I see what you're saying now. That's where I got confused...
Jack, W8TEE
From: DJ2AG <ya_duck@...>
To: [email protected]
Sent: Wednesday, March 1, 2017 5:04 AM
Subject: Re: [BITX20] Getting stuck
Hi Jack, you are right with what the compiler is doing when calling he function and that the cast on its own does not save anything, but Helmut was replacing printLine1("Raduino v1.01");
with strcpy(c, "Raduino v1.01");
printLine1(c); with the cast in? printLine1( (char *) "Raduino v1.01");??
the additional strcpy is not necessary. This is where memory is saved. When I was compiling a short sketch with both versions I got different values for program size and dynamic data. Your version of printLine looks much better to me. ?I would have proposed to add a pull request to github repository, ?but it looks like the code there is not the one which is actually burned into the Raduinos and the other pull requests from December and January have not been integrated. Armin, DJ2AG?
|
Can't check right now. My work computer is in my basement office. Last night the power went out, no sump pump, and it's sitting in about 6" of water. I'm using my backup system now.
Jack, W8TEE
From: DJ2AG <ya_duck@...>
To: [email protected]
Sent: Wednesday, March 1, 2017 5:11 AM
Subject: Re: [BITX20] Getting stuck
Jack,? did you enable compiler warnings in the Arduino IDE? Armin, DJ2AG
|
Re: Probing the Bitx40 transmit chain
I figured I had trouble in the mic amp when I saw the low voltage gain. ?So I removed C106, and the voltage gain jumped to 10. The two diodes in the modulator give a very low impedance load to the mic amp. ? Still 200mv after the fix. ?I found the voltage gain through those BiDi RF amps to be surprisingly low as well, will have to revisit this. ?Perhaps simulate in LTSpice. ?Am seeing on the order of 5W out, so likely all is well with my rig. ?My measurements should be taken with a grain of salt, they were made rather quickly. ?Should include DC levels too. ?But it's a step in the right direction. Jerry, KE7ER
On Wed, Mar 1, 2017 at 01:29 pm, <vk4bap@...> wrote: The mic amp gain is then somewhat higher than your 200mv at C107 would imply, ?
|
Re: Probing the Bitx40 transmit chain
Sorry, correct that - your af out of A0 should be 5v. The Si5351 output is 3v. Brian.
|
Re: Probing the Bitx40 transmit chain
Jerry, thanks for posting some ac/rf voltages. A couple of points. The output of the Raduino is 3v square wave. The mic amp gain is then somewhat higher than your 200mv at C107 would imply, nearer what one would expect but still a bit low. After cleaning/resoldering C107 do you still measure 200mv there? Brian VK4BAP.
|
Re: Volume, on/off switch
That linear pot should work fine, just that setting the volume just right will be kind of touchy at the low end when using headphones. ?Measure the linear pot with an ohmmeter, make sure you see 10k ohms across the two outside pins. ?Measure between one outside pin and the middle pin, should vary between 0 ohms and 10k ohms as you turn the knob. ?If that all checks out, then solder it back in place, being careful not to have cold solder joints. ?It should work just fine. Jerry, KE7ER
On Wed, Mar 1, 2017 at 12:06 pm, Michael Davis wrote: Ion, Well, I guess my age is showing. An audio taper (logrithmic) pot is what you meant and I SHOULD have bought yesterday. I remember seeing the word linear on the build sheet, but next to the 10k tuning pot...not the 10k volume control. I installed the linear one in the volume circuit and nada, nothing. No volume control. I put the old one back in and all ok for the time being. I'll head back to the parts store (35 miles each way) when it is again convenient to do so. I like the normal sized shaft on the new wrong pot. ?
|
Re: Volume, on/off switch
Ion, Well, I guess my age is showing. An audio taper (logrithmic) pot is what you meant and I SHOULD have bought yesterday. I remember seeing the word linear on the build sheet, but next to the 10k tuning pot...not the 10k volume control. I installed the linear one in the volume circuit and nada, nothing. No volume control. I put the old one back in and all ok for the time being. I'll head back to the parts store (35 miles each way) when it is again convenient to do so. I like the normal sized shaft on the new wrong pot. Also I bought a 1/8 earphone jack that is isolated so there is no electrical connection to the metal panel and will avoid grounding out the audio, which I did earlier in the build. I need to think about the tuning suggestion and either leave well enough alone, or make a modification as suggested. Raduino/Arduino is unfamiliar to me and I fear I'll mess up something if I start writing code. I am also considering a micro fan and larger heat sink for the PA. My concern for the fan is increased battery drain. While at the parts store, I saw a white backlit digital display. It was a 5 volt model and looked very similar to the Bitx display. Do you sense that the raduino power transistor gets quite warm? Not sure why. It must be quite a drain on power though. Enought questions/comments for now. Thanks, Mike
|
Not a bad idea. ?I think what Sandeep is suggesting is to use your fingers to keep the gate grounded to avoid a parasitic oscillation. ? Instead of using my fingers, I would first set RV1 fully clockwise for minimum bias voltage to the gate (remember, pot RV1 is backwards). ?Then add a wire from the IRF510 gate to ground, to make sure no parasitic oscillation takes off. ?Power up in receive mode, with an Amp meter in the PA 12v supply to the IRF510. ?There should be 0 Amps through the meter. ?If there is current through the meter, check if the IRF510 is getting hot. ?If it is getting hot, then the IRF510 is shorted internally, and must be replaced. ?If there is current and the IRF510 is not getting hot, this may be a shorted transformer. ? If there is 0 Amps, then power down, remove the ground wire from the IRF510 gate. ?Power up again with PA 12v to the IRF510 disconnected, check the gate voltage on the IRF510, verify that it is near zero. ?Now connect PA 12v up to the IRF510 again, if it pulls current through the meter and is getting hot, then we have a parasitic oscillation. ?Perhaps add a 10 ohm resistor in series with the IRF510 gate as per that other thread to cure this oscillation. ?Alternately, it could be that just substituting a different IRF510 will cure the oscillation. Jerry, KE7ER
On Wed, Mar 1, 2017 at 10:54 am, Sandeep Lohia wrote: Crosscheq with DVM if Drain & Source of IRF have become short... ( keep one finger on - 0 V ground & other finger on gate while testing )
?
|
Agree with Jerry abt ' abt parasitic oscillation in the IRF510 while in RX mode'Coz drain & source never gets disconnected here even in RX BITX, unlike other RF Power BJT design... parasitic oscillation can also trigger if gate is dry solder or short in transformer...
Crosscheq with DVM if Drain & Source of IRF have become short... ( keep one finger on - 0 V ground & other finger on gate while testing )
'Repair & Reuse or Recycle E-Waste'
On Mar 1, 2017 11:38 PM, "Jerry Gaffke via Groups.Io" <jgaffke= [email protected]> wrote: You are right, his initial post said 0.98A in RX mode, almost a factor of 10 too high.? I didn't read that closely enough. He did say that the IRF510 was getting hot, which means it probably is not the transformer.? There was another thread here where our best guess was a parasitic oscillation in the IRF510 while in RX mode, which can apparently occur even when the gate bias into the IRF510 is shut down at 0 volts. ? ?/g/BITX20/message/22548
Jerry, KE7ER
On Wed, Mar 1, 2017 at 09:24 am, Ashhar Farhan wrote: The IRF510 wouldnt have powered up in the RX mode. It looks more like the PA transformer was or something else was shorting to the ground. ?
|
You are right, his initial post said 0.98A in RX mode, almost a factor of 10 too high. ?I didn't read that closely enough. He did say that the IRF510 was getting hot, which means it probably is not the transformer. ?There was another thread here where our best guess was a parasitic oscillation in the IRF510 while in RX mode, which can apparently occur even when the gate bias into the IRF510 is shut down at 0 volts. ? ?/g/BITX20/message/22548
Jerry, KE7ER
On Wed, Mar 1, 2017 at 09:24 am, Ashhar Farhan wrote: The IRF510 wouldnt have powered up in the RX mode. It looks more like the PA transformer was or something else was shorting to the ground. ?
|
The IRF510 wouldnt have powered up in the RX mode. It looks more like the PA transformer was or something else was shorting to the ground.
- f
On Wed, Mar 1, 2017 at 8:20 PM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote: With 5 Amps, the IRF510 may have died.? Even when transmitting loud voice peaks, it should only be around 1 Amp, with no sound into the microphone the current into PA_12v connection for the IRF510 should only be 0.1 Amps. The instructions on under WireUp say in part: ?"Keep the PA BIAS preset (RV1) to fully clockwise position. Now when you press the PTT button, the ammeter should read about zero.? Increase PA BIAS without speaking into the mic until the PA current shows 100 ma" Note that for zero current, RV1 must be rotated fully clockwise.? That is opposite most knobs in this world, where fully clockwise would be the maximum setting.? If you did not read that closely enough and started out fully counter-clockwise, that could easily draw 5 Amps through the IRF510 when you push the PTT button, killing the IRF510.? I doubt any other parts were damaged. ? The IRF510 is very cheap, buy several when you place and order.? If you cannot easily buy them in Chile, perhaps you know some other ham experimenter who has one he could give you. Jerry, KE7ER
does sound like the IRF510 has? On Tue, Feb 28, 2017 at 04:33 pm, Miguel Villamor wrote:
Hi, i disconnect the PA and the current drawn its 0,16 A, the IRF510 its too hot!!!, when PA its connected the current varies till 5 A!!, how its happend?? Thanks ?
|
Re: Volume, on/off switch
For raduino tuning whether we? can use 100k linear pot instead of 10k ?
Recently i procure 100k conductive plastic film pot (fernel make ) which is very smooth and suppose to be long losting comparing with carbon film pot. Soundar Vu2RJW
On Wed, Mar 1, 2017 at 4:36 PM, Ion Petroianu <ion.petroianu@...> wrote: Hi Mike,
The ear sensitivity is not linear, so, that is the reason the volume pot should be logarithmic.
Now for the tuning, the way the software is written, you have 50 Khz of tuning range on 300 degrees of rotation and 1024 steps in the analog to digital converter (10 bit A/D). A change in position of the tuning pot with 0.3 deg. will change the frequency. Using a multi turn pot will increase the amount of movement required to have a change in frequency.
Another way of improving tuning feel will be by reducing the tuning range to 25 KHz or even 10 KHz by modifying the software, or installing a rotary encoder (also with modified software).
There is another sketch (firmware) that is using the pot in a different way. As long as the pot is in the middle position nothing happens. When you turn the pot frequency starts changing. The speed of change is increased with the angle of rotation. Once where you want to be return the pot to the middle position and you are tuned.
73,
Ion
VA3NOI
--
IonVA3NOI
|
With 5 Amps, the IRF510 may have died. ?Even when transmitting loud voice peaks, it should only be around 1 Amp, with no sound into the microphone the current into PA_12v connection for the IRF510 should only be 0.1 Amps. The instructions on hfsigs.com under WireUp say in part: ?"Keep the PA BIAS preset (RV1) to fully clockwise position. Now when you press the PTT button, the ammeter should read about zero. ?Increase PA BIAS without speaking into the mic until the PA current shows 100 ma" Note that for zero current, RV1 must be rotated fully clockwise. ?That is opposite most knobs in this world, where fully clockwise would be the maximum setting. ?If you did not read that closely enough and started out fully counter-clockwise, that could easily draw 5 Amps through the IRF510 when you push the PTT button, killing the IRF510. ?I doubt any other parts were damaged. ? The IRF510 is very cheap, buy several when you place and order. ?If you cannot easily buy them in Chile, perhaps you know some other ham experimenter who has one he could give you. Jerry, KE7ER
does sound like the IRF510 has?
On Tue, Feb 28, 2017 at 04:33 pm, Miguel Villamor wrote:
Hi, i disconnect the PA and the current drawn its 0,16 A, the IRF510 its too hot!!!, when PA its connected the current varies till 5 A!!, how its happend?? Thanks ?
|
Re: increase frequency coverage
Ricardo, You will have to change the frequency of the low pass filter.? Please look at L6 - L7 & C160 - C163.? It is currently designed to cut off frequencies higher than 7.35mhz or so.
Marco - KG5PRT?
On Mar 1, 2017 2:40 AM, "Ricardo Rivera via Groups.Io" <rivera761= [email protected]> wrote: ? ? Finally ?I was ?able to extend the freq bandwidth ?from 6950 mhz till 7520 ?by adding ?1N4007 diode across? ? the original varactor D9 ( very difficult to source varactor ?in my place) and add 200pf on C96 ?and lastly reduce L4 by? ? two turns ?and retuned C93. Thank you all for the good advised given. But noticed also that the output at higher freq ? ?were reduced appreciably any advise ?on how to make the ouput more broadband? ?
? ? Regards ?and 73 ? ? Ricardo Rivera ? ? DV3RWR
Ricardo, To calculate the frequency of a Clapp oscillator you should use the information found here: Now, BitX is using a VFO that oscillates between, roughly 4.5 MHz to 5 MHz. The C0 in the formula above is the combination of C96 in series with MV209 and those two in parallel with C93, C94 and C95. The equivalent capacitance of a series of capacitors is calculated as follow: C eq series = (C1 x C2)/(C1+C2) The equivalent capacitance of a parallel group of capacitors is calculated as follow: Ceq parallel = C1+C2+C3+C4 For our circuit C1=C93, C2=C94, C3=C95 and C4=(C96x MV209)/(C96+MV209) The nominal value of the inductance is stated on the schematic: L4=9 uH, but with the capacitors as per schematic I am expecting more like a 6 uH inductance. I used that value for may calculations. In my calculation, for the minimum VFO frequency, using the nominal values in the schematic, I ended up with a frequency range of 4.7MHz to 5 MHz, which looks consistent with a band coverage of 7 MHz to 7.3 MHz. With all those in mind, I think the best option for you is to place a second varactor diode in parallel, add another NPO capacitor of 220 pF or 300 pF in parallel with C96 and verify the new frequency range of your VFO. It calculates as 4.35 MHz to 4.85 MHz, or a band coverage of 7.65 MHz to 7.15 MHz for 220 pF. Good luck, --?
Ion VA3NOI
|
I think that now know the mistake, i energize with 13.8 V power supply, down to 12 V and the current its stable, including connected the PA, but when probe the TX, dont have any signal out (probe with a swr/pwr meter), the mosfet maybe will die? (sad)...help and thanks????
|
Re: Volume, on/off switch
Hi Mike,
The ear sensitivity is not linear, so, that is the reason the volume pot should be logarithmic.
Now for the tuning, the way the software is written, you have 50 Khz of tuning range on 300 degrees of rotation and 1024 steps in the analog to digital converter (10 bit A/D). A change in position of the tuning pot with 0.3 deg. will change the frequency. Using a multi turn pot will increase the amount of movement required to have a change in frequency.
Another way of improving tuning feel will be by reducing the tuning range to 25 KHz or even 10 KHz by modifying the software, or installing a rotary encoder (also with modified software).
There is another sketch (firmware) that is using the pot in a different way. As long as the pot is in the middle position nothing happens. When you turn the pot frequency starts changing. The speed of change is increased with the angle of rotation. Once where you want to be return the pot to the middle position and you are tuned.
73,
Ion
VA3NOI
-- Ion VA3NOI
|
Jack,? did you enable compiler warnings in the Arduino IDE? Armin, DJ2AG
|
Hi Jack, you are right with what the compiler is doing when calling he function and that the cast on its own does not save anything, but Helmut was replacing printLine1("Raduino v1.01");
with strcpy(c, "Raduino v1.01");
printLine1(c); with the cast in? printLine1( (char *) "Raduino v1.01");??
the additional strcpy is not necessary. This is where memory is saved. When I was compiling a short sketch with both versions I got different values for program size and dynamic data. Your version of printLine looks much better to me. ?I would have proposed to add a pull request to github repository, ?but it looks like the code there is not the one which is actually burned into the Raduinos and the other pull requests from December and January have not been integrated. Armin, DJ2AG?
|
Re: increase frequency coverage
? ? Finally ?I was ?able to extend the freq bandwidth ?from 6950 mhz till 7520 ?by adding ?1N4007 diode across? ? the original varactor D9 ( very difficult to source varactor ?in my place) and add 200pf on C96 ?and lastly reduce L4 by? ? two turns ?and retuned C93. Thank you all for the good advised given. But noticed also that the output at higher freq ? ?were reduced appreciably any advise ?on how to make the ouput more broadband? ?
? ? Regards ?and 73 ? ? Ricardo Rivera ? ? DV3RWR
On Friday, February 3, 2017 7:00 PM, Ion Petroianu <ion.petroianu@...> wrote:
Ricardo, To calculate the frequency of a Clapp oscillator you should use the information found here: Now, BitX is using a VFO that oscillates between, roughly 4.5 MHz to 5 MHz. The C0 in the formula above is the combination of C96 in series with MV209 and those two in parallel with C93, C94 and C95. The equivalent capacitance of a series of capacitors is calculated as follow: C eq series = (C1 x C2)/(C1+C2) The equivalent capacitance of a parallel group of capacitors is calculated as follow: Ceq parallel = C1+C2+C3+C4 For our circuit C1=C93, C2=C94, C3=C95 and C4=(C96x MV209)/(C96+MV209) The nominal value of the inductance is stated on the schematic: L4=9 uH, but with the capacitors as per schematic I am expecting more like a 6 uH inductance. I used that value for may calculations. In my calculation, for the minimum VFO frequency, using the nominal values in the schematic, I ended up with a frequency range of 4.7MHz to 5 MHz, which looks consistent with a band coverage of 7 MHz to 7.3 MHz. With all those in mind, I think the best option for you is to place a second varactor diode in parallel, add another NPO capacitor of 220 pF or 300 pF in parallel with C96 and verify the new frequency range of your VFO. It calculates as 4.35 MHz to 4.85 MHz, or a band coverage of 7.65 MHz to 7.15 MHz for 220 pF. Good luck, --?
Ion VA3NOI
|
Re: Volume, on/off switch
Michael, In a linear pot the resistance is directly proportional to the amount of shaft rotation. A logarithmic profile pot is more often called an Audio profile pot, and denoted by the letter A. The resistance changes logarithmically to match the human ear response to the audio power loudness curve.
toggle quoted message
Show quoted text
On Feb 28, 2017, at 8:44 PM, Michael Davis < maddmd818@...> wrote:
Thanks Ion. I made my trek to the parts store. I got a new linear 10k pot (per the instruction sheet). I didn't see a logarithmic there, nor have I heard of one. I am intrigued by your tuning pot suggestion or a way to gain a bandspread/fine tune feel.?
Sent from Mike's iPad WA1MADSent from Mike's iPad WA1MAD
|
Soundararajan Ra.
Ion Petroianu, VA3NOI
Ricardo Rivera