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Do it after the opto?? Just an inverter.

Amazing, I wonder how they figured out all the simulation stuff at Circuit Lab.

Others were built on the SPICE stuff done and released because it was funded by tax payers.

Yea, I guess the optocoupler doesn't need a full 5V to close the PTT circuit. I'll try it without R1 and see what happens.

This editor is Circuit Lab, which is a fantastic editor and simulator, but is (understandably) non-free. I normally do design in Eagle, but Circuit Lab?+ a screen shot is a quick and dirty way to share something.

On Fri, Dec 1, 2017 at 3:59 PM Michael Hagen <motdog@...> wrote:

That 1K in the emitter cuts your signal in half?? With Q1 fully on, D1 gets 1/2 of Vcc (5V).? So your output on D1 is less than 2V.

I like you schematic editor, what is it?

Mike, WA6ISP

On 12/1/2017 12:48 PM, David Arthur wrote:

Ok, got things working! All that was missing was a diode from the Collector.?

Here's my final circuit:?



PTT toggles on and off from WSJT-X as expected :)

Thanks for all the help!?

-- 
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID  "MotDog@..."
Mike@...

-- 
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID  "MotDog@..."
Mike@...

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That 1K in the emitter cuts your signal in half?? With Q1 fully on, D1 gets 1/2 of Vcc (5V).? So your output on D1 is less than 2V.

I like you schematic editor, what is it?

Mike, WA6ISP

Ok, got things working! All that was missing was a diode from the Collector.?

Here's my final circuit:?



PTT toggles on and off from WSJT-X as expected :)

Thanks for all the help!?

-- 
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID  "MotDog@..."
Mike@...

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By the way, he probably should have provided that circuit, and you get to select a inverted or non-inverted output.

It would have cost the 4 cents or so for parts?

Mike, WA6ISP

Hmm, not sure why that image uploaded so small, here's the PDF?

-- 
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID  "MotDog@..."
Mike@...

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Those are "Real" level RS232 voltages, so the opto turns on when either of those signals or both go positive.

They are large voltages and go both + and -.? So the diodes fix that and "OR" the signals.

The resistor below limits the opto diode current.

If you only need to invert the signal, you could do it at the other side.?

So, put a 10K resistor from PTT to +5V Raduino.? That puts a pullup on PTT.?? Then PTT to base of your transistor.

Emitter to ground and collector to Radio PTT relay pull down.? You might want to put a diode across the PTT Relay coil for

inductive kick suppression.? I think he left it out on that relay?

I think I got it?? Hopefully??

Mike, WA6ISP

Thanks for the suggestions, I'll give them a try and report back.

Michael, here's the schematic:

-- 
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID  "MotDog@..."
Mike@...

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I went to see the nifty device, but no schematic?

I am just guessing at a possible solution.

Is your RTS? 0-5V or the bigger RS232 voltage?

You may need a diode steering in +V or a clamp diode to ground.??? Keep the base from going into too much reversed bias.

While probably not needed, designs usually put a resistor

across base to ground to override any leakage current on the transistor.? 10K-100K.

I've got one the nifty little "EASY DIGI" isolator circuits from KF5INZ via ebay



I have the audio side working just fine, but running into trouble getting the PTT working. My first problem is that RTS logic levels are inverted from what is needed by the Easy Digi circuit. In Fldigi, I can select the +V option when configuring the Hardware PTT, but in WSJT-X there is no such option. So, I set off to find a simple inverter circuit (please excuse my resistor symbols..)



The transistor is a 2N3904 NPN BJT. I came up with the values for the resistors based on reading that I_c / I_b = 20 is a good rule of thumb. When I measure the voltages coming out of this inverter, things seem to be correct, but when I hook it up to the Easy Digi things go wonky.

Basically, what happens is: I set the RTS line low, the inverter output goes high, goes into the Easy Digi, and the PTT closes. But then when RTS goes high, the PTT stays closed. It seems that the transistor is getting latched open.

I'm guessing this has something to do with the PTT circuitry on the bitx. I'm not really sure how to proceed from here. Any ideas?

Tl;dr has anyone gotten the Easy Digi working with WSJT-X? If so, how?

Thanks!
David KM4NKU

-- 
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID  "MotDog@..."
Mike@...

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Of course, don't delete your REAL copy somewhere else.? ??

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For ME, anyway, a huge success this morning:? ?was able to measure both the BFO (crystal) and Raduino base (crystal) frequencies and then upload sketches with corrected values -- should essentially elminate the need for calibrating (I hope).? ?The goal of all this was to be able to correctly? transmit to WINLINK gateways, which rquire that you be within 200 Hz of the correct frquency.? ?Since I now have my raduino modified to allow both 80 and 40 meter performance, I wanted it to be on correct frquency no matter where I went, and a previous poster had already indicated measuring the internal crystals was the most straightforward way to do this.??

1.? I have available an ICOM-718 with digital freq readout; tuned it to WWV at 10 MHz at a time when receivable.? ?You can use upper sideband and tune for beat with the carrier, or offset exactly 500 Hz on the transceiver and then measure the audio frequency (e.g, with the waterfall display from FLDIGI or SOUNDMODEM or any other sound card program) --- my ICOM 718 was within 20 Hz.? ?

(I also tried to calibrate an ancient freq counter, which worked, but later I was unable to measure the bfo output even after the emitter follower with this device, so I gave up that approach.....using the calibrated ham receiver worked a lot easier anyway!!)

2. Knowing the ham transceiver's internal freq is accurate, I simply connected a test clip to the center of the antenna coax and dangled it near the bfo section of the BITX (at first I even put a resistors, 2000 ohms, in series but not necessary) --- just having the wire near the circuit I was able to pick up the BFO frequency quite easily and measure its frequency by going to the null on the carrier

I have two BITX's, one called "plywood" and the other called "breadpan" for how they are mounted:

? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?BFO FREQUENCY

BREADPAN? ? ? ? ? 11998.92 kHz

PLYWOOD? ? ? ? ? ? 11998.26 kHz

3.? Using a sketch where I intentionally forced the RADUINO to produce 25.00000000000 MHz (that of its underlying crystal), I loaded that sketch and then dangled the wire near the output of the raduino and again looked for the signal with my ICOM-718 transciever:

? ? ? ? ? ? ? ? ? ? ? ? ? ? ?RADUINO FREQUENCY

BREADPAN? ? ? ?25004.460 kHz

PLYWOOD? ? ? ? 25004.560 kHz

4.? I then compiled individual sketches (based on Allards wonderful 1.24 sketch)? for each of the two bitx's, using their individual BFO and Raduino cyrstal frequencies:

for example, for the plywood-mounted bitx:

#define bfo_freq (11998260UL)? ?// Hz? ? replaced the similar statement in the base sketch

#define SI5351BX_XTAL 25004560? ? ? ? ? // Crystal freq in Hz? ? ? ? replaced the similar statement on the cyrstal freqquency

When I repowered the devices, I don't completely understand it but I ended up having to "calibrate" the lower and upper offsets and basically set them to? zero.? ? ?

Preliminary testing then showed that the radio was now right on frequency.? ??