¿ªÔÆÌåÓýThis may be simple enough for me, if I understand what you want to do.? Does ¡°use the straight key and built-in keyer at the same time¡± mean simultaneously, or alternately without having to uplug one and plug in the other? ? I have a HAMKEY set which has the paddles and the key mounted on a common platform with separate RCA jacks for paddle left and right and straight key.? I simply jumped the hot lead from the key to one side (either will do) of the paddles (the base is electrical common).? When I plug in my keyer stereo mini-plug lead to the input of the QCX I now can choose to use the keyer (select IAMBIC in the keyer menu) and begin using the paddles, or I can choose straight key and use that without having to change any leads.? If you meant ¡°simultaneously¡±, then good luck. ? Tony N0BPA ? ? From: [email protected] [mailto:[email protected]] On Behalf Of HF via Groups.Io ? (The original subject line for this thread was Re: QCX Tune.? I added #qcx. If this launches a new thread, then search "QCX Tune" for the prior message context) I also want to be able to use the straight key and built-in keyer at the same time.? I'm considering the following modification: 1.? Install 1.0k resistor at Q6 base with the other end connected to the anode of a switching diode. 2.? Install a 10k resistor between RX and IC3D inputs.? IC3D doesn't require much current so this should be okay. 3.? Disconnect S1 terminal 3 from the DIT line and connect it to these inputs instead.? The 10k resistor of step 2 protects IC2 from excessive current when RX is high and S1 is pressed. 4.? Also connect S1 to the switching diode of step 1. 5.? Disconnect Q5 gate from RX and connect it to S1.? Now this gate is pulled high in RX mode via the 10k resistor instead of directly to connect the antenna to the receiver.? Hardly any current flows at this gate, so it should still work.? When S1 takes over, this gate is grounded, disconnecting the antenna from the receiver. ? This modification hijacks the RX line.? IC2 still "thinks" it's receiving.? For this to work, IC1-CLK2 has to run at the same frequency in TX and RX mode.? Does anyone know if it does?? Are there other functions of IC2 in TX mode that are needed for this radio to transmit?? I'm concerned that when S1 opens, the tail end of the transmitted signal will be cut off abruptly by the IC3D instead of gradually by Q6, causing a key click to be transmitted.? Any thoughts on how to prevent this? Does anyone have other ideas of why this shouldn't work, or have an easier solution? ? Cheers, Halden NR7V |
