开云体育

Would you please kindly implement an additional TX pin that would fall off about 4-5ms before the main TX pin and the associated TX signal into the FETs?

This additional pin will be used to drive a CW shaping switch, that would be inserted between +12 and the PA inductor.

Thanks and 73,?
Vojtech OK1IAK

Sorry if this has been already answered, any chance PTT signal could be implemented for a V2 too?
TIA

Giuseppe
IW2JWW - JN45RQ

On 14/07/2022 07:51, Giuseppe Marullo wrote:

Sorry if this has been already answered, any chance PTT signal could be implemented for a V2 too?

Giuseppe

If you compare the schematics you will see there is extra circuitry on v3. And two more connections to the processor.
So not really practical.

73 Alan G4ZFQ

I wrote a HDSDR ExtIO for Omnia


I am able to write a similar ExtIO plugin for QDX. How I would implement CW depends on our mutual contract. My time and energy is limited (I have 4 kids and a demanding job), however implementing an ExtIO plugin is not too difficult and I have done it already. If an ExtIO plugin for HDSDR works, I suppose others will pick up and implement support for FLDIGI or whatever. My personal dream is to have a remote Android application, for which I have an early sketch, but no energy to finish.

For example, I may just send CW tone with no shaping to QDX and expect QDX to extend each transmission after tone stops by 5ms while holding the last tone but keying off that new output pin at the instant the PC stops the tone. IMHO it would not hurt if this was being done all the time with the hardware CW shaping circuit in place. The FT8 signal would not be hurt and it would splatter less. RTTY bit length is 22ms, thus the very first bit would have the first 5ms rounded and the last stop bit would be 5ms longer, but I don't think that is an issue.

73, Vojtech OK1IAK

I am not sure how you implemented the VOX functionality.

We may add a new CAT control command to tell QDX that it is in CW mode, so it would do the procedure above each time the tone stops: it would key off PA power into the CW shaping circuit, it would extend the last tone by 5ms and then it would key off and switch to receive. IMHO that is all we need to implement keyboard CW.

It would be even greater if QDX implemented a built in keyer with standalone transmit function. This is what I have done for my Omnia: My HDSDR ExtIO plugin sends to the Omnia firmware the TX frequency every time user retunes. If one touches the paddles connected to the transceiver, the transceiver starts to transmit at the last known TX frequency while sending zero audio to the host, thus the host recognizes that the radio is transmitting. Quite simple protocol and very effective with zero TX latency. With the CW completely generated by the Omnia firmware, I was able to implement precise PA control by delaying the CW tones by the time required for the PA to switch in.

Vojtech

I can't provide a signal that falls 4-5ms before the main TX pin because I don't know that the main TX pin is going to fall (when the audio tone ends).

Hans, what if we design a protocol for CW for qdx? There are 2 options I can think of. First option, we embed the key shaping signal into the audio signal as AFSK. For example, assuming 20wpm, when we key down for dit, the computer first sends a tone of frequency of f0. Then 60ms later it changes the frequency to f1 and lasts for 5ms. When in CW mode, QDX can detect f0 and f1. When QDX sees f0, it turns on both the main tx and the shaping signals. When it sees f1, it keeps the main tx on but turns off the shaping signal, and it keeps the output frequency unchanged (always at vfo). Finally the computer stops sending the tone and QDX turns off the main tx.

The second option is even simpler. We simply use a mono tone, and when the tone stops (key up), QDX turns off the shaping signal but keeps the main TX on for another 5ms as if the computer is still sending the tone.

I can implement the required keyer software for either protocol.?