Parasites noises
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Hello,
On my homebrew , I have parasitic noises. These noises are like crackling, whistling. I put the antenna entrance to the ground, it¡¯s the same. It seems to come from the first converter stage. What I¡¯ve already done: I added additional decoupling capacitors (47?) on the RX power supply before and after resistance R18.( By default there is already a 0.1?f) It reduces noise but not enough. The value may not be good.?On what parameters set its value? Also if I touch the 12vRX connection as close as R18 or the collector of Q12 with a small screwdriver, but my hand connected on the tip, this greatly reduces the noise. I thought the cracking was coming from a toroid.?For example, I replaced one of the wires with fake contacts, but that¡¯s not the case.?In fact, depending on who you touch, you cause suspicious noises. For cracking, I think this is more due to a result of frequency mixing on first converter .T cdt his stage being very sensitive, you see, even with the antenna to the ground, of the HF modulation capture. My conclusion, is that the pb is more on Q12, but a failing transistor can it do this type of phenomenon? |
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hello,
Hello, To clarify I have this problem on my 2nd prototype The first one had 12MHZ filters and worked well the first time. Careful, the implantations are different. The 2nd is in filters 11059MHZ Of course, I reloaded another PGM in the Arduino;?I took the version for Ubitx V5 of Kd8CEC. I think the anomaly is at the output of the SSB filter and is more visible with the amplification of Q70. It is very strange and has a modulation of 1.3?s with an internal oscillation of 0.08?s. It is the M1 signal which with the relay passes to M2 for amplification. So this causes a global interaction, which produces these strange crackles and noises. For the moment I don¡¯t know where this modulation at 1.3 ?s comes from. Some id¨¦a? so?I would like to test the SSB filter by this method I only have a generator and oscillo, how to test without desoldering? Give me the connection points in relation to a V6 schema --> It's write to use the transformers for a best measurement. cdt |
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Christian,
For my tests the screen Nextion is completly deconnected. i know it can make some noise but is't? completly different in my case. I have gained experience on this type of assembly The noise comme from Q70 I isolated Q70 which is a SMD model on my construction. it oscillates alone at 40 MHZ!!! so therefore parasitizes the upper stages by modulation effect I changed it, it¡¯s the same. So I will do a test with a good old 2N3906 as on my first proto. cdt |
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hello,
I think I have found, but I will almost give my tongue to the cat! If I load the Ubitx version of KD8CEC for model 234 with Smeter or not, I have no more problems. Whether I take the one for V5 with Smeter or not the noise come back!!! you will tell me, it is not the same SSB filter (I put 11059mhz quartz), yes, but the anomalies are due to frequency interactions. look at the posts I had with Evan, we discovered that there was still a residual frequency of 12/15 kilohetz in the output of the SSB filter with version 234 of KD8CEC I attach the used versions that fit into the Arduino with Xloader Some Ideas? |
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hello,
Without being a specialist, I looked at the source codes of KD8CEC and that of the V6. Can you explain the USB frequency difference between the KD8CEC software and the V6. It¡¯s not huge, but it¡¯s about 3KHZ. Same for BFO values, but I¡¯m not so sure. So, if I want to change the USB value in the KD8CEC program and set it to 11059200l as in the V6, how much do I have to change for the SECOND_OSC_USB and SECOND_OSC_LSB values? Maybe this could fix my interference issues? Kd8CEC
?#define SECOND_OSC_USB (56058700l)
? #define SECOND_OSC_LSB (33945800l)?
?
? //Not used, Just comment (Default)
? #define INIT_USB_FREQ? ?(11056500l)
?
V6 Ubitx
#define INIT_USB_FREQ? ?(11059200l)
unsigned long vfoA=7150000L, vfoB=14200000L, sideTone=800, usbCarrier;
? |
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The V6 should be 11,055.5 as I checked with multiple V5 boards. Why
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it at 11,059.2 is a mystery to me. Raj At 02/05/2021, you wrote: hello, |
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Raj and all
I do not understand why this value on version 5 of KD8CEC for USB.
The values should be close to that of the SSB filter. (11059000) on the pgm 11056500 My mount works very well with version 234 of KD8CEC. There the USB value is 11996500, so very close to the SSB filter at 12MHZ #define INIT_USB_FREQ? ?(11996500l) I can try to change it and recompile it cdt |
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Hello,
I am a bit taken by the time. I will change the 11059 quartzs + capacitors filters and give 12Mhz + KD8CEC 234 version. On my PCB, I had planned removable filters, this is the opportunity to manufacture them This will allow me to recontrol easily by simple permutation of them + PGM NB: My sockets for relays works fine cdt |
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Hello,
I found this review interesting provided by KD8CEC Did he cause my problem? see here: I could not find the 45 Mhz filter part changed on the V5 circuit.?Only the IF filter has been changed from 12Mhz to 11.059Mhz.
However, the V5 source code shows that the frequency is increased by 5khz when mixing frequencies to pass 45Mhz. I do not quite understand why. It seems that uBITX V5 should be purchased and measured by an instrument.?I think that if the 45Mhz filter has not changed, this part should be kept, but it is not accurate because I have not tried V5 yet. I need help from someone with V5.?I would like to offer two firmware and check the difference in the reception ratio of the two firmware. I modified this part as follows. I respect the original author's intentions. modified the 45Mhz filter section to pass 45005000 like Farhan as below. If anyone can test this, I would like to test a few passes through 45Mhz. So my question is: Has anyone really tested the 1.2 CEC version of KD8CEC with an 11.059Mhz filter and a Nextion screen? For your information, I had planned the possibility of putting a removable USB filter on my Cocorico Ubitx. It is done and it will be easy to do tests here my filters. The smd capacitors are below cdt |
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Hello,
I found the source of one of my parasitic noises. LOL Indeed, I have in the speaker a "beep" of a few milliseconds and almost every 1 or 2s , a bit like a heart analyzer. The noise disappears if I make a permanent reset of the Arduino This noise is generated by one of the following 2 signals: SDA and SCL (A4, A5) of the arduino. (Bus IC2) These two connections go to my S5153 circuit. The? input? amplifier? connection is not nearby, but you can see the pulse at the amp input. Maybe it goes through the CW-Tone, input? amplifier, via 5v, ground?? we see the pulse too. At this time,? I put capacitors at the most of the Arduino power supply (Directly on it, also on the S5153 module) without improvement. No test with a wire to modifify + 5v power or ground.??I haven¡¯t made any changes on the 5v regulator yet.? Question of time.... Anyway, trying to put a capacitor on SDA or SCL, "bug" the arduino, so bad idea. Worst case, I¡¯d put two shields wires. Not easy, An idea? cdt |
Gerard
Christian Schwabedal
Raj vu2zap
