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Re: Bitx40 low volume oscillation squeal
Graham
开云体育nothing ventured, nothing gained - I will see if I have one lying around and will give it a try.I still don't understand what causes this behaviour. I will have to breadboard the circuit and play some with it. cheers, Graham ve3gtc On 2017-03-26 21:32, Ozemail wrote:
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Re: Bitx40 low volume oscillation squeal
That is strange. This was the problem with mine and 2 others had the same problem. I am assuming your smd version is built the same as the through hole version. 73 Ken On Sun, Mar 26, 2017 at 5:29 PM, Graham <planophore@...> wrote:
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Re: Bitx40 low volume oscillation squeal
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On Mar 27, 2017, at 8:29 AM, Graham <planophore@...> wrote:
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Re: Bitx40 low volume oscillation squeal
Graham
开云体育I tried a second one and had the same behavior.? I will dig through my junk box and see if I can find another to try.I am not sure how a pot that has dead zones on one or both ends would cause this type of behavior. cheers, Graham ve3gtc On 2017-03-26 21:05, Ken wrote:
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Re: PTT line to Raduino?
开云体育It is the letter L not the number one.? You can determine this by using the” find” function under “edit”.? If you search for ?8001 (with a one) you will not find it in the referenced line but you will if you search for 800l (with the letter “L”) Mike K5ESS ? From: [email protected] [mailto:[email protected]] On Behalf Of John Smith via Groups.Io ? Yea I see it. I was thinking of that when I saw it this time. So this time I looked very carefully and saw it is a number one. ?#define CW_OFFSET (800l) pasted in here on this page with this font, you can't tell what it is. But in the Arduino IDE it's easier to see it is a number 1 on line #178 of my copy. I made a mistake before, but now I know what to be mindful of before I make a statement that might mislead someone who doesn't know better to figure it for themselves. Another one down, a bunch more to go. I know I said I wanted to use it as a simple SSB. But I would like to implement a change of starting up on USB with the knob turned all the way to the right so I can try line in audio for a digital mode. I saw something in the code before, but I also saw someone else mention the knob thing. Does anyone have a code snippet that be pasted in for an easy upgrade? |
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Re: Continuity
I measured 3.1 kOhm at main PWR. So same like with your rig. Measuring ?PA-PWR ?between + and GND ?is around 60 MOhm (starting with lower value as Jerry explained) and switching test leads on this connector gives about 40kOhm after a few seconds. Having high resistance here on your board too is a good sign. I understand that you want to ensure that everything ?is setup correct before you power up everything. Thats good practice. To make things a little bit easier I would recommend to not power up everything together but do it in steps like I've done it: 1. Radudino. I first connected a USB cable to the Raduino and plugged it into a USB power adapter. Don't use the 12V power supply yet. ?You also could connect it to a PC port, but its maybe more save for a first test not to do this. You should see Version and a frequency in the LCD Display. Adjust Display contrast if necessary. 2. If this is OK, remove USB cable and connect 12V power to the Raduino 12V power(orange wire = 12V, Black = GND . Raduino should work exactly as before. 3. disconnect 12V ?power from Raduino and connect it to 12 PWR of BITX40. ?You should hear some noise in the loudspeaker, even without antenna connected To be on the save side, measure current and it should be no more than 150mA. 4. If everything looks good you could also connect Power to Raduino and you should be able to tune and here some changes in the noise, possibly some clicks while tuning and at around 7.2MHz a beep (birdie). 5 Now connecting 12V to PA-PWR. There shouldn't be a big difference in current measurement. I wouldn't press PTT at ?this stage ?because I first would check the system with a 50 Ohm Dummyload to see if ?current in transmit mode is still in range and eventually align it according to Wire Up Instructions before connecting it to a real ?tuned antenna. I don't know what test equipment you have at hand so maybe its now the time to ask for support in your local ham radio club. I'm sure that OMs there are more than willing to support you with your BITX40. ? |
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Re: Bitx40 low volume oscillation squeal
Try a new one. I found that mine had dead zones at both ends of travel. Replace with a log or audio taper. 73 Ken VA3ABN On Sun, Mar 26, 2017 at 5:04 PM, Graham <planophore@...> wrote:
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Re: Bitx40 low volume oscillation squeal
Graham
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Re: Bitx40 low volume oscillation squeal
Graham Are you using the original volume control that came with the Bitx40? 73 Ken VA3ABN On Sun, Mar 26, 2017 at 4:51 PM, Graham <planophore@...> wrote: Good day all, |
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Re: am broadcast break throgh
Are these shortwave stations, can you hear them on 41 meters with some other shortwave receiver? ?If so, read this thread: ?/g/BITX20/message/21996 Some success has been reported in filtering the VFO before it enters the mixer in reducing these images. ? Another possible fix is to move the VFO to 19mhz for high side injection into the mixer. ?But then your analog vfo won't be stable at 19mhz, ?the skirt on that side of the 12mhz crystal filter is not quite so steep, ?and you will need to reduce the 12mhz bfo frequency by about 3khz to get back to 40m lower sideband operation. The bandpass filter at L1,L2,L3 should knock out any medium wave (550-1700 khz) AM broadcast stations, and hard to imagine how they would get by the mixer and IF filter anyway.? Jerry, KE7ER On Sun, Mar 26, 2017 at 01:23 pm, Mark wrote:
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Bitx40 low volume oscillation squeal
Graham
Good day all,
I have been messing about with my Bitx40 SMD on an off for a couple of weeks working towards getting it mounted in a case. I have removed C113 across the LM386 pins 1 and 8 to reduce the gain, makes a big difference. Problem is that I get a high pitched "squeal" or oscillation at very LOW volume setting; turning the volume up a bit more and it disappears. I have spent some time searching the archives for similar posts and fixes but just haven't managed to find much that is relevant. Ideas? Better bypassing on the power lines to the LM386? Speaker is smallish 3" diameter generic 8 ohm speaker. cheers, Graham ve3gtc |
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Re: Pa3fat sketch
开云体育5351 libarary 1.1.2 not latest
Sent from my iPhone
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Re: Pa3fat sketch
开云体育Should be under w5kub fb page
Sent from my iPhone
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am broadcast break throgh
Hi all I don't know if this subject has been covered before but after blowing my raduino and converting my Bitx 40 to analogue tuning I am having a lot of am broadcast stations breaking through the bitx. Is there a mod or two to stop this? If the subject has been disgust before could someone please point me in the right direction please. Mark 2w0jmk |
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Re: PTT line to Raduino?
Yea I see it. I was thinking of that when I saw it this time. So this time I looked very carefully and saw it is a number one. ?#define CW_OFFSET (800l) pasted in here on this page with this font, you can't tell what it is. But in the Arduino IDE it's easier to see it is a number 1 on line #178 of my copy. I made a mistake before, but now I know what to be mindful of before I make a statement that might mislead someone who doesn't know better to figure it for themselves. Another one down, a bunch more to go. I know I said I wanted to use it as a simple SSB. But I would like to implement a change of starting up on USB with the knob turned all the way to the right so I can try line in audio for a digital mode. I saw something in the code before, but I also saw someone else mention the knob thing. Does anyone have a code snippet that be pasted in for an easy upgrade? |
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Re: Continuity
Simon Thompson
开云体育Thanks!
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It looks just like what's in the Arduino IDE except the top is not slanted down. Indicating a lower case L. You guys are right. I am glad I didn't make a bigger ass of myself than I did.
Don, ND6T
Mark