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Re: CW Offset does NOT work on Raduino_v1.14.1 for BITX40
Jack Purdum
Allard: I'd give this a try. Jack, W8TEE From: Allard PE1NWL <pe1nwl@...> To: [email protected] Sent: Wednesday, June 14, 2017 1:09 PM Subject: Re: [BITX20] CW Offset does NOT work on Raduino_v1.14.1 for BITX40 Hmm, yes you may be right that in some cases the 7805 output hasn't dropped sufficiently to represent a digital LOW. Another way to circumvent this situation might be to define A0 as an analog input and define a higher threshold for a digital LOW/HIGH. What do you think? 73 Allard PE1NWL On Wed, June 14, 2017 18:07, Jerry Gaffke via Groups.Io wrote: > 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. > ?? > > On Wed, Jun 14, 2017 at 08:28 am, Jack Purdum wrote: > >> >> Given your code, Allard, I'm surprised he needs a dropping resistor on >> that line. >> ?? >> > |
Re: CW Offset does NOT work on Raduino_v1.14.1 for BITX40
Vince Vielhaber
Funny you should ask.. As I was reading Jack's post I was thinking, it's
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an analog line, use it like one. Vince. Hmm, yes you may be right that in some cases the 7805 output hasn't --
Michigan VHF Corp. |
Re: CW Offset does NOT work on Raduino_v1.14.1 for BITX40
Hmm, yes you may be right that in some cases the 7805 output hasn't
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dropped sufficiently to represent a digital LOW. Another way to circumvent this situation might be to define A0 as an analog input and define a higher threshold for a digital LOW/HIGH. What do you think? 73 Allard PE1NWL On Wed, June 14, 2017 18:07, Jerry Gaffke via Groups.Io wrote:
The code is doing a digitalRead(PTT_SENSE), I'd expect the threshold on |
Re: CW Offset does NOT work on Raduino_v1.14.1 for BITX40
Jack Purdum
I must have misunderstood. If the internal pull-up resistors on a pin are activated, doesn't that impact the voltage seen on the pin? Also, if the code does a digitalRead(), the documentation says it returns HIGH or LOW. Is it true a digital read of a pin can return an "in-between" value with the internal pull-ups active?? Jack, W8TEE From: Jerry Gaffke via Groups.Io <jgaffke@...> To: [email protected] Sent: Wednesday, June 14, 2017 12:07 PM Subject: Re: [BITX20] CW Offset does NOT work on Raduino_v1.14.1 for BITX40 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. ? On Wed, Jun 14, 2017 at 08:28 am, Jack Purdum wrote:
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Re: Usb sound card.
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.?
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Re: CW Offset does NOT work on Raduino_v1.14.1 for BITX40
The code is doing a digitalRead(PTT_SENSE), I'd expect the threshold on the nano to be somewhere between 1 and 2 volts
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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. ? On Wed, Jun 14, 2017 at 08:28 am, Jack Purdum wrote:
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Re: CW Offset does NOT work on Raduino_v1.14.1 for BITX40
Jack Purdum
Given your code, Allard, I'm surprised he needs a dropping resistor on that line. Jack, W8TEE From: Allard PE1NWL <pe1nwl@...> To: [email protected] Sent: Wednesday, June 14, 2017 10:51 AM Subject: Re: [BITX20] CW Offset does NOT work on Raduino_v1.14.1 for BITX40 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 On Wed, June 14, 2017 15:33, qrper72@... wrote: > 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. > |
Re: CW Offset does NOT work on Raduino_v1.14.1 for BITX40
Hi Hidehiko-san
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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 On Wed, June 14, 2017 15:33, qrper72@... wrote:
I've put the 10k pull-down register at the "A0" and maybe the problem |
Re: Usb sound card.
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. |
Re: CW Offset does NOT work on Raduino_v1.14.1 for BITX40
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. |
Re: CW Offset does NOT work on Raduino_v1.14.1 for BITX40
Hidehiko-san,
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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 On Wed, June 14, 2017 11:58, qrper72@... wrote:
Hi all, |
Re: BITX QSO Night, Sunday, June 18, 7pm Local Time, 7277 kHz in North America, 7177 kHz elsewhere
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. |
Re: BITX QSO Night, Sunday, June 18, 7pm Local Time, 7277 kHz in North America, 7177 kHz elsewhere
On Mon, Jun 12, 2017 at 07:24 pm, Al Duncan VE3RRD wrote:
How about using QRPspots? ? to advertise frequencies in use by BITXers? 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.? |
Re: Standoffs for mounting the board
here's a YouTube to review ? ? ? 73 WA9DOH On Fri, Jun 9, 2017 at 9:37 PM, John Smith via Groups.Io <johnlinux77@...> wrote: I used plastic standoffs with a flat foot, and some double sided foam mounting tape to mount it in a holiday tin. Like the stuff on the back of a breadboard. Here is a link to what I have, and the feet are half inch. I got some bigger ones but the post was too big for the BITX holes. |