Date   
#bitx40help Probably need new Raduino #bitx40help

Kevin Luxford
 

Yep I think I did it.  I applied reverse polarity to my BITX40 from HFSignals.  The power to the board was connected but no power to the PA.  (The connector I used had the positive connected to the outside and the negative to the central - was for an odd piece of test gear I used years ago).  Anyway, correcting the connector results in no sign of life on the display.  Reading through the posts, it would appear that I may well have bricked the raduino.  Hence I would like to contact Mike Hagen to enquired about his improved raduino.  So could Mike please contact me off list so we can discuss features, costs etc.  And the irony is that components toprotect against reverse polarity are on order but have not yet arrived. vivimus atque discimus.

Re: Lost audio from receiver

Lawrence Galea
 

On Sun, Feb 11, 2018 at 10:46 PM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:
I think you're right, probably blew the LM386.
And nothing else.

Clipping leads and just leaving them in place sounds fine, or could 
heat them up and pull them out one by one using soldering iron and needle nose pliers.
I would not bother trying to suck the solder out of all those holes, just snip the bottom half of the legs off the new part
and solder it to the surface of the board.

An alternative is to buy some LM386 amp kit, and wire it into the existing volume control pot:
    http://www.kitsandparts.com/audioamp386v2.php


On Sun, Feb 11, 2018 at 12:52 pm, Vic WA4THR wrote:
After some other testing on a BitX40 that was working well, it is likely that 12v (or even 24v) touched one of the speaker leads. Now I have essentially no audio out from the radio. On very strong signals and at maximum volume I can hear a weak and very distorted sound out of either the speaker or a separate speaker/mic, but it is not copyable and only just recognizeable as a signal. Listening on another receiver and watching the output, transmit seems fine. It sounds clear and undistorted and the power out is pretty normal. I checked the voltages around Q16 and they are exactly as expected in receive and transmit. The suspicion to me is that the LM386 has "blown", but there are no obvious marks on the board on any components. Is there someplace else I should look before trying to replace that chip?

As to technique for repairing that IC, if it is the problem, I seem to recall a method that involved just cutting the legs off and soldering them to a new chip. Is that a viable way to go?

While I've never owned a barrel of monkees, it  is hard to imagine that could be more fun than the BitX, but I do seem to get myself in trouble playing with it.

=Vic=


Re: Bitx40 - receiver works great, but do not transmit #bitx40help

Ivan Ilyichev
 

Thank you for answers. I have a lot of good germanium detector diodes D9B (full analogue of 1N34A). At evening i try to built a RF probe and measure output power.
Also i try to check toroid trifillar transformers - they bother me to.

Re: wrong frequency after software change. #ubitx

at91r40008
 

Thanks Ron. 
Never too old to learn something new. And be embarrassed that it was in my face.
--
73, Yvon NU6I

Re: wrong frequency after software change. #ubitx

at91r40008
 

Thanks Jack. I missed that one.
It still doesn't show me the exact location of my project.
The problem is only I open more than one project at a 
time for comparison.
From now on when I download a project I'll rename it
immediately and insert a note where it is coming from.

--
73, Yvon NU6I

Re: Blown by nearby transceiver #bitx40help

Jerry Gaffke
 

Possible.

Do we know what the transmitted frequency was?  Was it 40m?
I figure the series loop of L3,C6,C7,C5 to be resonant at 7.45mhz,
    C-total-in-pf = 1/(1/1000 + 1/470 + 1/100) = 76pf
    F-resonance =  1/(2*pi*sqrt(L*C)) = 1/(6.28*sqrt(76e-12 * 6e-6)) = 7.46mhz
Loading from C4,C11,C41 will likely bring that down a bit in frequency.

I'd be looking at the base and emitter DC voltages of Q1 (during receive) and,Q13 (during transmit)
to see if they got blown.  Compare to Randy's chart as previously suggested by Marco: 
    https://groups.io/g/BITX20/files/K7AGE/BITX40%20Voltage%20Measurments.pdf
If  Q1 got blown, then also check Q4.

I am still quite surprised that enough energy got coupled in to blow the trace. 
The traces do form a moderately large loop, a single turn inductor, perhaps that was all it took.
Or perhaps those toroids are not as self shielding as I had figured.

Jerry, KE7ER


On Sun, Feb 11, 2018 at 08:27 pm, Raj vu2zap wrote:
Looks the L and C formed a series resonant circuit at the transmitted frequency.

Re: uBITX woes, feeling disheartened. #ubitx

 

Thats not OK.. your rx will not work!

Switch off power and check the contact continuity as per table I sent you!

At 12-02-2018, you wrote:
make that K1 Rec. pin3=0 volts sorry 73's de AC8XZ

Re: Blown by nearby transceiver #bitx40help

 

Jerry,

Looks the L and C formed a series resonant circuit at the transmitted frequency.

Raj

At 12-02-2018, you wrote:
From the photo, looks like a burned trace from C6 to L3.
From the Bitx40 schematic it's hard to imagine how that might have happened.

Re: uBITX woes, feeling disheartened. #ubitx

 

Now the readings looks normal!

At 12-02-2018, you wrote:
ok how about these readings; K1 Rec. pin1=0volts pin3=12volts pin5=12 volts pin =8 12 volts pin9=12 volts pin12=0volts pin14=0volts pin16=0 volts K1 Trans pin1=12 pin3=0volts pin5=12volts pin8=12volts pin9=0volts pin12=0volts pin14=0volts pin16=0 volts K3 Trans. pin1=0 volts pin3=0 volts pin5=0 volts pin8=12 volts pin9=0 volts pin12=0 volts pin12=0 volts pin14=0 volts pin16=0 volts KT1 Trans. pin1=0 volts pin3=0 volts pin5=0 volts pin8=12 volts pin9=0 volts pin12=0 volts pin14=0 volts pin16=0 volts KT2 Trans. pin1=0 volts pin3=0 volts pin5=0 volts pin8=12 volts pin9=0 volts pin12=0 volts pin14=0 volts pin16=0 volts KT3 Trans. pin1=0 volts pin3=0 volts pin5=0 volts pin8=12 volts pin9=0 volts pin12=0 volts pin14=0 volts pin16=0 volts. VOM Black to Antenna Ground Red to pin being tested. hope this is good readings 73's de AC8XZ

Re: Blown by nearby transceiver #bitx40help

 

Very mysterious, looks like ball lightening.

I have seen one right outside my shack window and it was a real treat!

Raj

At 12-02-2018, you wrote:
From the photo, looks like a burned trace from C6 to L3.
From the Bitx40 schematic it's hard to imagine how that might have happened

Do let us know what parts had to be replaced once you get this fixed.
And any guesses as to how it happened.
For me at least, truly a mystery.

Jerry, KE7ER

Re: uBITX woes, feeling disheartened. #ubitx

rlawson695@...
 

raj ;  I messed up twice on pin3=12 volt on rec. sorry had some people drop in while I was trying to post.

Re: Raduino for Sale

Dennis Zabawa
 

Unit is sold.
Dennis KG4RUL

Re: Bitx40 - receiver works great, but do not transmit #bitx40help

 

Ivan even if all voltages are correct the R141 can be open, please switch off power and check
with ohm meter.

Raj

At 11-02-2018, you wrote:
I use a 13.5 , 2 amp power source instead of 12 volts lead-acid battery, like in shown voltages chart.
Remeasured voltages are:
Q13: collector 13.34 v, base 4.21 v, emmitter 3.57 v
As i see they are practically the same as in voltage chart.

Re: uBITX woes, feeling disheartened. #ubitx

 

That is correct, you count the pins in a clockwise direction. From your last readings things looks haywire.
Please see the table I sent you by PM.

Also when you reply please edit the previous message to keep only the relevant part. It will be clear as to
who or what question you are replying to. If you don't and leave the whole message then the whole previous
parts are removed.

Raj

At 11-02-2018, you wrote:
I am putting black lead of vom on ground (black wire of the power connection and red lead of vom on the pin I am measuring. Is this correct? The square pin 1is [] ok you said go clockwise counting so the pin under pin1 is next pin to count. Than at bottom of that row cross over to next row at bottom and that should be next pin to start counting. Am I correct. I will try today again to measure voltage again. Thanks for your help. 73s de AC8XZ

Re: Bitx40 - receiver works great, but do not transmit #bitx40help

 

Ivan,

Check T5,6,7 .. it will be a solder problem or a short. Shake eaxh toroid while provinding a "hallow" in the mic
and see if the power suddenly jumps.

Raj

At 11-02-2018, you wrote:
I have a trouble with BITX40 kit from HFSignals.
Receiver work great - i hear a lot of stations all over the world. But there are no transmission when pressing PTT.
I check currencies al described in instruction (both main board power and PA power connected):
In receive mode current is 136 mA
When press PTT - 330 mA
If saying HAAAAALO to microphone when PTT pressed - the current still 330 mA and not changed.
I try to adjust PA as described in instrunction - connect ammeter directly to PA power line. First step is adjust VR1 to PA currency 100 mA. It is ok. Second step - saying HAAAALO microphone - fail, PA currency still 100 mA and not changes. I try to change value of VR136 - PA currency changes a little.
Also i try to check microphone amplifier - i connect external LM386 amp board to negative pin of C122 capacitor. When pushing PTT and saying anything do microphone - hear me from external amplifier, it means that mic amp works ok.
At the next step i connect an external continuous wave oscillator worked at 7.100 Mhz to input of PA - left pin of C132. The PA currency raise to 1 A and there is a CW output in antenna. It means that PA works.
At the next i connect continuous wave oscillator worked at 7.100 Mhz to to the right end of C43. The PA currency raise to more than 1 A and there is a CW output in antenna. It means that preamp Q4 also works.
I have no ideas what to check more with my equipment - i have no oscilloscope, have only digital multimeter, frequency meter (up to 70 Mhz), and a continuous wave oscillator (up to 70 Mhz).

Mailbox metal case 3x6x9 inch #ubitx

Xcott Craver
 

Yos,

I was looking for a suitable metal case for the uBITX and ended up wandering down the mailboxes section of the local Lowes.  They had a slim upright letterbox, the Gibraltar City Classic, for under $13.  

The letterbox has a recessed back panel that limits the interior thickness to 2.5", but all you have to do is pop the panel it off and turn it around, and you get the full 3" of space.  I added some rubber feet and used some scrap metal to hold the jacks and knobs on the same side as the board.  The front lid neatly flips open to reveal the goods. 

These cases are in bronze and black, without any US MAIL detail on them---there is a snap-on plastic fleur-de-lis if you want it, but beyond that it's just a case.

Now I can tell people that I got my uBITX in the mail, wah wah wahhhhh....

Thanks, Xcott K2CAJ

Re: wrong frequency after software change. #ubitx

Jack, W8TEE
 

You can also set the default using File --> Preferences from the menu bar. I usually just create a directory for each project, placed in an appropriate subdirectory.

Jack, W8TEE



From: Ronald Pfeiffer via Groups.Io <w2ctx@...>
To: BITX20@groups.io
Sent: Sunday, February 11, 2018 10:36 PM
Subject: Re: [BITX20] wrong frequency after software change. #ubitx

If using Arduino IDE just select  Sketch / Show Sketch Folder

rOn



From: Ian Lee <kd8cec@...>
To: BITX20@groups.io
Sent: Sunday, February 11, 2018 10:29 PM
Subject: Re: [BITX20] wrong frequency after software change. #ubitx

Yvon

I agree with you.
I am similar to you. I used arduino for the first time.
You seem to be similar to me.
I have run only one IDE since I experienced something similar to you.
There is no indication in the Arduino IDE so sometimes i press the Save As button (To check the working directory. lol)

Now I am a little familiar with the Arduino IDE. I still do not know yet.

Anyway the problem has been solved and I am very glad that your uBITX is back.

73
Ian KD8CEC


2018-02-12 12:08 GMT+09:00 at91r40008 <yvon@...>:
thank you Ian.

I have been writing embedded (?) software since the pdp8.
And I am still working and writing embedded software (pic32
and ARM).
What bugs me with the Arduino is the lack of proper naming
convention. Whatever software I download from the web
or github, once it is loaded in the IDE, be it Arduino or
UCIDE it always shows as uBix20. Looking in the output 
window doesn't show the project/file path. Easy to be confused.


73, Yvon NU6I


--
Best 73
KD8CEC / Ph.D ian lee
kd8cec@...
www.hamskey.com (my blog)




Re: Bitx40 - receiver works great, but do not transmit #bitx40help

Arv Evans
 

FYI

It is possible to forward bias the detector diode to get much higher sensitivity.

https://goo.gl/mgZuYA


Of course this does require DC power to the RF detector probe, or a small battery.

Arv K7HKL
_._

On Sun, Feb 11, 2018 at 8:30 PM, Jack Purdum via Groups.Io <jjpurdum@...> wrote:
taydaelectronics.com has the 1N34a for $.24. Combine with some other stuff you need/want to cut down on shipping costs.

Jack, W8TEE



From: Jerry Gaffke via Groups.Io <jgaffke=yahoo.com@groups.io>
To: BITX20@groups.io
Sent: Sunday, February 11, 2018 5:08 PM
Subject: Re: [BITX20] Bitx40 - receiver works great, but do not transmit #bitx40help

Good advice, build a diode RF probe.
A germanium diode such as the 1n34a or 1n60 works well, but they are expensive now and hard to get.
A schottky diode (such as the Bat54s used on the Bitx40 diode mixers) works reasonably well.
A standard silicon diode such as a 1n4148 might be good enough for measuring fairly high RF power nodes 
such as at the antenna port of a working transmitter, but definitely will not see the expected RF voltage at the base of Q13.
The issue here is the forward voltage drop for small currents, perhaps 0.3v for the Schottky and 0.6v for the 1n4148.

The germanium diodes will be less than the Schottky but dependent on temperature.
The datasheet punts, and says 1 volt max at 5ma, should be good down to 100mv or so with the currents involved in an RF probe at 10megaohms:
    http://www.nteinc.com/specs/original/1N34A.pdf
    https://electronics.stackexchange.com/questions/223813/the-classic-1n34a-ge-diode-has-a-vf-of-1v-how-could-a-diode-with-such-a-high

N5ESE tries to explain the probe, but only goes so far.
That RF probe design assumes a voltmeter with an input resistance of 10megaohms,
some DVM's will have an input resistance that is considerably less.
So don't count on that probe reading RMS voltages accurately until somehow calibrated.
As the RF voltages approach the forward voltage drop across the diode it will become less and less accurate,
though can still be surprisingly useful (perhaps with a calibration chart) down to a few tens of millivolts if you have the right diode.
Also, N5ESE fails to mention that the capacitance between the probes into the DVM is an integral part of the design,
that capacitance along with his 4.7megaohm resistor forms a low pass filter so that the meter sees DC instead of rectified RF.


We should have a spare Bat54s plus cap and resistor into an analog Nano pin, 
so we can all have a common way of measuring RF voltages when debugging.
With different diodes and different voltmeters, we will all get different results and cannot usefully compare our measurements.

Jerry, KE7ER



On Sun, Feb 11, 2018 at 01:14 pm, M Garza wrote:
Since you do not have a watt meter, and you have a multimeter, you could build a rf probe.  You can see the rf voltage and calculate the wattage.
Here is a link to one you can build.  It is very easy:
 



Re: wrong frequency after software change. #ubitx

W2CTX
 

If using Arduino IDE just select  Sketch / Show Sketch Folder

rOn



From: Ian Lee <kd8cec@...>
To: BITX20@groups.io
Sent: Sunday, February 11, 2018 10:29 PM
Subject: Re: [BITX20] wrong frequency after software change. #ubitx

Yvon

I agree with you.
I am similar to you. I used arduino for the first time.
You seem to be similar to me.
I have run only one IDE since I experienced something similar to you.
There is no indication in the Arduino IDE so sometimes i press the Save As button (To check the working directory. lol)

Now I am a little familiar with the Arduino IDE. I still do not know yet.

Anyway the problem has been solved and I am very glad that your uBITX is back.

73
Ian KD8CEC


2018-02-12 12:08 GMT+09:00 at91r40008 <yvon@...>:
thank you Ian.

I have been writing embedded (?) software since the pdp8.
And I am still working and writing embedded software (pic32
and ARM).
What bugs me with the Arduino is the lack of proper naming
convention. Whatever software I download from the web
or github, once it is loaded in the IDE, be it Arduino or
UCIDE it always shows as uBix20. Looking in the output 
window doesn't show the project/file path. Easy to be confused.


73, Yvon NU6I


--
Best 73
KD8CEC / Ph.D ian lee
kd8cec@...
www.hamskey.com (my blog)


Re: Bitx40 - receiver works great, but do not transmit #bitx40help

Jack, W8TEE
 

taydaelectronics.com has the 1N34a for $.24. Combine with some other stuff you need/want to cut down on shipping costs.

Jack, W8TEE



From: Jerry Gaffke via Groups.Io <jgaffke@...>
To: BITX20@groups.io
Sent: Sunday, February 11, 2018 5:08 PM
Subject: Re: [BITX20] Bitx40 - receiver works great, but do not transmit #bitx40help

Good advice, build a diode RF probe.
A germanium diode such as the 1n34a or 1n60 works well, but they are expensive now and hard to get.
A schottky diode (such as the Bat54s used on the Bitx40 diode mixers) works reasonably well.
A standard silicon diode such as a 1n4148 might be good enough for measuring fairly high RF power nodes 
such as at the antenna port of a working transmitter, but definitely will not see the expected RF voltage at the base of Q13.
The issue here is the forward voltage drop for small currents, perhaps 0.3v for the Schottky and 0.6v for the 1n4148.

The germanium diodes will be less than the Schottky but dependent on temperature.
The datasheet punts, and says 1 volt max at 5ma, should be good down to 100mv or so with the currents involved in an RF probe at 10megaohms:
    http://www.nteinc.com/specs/original/1N34A.pdf
    https://electronics.stackexchange.com/questions/223813/the-classic-1n34a-ge-diode-has-a-vf-of-1v-how-could-a-diode-with-such-a-high

N5ESE tries to explain the probe, but only goes so far.
That RF probe design assumes a voltmeter with an input resistance of 10megaohms,
some DVM's will have an input resistance that is considerably less.
So don't count on that probe reading RMS voltages accurately until somehow calibrated.
As the RF voltages approach the forward voltage drop across the diode it will become less and less accurate,
though can still be surprisingly useful (perhaps with a calibration chart) down to a few tens of millivolts if you have the right diode.
Also, N5ESE fails to mention that the capacitance between the probes into the DVM is an integral part of the design,
that capacitance along with his 4.7megaohm resistor forms a low pass filter so that the meter sees DC instead of rectified RF.


We should have a spare Bat54s plus cap and resistor into an analog Nano pin, 
so we can all have a common way of measuring RF voltages when debugging.
With different diodes and different voltmeters, we will all get different results and cannot usefully compare our measurements.

Jerry, KE7ER



On Sun, Feb 11, 2018 at 01:14 pm, M Garza wrote:
Since you do not have a watt meter, and you have a multimeter, you could build a rf probe.  You can see the rf voltage and calculate the wattage.
Here is a link to one you can build.  It is very easy: