRP Frontend 02 is a BP filter board with RX preamplifier MAR-6 or a discreet PIN-diode attenuator, controlled by a dac. The same BP filter and the attenuator is used in Tx and is driving a amplifier SGA-3486Z as driver for the QRP PA earlier described. All BP filter is controlled from I2C bus. BP filter is from YU1LM i i think it is rely good result, no alignment.

I has started working on a front panel board, the latest before putting all this together to a QRP Transceiver. Stay tuned!

QRP LP filter and SWR board

QRP LP filter and SWR board

Here is the LP-Filter mounted on the earlier described PA.

QRP LP-SWR 01 is a LP filter board 1.8MHz - 52MHz and added SWR Meter, all relay for filter is controlled from I2C bus. The filter is design from GQRP Club Datasheet W3NQN, Filter PDF. I have rely problem to get low insertion loss, so I think it was the toroid was the problem. Now I know it is the capacitor I firs used has really bad Q value. I has change to SMD GC0 500V capacitor and they has much higher Q value than the hole mounted capacitor I bayed first. The SWR was presented in QRP-Quarterly January 2018, SWR Meter. I lock for different diodes then 1N60 and tried a few types and get god result with HSMS2800. Her is the result. 

Exemple 80m and 10m.

Backside off the filter.

Part off shematic

I have a few PCB left, e-mail if you ar intrested xxx@gmail.com.