Topics

AE7EU Top Level PCB Mod

Diver Martin <diver.martin@...>
 

So, I've finally got a rough draft of what I'm thinking for my uBitx top PCB mod.  Features at this point are:

No modifications required to uBitx board itself (not to say a 470uF anti-pop mod might be bad, or other things couldn't be done)
ATU: 7-inductor, 8-capacitor with Hi-Z/Lo-Z switch.
Selectable Power output (two power input connectors)
Brain transplant:  Teensy3.2 96MHz ARM processor
All connections on side edges - no wiring to enclosure
Front panel with pushbutton switches
DSP Audio (Via Teensy32, would require headphones or amplified speakers)
Solderless AGC modification (Attenuator at the front end switched in during RX)
Realtime clock (via Teensy32)
Linear amplifier control (just a reed relay on a 3.5mm header, sorry, not an RCA, but you could easily change it...)
Top side only construction (would make assembly cost lower)

BoM cost:  Probably way higher than it should be.  Needs optimization, and I still need to enter in costs.
Complexity:  Probably way more than it should be.
Layout:  An ugly mess of routing.  I can't say I like it, but the constraints I put on myself made it really hard to route.  There's lots of open areas to cross with lots of signals going all different directions.

Picture of the layout and schematic PDF attached, along with a 3D view.

I think the one modification that I still need to consider is a microphone preamp.  But, I have no flippin' clue where on the PCB I'd put the gain control knob!  Might have to be an internal potentiometer....

--
Martin Held - AE7EU
http://ae7eu.com/
-------------------------------------------------------------------------------
If there aren't any questions, then what is there to learn?

M Garza <mgarza896@...>
 

All I can say is....  WOW.  Very impressive!

Marco - KG5PRT

On Thu, Jan 11, 2018 at 12:39 AM, Diver Martin <diver.martin@...> wrote:
So, I've finally got a rough draft of what I'm thinking for my uBitx top PCB mod.  Features at this point are:

No modifications required to uBitx board itself (not to say a 470uF anti-pop mod might be bad, or other things couldn't be done)
ATU: 7-inductor, 8-capacitor with Hi-Z/Lo-Z switch.
Selectable Power output (two power input connectors)
Brain transplant:  Teensy3.2 96MHz ARM processor
All connections on side edges - no wiring to enclosure
Front panel with pushbutton switches
DSP Audio (Via Teensy32, would require headphones or amplified speakers)
Solderless AGC modification (Attenuator at the front end switched in during RX)
Realtime clock (via Teensy32)
Linear amplifier control (just a reed relay on a 3.5mm header, sorry, not an RCA, but you could easily change it...)
Top side only construction (would make assembly cost lower)

BoM cost:  Probably way higher than it should be.  Needs optimization, and I still need to enter in costs.
Complexity:  Probably way more than it should be.
Layout:  An ugly mess of routing.  I can't say I like it, but the constraints I put on myself made it really hard to route.  There's lots of open areas to cross with lots of signals going all different directions.

Picture of the layout and schematic PDF attached, along with a 3D view.

I think the one modification that I still need to consider is a microphone preamp.  But, I have no flippin' clue where on the PCB I'd put the gain control knob!  Might have to be an internal potentiometer....

--
Martin Held - AE7EU
http://ae7eu.com/
-------------------------------------------------------------------------------
If there aren't any questions, then what is there to learn?


Dave Bottom <ars.kd6az@...>
 

Martin 

Looks good so far.

I have one of the Mic AGC amplifiers coming, so I will let you know how it works out.  I think a set and forget gain control will be fine.  It should be set so as not to over drive and be left alone.  Almost all cell phones use these 3 stage low noise AGC amplifiers for the Electret Mic so I’m expecting it to work well here too.

Dave WI6R



Sent from my iPhone

On Jan 10, 2018, at 10:39 PM, Diver Martin <diver.martin@...> wrote:

So, I've finally got a rough draft of what I'm thinking for my uBitx top PCB mod.  Features at this point are:

No modifications required to uBitx board itself (not to say a 470uF anti-pop mod might be bad, or other things couldn't be done)
ATU: 7-inductor, 8-capacitor with Hi-Z/Lo-Z switch.
Selectable Power output (two power input connectors)
Brain transplant:  Teensy3.2 96MHz ARM processor
All connections on side edges - no wiring to enclosure
Front panel with pushbutton switches
DSP Audio (Via Teensy32, would require headphones or amplified speakers)
Solderless AGC modification (Attenuator at the front end switched in during RX)
Realtime clock (via Teensy32)
Linear amplifier control (just a reed relay on a 3.5mm header, sorry, not an RCA, but you could easily change it...)
Top side only construction (would make assembly cost lower)

BoM cost:  Probably way higher than it should be.  Needs optimization, and I still need to enter in costs.
Complexity:  Probably way more than it should be.
Layout:  An ugly mess of routing.  I can't say I like it, but the constraints I put on myself made it really hard to route.  There's lots of open areas to cross with lots of signals going all different directions.

Picture of the layout and schematic PDF attached, along with a 3D view.

I think the one modification that I still need to consider is a microphone preamp.  But, I have no flippin' clue where on the PCB I'd put the gain control knob!  Might have to be an internal potentiometer....

--
Martin Held - AE7EU
http://ae7eu.com/
-------------------------------------------------------------------------------
If there aren't any questions, then what is there to learn?
<uBitx_top.png>
<uBitx_top.pdf>
<uBitx_top_3d.png>

Diver Martin <diver.martin@...>
 

Dave,

Can you point me towards which chip/board you're going to try out?

On Jan 10, 2018 11:05 PM, "Dave Bottom" <ars.kd6az@...> wrote:
Martin 

Looks good so far.

I have one of the Mic AGC amplifiers coming, so I will let you know how it works out.  I think a set and forget gain control will be fine.  It should be set so as not to over drive and be left alone.  Almost all cell phones use these 3 stage low noise AGC amplifiers for the Electret Mic so I’m expecting it to work well here too.

Dave WI6R



Sent from my iPhone

On Jan 10, 2018, at 10:39 PM, Diver Martin <diver.martin@...> wrote:

So, I've finally got a rough draft of what I'm thinking for my uBitx top PCB mod.  Features at this point are:

No modifications required to uBitx board itself (not to say a 470uF anti-pop mod might be bad, or other things couldn't be done)
ATU: 7-inductor, 8-capacitor with Hi-Z/Lo-Z switch.
Selectable Power output (two power input connectors)
Brain transplant:  Teensy3.2 96MHz ARM processor
All connections on side edges - no wiring to enclosure
Front panel with pushbutton switches
DSP Audio (Via Teensy32, would require headphones or amplified speakers)
Solderless AGC modification (Attenuator at the front end switched in during RX)
Realtime clock (via Teensy32)
Linear amplifier control (just a reed relay on a 3.5mm header, sorry, not an RCA, but you could easily change it...)
Top side only construction (would make assembly cost lower)

BoM cost:  Probably way higher than it should be.  Needs optimization, and I still need to enter in costs.
Complexity:  Probably way more than it should be.
Layout:  An ugly mess of routing.  I can't say I like it, but the constraints I put on myself made it really hard to route.  There's lots of open areas to cross with lots of signals going all different directions.

Picture of the layout and schematic PDF attached, along with a 3D view.

I think the one modification that I still need to consider is a microphone preamp.  But, I have no flippin' clue where on the PCB I'd put the gain control knob!  Might have to be an internal potentiometer....

--
Martin Held - AE7EU
http://ae7eu.com/
-------------------------------------------------------------------------------
If there aren't any questions, then what is there to learn?
<uBitx_top.png>
<uBitx_top.pdf>
<uBitx_top_3d.png>

Michael Hagen
 

I used the MAX 9814, follow the datasheet suggestions. Set the final output with a pot.

Shown is the PCB and Mic.

73's

Mike, WA6ISP



On 1/11/2018 7:44 AM, Diver Martin wrote:
Dave,

Can you point me towards which chip/board you're going to try out?

On Jan 10, 2018 11:05 PM, "Dave Bottom" <ars.kd6az@...> wrote:
Martin 

Looks good so far.

I have one of the Mic AGC amplifiers coming, so I will let you know how it works out.  I think a set and forget gain control will be fine.  It should be set so as not to over drive and be left alone.  Almost all cell phones use these 3 stage low noise AGC amplifiers for the Electret Mic so I’m expecting it to work well here too.

Dave WI6R



Sent from my iPhone

On Jan 10, 2018, at 10:39 PM, Diver Martin <diver.martin@...> wrote:

So, I've finally got a rough draft of what I'm thinking for my uBitx top PCB mod.  Features at this point are:

No modifications required to uBitx board itself (not to say a 470uF anti-pop mod might be bad, or other things couldn't be done)
ATU: 7-inductor, 8-capacitor with Hi-Z/Lo-Z switch.
Selectable Power output (two power input connectors)
Brain transplant:  Teensy3.2 96MHz ARM processor
All connections on side edges - no wiring to enclosure
Front panel with pushbutton switches
DSP Audio (Via Teensy32, would require headphones or amplified speakers)
Solderless AGC modification (Attenuator at the front end switched in during RX)
Realtime clock (via Teensy32)
Linear amplifier control (just a reed relay on a 3.5mm header, sorry, not an RCA, but you could easily change it...)
Top side only construction (would make assembly cost lower)

BoM cost:  Probably way higher than it should be.  Needs optimization, and I still need to enter in costs.
Complexity:  Probably way more than it should be.
Layout:  An ugly mess of routing.  I can't say I like it, but the constraints I put on myself made it really hard to route.  There's lots of open areas to cross with lots of signals going all different directions.

Picture of the layout and schematic PDF attached, along with a 3D view.

I think the one modification that I still need to consider is a microphone preamp.  But, I have no flippin' clue where on the PCB I'd put the gain control knob!  Might have to be an internal potentiometer....

--
Martin Held - AE7EU
http://ae7eu.com/
-------------------------------------------------------------------------------
If there aren't any questions, then what is there to learn?
<uBitx_top.png>
<uBitx_top.pdf>
<uBitx_top_3d.png>

-- 
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID  "MotDog@..."
Mike@...

Jerry Gaffke
 

The MAX9814 could work well
But be aware that while the AGC will reduce gain when your audio level gets too high,
it will also increase gain when there is nothing but background noise.
So during pauses in speech, your friends will be impressed by the sound of the
apparently monstrous cooling fan required to cool the mighty uBitx. 

Might be worth looking at the SSM2167
    http://www.analog.com/media/en/technical-documentation/data-sheets/SSM2167.pdf
You can disable the speech compression feature if that's not what you want.
Still provides AGC style gain reduction when audio levels get too high,
and also reduces gain when audio levels are too low.

Jerry, KE7ER



On Thu, Jan 11, 2018 at 07:51 am, Michael Hagen wrote:

I used the MAX 9814, follow the datasheet suggestions. Set the final output with a pot.

 

Dave Bottom <ars.kd6az@...>
 

The MAX9814 Chip.

As commented the gain should be set between the second and third stage not after to prevent to reduce noise and the chip has a very well filtered BIAS supply for the Electret Mic so they are doing everything to make it quiet. .  This works well with Cell Phones to clear background noise.  We'll see how it turns out here, but I am using a boom Mic headset with really good acoustic noise cancellation.  85 db on train isn't heard and my F250 Diesel Truck isn't heard either while mobile.  Drive from audio needs to match levels in the Balanced Modulator or there will be distortion.  As I said we'll see how it works here.  

BTW - Nice job on your hand Mic Mike!

Dave WI6R

On Thu, Jan 11, 2018 at 7:44 AM, Diver Martin <diver.martin@...> wrote:
Dave,

Can you point me towards which chip/board you're going to try out?

On Jan 10, 2018 11:05 PM, "Dave Bottom" <ars.kd6az@...> wrote:
Martin 

Looks good so far.

I have one of the Mic AGC amplifiers coming, so I will let you know how it works out.  I think a set and forget gain control will be fine.  It should be set so as not to over drive and be left alone.  Almost all cell phones use these 3 stage low noise AGC amplifiers for the Electret Mic so I’m expecting it to work well here too.

Dave WI6R



Sent from my iPhone

On Jan 10, 2018, at 10:39 PM, Diver Martin <diver.martin@...> wrote:

So, I've finally got a rough draft of what I'm thinking for my uBitx top PCB mod.  Features at this point are:

No modifications required to uBitx board itself (not to say a 470uF anti-pop mod might be bad, or other things couldn't be done)
ATU: 7-inductor, 8-capacitor with Hi-Z/Lo-Z switch.
Selectable Power output (two power input connectors)
Brain transplant:  Teensy3.2 96MHz ARM processor
All connections on side edges - no wiring to enclosure
Front panel with pushbutton switches
DSP Audio (Via Teensy32, would require headphones or amplified speakers)
Solderless AGC modification (Attenuator at the front end switched in during RX)
Realtime clock (via Teensy32)
Linear amplifier control (just a reed relay on a 3.5mm header, sorry, not an RCA, but you could easily change it...)
Top side only construction (would make assembly cost lower)

BoM cost:  Probably way higher than it should be.  Needs optimization, and I still need to enter in costs.
Complexity:  Probably way more than it should be.
Layout:  An ugly mess of routing.  I can't say I like it, but the constraints I put on myself made it really hard to route.  There's lots of open areas to cross with lots of signals going all different directions.

Picture of the layout and schematic PDF attached, along with a 3D view.

I think the one modification that I still need to consider is a microphone preamp.  But, I have no flippin' clue where on the PCB I'd put the gain control knob!  Might have to be an internal potentiometer....

--
Martin Held - AE7EU
http://ae7eu.com/
-------------------------------------------------------------------------------
If there aren't any questions, then what is there to learn?
<uBitx_top.png>
<uBitx_top.pdf>
<uBitx_top_3d.png>




--
73 Dave WI6R

Michael Hagen
 

Yes, that is the application note on the Max part.  That is what they designed the part for.

I followed its suggestions for settings.  There are several capacitors to pick.  The main thing is to turn it down, do not overdrive Bit.  Sp I put the 2K pot on the final output.

AND this lead to yet another PCB project.   In BitX I have a PTT board.  It has a comparitor that senses the small current (a few ma.)  when the PTT is pushed.  The PTT is just connected to the Max PCB, connecting it to 5V.

So now I only have 3 wires going to Mic.... Gnd, Mic, +5V.  I can use a cheap 3.5mm stereo cable from 99 cent store.  I have experimented with this board and a couple FETs for Pop reduction.  One FET turns on fast and off slow to mute the LM380.

The other one times the relay to have it actuate while mute is active.   Then there is an inverter that give an +5V to Raduino to be complient with Allard's PTT signal.

There are 6 3D Printed ABS parts to the Microphone.  Worked out better than I expected!

73's

Mike, WA6ISP


On 1/11/2018 9:35 AM, Dave Bottom wrote:
The MAX9814 Chip.

As commented the gain should be set between the second and third stage not after to prevent to reduce noise and the chip has a very well filtered BIAS supply for the Electret Mic so they are doing everything to make it quiet. .  This works well with Cell Phones to clear background noise.  We'll see how it turns out here, but I am using a boom Mic headset with really good acoustic noise cancellation.  85 db on train isn't heard and my F250 Diesel Truck isn't heard either while mobile.  Drive from audio needs to match levels in the Balanced Modulator or there will be distortion.  As I said we'll see how it works here.  

BTW - Nice job on your hand Mic Mike!

Dave WI6R

On Thu, Jan 11, 2018 at 7:44 AM, Diver Martin <diver.martin@...> wrote:
Dave,

Can you point me towards which chip/board you're going to try out?

On Jan 10, 2018 11:05 PM, "Dave Bottom" <ars.kd6az@...> wrote:
Martin 

Looks good so far.

I have one of the Mic AGC amplifiers coming, so I will let you know how it works out.  I think a set and forget gain control will be fine.  It should be set so as not to over drive and be left alone.  Almost all cell phones use these 3 stage low noise AGC amplifiers for the Electret Mic so I’m expecting it to work well here too.

Dave WI6R



Sent from my iPhone

On Jan 10, 2018, at 10:39 PM, Diver Martin <diver.martin@...> wrote:

So, I've finally got a rough draft of what I'm thinking for my uBitx top PCB mod.  Features at this point are:

No modifications required to uBitx board itself (not to say a 470uF anti-pop mod might be bad, or other things couldn't be done)
ATU: 7-inductor, 8-capacitor with Hi-Z/Lo-Z switch.
Selectable Power output (two power input connectors)
Brain transplant:  Teensy3.2 96MHz ARM processor
All connections on side edges - no wiring to enclosure
Front panel with pushbutton switches
DSP Audio (Via Teensy32, would require headphones or amplified speakers)
Solderless AGC modification (Attenuator at the front end switched in during RX)
Realtime clock (via Teensy32)
Linear amplifier control (just a reed relay on a 3.5mm header, sorry, not an RCA, but you could easily change it...)
Top side only construction (would make assembly cost lower)

BoM cost:  Probably way higher than it should be.  Needs optimization, and I still need to enter in costs.
Complexity:  Probably way more than it should be.
Layout:  An ugly mess of routing.  I can't say I like it, but the constraints I put on myself made it really hard to route.  There's lots of open areas to cross with lots of signals going all different directions.

Picture of the layout and schematic PDF attached, along with a 3D view.

I think the one modification that I still need to consider is a microphone preamp.  But, I have no flippin' clue where on the PCB I'd put the gain control knob!  Might have to be an internal potentiometer....

--
Martin Held - AE7EU
http://ae7eu.com/
-------------------------------------------------------------------------------
If there aren't any questions, then what is there to learn?
<uBitx_top.png>
<uBitx_top.pdf>
<uBitx_top_3d.png>



--
73 Dave WI6R

-- 
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID  "MotDog@..."
Mike@...

David Arthur
 

Looks pretty awesome! 

Can I recommend using headers for the Teensy board (as opposed to directly soldering to the board). It adds a little to the cost, but saves headaches down the road when replacing/upgrading the board :) 
--
David K4DBZ
Unofficial bitx chatroom: https://discord.gg/CrHvWFc

David Arthur
 

Also, I wonder if a modular design approach could be used, instead of monolithic. Say a better AGC is devised at some point - how to upgrade/replace it? Same question for the filter banks, what about expanding for additional bands? How about injecting a separate DSP module to the audio chain?

Sorry, just thinking out loud. This design is awesome and has made the wheels upstairs start turning

--
David K4DBZ
Unofficial bitx chatroom: https://discord.gg/CrHvWFc

Diver Martin <diver.martin@...>
 

Hi David,

No reason the teensy couldn't be put on headers.  If I end up selling this particular PCB, the kit form would be SMT pre-done, all the through-hole to be done by the end user (Which isn't a huge amount - Headers, Front panel, uBitx connectors, inductors, and the teensy32).  If I don't end up selling it (i.e. there isn't much demand to make it worth the time), I'd open source the entire design leaving it to anyone else to fabricate & sell, or modify and use for their own purposes.



On Thu, Jan 11, 2018 at 1:27 PM, David Arthur <mumrah@...> wrote:
Looks pretty awesome! 

Can I recommend using headers for the Teensy board (as opposed to directly soldering to the board). It adds a little to the cost, but saves headaches down the road when replacing/upgrading the board :) 
--
David K4DBZ
Unofficial bitx chatroom: https://discord.gg/CrHvWFc




--
Martin Held - AE7EU
http://ae7eu.com/
-------------------------------------------------------------------------------
If there aren't any questions, then what is there to learn?

Diver Martin <diver.martin@...>
 

I like the SSM2167 for one big reason: Simpler package.  While QFN is easy to do in a mass-production environment and I've never even had a problem with my hot air station, I hate QFN's/ TDFN' (Tiny Damned Frickin No-leaded packages) when doing prototyping or small quantity stuff.  

For the first run of this PCB, I'm sure there will be problems, and being able to probe the pins directly is always nice.  It's an extra dollar in low quantities, but the compression part is nice. I added it to my design, made a few changes, so I should be pretty good to go with this first revision.

That said, in my many many years of making circuit boards, I have had a design work and fit_exactly_ as intended and specified only once in my life.  It was quite the celebration!  With this particular system, I'm sure there will be no exceptions to my rule that there's always a revB :)

Changes:

Moved mic/speaker output headers outwards by 0.2" to make front panel mating better
Added SSM2167 mic amplifier, variable resistor for gain, adds speech compression (1:1 to 1:10)
Other features not stated earlier, S-meter and SWR measurement.

Here we goooo......

On Thu, Jan 11, 2018 at 8:24 AM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:
The MAX9814 could work well
But be aware that while the AGC will reduce gain when your audio level gets too high,
it will also increase gain when there is nothing but background noise.
So during pauses in speech, your friends will be impressed by the sound of the
apparently monstrous cooling fan required to cool the mighty uBitx. 

Might be worth looking at the SSM2167
    http://www.analog.com/media/en/technical-documentation/data-sheets/SSM2167.pdf
You can disable the speech compression feature if that's not what you want.
Still provides AGC style gain reduction when audio levels get too high,
and also reduces gain when audio levels are too low.

Jerry, KE7ER



On Thu, Jan 11, 2018 at 07:51 am, Michael Hagen wrote:

I used the MAX 9814, follow the datasheet suggestions. Set the final output with a pot.

 




--
Martin Held - AE7EU
http://ae7eu.com/
-------------------------------------------------------------------------------
If there aren't any questions, then what is there to learn?

Mike Woods
 

Very exciting!  We are looking forward to the shake down testing outcome.

Mike ZL1AXG


On Fri, 12 Jan 2018 at 7:03 PM, Diver Martin <diver.martin@...> wrote:
I like the SSM2167 for one big reason: Simpler package.  While QFN is easy to do in a mass-production environment and I've never even had a problem with my hot air station, I hate QFN's/ TDFN' (Tiny Damned Frickin No-leaded packages) when doing prototyping or small quantity stuff.  

For the first run of this PCB, I'm sure there will be problems, and being able to probe the pins directly is always nice.  It's an extra dollar in low quantities, but the compression part is nice. I added it to my design, made a few changes, so I should be pretty good to go with this first revision.

That said, in my many many years of making circuit boards, I have had a design work and fit_exactly_ as intended and specified only once in my life.  It was quite the celebration!  With this particular system, I'm sure there will be no exceptions to my rule that there's always a revB :)

Changes:

Moved mic/speaker output headers outwards by 0.2" to make front panel mating better
Added SSM2167 mic amplifier, variable resistor for gain, adds speech compression (1:1 to 1:10)
Other features not stated earlier, S-meter and SWR measurement.

Here we goooo......

On Thu, Jan 11, 2018 at 8:24 AM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:
The MAX9814 could work well
But be aware that while the AGC will reduce gain when your audio level gets too high,
it will also increase gain when there is nothing but background noise.
So during pauses in speech, your friends will be impressed by the sound of the
apparently monstrous cooling fan required to cool the mighty uBitx. 

Might be worth looking at the SSM2167
    http://www.analog.com/media/en/technical-documentation/data-sheets/SSM2167.pdf
You can disable the speech compression feature if that's not what you want.
Still provides AGC style gain reduction when audio levels get too high,
and also reduces gain when audio levels are too low.

Jerry, KE7ER



On Thu, Jan 11, 2018 at 07:51 am, Michael Hagen wrote:

I used the MAX 9814, follow the datasheet suggestions. Set the final output with a pot.

 




--
Martin Held - AE7EU
http://ae7eu.com/
-------------------------------------------------------------------------------
If there aren't any questions, then what is there to learn?

Diver Martin <diver.martin@...>
 

Did a hail mary and off to china they go.  $105 and 2 weeks and we should have some answers....

On Thu, Jan 11, 2018 at 10:09 PM, Mike Woods <mhwoods@...> wrote:
Very exciting!  We are looking forward to the shake down testing outcome.

Mike ZL1AXG

On Fri, 12 Jan 2018 at 7:03 PM, Diver Martin <diver.martin@...> wrote:
I like the SSM2167 for one big reason: Simpler package.  While QFN is easy to do in a mass-production environment and I've never even had a problem with my hot air station, I hate QFN's/ TDFN' (Tiny Damned Frickin No-leaded packages) when doing prototyping or small quantity stuff.  

For the first run of this PCB, I'm sure there will be problems, and being able to probe the pins directly is always nice.  It's an extra dollar in low quantities, but the compression part is nice. I added it to my design, made a few changes, so I should be pretty good to go with this first revision.

That said, in my many many years of making circuit boards, I have had a design work and fit_exactly_ as intended and specified only once in my life.  It was quite the celebration!  With this particular system, I'm sure there will be no exceptions to my rule that there's always a revB :)

Changes:

Moved mic/speaker output headers outwards by 0.2" to make front panel mating better
Added SSM2167 mic amplifier, variable resistor for gain, adds speech compression (1:1 to 1:10)
Other features not stated earlier, S-meter and SWR measurement.

Here we goooo......

On Thu, Jan 11, 2018 at 8:24 AM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:
The MAX9814 could work well
But be aware that while the AGC will reduce gain when your audio level gets too high,
it will also increase gain when there is nothing but background noise.
So during pauses in speech, your friends will be impressed by the sound of the
apparently monstrous cooling fan required to cool the mighty uBitx. 

Might be worth looking at the SSM2167
    http://www.analog.com/media/en/technical-documentation/data-sheets/SSM2167.pdf
You can disable the speech compression feature if that's not what you want.
Still provides AGC style gain reduction when audio levels get too high,
and also reduces gain when audio levels are too low.

Jerry, KE7ER



On Thu, Jan 11, 2018 at 07:51 am, Michael Hagen wrote:

I used the MAX 9814, follow the datasheet suggestions. Set the final output with a pot.

 




--
Martin Held - AE7EU
http://ae7eu.com/
-------------------------------------------------------------------------------
If there aren't any questions, then what is there to learn?




--
Martin Held - AE7EU
http://ae7eu.com/
-------------------------------------------------------------------------------
If there aren't any questions, then what is there to learn?

Terence Taylor
 

Well, I certainly would be interested in buying one....

On 1/11/2018 6:21 PM, Diver Martin wrote:
Hi David,

No reason the teensy couldn't be put on headers.  If I end up selling this particular PCB, the kit form would be SMT pre-done, all the through-hole to be done by the end user (Which isn't a huge amount - Headers, Front panel, uBitx connectors, inductors, and the teensy32).  If I don't end up selling it (i.e. there isn't much demand to make it worth the time), I'd open source the entire design leaving it to anyone else to fabricate & sell, or modify and use for their own purposes.

M Garza <mgarza896@...>
 

Same here!

On Fri, Jan 12, 2018 at 9:51 AM, Terence Taylor <n6mon@...> wrote:
Well, I certainly would be interested in buying one....


On 1/11/2018 6:21 PM, Diver Martin wrote:
Hi David,

No reason the teensy couldn't be put on headers.  If I end up selling this particular PCB, the kit form would be SMT pre-done, all the through-hole to be done by the end user (Which isn't a huge amount - Headers, Front panel, uBitx connectors, inductors, and the teensy32).  If I don't end up selling it (i.e. there isn't much demand to make it worth the time), I'd open source the entire design leaving it to anyone else to fabricate & sell, or modify and use for their own purposes.






Diver Martin <diver.martin@...>
 

$1million dollars!  

<haha>

When I have a better price point, I'll post.  Right now, the base cost is $11 / PCB, no parts.  I'm guessing $100 in parts & Assembly, but it's a SWAG.

On Fri, Jan 12, 2018 at 7:53 AM, M Garza <mgarza896@...> wrote:
Same here!

On Fri, Jan 12, 2018 at 9:51 AM, Terence Taylor <n6mon@...> wrote:
Well, I certainly would be interested in buying one....


On 1/11/2018 6:21 PM, Diver Martin wrote:
Hi David,

No reason the teensy couldn't be put on headers.  If I end up selling this particular PCB, the kit form would be SMT pre-done, all the through-hole to be done by the end user (Which isn't a huge amount - Headers, Front panel, uBitx connectors, inductors, and the teensy32).  If I don't end up selling it (i.e. there isn't much demand to make it worth the time), I'd open source the entire design leaving it to anyone else to fabricate & sell, or modify and use for their own purposes.









--
Martin Held - AE7EU
http://ae7eu.com/
-------------------------------------------------------------------------------
If there aren't any questions, then what is there to learn?

Art Olson
 

Count me in for one
Art N2AJO 

Sent from my iPhone

On Jan 12, 2018, at 10:53 AM, M Garza <mgarza896@...> wrote:

Same here!

On Fri, Jan 12, 2018 at 9:51 AM, Terence Taylor <n6mon@...> wrote:
Well, I certainly would be interested in buying one....


On 1/11/2018 6:21 PM, Diver Martin wrote:
Hi David,

No reason the teensy couldn't be put on headers.  If I end up selling this particular PCB, the kit form would be SMT pre-done, all the through-hole to be done by the end user (Which isn't a huge amount - Headers, Front panel, uBitx connectors, inductors, and the teensy32).  If I don't end up selling it (i.e. there isn't much demand to make it worth the time), I'd open source the entire design leaving it to anyone else to fabricate & sell, or modify and use for their own purposes.






Rick Price
 

Haven't even received my uBitz yet, still waiting, but want one of these.  So far it looks great! 
 
Rick KN4AIE



From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Art Olson
Sent: Friday, January 12, 2018 11:34 AM
To: BITX20@groups.io
Subject: Re: [BITX20] AE7EU Top Level PCB Mod

Count me in for one
Art N2AJO 

Sent from my iPhone

On Jan 12, 2018, at 10:53 AM, M Garza <mgarza896@...> wrote:

Same here!

On Fri, Jan 12, 2018 at 9:51 AM, Terence Taylor <n6mon@...> wrote:
Well, I certainly would be interested in buying one....


On 1/11/2018 6:21 PM, Diver Martin wrote:
Hi David,

No reason the teensy couldn't be put on headers.  If I end up selling this particular PCB, the kit form would be SMT pre-done, all the through-hole to be done by the end user (Which isn't a huge amount - Headers, Front panel, uBitx connectors, inductors, and the teensy32).  If I don't end up selling it (i.e. there isn't much demand to make it worth the time), I'd open source the entire design leaving it to anyone else to fabricate & sell, or modify and use for their own purposes.






Mike Woods
 

Martin

In examining your circuit more carefully, I wonder if you could explain how the AGC works?  The mixer chip appears to be unbalanced by a DC signal from the AGC circuit (derived from the volume control input). However,  I don’t understand why you are injecting this into the IF output of the transformer and why the input from the antenna is taken to the LO input.  It looks like a design idea that could be used more widely on Bitx designs and won’t require track cutting ...

Mike ZL1AXG


On Thu, 11 Jan 2018 at 7:42 PM, Diver Martin <diver.martin@...> wrote:
So, I've finally got a rough draft of what I'm thinking for my uBitx top PCB mod.  Features at this point are:

No modifications required to uBitx board itself (not to say a 470uF anti-pop mod might be bad, or other things couldn't be done)
ATU: 7-inductor, 8-capacitor with Hi-Z/Lo-Z switch.
Selectable Power output (two power input connectors)
Brain transplant:  Teensy3.2 96MHz ARM processor
All connections on side edges - no wiring to enclosure
Front panel with pushbutton switches
DSP Audio (Via Teensy32, would require headphones or amplified speakers)
Solderless AGC modification (Attenuator at the front end switched in during RX)
Realtime clock (via Teensy32)
Linear amplifier control (just a reed relay on a 3.5mm header, sorry, not an RCA, but you could easily change it...)
Top side only construction (would make assembly cost lower)

BoM cost:  Probably way higher than it should be.  Needs optimization, and I still need to enter in costs.
Complexity:  Probably way more than it should be.
Layout:  An ugly mess of routing.  I can't say I like it, but the constraints I put on myself made it really hard to route.  There's lots of open areas to cross with lots of signals going all different directions.

Picture of the layout and schematic PDF attached, along with a 3D view.

I think the one modification that I still need to consider is a microphone preamp.  But, I have no flippin' clue where on the PCB I'd put the gain control knob!  Might have to be an internal potentiometer....

--
Martin Held - AE7EU
http://ae7eu.com/
-------------------------------------------------------------------------------
If there aren't any questions, then what is there to learn?