A New Transceiver for 2018
Build this transceiver for $120!
This transceiver will leap tall buildings in a single bound, will go faster than a speeding bullet and is stronger than cobalt steel. Save your Christmas money for this project.
The basic circuit uses the Plessey PNP NPN bilateral amplifier as found in EMRFD ahead and following the Crystal filters which are diode steered. I have found you can use 8 VDC versus the recommended 6 VDC and you see a significant gain improvement. Ahead and following the IF amp block are ADE-1's where on the front end it is used as the Rx Tx mixer stage. On the back end the ADE-1 is used as the Product Detector on receive and as the Balanced Modulator on transmit.
While this test setup used a signal 2N3904 as the Rx RF Amplifier the final configuration will have two J310's configured as a Dual Gate MOSFET. There will be two small communications relays that will switch signals so that on Rx it is the receiver RF amp and on Tx it will be the transmit Pre-Driver. I have used this approach on the Simpleceiver Plus SSB transceiver and the Teensy 3.5 SDR transceiver. It works well!!!!
The audio amplifier stage use an NE5534 driving an LM380. For the microphone amp the 2N3904 is pressed into service. The Driver is the 2N2222 followed by a BD139. The Final is an IRF510. The current plan is to have this as a two band transceiver ~ very likely 40 and 20 Meters.
The basic circuit uses the Plessey PNP NPN bilateral amplifier as found in EMRFD ahead and following the Crystal filters which are diode steered. I have found you can use 8 VDC versus the recommended 6 VDC and you see a significant gain improvement. Ahead and following the IF amp block are ADE-1's where on the front end it is used as the Rx Tx mixer stage. On the back end the ADE-1 is used as the Product Detector on receive and as the Balanced Modulator on transmit.
While this test setup used a signal 2N3904 as the Rx RF Amplifier the final configuration will have two J310's configured as a Dual Gate MOSFET. There will be two small communications relays that will switch signals so that on Rx it is the receiver RF amp and on Tx it will be the transmit Pre-Driver. I have used this approach on the Simpleceiver Plus SSB transceiver and the Teensy 3.5 SDR transceiver. It works well!!!!
The audio amplifier stage use an NE5534 driving an LM380. For the microphone amp the 2N3904 is pressed into service. The Driver is the 2N2222 followed by a BD139. The Final is an IRF510. The current plan is to have this as a two band transceiver ~ very likely 40 and 20 Meters.
73's
Pete N6QW