Title: PTT OUTPUT?
Post by: WM0I on 09. February 2018, 23:21:36
I have been looking at the Schematic and the the new 2.8.0 firmware for any clue on how to have a PTT output when transmitting to key those small 50 to 100 watt amplifiers. Anyone know how to get a 0 volt to 5 volt transition when in TX mode?
Best regards
Richard WM0I
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Title: Re:PTT OUTPUT?
Post by: DF8OE on 10. February 2018, 08:32:05
You already have a plug called "acc" at your mcHF. This can b used for external keying. Unfortunately the element which is used originally (and by all known clones) is a simple optocoupler whichs characteristic is not very good for those switching purposes. A much better choice would have been a semiconductor relais which is available in MOS technology. You can swap it by yourself.
vy 73
Andreas |
Title: Re:PTT OUTPUT?
Post by: peter_77 on 10. February 2018, 13:28:41
Here is a solution (DF5LI's diagram) which works perfectly fine:
https://www.amateurfunk-sulingen.de/forum/index.php?board=15;action=display;threadid=687;start=15 (https://www.amateurfunk-sulingen.de/forum/index.php?board=15;action=display;threadid=687;start=15)
Following thread entries also describe the somehow better solution in replacing the optocoupler with a semiconductor relais PANASONIC AQV255GSX like Andreas mentioned above.
Unfortunately the thread requires Google translator :-\ |
Title: Re:PTT OUTPUT?
Post by: DF5LI on 10. February 2018, 15:15:03
But all this solutions are mor or less open collector-switcher to ground. A transition from zero to 5 volt in transmit mode is not so easy to manage. If you are looking at the schematic, you can find pin 1 at U7 (72HTC02), which will have the desired behavior. But be careful, this pin cannot deliver much current...
And your problem is not firmware-related.
[color=Red]edit by Mod: correct!
Thread verschoben[/color] |
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