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thanks ... where is that done in the sbitx? -- Mike KB2ML

Mike, the Rx line is derived by inverting and delaying the tx line. [email protected]> wrote:

Ashar, I have been studying the tr_switch code sin sbitx.c. I see code like digitalWrite(TX_LINE, HIGH); which seems to control the TR switch (disconnecting the rcvr from the PA) and controlling the

Thanks for the advice. I will take a look. -- '72 Aaron K5ATG ( http://k5atg.com )

Ashhar, Thanks a lot for the advice!! Taking a closer look at the schematic of the gpa10 amplifier, it looks like the pa gets completly disconected when on rx. But still have to attention to the

In the sbitx.c, there is an array that defines the band edges. You can edit them to get to your desired frequency. Remember to rebuild the program after editing it. <gary.video@...>

Juan, There is lurking danger with the t/r circuitry. As the entire receiver is bidirectional, when you go from transmit back to receive, there can a millisecond or less of time when the rx power

The ideal place to tap would be between the crystal filter and the mixer. This can be a very interesting and powerful second receiver. Here is how it will work. 1. Consider that an rtl sdr is

I meant to say from 30m to 6m

Hi everyone, Today to test the amp, did setup the lpf bits manually from 10m to 6m. Had to add 20db amp between the 2nd if output and the bandpass filter board. Power output is 14-15w up to 10m and

On the hardware side of things you have to consider band pass filters which are band specific.

thanks

The IF frequency is approximately 40 MHz. ?I am not sure of the actual frequency. ?It would be the center of the 40 MHz crystal filter which should be a few KHz less that 40 MHz. 73 Evan AC9TU

Another question.? If I wanted to tap in an external SDR for more spectrum bandwidth.? I'm assuming J7 before the crystal filter would be the place to connect.? What is the IF frequency?

A good buddy of mine got an sBITX V3 and I upgraded his and mine with V4.1. Now he is really wanting me to set his up to transmit outside our frequency privileges. I'm pretty sure that is something

Thanks!? I knew there was an answer.

Hi William, The limiting factor is the 40MHz crystal filter, not the audio codec.? Farhan used the higher-frequency 40MHz crystals to accommodate the 25 MHz bandwidth.? The original uBiTx used 12

Processing power of the RPi in the radio? That would be my initial thought... Ken, N2VIP

The audio codec supports up to 96k, so wondering why the sbitx is limited to 25k?

Raj, The amplifier I plan to use is from and old sdr kit and it has that chip. So I bave to modify the software to generate the three outputs. Will keep looking for ideas how to