The project I present here is my attempt at a universal QRP T/R switch. The idea is to take care of the essentials, so that any QRP (i. e. , less than 10W) receiver *AND* CW transmitter can be connected, and work seamlessly. These are what I considered the `essentials` to be: The operational scenario would be as follows, and could easily be applied to any QRP
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transmitter (or transceiver used as a transmitter) and any receiver (or transceiver used as a receiver). But the device is especially designed to accommodate a simple transmitter and receiver, each having few embellishments, and requiring none. Operationally, here`s how a typical case would work: When Steve Weber, KD1JV, used three 2N7000 power MosFETs in the final of his AT Sprint transceiver, and managed to produce 6 watts with same (4W at 20 Meters), it really opened my eyes to these little devices. I had always thought of these as audio or power-control devices, but now I began to think in a different direction. One thing that immediately occured to me is that these devices might be configured in such a manner as to provide an "on/off" switch to RF energy between the transmit line and the receiver`s antenna input. They could additionally provide protection to the receiver, by shunting any unwanted energy that might make it as far as the receiver`s antenna input. This led to some experimenting in SPICE, and eventually to the following essential T/R switch circuit: Let`s review the schematic. The transmit signal is tapped at the transmitter output - the transmitter remains connected to the antenna at all times - and arrives at the left "TX-ANT" port. Q1 serves to connect the receiver antenna port (right, "TO RX") to the antenna (during receive), or isolate it (during transmit). Because Q1 does not completely isolate the...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
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This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
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