Re: Solid-state T/R switching #ubitx


Bill Cromwell
 

Hi Ted,

Your idea is not new and there are a lot of radios that use solid state switching. You can implement QSK with electronic switching. "Semi-breakin" really means "not breakin":) I have been considering that too but in a different radio that uses a mechanical bandswitch.

You will have to consider how you are are going to select the appropriate low pass filters if you want to eliminate all of the relays. That is not meant to say nay nor to discourage you. You might keep the relays controlled by the raduino for low pass filter selections and just use the electronic switching for the T-R changeover. I may do the same thing. But it is also possible to eliminate those relays. A lot more thought and mechanical work.

In the radio I am making plans for bandswitch is already designed, built. and operational. It is not needed for the T-R function. You could just do that with your uBitX. Keep us posted.

73,

Bill KU8H

bark less - wag more

On 10/17/20 3:36 PM, Ted via groups.io wrote:
I've thought of doing away with the physical relay switching between TX & RX, by using a power transistor to activate the RX whenever TX is not otherwise invoked, and another one to activate the TX path (and drop the RX switch device) when called upon.
It sounds plain enough. Has anyone else done this already?  I'm not necessarily trying to address anything that I'd call a shortcoming, other than that it IS a mechanical switch [and "because I think I can"].
For the rig in question - a V5 board - I use almost exclusively CW and I believe I can get better semi-qsk this way and lose the relay noise at the same time. More instantaneous reaction to Dits would be a
win, not that I think this build with its CEC firmware necessarily suffers so badly from that like the stock V6  does, but I'd like to see what effect such switching has on operation.
Comments?
Ted
K3RTA

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