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That's another option. I already have right channel PTT circuit in the form of the Fldigi CW keying circuit. I was wondering if I will incorporate it. The final design is still floating around in my head. When this and Allard's added functionalities are done, this will be like a all mode 40 meter radio.?

The code is doing a digitalRead(PTT_SENSE), I'd expect the threshold on the nano to be somewhere between 1 and 2 volts
The problem is that when the +12v TX line into the LM78L05 at U3 goes to zero volts, the output of U3 remains up around 5v because there is no place for the charge on C150 and C151 to go. ?The pulldown resistor will eventually discharge those caps. ?The RC time constant of 0.2uF*20k = 4 milliseconds, which should be fast enough. ?I'd put that new 10k resistor from U3-1 to ground, rather than from A0 to ground, the latter case would reduce the maximum voltage into the Nano A0 pin down from 5v to 2.5v. ?This also reduces the RC time constant to 2 milliseconds.
?

Hi Hidehiko-san

Yes you could be right.
Another possible cause could be poor grounding of BITX main board and
Raduino board.
If Raduino board is not grounded perfectly, some small potential
difference may exist between BITX board and Raduino. As a result, A0 input
will not be perfectly zero volts when PTT is not pressed.

73 Allard PE1NWL

I've put the 10k pull-down register at the "A0" and maybe the problem seems to be fixed now. This issue caused by the threshold problem?

ja9mat Hidehiko.

If you're using FLDIGI take a look at??

The PTT tone on the right channel eliminates the need for a USB serial adapter and relay circuit; you only need the mic and speaker wires between the sound card and BITX40. In my setup there is no difference in performance with or without the transformers but they're only $1 on Amazon so why not.

TKS Allar,

OK but it is not a display issue.
800Hz frequency shift does not occur so I can not QSO with hi..

When I attach the voltmeter between "A0" and "GND" the problem is solved sometimes
but not stable. hi...

Maybe the "A0" PTT-SENSE signal line should be pull-up or pull-down?

ja9mat hidehiko.

hi

i have decided that the best way to go cw on the bitx40 is to build a separate tx and use the bitx40 in receive mode only.

terry

I have reciently purchased a Usb picoscope ...
In order to check and align things up I find hard to know the points and expecting measuremnts that I should get.?
Anyone with experience out there?

Hidehiko-san,

The frequency as shown on the display is always the TX carrier frequency.
In CW mode, the RX frequency is shifted by 800 Hz, not the TX frequency.

73, Allard PE1NWL

Hi all,

Does anyone try to QRV the CW mode by Raduino_v1.14.1 for BITX40?
Does it really works?

Here in my situation. The TX frequency does not down 800Hz when I select LSB mode.
Any suggestions welcome.

ja9mat hidehiko.

I have been listening to 7.277 a bit while sweating in the shack. So an anytime BITX40 calling frequency must be a good idea. Now, does anyone have a youtube for dummies video they especially like about qrp spots, and dx summit? I haven't focused my energy that way yet. I guess nows the time.
I heard Mexican activity last night on 7.210. It would have been no problem to work with it I had a regular radio. to be rude and talk over them with.
Do the extras want to have a frequency just for them? it's okay if thay do.

thank you Phil.
now that makes more sense to me. i can follow that.?
back to a bit of playing at lunchtime with the old soldering gun.
thanks ill post a photo or two once its done.

On Mon, Jun 12, 2017 at 07:24 pm, Al Duncan VE3RRD wrote:

How about using QRPspots? ? to advertise frequencies in use by BITXers?
QRPspots doesn't get very busy so it is easy to see a BITX spot if we put "bitx40" or "bitx40 group" in the comments.

This is also a good idea but it does not need to be limited to Sunday night at 7pm.? Anytime that band conditions seem good would be a good time to post at and . Post in this messageboard as well to see if anyone else is interested.?

Another strategy is to agree on a certain frequency to call CQ, this allows people to monitor a frequency to see if anyone from the group is calling.? At one time, 7285 was designated as a QRP frequency, but I hear a net there (not QRP) quite often. 7277 seems to be in an area that is somewhat unused with low noise if we are lucky.

I would like to see a QRP night and a new QRP frequency but I am reluctant to mix general QRP stations with the BITX group.? We already have a lot of participants in the BITX40 QSO Night in eastern North America and if it gets busier, we will need to go to a net format with a net control operator.? Of course everyone is welcome to participate, but I am not going out and advertising the event to other QRP operators.

Our event is really just an informal gathering on the radio waves.? It is surprising how popular it has become.? This has taught me how effective event organizing can be.? There were a few scheduled nights, and then I thought I should write up an event description based on how I thought it would work best for low power QSOs.? The entire organization of our event is that I copy/paste a text file in this messageboard it with a new date every week.? I try to ask for comments on how to improve things so we can keep learning how to work a QRP net.? Now there are a lot of participants and it is impressive how many people join in and keep the contacts going, sort of a self-organizing net.? All we need is good propagation and we can ragchew just like the kilowatters.

Just for fun I registered?? ?It just redirects to the Google maps page. ?The other link still works and always will I just figured everyone was tired of the long url.?

I agree that Spanish speaking stations operating on 7175 would suggest that we go up a bit.
7178 is better, going higher gets interference from group operating on 7181.
A couple of weeks ago, I had a high power station tuning up on top of us. I cranked up the power
a little and cleared the frequency alerting other stations that QRP is being used on frequency.
Willy heard me and I guess the guy tuning up did too. I know that a lot of us don't have the power
to fight back the QRM. I can go from 5 to 1000 watts. If we need to clear the frequency
we will. I'm in Iowa maybe an East Coast station could do the same.
Ed

By bolts, do you mean screws from the bottom up through the enclosure and into the standoffs?

Yes, the address search bar comes up now. TKS