Date   
Officially done with my uBITX!

 

Just finished my uBITX this morning, works great and will live it's life beside my bed on the night stand.

Joel
N6ALT

Re: Officially done with my uBITX!

adelolly07@...
 

Wow, looks great. Well done ūüĎ欆

Re: Officially done with my uBITX!

ae1ct1998 <AE1CT1998@...>
 

Where did you get the mic from


On Wed, Mar 14, 2018, 11:58 Joel Caulkins <caulktel@...> wrote:
Just finished my uBITX this morning, works great and will live it's life beside my bed on the night stand.

Joel
N6ALT

Re: Officially done with my uBITX!

Jeffrey Peters <dek9jp@...>
 

Greetings Joel,

Excellent job! Very Well Done.  I also would like to know more about how you made your microphone.

73, Jeff K9JP

On Wed, Mar 14, 2018 at 11:57 AM, Joel Caulkins <caulktel@...> wrote:
Just finished my uBITX this morning, works great and will live it's life beside my bed on the night stand.

Joel
N6ALT




--
Not all of me will die - - - The good I do will live forever.  <><

Re: Raduino oscilators. 33mhz and 57mhz. Documentation says one thinng, but this is what I measured.

Michael Shreeve
 

Thankyou Jerry for trying and fairly successfully explaining what Ashhar is doing by using the ACTUAL frequencies used in the uBITX. This is VERY important to this discussion. Any other explanation using completely different frequencies is re-inventing a completely different wheel in my opinion, very confusing. Hopefully discussions about this will continue to use Ashhars frequency plan, thus eliminating much of the confusion.  Thanks again for not being confusing.

On Wed, Mar 7, 2018 at 12:57 PM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:
I hate sitting through videos. 
The math involved is addition and subtraction,  no need to solve any differential equations.

The 12mhz crystal filter has a 3dB passband of around 11.996 to 11.998 mhz, something like that.
The BFO on clk0 should be roughly 500hz away from the passband, so either 11.9955 or 11.9985 mhz.
Will vary from rig to rig, crystals get sorted by frequency so each rig has a matched set of crystals for the filter.

Original plan had been to switch the BFO between high and low side when selecting USB vs LSB.
But the 11.9985 mhz BFO had harmonics that beat with the 16mhz harmonics from the Nano processor,
so Farhan elected to freeze the BFO at 11.9955 mhz.  Instead moves the second oscillator
between 33 and 57 mhz when selecting between USB and LSB.
The VFO is always 45mhz higher than the operating frequency.

Here's an old discussion of how it worked on the Bitx40, using very round numbers to make it easy to follow:
    https://groups.io/g/BITX20/message/24724

Jerry, KE7ER
 

On Wed, Mar 7, 2018 at 12:24 pm, Michael Shreeve wrote:
And first of all, this uBITX works perfectly. It sounds great. Its very sensitive and has good tone quality. Literature says this : "To invert the sideband between USB and LSB, the second oscillator is switched between 33 MHz and 57 MHz. " . If usb matches with 33 and lsb matches with 57 which it does at the site here : (clearly on the diagram where it clearly says 33 usb, 57 lsb, then its time to do the math ? So I checked very clearly the radio in the next video. Block diagram is here. http://www.hfsignals.com/index.php/ubitx-circuit-description/ Ashhar says we should do the math. Now, if I can figure out how to do that math, its another video lol. https://youtu.be/4eG9VPeefwY




--
Michael Shreeve N6GRG

Re: Officially done with my uBITX!

 

I made the mic from a old ink pen.

Joel
N6ALT

Re: Complaint Department

Jerry Gaffke
 

Here's where that addenda needs to be curated,
and not the cacophony of firmly held differing opinions we would get with a wiki.
My firmly held (for the moment) differing opinions are:

Operating from 12v, any TDA2822 can blow, even while driving 8 ohms, if you have the volume too high (chip gets too hot). 

If you don't have the volume turned up, shorting the headphones to ground shouldn't blow the TDA2822

Best to limit voltage into the TDA2822 to 5 or 6v, avoids clone Vcc-max trouble and limits power dissipation.
Get the same dB of gain, just distorts sooner when you turn the volume way up.

For a headphone jack, an 8 ohm series resistor avoids any trouble from a short if that's what worries you.
Headphones don't need much power. 

If you also want to drive an external speaker, have a separate mono jack without the series resistor
if you want to avoid shorts to ground.
 
I could go on ....
and probably will.

Jerry, KE7ER


On Wed, Mar 14, 2018 at 08:27 am, Vince Vielhaber wrote:
And the speaker jack is STILL wired up to both the tip and ring. As has been pointed out, a mono plug plugged into it shorts the audio to ground.

Re: Officially done with my uBITX!

Daniel Conklin
 

Beautiful!  I love the Heathkit-like colors too.
Dan, W2DLC

Re: Officially done with my uBITX!

K4OSS <k4oss@...>
 

Looks fabulous, Joel! Could you share the source of your enclosure? Thanks!

Re: Officially done with my uBITX!

 

Sure, I bought it from this eBay seller, https://www.ebay.com/itm/123008133070?ViewItem=&item=123008133070

Joel
N6ALT

Re: Ubitx audio debug question

WA9GQT@...
 

I was very cautious and finally got the uBITX wiring correct after looking at all the posts.  It was receiving great until I unplugged my headphones and
plugged in a speaker.  I fried U1!  My speaker plug was not stereo it was mono plug!  So that's why U1 audio amp fried.  So I just ordered 2 TDA2822M's
from Amazon.com.  I am unable to use the uBITX until I replace U1.
I am very upset about this audio circuit design!  This circuit seems to be the Achilles heal of this radio, including a very loud popping between receive/
transmit.  I would like to use a speaker in the future.  I will be sure to be very careful of the wiring of any speaker.  I hope to have my first contact soon!

A very unhappy
Rod, WA9GQT

Re: Complaint Department

Vince Vielhaber
 

I'm referring to the wiring diagram. It still has the tip and ring connected together. A mono plug WILL short it out. 8 ohms in series or not, plugging in a mono plug will result in no audio, regardless if the 2822 blows. No audio = unhappy builder. Nowhere in the wireup does it say not to use a mono plug. But it does say, "The brown wire has to be connected to the (both) the tip and the ring of the headphone socket."

Vince.

On 03/14/2018 12:24 PM, Jerry Gaffke via Groups.Io wrote:
Here's where that addenda needs to be curated,
and not the cacophony of firmly held differing opinions we would get
with a wiki.
My firmly held (for the moment) differing opinions are:

Operating from 12v, any TDA2822 can blow, even while driving 8 ohms, if
you have the volume too high (chip gets too hot).

If you don't have the volume turned up, shorting the headphones to
ground shouldn't blow the TDA2822

Best to limit voltage into the TDA2822 to 5 or 6v, avoids clone Vcc-max
trouble and limits power dissipation.
Get the same dB of gain, just distorts sooner when you turn the volume
way up.

For a headphone jack, an 8 ohm series resistor avoids any trouble from a
short if that's what worries you.
Headphones don't need much power.

If you also want to drive an external speaker, have a separate mono jack
without the series resistor
if you want to avoid shorts to ground.

I could go on ....
and probably will.

Jerry, KE7ER


On Wed, Mar 14, 2018 at 08:27 am, Vince Vielhaber wrote:

And the speaker jack is STILL wired up to both the tip and ring. As
has been pointed out, a mono plug plugged into it shorts the audio
to ground.

more cases

Vince Vielhaber
 

Two ebay auctions ending in a couple hours. These look like good cases AND they have power supplies built in. Also looks like the display opening may be the right size. They also have turns counter dials in case you are putting a B40 in it with a 10 turn pot! I thought about bidding on both but I'm trying to get rid of stuff, not add to it.

Note: One auction is for 2 cases and the other is for 3.

https://www.ebay.com/itm/352299039701

https://www.ebay.com/itm/352299039811

No relation to the seller, of course, except that I've bought from them before.

Vince.
--
Michigan VHF Corp. http://www.nobucks.net/ http://www.CDupe.com/
http://www.metalworkingfun.com

Re: Raduino oscilators. 33mhz and 57mhz. Documentation says one thinng, but this is what I measured.

Jerry Gaffke
 

Here's a current and more complete summary of what's going on with the uBitx.
For the few who really really want to know.
Not many, judging from the response to post 44278.


Actual frequencies used in the original uBitx code are to have clk0 (bfo) fixed at 11996500 hz,
maybe 500hz below the 12mhz filter's 2000 hz wide 3dB passband.
Oscillator clk1 (second local oscillator) is fixed at 56995000 hz for USB and 32995000 hz for LSB.
You can find those three numbers in file ubitx_20.ino at lines 166, 163, 164 respectively.
I'm looking at the version dated Dec 6, 2017:      https://github.com/afarhan/ubitx

The vfo is used to select the operating frequency Fop according to these formulas.
For USB:    Fop  = vfo - (clk1-bfo)       so    vfo = Fop + (clk1-bfo)       where clk1 is around 45mhz+12mhz
For LSB:    Fop  = vfo - (clk1+bfo)       so    vfo = Fop + (clk1+bfo)      where clk1 is around 45mhz-12mhz

To receive a 7.2mhz LSB signal (where 7.2mhz is the frequency of the suppressed carrier),
the VFO gets set to   7200000+(32995000+11996500) = 52191500 hz.
That formula gives an exact result, not an approximation.

Regarding USB vs LSB:
The BFO corresponds to the carrier frequency of the station being received or transmitted.
The 12mhz filter is always above the BFO, so within the 12mhz IF it allows through only the upper sideband.
The VFO is always above the 45mhz first intermediate frequency, and so always inverts the sidebands:
    A carrier at 7200000 would get translated to vfo-Fop = 52191500 - 7200000 = 44991500 hz
    A lower sideband at 7198500 would get translated to 52191500 - 7198500 = 44993000 hz

In this example we assume the lower sideband is generated from a single audio tone into the mike of 1500 hz.
I have chosen 1500 hz because it will land in the middle of the 12mhz filter's passband, assuming the filter
has a 3 dB passband that's 2000 hz wide and the BFO is 500 hz below that passband.
The actual range of frequencies passed will be 500 to 2500 hz.
Those assumptions of 2000 hz and 500 hz might be off by a couple hundred hz.

Likewise, a high side clk1 of 56995000 hz  for USB always flips the sidebands when translating to 12mhz,
however the low side clk1 of 32995000 hz we use to receive the 7.2mhz LSB signal does not:
    Our 7.2mhz carrier:    44991500 - 32995000 =  11996500 hz    (exactly equal to our BFO frequency)
    Our 7.2mhz lower sideband:  44993000 - 32995000 = 11998000 hz  (in the middle of the crystal filter passband)

That's how the original uBitx code works.
I believe there is a problem because where an LSB signal hits the 45mhz filter will be 4khz removed from
where a USB signal hits it, resulting in a different audio quality between the two.
A solution to this is found in post 44278, review the previous posts in that thread to see why.
Even with the fix, there will be differences in the audio unless the 45mhz filter response is flat
across the 2000 hz at the center.

Jerry, KE7ER


On Wed, Mar 14, 2018 at 09:07 am, Michael Shreeve wrote:
Thankyou Jerry for trying and fairly successfully explaining what Ashhar is doing by using the ACTUAL frequencies used in the uBITX.

Re: more cases

Roy Appleton
 

Any clue as to the inside dimensions of these?

Roy
WA0YMH

On Mar 14, 2018 12:53 PM, "Vince Vielhaber" <vev@...> wrote:

Two ebay auctions ending in a couple hours.  These look like good cases AND they have power supplies built in.  Also looks like the display opening may be the right size.  They also have turns counter dials in case you are putting a B40 in it with a 10 turn pot!  I thought about bidding on both but I'm trying to get rid of stuff, not add to it.

Note: One auction is for 2 cases and the other is for 3.

https://www.ebay.com/itm/352299039701

https://www.ebay.com/itm/352299039811

No relation to the seller, of course, except that I've bought from them before.

Vince.
--
  Michigan VHF Corp.   http://www.nobucks.net/   http://www.CDupe.com/
                          http://www.metalworkingfun.com




Re: [uBiTx] last frequency memory?

Mike Hoddy
 

Thanks Mike, I'll find the link and give it a go on my 'breadboard' version!  73 de Mike, G0JXX

Re: Complaint Department

Jerry Gaffke
 

Like I say, a wiki would have a lot of competing firmly held opinions.

You are correct, if the primary use of that jack is to plug in an external speaker.

A builder that always uses stereo headphones is best off with tip and ring wired together, plus the series resistor.
Both options could be presented in that addenda, with an explanation of the pros and cons for each.
Including a warning that a mono plug will result in no audio if the jack is wired for stereo.



On Wed, Mar 14, 2018 at 10:43 am, Vince Vielhaber wrote:
I'm referring to the wiring diagram. It still has the tip and ring connected together. A mono plug WILL short it out. 8 ohms in series or not, plugging in a mono plug will result in no audio, regardless if the 2822 blows. No audio = unhappy builder. Nowhere in the wireup does it say not to use a mono plug. But it does say, "The brown wire has to be connected to the (both) the tip and the ring of the headphone socket."

Re: Ubitx audio debug question

Jerry Gaffke
 

What was the logo on the fried U1?
Does it  say "WX TDA2822"?
Does it say "FCI TDA2822"?

This is important.
I suspect that a good TDA2822 will not fry with a short unless you have the volume turned way way up.
And that you have the WX clone.
But I could be wrong.

Here's the latest news regarding the bad chips:
    https://groups.io/g/BITX20/message/44394
    http://ubitx.net/fix-tda2822-audio-amp/

You can probably find an LM386 locally or in some older project that can be hacked in there temporarily
till you get a new TDA2822 in from Mouser or Tayda or similar.
Choosing a $109 all HF band SSB transceiver means you get to deal with this sort of thing.

Jerry


On Wed, Mar 14, 2018 at 10:31 am, <WA9GQT@...> wrote:
I was very cautious and finally got the uBITX wiring correct after looking at all the posts.  It was receiving great until I unplugged my headphones and
plugged in a speaker.  I fried U1!  My speaker plug was not stereo it was mono plug!  So that's why U1 audio amp fried.  So I just ordered 2 TDA2822M's
from Amazon.com.  I am unable to use the uBITX until I replace U1.
I am very upset about this audio circuit design!  This circuit seems to be the Achilles heal of this radio, including a very loud popping between receive/
transmit.  I would like to use a speaker in the future.  I will be sure to be very careful of the wiring of any speaker.  I hope to have my first contact soon!

A very unhappy
Rod, WA9GQT

Re: more cases

Vince Vielhaber
 

No, I tried to find info on what it actually is but all I found was ebay listings. Didn't bother looking at them.

Vince.

On 03/14/2018 01:59 PM, Roy Appleton wrote:
Any clue as to the inside dimensions of these?

Roy
WA0YMH

On Mar 14, 2018 12:53 PM, "Vince Vielhaber" <vev@...
<mailto:vev@...>> wrote:


Two ebay auctions ending in a couple hours. These look like good
cases AND they have power supplies built in. Also looks like the
display opening may be the right size. They also have turns counter
dials in case you are putting a B40 in it with a 10 turn pot! I
thought about bidding on both but I'm trying to get rid of stuff,
not add to it.

Note: One auction is for 2 cases and the other is for 3.

https://www.ebay.com/itm/352299039701
<https://www.ebay.com/itm/352299039701>

https://www.ebay.com/itm/352299039811
<https://www.ebay.com/itm/352299039811>

No relation to the seller, of course, except that I've bought from
them before.

Vince.
--
Michigan VHF Corp. http://www.nobucks.net/ http://www.CDupe.com/
http://www.metalworkingfun.com




Re: Digital BFO Mod: Terrible Audio! #bitx40help

Ryan Flowers
 

Hi Jerry and Allard,

I was hoping you two would chime in. I chose the uBITX sketch for several reasons: 1) already has band switching 2) already has rotary encoder 3) already has BFO 4) wanted the challenge of making it work on an Uno R3 and i2c LCD. I *think* I have the nuts and bolts of all those things correct but I'm just missing something somewhere else. I'll do a bit more testing and possibly a video to describe it, and get back to you.

--
Ryan Flowers - W7RLF
MiscDotGeek.com
Multi Band BITX40
The BITX40 FAQ