Date   
Re: Good mic for Ubitx and Bitx40

_Dave_ K0MBT
 

I would add that I get a lot of good signal reports using the stock electret mic element.

Re: Adding uv meter .board and leads to ubitx

_Dave_ K0MBT
 

I took a used computer speaker apart and removed the amplifier. Stripped off the switch, volume control, and plug in ports. Mounted it in the case with a couple of standoffs and bolts.Ran the output of the v4 into the input of the amp. I bought the v4 used with an indian case. The volume control was biased with equal 4.7 k resisters The power comes from the main switch of the radio.

Re: Audio problem in my ubitx

Jerry Gaffke
 

No receiver audio, sounds like it could be a wiring error around either
the volume control or the output of the audio amp to the speaker.
Triple check that wiring.  What kind of speaker or headphones are you using?

First, lets make sure it is receiving.
Verify that RX has 12 volts (measured to ground) for receive (measure either end of either R18 or R38,
near the top of the schematic) and that TX is low (measure either end of R28 or R40,
which are below R18 and R38). 
If TX is 12v and RX is 0v, then it is trying to transmit, perhaps a problem with how 
the PTT switch or the key got wired up.

Maybe wire the SPK output directly from the uBitx to an 8 ohm speaker, and then to board ground,
this will go around any wring errors at the speaker/headphone jack.
Then remove the volume pot, wire directly from M1 to VOL-M to go around the relay
between M1 and M2, the volume control  (and the AGC circuit at Q74 if this is a v4 uBitx).
Power up, the sound through the speaker will be very very loud if it now works.

Touch the end of one meter of wire (we are using it as an antenna to pick up local radio noise)
to the test point TP20 (on the right side of the v4 schematic, between modulator and audio pre-amp).
This will make a pop in the speaker if the audio amps are working.

If none of that gets the audio amplifier going, you might try replacing the final stage between VOL-M and SPK
with a small LM386 amplifier such as this:  https://www.elecrow.com/lm386-audio-amplifier-module.html

You also seem to have a problem with the transmitter.
Let's get the receiver working first.

It will help if you tell us exactly what you have.
What version of the uBitx, v3 or v4?
Speaker or headphones?
Power supply?
Any mistakes you might have made already that could have damaged the radio,
such as reversing the power supply leads or a power supply more than 13 volts?
Did you power it up with the Raduino connector not quite lined up correctly?
Does the raduino power up, can you select a frequency in the display by turning the encoder knob?
Perhaps a picture or two showing us how you wired it up?

Jerry


On Sat, Jan 19, 2019 at 09:00 PM, Avijit wrote:
Hello,
I have assembled my Ubitx yesterday but I am not getting any audio. Here are the details :
1. No audio coming out on speaker as well as headphones.
2. When I am turning the volume control to the full only a screeching sound is emanating.
3. Tried with another volume pot but no difference.
4. When i am connecting the cw key occasional cw tone is heard very faintly but nothing happens with pressing the key.
5. No rf power is visible on the meter when key is pressed.
 
Please help. 
Thanks and regards 
Avijit 

Re: Audio problem in my ubitx

Bill Cromwell <wrcromwell@...>
 

Hi Jerry,

One of your questions was already answered and you even requoted it. He said there is no audio in the speaker nor in the earphones. It could still be wired wrong.

In my V3 with CEC software there is a setting in the setup menu to disable the transmit. I thought I would use that to play with the sidetone and use the uBitx as a $150 code practice oscillator. There was very little sidetone, extremely faint. I don't know if his software has a feature to disable the transmitter. He may also not have wired the brown wire to the power supply so there is no drain voltage applied to the finals. No transmit output.

And what about that resistor to the key jack? That produces at least some of the symptoms. Other hams have decided they don't use CW and don't need that resistor. WRONG! There new rigs worked right AFTER they installed that.

I hope all of this helps him make progress toward a working radio.

73,

Bill KU8H

On 1/20/19 9:44 AM, Jerry Gaffke via Groups.Io wrote:
No receiver audio, sounds like it could be a wiring error around either
the volume control or the output of the audio amp to the speaker.
Triple check that wiring.  What kind of speaker or headphones are you using?
First, lets make sure it is receiving.
Verify that RX has 12 volts (measured to ground) for receive (measure either end of either R18 or R38,
near the top of the schematic) and that TX is low (measure either end of R28 or R40,
which are below R18 and R38).
If TX is 12v and RX is 0v, then it is trying to transmit, perhaps a problem with how
the PTT switch or the key got wired up.
Maybe wire the SPK output directly from the uBitx to an 8 ohm speaker, and then to board ground,
this will go around any wring errors at the speaker/headphone jack.
Then remove the volume pot, wire directly from M1 to VOL-M to go around the relay
between M1 and M2, the volume control  (and the AGC circuit at Q74 if this is a v4 uBitx).
Power up, the sound through the speaker will be very very loud if it now works.
Touch the end of one meter of wire (we are using it as an antenna to pick up local radio noise)
to the test point TP20 (on the right side of the v4 schematic, between modulator and audio pre-amp).
This will make a pop in the speaker if the audio amps are working.
If none of that gets the audio amplifier going, you might try replacing the final stage between VOL-M and SPK
with a small LM386 amplifier such as this:  https://www.elecrow.com/lm386-audio-amplifier-module.html
You also seem to have a problem with the transmitter.
Let's get the receiver working first.
It will help if you tell us exactly what you have.
What version of the uBitx, v3 or v4?
Speaker or headphones?
Power supply?
Any mistakes you might have made already that could have damaged the radio,
such as reversing the power supply leads or a power supply more than 13 volts?
Did you power it up with the Raduino connector not quite lined up correctly?
Does the raduino power up, can you select a frequency in the display by turning the encoder knob?
Perhaps a picture or two showing us how you wired it up?
Jerry
On Sat, Jan 19, 2019 at 09:00 PM, Avijit wrote:
Hello,
I have assembled my Ubitx yesterday but I am not getting any audio.
Here are the details :
1. No audio coming out on speaker as well as headphones.
2. When I am turning the volume control to the full only a
screeching sound is emanating.
3. Tried with another volume pot but no difference.
4. When i am connecting the cw key occasional cw tone is heard very
faintly but nothing happens with pressing the key.
5. No rf power is visible on the meter when key is pressed.
Please help.
Thanks and regards
Avijit
--
bark less - wag more

Re: spurs & harmonics, whew!

Jerry Gaffke
 

Kees,

Since you heard about the Axicom relays, you are pretty much caught up.

Replacing relays KT1, KT2, KT3 with Axicom relays flat on the board (without any sockets)
seems to bring harmonics down far enough to be acceptable for the FCC (-43dBc spec). 
More aggressive hacks (or using an offboard switchable bank of LPF's) is an option 
if you want better.

Spur fixes remain at a choice between Raj's swapping out L5, L7 with some specific shielded 1210 size 
surface mount inductors, or going with Farhan's low pass LC filter between the 45mhz IF and the D1,D2 mixer.
Farhan has an additional solution for the 12mhz spur due to CLK0-to-CLK2 crosstalk,
involves increasing the 45mhz IF gain (to drown out the 12mhz coming in on CLK2)
and a 12mhz trap installed after that mixer.  These spurs are not an issue at all for CW operation.

Farhan is working on a v5 board.  He had put out preliminary schematics showing minimal changes
from v4, conforming roughly to his recommendations above.  But is now looking at more aggressive
changes to ensure compliance at -50 dBc, and perhaps reduce IMD somewhat as well.

Well, that's my understanding.  Corrections welcome.

Jerry, KE7ER



On Sat, Jan 19, 2019 at 05:56 PM, Kees T wrote:
I'm interested in V3 and V4 rework...........

I understand Allison's approach to wiring the LPF relays, leaving the 10M LPF in series (not a problem), and requiring a small modification of the Arduino code. 

For the V3 and V4 boards why not pull the 3 relays, add connector pins in their locations (2 rows of pins per relay with appropriate pins pulled), and add a small daughter board with the same 3 relays wired per Allison's suggestion ? Use the existing LPF components on the uBITX board.

What happened to the Axicom relay fix ?  ....I haven't read the reflector for a while.

73 Kees K5BCQ

Re: Audio problem in my ubitx

Jerry Gaffke
 

Yup, good points.

I think in a case like this, verifying it is in receive mode (check TX and RX),
and getting the receiver to work is the first step.
Lots of things could make it decide to go into transmit mode, 
but especially your resistor at the key jack, and PTT wiring.

I'm not sure what all is going on with sidetone levels here.
Had been complaints early on about it being too loud, then R253 got changed.

Best to get it going first with the stock firmware.
Should not be necessary to do any mods to get a working radio.

Jerry



On Sun, Jan 20, 2019 at 08:29 AM, Bill Cromwell wrote:
Hi Jerry,

One of your questions was already answered and you even requoted it. He said there is no audio in the speaker nor in the earphones. It could still be wired wrong.

In my V3 with CEC software there is a setting in the setup menu to disable the transmit. I thought I would use that to play with the sidetone and use the uBitx as a $150 code practice oscillator. There was very little sidetone, extremely faint. I don't know if his software has a feature to disable the transmitter. He may also not have wired the brown wire to the power supply so there is no drain voltage applied to the finals. No transmit output.

And what about that resistor to the key jack? That produces at least some of the symptoms. Other hams have decided they don't use CW and don't need that resistor. WRONG! There new rigs worked right AFTER they installed that.

I hope all of this helps him make progress toward a working radio.

Re: CW operation on microBITX

geoffg3wzp@...
 

Thanks for the info.....I will get the mic etc fitted tomorrow and see if the rig is ok on SSB    ...then have a look at the CW again.....evne if I short the contact on kack socket to ground directly it still goes to transmit send a  R then reverts to rx .....am I missing something ?  When I go to CW setting on the SELECT control it just asks me to set speed ...is that correct ??
Sorry if this all sounds a bit stupid but upto now I have been a valve ( tube) man !!
73

Re: Audio problem in my ubitx

Bill Cromwell <wrcromwell@...>
 

Hi Jerry,

I had the overwhelming sidetone volume in my V3 and corrected that before I even tried to use it on the air. And I agree about getting it working stock before making mods. When I was still using the stock software I did not look to see everything that might be on the menus. I don't know if it will disable the TX. I disabled the TX by disconnecting the brown wire when I was using the stock software.

Checking those voltages to see if it is going into TX mode is the way to know for sure. But he surely knows if he did or did not install that resistor.

73,

Bill KU8H

On 1/20/19 11:46 AM, Jerry Gaffke via Groups.Io wrote:
Yup, good points.
I think in a case like this, verifying it is in receive mode (check TX and RX),
and getting the receiver to work is the first step.
Lots of things could make it decide to go into transmit mode,
but especially your resistor at the key jack, and PTT wiring.
I'm not sure what all is going on with sidetone levels here.
Had been complaints early on about it being too loud, then R253 got changed.
Best to get it going first with the stock firmware.
Should not be necessary to do any mods to get a working radio.
Jerry
On Sun, Jan 20, 2019 at 08:29 AM, Bill Cromwell wrote:
Hi Jerry,
One of your questions was already answered and you even requoted it.
He said there is no audio in the speaker nor in the earphones. It
could still be wired wrong.
In my V3 with CEC software there is a setting in the setup menu to
disable the transmit. I thought I would use that to play with the
sidetone and use the uBitx as a $150 code practice oscillator. There
was very little sidetone, extremely faint. I don't know if his
software has a feature to disable the transmitter. He may also not
have wired the brown wire to the power supply so there is no drain
voltage applied to the finals. No transmit output.
And what about that resistor to the key jack? That produces at least
some of the symptoms. Other hams have decided they don't use CW and
don't need that resistor. WRONG! There new rigs worked right AFTER
they installed that.
I hope all of this helps him make progress toward a working radio.
--
bark less - wag more

Re: CW operation on microBITX

Bill Cromwell <wrcromwell@...>
 

Hi Geoff,

Not stupid at all. Please refrain from referring to list members as 'stupid' - even it that member is yourself:)

I recall that some hams had to play with resistor values to get the CW keying to work right. I was going to do that until I tried a Vibroplex bug that I used the dash lever as a sideswiper straight key. It made an awesome difference. I had burnished the contacts on my 50 year old straight key but CW was still "flakey" on the uBitx - okay on other radios. Finally I used some DeOxit - just a tiny touch - on the key contacts and now the uBitx behaves nicely. Be very sure your keying contacts are absolutely clean.

73,

Bill KU8H

On 1/20/19 12:02 PM, geoffg3wzp@... wrote:
Thanks for the info.....I will get the mic etc fitted tomorrow and see if the rig is ok on SSB    ...then have a look at the CW again.....evne if I short the contact on kack socket to ground directly it still goes to transmit send a  R then reverts to rx .....am I missing something ? When I go to CW setting on the SELECT control it just asks me to set speed ...is that correct ??
Sorry if this all sounds a bit stupid but upto now I have been a valve ( tube) man !!
73
--
bark less - wag more

Re: No detent rotary encoder

David Feldman
 

Ken VA3ABN,

This is a very helpful file - I noticed it is page 22 (!) --- is this part of a larger document?

Thank you!

Spurs/Harmonics fixes for v4 based on v5 board design?

Dave Space
 

Based on the recent v5 findings/design to replace R26 and add a filter L31, C205, L32
https://groups.io/g/BITX20/topic/spurs_harmonics_whew/28982939?p=,,,20,0,0,0::recentpostdate%2Fsticky,,,20,2,0,28982939

Any have any thoughts on how best to patch the v4 boards?

My current thinking was to since I don't have any surface mount resistors I was going to parallel a ~470 ohm resistor on top of R26 to get close to the desired 220 ohms.
Then to cut the trace out from the transformer heading towards TP13 into sections to allow jumpering with the 2 surface mount 1210 330nH inductors (B82422A3331K ) - since many of us ordered parts from the ebay link to try to remove spurs by replacing L5 and L7 those came in the assortment. 

Then the problem is C205 I don't have any surface mount capacitors I think and need a way to have one side to the trace and one side to ground, could drill a hole through the board put in a post to get access to ground maybe next to TP13 there is a bunch of open space and I don't think see any traces that might be accidentally cut there (might need a small jumper wire to get there.

Any other ideas?

Re: spurs & harmonics, whew!

Kees T
 

Thanks Jerry,

I am still looking for the best "Low buck" approach since another V4 followed me home and my V4 board is pretty well cut up. I thought the Axicom relay "fix" was not set in stone but if it is, that is by far the easiest for the harmonics, I won't pursue the daughter board mentioned in my note. 

73 Kees K5BCQ

Re: For Sale

Bob Lunsford <nocrud222@...>
 

Just got an eBay notice for this...

https://www.ebay.com/i/163479080437?ul_noapp=true

Re: For Sale

RICHARD
 

Has ben there for a week.

 

Sent from Mail for Windows 10

 


From: BITX20@groups.io <BITX20@groups.io> on behalf of Bob Lunsford via Groups.Io <nocrud222@...>
Sent: Sunday, January 20, 2019 1:54:05 PM
To: BITX20@groups.io
Subject: Re: [BITX20] For Sale
 
Just got an eBay notice for this...

https://www.ebay.com/i/163479080437?ul_noapp=true



Re: For Sale

Bob Lunsford <nocrud222@...>
 

RE: Has been there for a week.

Yep and for someone who really want one, it maybe a
good deal but the seller is honest with his full description.
For someone determined to get one OR for someone
that wants another one, it may be a good thing.

Bob — KK5R

--------------------------------------------

On Sun, 1/20/19, RICHARD <k6kwq@...> wrote:

Subject: Re: [BITX20] For Sale
To: "BITX20@groups.io" <BITX20@groups.io>
Date: Sunday, January 20, 2019, 4:56 PM



#yiv2070952714 #yiv2070952714 _filtered #yiv2070952714 {}
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Re: For Sale

Bob Lunsford <nocrud222@...>
 

RE: Has been there for a week.

Yep and for someone who really want one, it maybe a
good deal but the seller is honest with his full description.
For someone determined to get one OR for someone
that wants another one, it may be a good thing.

Bob — KK5R

--------------------------------------------

On Sun, 1/20/19, RICHARD <k6kwq@...> wrote:

Subject: Re: [BITX20] For Sale
To: "BITX20@groups.io" <BITX20@groups.io>
Date: Sunday, January 20, 2019, 4:56 PM



#yiv2070952714 #yiv2070952714 _filtered #yiv2070952714 {}
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Has ben there for a
week.
 
Sent from
Mail for Windows 10
 


From: BITX20@groups.io
<BITX20@groups.io> on behalf of Bob Lunsford via
Groups.Io <nocrud222=yahoo.com@groups.io>

Sent: Sunday, January 20, 2019 1:54:05 PM

To: BITX20@groups.io

Subject: Re: [BITX20] For Sale
 



Just got an eBay notice for
this...



https://www.ebay.com/i/163479080437?ul_noapp=true

Re: Adding uv meter .board and leads to ubitx

Bob Lunsford <nocrud222@...>
 

Good idea. Those amps are usually pretty small. Most
I have seen are on a board about 2-in square.

Bob — KK5R

--------------------------------------------

On Sun, 1/20/19, d balfour <davesters@...> wrote:

Subject: Re: [BITX20] Adding uv meter .board and leads to ubitx
To: BITX20@groups.io
Date: Sunday, January 20, 2019, 8:32 AM

I took a used computer speaker
apart and removed the amplifier. Stripped off the switch,
volume control, and plug in ports. Mounted it in the case
with a couple of standoffs and bolts.Ran the output of the
v4 into the input of the amp. I bought the v4 used with an
indian case. The volume control was biased with equal 4.7 k
resisters The power comes from the main switch of the
radio.

Re: Spurs/Harmonics fixes for v4 based on v5 board design?

Curt
 

Dave

I suggest keeping this surgery within your comfort zone.  Nothing sacred about surface mount parts, but at 45 MHz keep connections short.  I am not yet considering this particular mod - but you could consider using a small daughter board connected with leads to main board.  At the moment with lower bands doing the best - I suggest the LPF filter relay issue is a bigger deal.  Here in our club build we are adding 3 relays on a daughter board. 

I have been trying the approach of using an added xtal filter at C22 - while it corrects spurious we find it inhibits CW transmit power on 40m. 

I suggest insuring your work can be reversed if correction is found not to work well enough - been there, doing that. 

73 Curt

Re: CW operation on microBITX

Curt
 

Geoff

fantastic to have you aboard ! 

for CW - there isn't a specific mode.  for 40m - note rig will say LSB.  then press the key - display should read CW and you should hear sidetone.  if you got rig doing this - I would observe on your power meter if you have transmitted power. 

that 4.7k resistor must be in place.  what happens is the controller reads the voltage across this resistor - and knows to do CW.  this only works with a straight key.  with a paddle there is need to externally add 2 resistors - I can talk you through this as required. 

that thing you found is a menu setting -- yes speed and I forget what else.  honestly the most important menu operation here is to press the button - see BAND SELECT - press again without turning knob - and you can QSY between bands by turning the knob. 

this rig has its own coolness - be patient and enjoy the ride.  I can discuss via email - see qrz.com.  when I get this rig sufficiently worked - I may need your help when I build a valve rig. 

Curt WB8YYY

Re: Spurs/Harmonics fixes for v4 based on v5 board design?

Dave Space
 

Yep good ideas.  I'm also considering the daughter card filtering option.  Unfortunately I tried to buy from QRP labs but it didn't like my credit card for some reason.  Luckily they give instructions on most of it so I bought some of the parts from other places to try to assemble some variation of my own.

Checking with just an RTL-SDR transmitting at 7.15 MHZ I saw a harmonic at about 21 MHZ range that was at the same power as my transmit frequency.  Plus I presume lots of IMD / spurs around 0.75MHZ up and down away from the main transmit frequency at only about -30db.

So definitely need to do something to be able to use it.


On Sun, Jan 20, 2019 at 05:31 PM, Curt wrote:
Dave

I suggest keeping this surgery within your comfort zone.  Nothing sacred about surface mount parts, but at 45 MHz keep connections short.  I am not yet considering this particular mod - but you could consider using a small daughter board connected with leads to main board.  At the moment with lower bands doing the best - I suggest the LPF filter relay issue is a bigger deal.  Here in our club build we are adding 3 relays on a daughter board. 

I have been trying the approach of using an added xtal filter at C22 - while it corrects spurious we find it inhibits CW transmit power on 40m. 

I suggest insuring your work can be reversed if correction is found not to work well enough - been there, doing that. 

73 Curt