Ed,
I am evaluating a pcboard relay for switching RF (Tx/Rx) and need to know what speed that the relay needs to qualify for semi-break in. Also, a precise definition of semi-breakin would be nice.
I don't know that there is a precise definition of the speed needed for semi-break in. However, you can approach it be considering that most transceivers have between 5 and 10 msec (the K3 is 8 msec) from key closure to the onset of RF. *Any* proposed T/R system for an amplifier needs to transfer from receive to transmit *and settle* in that time. The transmit to receive time - following the cessation of RF - may be a bit slower but that is usually set by the semi-break in delay (VOX delay) in the transceiver - not necessarily the relay transfer speed. If I were writing specifications "out of the air" - I would probably shoot for a receive to transmit time between 3 and 7 msec and transmit to receive time of less than 10 msec but those numbers are essentially SWAG based on the overall system considerations. Yes, with those transfer speeds, the same relay(s) could probably qualify as "QSK" if the transceiver PTT keying line had no delay. 73, ... Joe, W4TV On 12/4/2012 7:28 PM, Edward R Cole wrote:
I suppose this forum is a good place to ask as so many are CW ops. I am evaluating a pcboard relay for switching RF (Tx/Rx) and need to know what speed that the relay needs to qualify for semi-breakin. Also, a precise definition of semi-breakin would be nice. I get that QSK results in transfer from Tx to Rx after every CW character. I'm guessing semi-breakin switches when there is a pause in transmitting. I can evaluate the switching speed of my candidate relays using a storage scope but need a precise number on how fast they need to be. 73, Ed - KL7UW PS: these relays will be switching 300w RF. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
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