Topics

uBITX full design

Jonathan Kayne, KM4CFT
 

Hi,
I am trying to see if I can do a full assembly of the uBITX, that is, I want to start with a BARE PCB and hand solder on the SMD components. 
I was wondering if the KiCAD files were available or perhaps a BOM so I know what type of transformers are being used.
I am planning on using it in a school project, so that's why I am asking.
I am more than happy to reverse engineer the PCBs if need be.
Also, I was wondering if there was anything particular I would need to know about the trace layout for the boards. Is there a ground plane on the bottom layer with the other traces on the top? (I couldn't find pics of the bottom side so I wasn't sure)
Any help would be much appreciated!
73,
-Jonathan Kayne, KM4CFT
Virginia Tech Electrical Engineering (RF and Microwave Concentration)
Virginia Tech ARA Vice President

Jerry Gaffke
 

Jonathan,

Be aware it might not be as trivial as it looks.

The transformers are described here:
    http://www.hfsignals.com/index.php/ubitx-circuit-description/
Search for "Coil Details".

The KiCad files are not available, that was some sort of requirement
when they set up HFSignals to build this stuff.
Perhaps to get a business loan they had to keep some part of the design private.
The remainder of the design is open source, and building from scratch is encouraged.
The uBitx is a two layer board, the bottom side is mostly ground plane.
Perhaps just build "ugly style" or "Manhatten style" on copper clad circuit board,
that way you have a solid ground plane under the entire design, which is highly recommended.

All quartz crystals in that IF filter should be matched by hand to within 100hz or so,
that means building a crystal oscillator and having some way to accurately measure frequency..
If your quartz crystals have different characteristics than what hfsignals uses,
you will need some way to determine the passband of the IF filter and adjust the filter shape
as described in Experimental Methods in RF Design (and/or search for Dishal on the web).

You will need some way to sniff and measure RF, an Antuino would be ideal,
though you might get by with a diode RF probe and a Harbor Freight DVM.
A good scope would be nice, perhaps 50mhz or more of bandwidth.
The nanoVNA would be worth looking into, shows complex of 1 and 2 port networks,
and thus is an education in itself.

If you are serious about studying "RF and Microwave", all of the above is worth the investment.

And lastly, maybe get a working uBitx from hfsignals, so you can
know for sure what the signals levels really should be when yours does not work.

Many have built radios like the uBitx from scratch.
But few find it easy.

Jerry, KE7ER


Curt
 

Jonathan

Contact Farhan direct to explore what's possible. it might be possible to get boards assembled without toroids and the larger parts installed. I imagine the board is the primary IP to preserve the work for folk in India. Perhaps the effort can expose the students also to manufacturing by some video perhaps. I am confident Farhan will share some fine details with the students on PA circuitry, filters and isolation. Great to see your interest.

Curt wb8yyy rf engineer

Jerry Gaffke
 

Jonathan,

A search on the web and on ebay for "ssb transceiver kit" gives a few kits
that require more assembly than a uBitx, but none that I am familiar with.
Perhaps the Klopik out of Russia, if wanting a challenge?
    https://www.eham.net/ehamforum/smf/index.php?topic=106044.0
    https://forums.qrz.com/index.php?threads/russian-klopik-2-transceiver-kit.500188/

Some of the ebay kits come with no power amp, no low pass filters, no vfo, ...
And some just plain don't work.

Farhan encourages others to produce his designs and sell them.
There have been several Bitx20 kits, and even multiband versions of it.
But I'm not seeing any just now, the uBitx is very competitive.

QRP-Labs has the successful QCX transceiver, but it is single band, and for CW, not SSB.
QRP-Labs is planning to someday release the very promising QSX all-HF SSB transceiver, 
that might be worth waiting for.    https://www.qrp-labs.com/qsx.html

If what you really want is a uBitx where you install all the surface mount parts yourself
on a known-to-work PCB, your best bet might be to buy one from hfsignals
and take a heatgun to it.

Jerry, KE7ER



On Sun, Sep 22, 2019 at 12:32 PM, Jerry Gaffke wrote:
Perhaps just build "ugly style" or "Manhatten style" on copper clad circuit board,

Curt
 

Jonathan

now after reading your QRZ listing I see you are a student, not working on a faculty project idea, but a personal project for your program there. 

as Jerry mentioned, the full component BOM is available.  even if they shipped you a board, still not a worthy student project to assemble a ubitx.  there are some things that could be expanded, like adding VHF capability (the existing 45 MHz may not be so good).  I have a paper where KK7B (a prof) has related HF layout to microwave MMIC chip design.  so some analogous learning is indeed possible. 

Jerry gave a nice description of the board.  An EE named Allison has separately commented on optimizing the PA portion - and she went out and designed a better PA layout assisting Hans Summers at QRP-Labs (they currently offer this PA kit over there).  Years ago a prof somewhere got his students to build a QRP rig, Norcal 40A maybe.  I see you already built a McHF so I don't see a lot of upside to you building your own ubitx from scratch.  likely you have already dug into the nifty synthesizer components that are a key piece of modern QRP likes ubitx and QCX. 

best wishes in your study and remaining time at that nice (rather Hokie) venue.

Curt

Jerry Gaffke
 

I agree with Curt.
A good student project would be to get the uBitx, and then try to improve it somehow.
Lots of fodder in this forum if looking for ideas of what to do.

Jerry


On Sun, Sep 22, 2019 at 03:27 PM, Curt wrote:
Jerry gave a nice description of the board.  An EE named Allison has separately commented on optimizing the PA portion - and she went out and designed a better PA layout assisting Hans Summers at QRP-Labs (they currently offer this PA kit over there).  Years ago a prof somewhere got his students to build a QRP rig, Norcal 40A maybe.  I see you already built a McHF so I don't see a lot of upside to you building your own ubitx from scratch.  likely you have already dug into the nifty synthesizer components that are a key piece of modern QRP likes ubitx and QCX. 

Ashhar Farhan
 

Jonathan,

I can arrange for a blank PCB if you want to solder it all up. it  hurts my wrist to do it all over again. i have done it several times to test the new boards. there is very little education in it. 
on the other hand, you might want to build a ubitx all by yourself. although it is a double conversion design, it is actually quite easy to build, stage-wise. beign by building the IF amplifiers. you will have to build six of those. get one going and duplicat the rest. each on a separate 2"x2" copper board.  you can hook up a raduino from the Si5351 board from qrp-labs and an antuino. using that as a signal generator, you can test/align the 45 Mhz filter and the LPF. At that point, you are done with the RF parts and you can choose to go with any audio amplification system.
i would encourage you to build it one stage at a time, test, measure and move on. great education!!

73, f

On Mon, Sep 23, 2019 at 4:06 AM Jerry Gaffke via Groups.Io <jgaffke=yahoo.com@groups.io> wrote:
I agree with Curt.
A good student project would be to get the uBitx, and then try to improve it somehow.
Lots of fodder in this forum if looking for ideas of what to do.

Jerry


On Sun, Sep 22, 2019 at 03:27 PM, Curt wrote:
Jerry gave a nice description of the board.  An EE named Allison has separately commented on optimizing the PA portion - and she went out and designed a better PA layout assisting Hans Summers at QRP-Labs (they currently offer this PA kit over there).  Years ago a prof somewhere got his students to build a QRP rig, Norcal 40A maybe.  I see you already built a McHF so I don't see a lot of upside to you building your own ubitx from scratch.  likely you have already dug into the nifty synthesizer components that are a key piece of modern QRP likes ubitx and QCX. 

MadRadioModder
 

In my mind… this is the obvious next step for the uBITx.  There is a good following of people here that wouldn’t mind building the radio from scratch… and it also allows for experimentation in each of the stages as one builds and tests.  If I ever get time, my goal is to make a set of boards stage by stage that can be fit together on a motherboard.  What better teaching tool?

 

For the rest, there is the completed (prebuilt board) uBITx that has become so successful.

 

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Ashhar Farhan
Sent: Monday, September 23, 2019 1:13 AM
To: BITX20@groups.io
Subject: Re: [BITX20] uBITX full design

 

Jonathan,

 

I can arrange for a blank PCB if you want to solder it all up. it  hurts my wrist to do it all over again. i have done it several times to test the new boards. there is very little education in it. 

on the other hand, you might want to build a ubitx all by yourself. although it is a double conversion design, it is actually quite easy to build, stage-wise. beign by building the IF amplifiers. you will have to build six of those. get one going and duplicat the rest. each on a separate 2"x2" copper board.  you can hook up a raduino from the Si5351 board from qrp-labs and an antuino. using that as a signal generator, you can test/align the 45 Mhz filter and the LPF. At that point, you are done with the RF parts and you can choose to go with any audio amplification system.

i would encourage you to build it one stage at a time, test, measure and move on. great education!!

 

73, f

 

On Mon, Sep 23, 2019 at 4:06 AM Jerry Gaffke via Groups.Io <jgaffke=yahoo.com@groups.io> wrote:

I agree with Curt.
A good student project would be to get the uBitx, and then try to improve it somehow.
Lots of fodder in this forum if looking for ideas of what to do.

Jerry


On Sun, Sep 22, 2019 at 03:27 PM, Curt wrote:

Jerry gave a nice description of the board.  An EE named Allison has separately commented on optimizing the PA portion - and she went out and designed a better PA layout assisting Hans Summers at QRP-Labs (they currently offer this PA kit over there).  Years ago a prof somewhere got his students to build a QRP rig, Norcal 40A maybe.  I see you already built a McHF so I don't see a lot of upside to you building your own ubitx from scratch.  likely you have already dug into the nifty synthesizer components that are a key piece of modern QRP likes ubitx and QCX. 


Virus-free. www.avg.com

--

…_. _._

Lawrence Galea
 

Farhan.
Did you ever think of making available a raduino with switching for every one of the 10 HF bands so that one could use external BPFs instead of the ones on the board or perhaps a program for those who want to change the original software to do so?
Or is there any programmer on this list who is willing to do it?
Thanks to all
Lawrence

On Mon, Sep 23, 2019 at 2:41 PM MadRadioModder <madradiomodder@...> wrote:

In my mind… this is the obvious next step for the uBITx.  There is a good following of people here that wouldn’t mind building the radio from scratch… and it also allows for experimentation in each of the stages as one builds and tests.  If I ever get time, my goal is to make a set of boards stage by stage that can be fit together on a motherboard.  What better teaching tool?

 

For the rest, there is the completed (prebuilt board) uBITx that has become so successful.

 

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Ashhar Farhan
Sent: Monday, September 23, 2019 1:13 AM
To: BITX20@groups.io
Subject: Re: [BITX20] uBITX full design

 

Jonathan,

 

I can arrange for a blank PCB if you want to solder it all up. it  hurts my wrist to do it all over again. i have done it several times to test the new boards. there is very little education in it. 

on the other hand, you might want to build a ubitx all by yourself. although it is a double conversion design, it is actually quite easy to build, stage-wise. beign by building the IF amplifiers. you will have to build six of those. get one going and duplicat the rest. each on a separate 2"x2" copper board.  you can hook up a raduino from the Si5351 board from qrp-labs and an antuino. using that as a signal generator, you can test/align the 45 Mhz filter and the LPF. At that point, you are done with the RF parts and you can choose to go with any audio amplification system.

i would encourage you to build it one stage at a time, test, measure and move on. great education!!

 

73, f

 

On Mon, Sep 23, 2019 at 4:06 AM Jerry Gaffke via Groups.Io <jgaffke=yahoo.com@groups.io> wrote:

I agree with Curt.
A good student project would be to get the uBitx, and then try to improve it somehow.
Lots of fodder in this forum if looking for ideas of what to do.

Jerry


On Sun, Sep 22, 2019 at 03:27 PM, Curt wrote:

Jerry gave a nice description of the board.  An EE named Allison has separately commented on optimizing the PA portion - and she went out and designed a better PA layout assisting Hans Summers at QRP-Labs (they currently offer this PA kit over there).  Years ago a prof somewhere got his students to build a QRP rig, Norcal 40A maybe.  I see you already built a McHF so I don't see a lot of upside to you building your own ubitx from scratch.  likely you have already dug into the nifty synthesizer components that are a key piece of modern QRP likes ubitx and QCX. 


Virus-free. www.avg.com

--

…_. _._

Scott McDonald
 

FWIW, if you haven’t already seen them, the IF amp boards - SMT type- are available on OSH Park very reasonably and are a great start for a stage by stage build.  They don’t have holes for mounting posts so a bit of ingenuity is required but they work well otherwise.

Good luck.  Scott Ka9p


On Sep 23, 2019, at 1:40 PM, MadRadioModder <madradiomodder@...> wrote:

In my mind… this is the obvious next step for the uBITx.  There is a good following of people here that wouldn’t mind building the radio from scratch… and it also allows for experimentation in each of the stages as one builds and tests.  If I ever get time, my goal is to make a set of boards stage by stage that can be fit together on a motherboard.  What better teaching tool?

 

For the rest, there is the completed (prebuilt board) uBITx that has become so successful.

 

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Ashhar Farhan
Sent: Monday, September 23, 2019 1:13 AM
To: BITX20@groups.io
Subject: Re: [BITX20] uBITX full design

 

Jonathan,

 

I can arrange for a blank PCB if you want to solder it all up. it  hurts my wrist to do it all over again. i have done it several times to test the new boards. there is very little education in it. 

on the other hand, you might want to build a ubitx all by yourself. although it is a double conversion design, it is actually quite easy to build, stage-wise. beign by building the IF amplifiers. you will have to build six of those. get one going and duplicat the rest. each on a separate 2"x2" copper board.  you can hook up a raduino from the Si5351 board from qrp-labs and an antuino. using that as a signal generator, you can test/align the 45 Mhz filter and the LPF. At that point, you are done with the RF parts and you can choose to go with any audio amplification system.

i would encourage you to build it one stage at a time, test, measure and move on. great education!!

 

73, f

 

On Mon, Sep 23, 2019 at 4:06 AM Jerry Gaffke via Groups.Io <jgaffke=yahoo.com@groups.io> wrote:

I agree with Curt.
A good student project would be to get the uBitx, and then try to improve it somehow.
Lots of fodder in this forum if looking for ideas of what to do.

Jerry


On Sun, Sep 22, 2019 at 03:27 PM, Curt wrote:

Jerry gave a nice description of the board.  An EE named Allison has separately commented on optimizing the PA portion - and she went out and designed a better PA layout assisting Hans Summers at QRP-Labs (they currently offer this PA kit over there).  Years ago a prof somewhere got his students to build a QRP rig, Norcal 40A maybe.  I see you already built a McHF so I don't see a lot of upside to you building your own ubitx from scratch.  likely you have already dug into the nifty synthesizer components that are a key piece of modern QRP likes ubitx and QCX. 


Virus-free. www.avg.com

--

…_. _._

Dale Hardin
 

Scott, I searched shared projects on OshPark and  couldn't find the IF amp.  Could you provide a link?  Thanks, Dale
--
Dale Hardin, KS4NS
Elberta, AL

Scott McDonald
 

Hi Dale, there’s an embedded link in the article here, just checked it and it still seems good.


If for some reason that doesn’t work please let me know and Ill dig in out the direct link, but that article is worth a look.

73 Scott Ka9p


On Sep 23, 2019, at 5:24 PM, Dale Hardin <joe.dale.hardin@...> wrote:

Scott, I searched shared projects on OshPark and  couldn't find the IF amp.  Could you provide a link?  Thanks, Dale
--
Dale Hardin, KS4NS
Elberta, AL

ajparent1/KB1GMX <kb1gmx@...>
 

On Mon, Sep 23, 2019 at 08:34 AM, Lawrence Galea wrote:
Farhan.
Did you ever think of making available a raduino with switching for every one of the 10 HF bands so that one could use external BPFs instead of the ones on the board or perhaps a program for those who want to change the original software to do so?
Or is there any programmer on this list who is willing to do it?
Thanks to all
Likely no as its too great a change to the Raduino and the ubitx.

The existing version is at best good for 8 bands if one uses TXA,TXB,TXC as 
a binary band select along with an external decoder chip like 74138 (3-8 decode).

If one is willing a ground up build and a improved raduino-like approach would be doable.
The trick with the Nano is using a I2C display to free up pins and readjusting what pins are
used where.

Allison

Laurence Oberman
 

Hello
The other option is the one I have been messing with and now that
summer is over hope to carry on with my project on the external amp
and the the much larger arduino Mega 25xx

That has plenty of pins for all sort of extras.
Regards
Laurence

On Mon, Sep 23, 2019 at 1:05 PM ajparent1/KB1GMX <kb1gmx@...> wrote:

On Mon, Sep 23, 2019 at 08:34 AM, Lawrence Galea wrote:

Farhan.
Did you ever think of making available a raduino with switching for every one of the 10 HF bands so that one could use external BPFs instead of the ones on the board or perhaps a program for those who want to change the original software to do so?
Or is there any programmer on this list who is willing to do it?
Thanks to all

Likely no as its too great a change to the Raduino and the ubitx.

The existing version is at best good for 8 bands if one uses TXA,TXB,TXC as
a binary band select along with an external decoder chip like 74138 (3-8 decode).

If one is willing a ground up build and a improved raduino-like approach would be doable.
The trick with the Nano is using a I2C display to free up pins and readjusting what pins are
used where.

Allison

Jerry Gaffke
 

If building a new board for external low pass filters, 
could spend an extra $0.50 on a processor to interpret serial commands from the Raduino.
If wires kept short could use the i2c bus, pin count impact on the Raduino is a minus 3
since this frees up the TXA,TXB,TXC pins.
And perhaps include a tandem match style SWR detector out there, 
communicates back to the Raduino over that same serial bus.

None of the communications out to this LPF board need speed,
this LPF board is a better choice for i2c than the display.

Not that I feel any real need for 10 LPF's.  
The 4 we have on the uBitx adequately cover the WARC bands.
Putting the corner frequencies closer to the top edge of each band
would allow better attenuation of harmonics, but in some jurisdictions at least
the v5 uBitx meets regulatory requirements.
Sufficient in my book for a QRP rig.
Actually, 20/40/80m is sufficient in my book for an $129 SSB transceiver.

There were several reports in this forum of Raduino clones being built
that had more IO pins.  Moving to an Arm blue pill would seem ideal
for a Raduino upgrade.  W3JDR got most of the way there:
    https://groups.io/g/BITX20/topic/19284407

I'd much prefer something like that for getting extra pins for tasks where
execution time is a consideration, serial access over i2c is awfully slow.

If doing a Raduino clone, address these issues of the current Raduino:
    No reverse polarity protection for the 12v supply
    No protection for the IO pins that go off board, please add 100 or 1000 ohm series resistors.
    Avoid having Raduino oscillators create birdies in the receiver
    Perhaps improve si5351 drive power to 7dBm,  have optional second si5351 to avoid crosstalk?
Might be a good project for some engineering student.
Jonathan, you still out there?

Jerry, KE7ER


On Mon, Sep 23, 2019 at 10:05 AM, ajparent1/KB1GMX wrote:
On Mon, Sep 23, 2019 at 08:34 AM, Lawrence Galea wrote:
Farhan.
Did you ever think of making available a raduino with switching for every one of the 10 HF bands so that one could use external BPFs instead of the ones on the board or perhaps a program for those who want to change the original software to do so?
Or is there any programmer on this list who is willing to do it?
Thanks to all
Likely no as its too great a change to the Raduino and the ubitx.

The existing version is at best good for 8 bands if one uses TXA,TXB,TXC as 
a binary band select along with an external decoder chip like 74138 (3-8 decode).

If one is willing a ground up build and a improved raduino-like approach would be doable.
The trick with the Nano is using a I2C display to free up pins and readjusting what pins are
used where.

Allison

Lawrence Galea
 

Thanks all for your feedback
Regards
Lawrence

On Mon, Sep 23, 2019 at 8:35 PM Jerry Gaffke via Groups.Io <jgaffke=yahoo.com@groups.io> wrote:
If building a new board for external low pass filters, 
could spend an extra $0.50 on a processor to interpret serial commands from the Raduino.
If wires kept short could use the i2c bus, pin count impact on the Raduino is a minus 3
since this frees up the TXA,TXB,TXC pins.
And perhaps include a tandem match style SWR detector out there, 
communicates back to the Raduino over that same serial bus.

None of the communications out to this LPF board need speed,
this LPF board is a better choice for i2c than the display.

Not that I feel any real need for 10 LPF's.  
The 4 we have on the uBitx adequately cover the WARC bands.
Putting the corner frequencies closer to the top edge of each band
would allow better attenuation of harmonics, but in some jurisdictions at least
the v5 uBitx meets regulatory requirements.
Sufficient in my book for a QRP rig.
Actually, 20/40/80m is sufficient in my book for an $129 SSB transceiver.

There were several reports in this forum of Raduino clones being built
that had more IO pins.  Moving to an Arm blue pill would seem ideal
for a Raduino upgrade.  W3JDR got most of the way there:
    https://groups.io/g/BITX20/topic/19284407

I'd much prefer something like that for getting extra pins for tasks where
execution time is a consideration, serial access over i2c is awfully slow.

If doing a Raduino clone, address these issues of the current Raduino:
    No reverse polarity protection for the 12v supply
    No protection for the IO pins that go off board, please add 100 or 1000 ohm series resistors.
    Avoid having Raduino oscillators create birdies in the receiver
    Perhaps improve si5351 drive power to 7dBm,  have optional second si5351 to avoid crosstalk?
Might be a good project for some engineering student.
Jonathan, you still out there?

Jerry, KE7ER

On Mon, Sep 23, 2019 at 10:05 AM, ajparent1/KB1GMX wrote:
On Mon, Sep 23, 2019 at 08:34 AM, Lawrence Galea wrote:
Farhan.
Did you ever think of making available a raduino with switching for every one of the 10 HF bands so that one could use external BPFs instead of the ones on the board or perhaps a program for those who want to change the original software to do so?
Or is there any programmer on this list who is willing to do it?
Thanks to all
Likely no as its too great a change to the Raduino and the ubitx.

The existing version is at best good for 8 bands if one uses TXA,TXB,TXC as 
a binary band select along with an external decoder chip like 74138 (3-8 decode).

If one is willing a ground up build and a improved raduino-like approach would be doable.
The trick with the Nano is using a I2C display to free up pins and readjusting what pins are
used where.

Allison

Ashhar Farhan
 

If you are thinking of a bank if band pass filters, then you dont need the complexity and performance hit of the double conversion  ubitx. Go for single conversion like the bitx40 or bitx20. The performance is kuch superior. 


On Tue 24 Sep, 2019, 1:29 AM Lawrence Galea, <9h1avlaw@...> wrote:
Thanks all for your feedback
Regards
Lawrence

On Mon, Sep 23, 2019 at 8:35 PM Jerry Gaffke via Groups.Io <jgaffke=yahoo.com@groups.io> wrote:
If building a new board for external low pass filters, 
could spend an extra $0.50 on a processor to interpret serial commands from the Raduino.
If wires kept short could use the i2c bus, pin count impact on the Raduino is a minus 3
since this frees up the TXA,TXB,TXC pins.
And perhaps include a tandem match style SWR detector out there, 
communicates back to the Raduino over that same serial bus.

None of the communications out to this LPF board need speed,
this LPF board is a better choice for i2c than the display.

Not that I feel any real need for 10 LPF's.  
The 4 we have on the uBitx adequately cover the WARC bands.
Putting the corner frequencies closer to the top edge of each band
would allow better attenuation of harmonics, but in some jurisdictions at least
the v5 uBitx meets regulatory requirements.
Sufficient in my book for a QRP rig.
Actually, 20/40/80m is sufficient in my book for an $129 SSB transceiver.

There were several reports in this forum of Raduino clones being built
that had more IO pins.  Moving to an Arm blue pill would seem ideal
for a Raduino upgrade.  W3JDR got most of the way there:
    https://groups.io/g/BITX20/topic/19284407

I'd much prefer something like that for getting extra pins for tasks where
execution time is a consideration, serial access over i2c is awfully slow.

If doing a Raduino clone, address these issues of the current Raduino:
    No reverse polarity protection for the 12v supply
    No protection for the IO pins that go off board, please add 100 or 1000 ohm series resistors.
    Avoid having Raduino oscillators create birdies in the receiver
    Perhaps improve si5351 drive power to 7dBm,  have optional second si5351 to avoid crosstalk?
Might be a good project for some engineering student.
Jonathan, you still out there?

Jerry, KE7ER

On Mon, Sep 23, 2019 at 10:05 AM, ajparent1/KB1GMX wrote:
On Mon, Sep 23, 2019 at 08:34 AM, Lawrence Galea wrote:
Farhan.
Did you ever think of making available a raduino with switching for every one of the 10 HF bands so that one could use external BPFs instead of the ones on the board or perhaps a program for those who want to change the original software to do so?
Or is there any programmer on this list who is willing to do it?
Thanks to all
Likely no as its too great a change to the Raduino and the ubitx.

The existing version is at best good for 8 bands if one uses TXA,TXB,TXC as 
a binary band select along with an external decoder chip like 74138 (3-8 decode).

If one is willing a ground up build and a improved raduino-like approach would be doable.
The trick with the Nano is using a I2C display to free up pins and readjusting what pins are
used where.

Allison

Lawrence Galea
 

Farhan
I have the μbitx 3 and was thinking aloud about separate filters for each band
Thanks and regards
Lawrence

On Tue, Sep 24, 2019 at 4:10 AM Ashhar Farhan <farhanbox@...> wrote:
If you are thinking of a bank if band pass filters, then you dont need the complexity and performance hit of the double conversion  ubitx. Go for single conversion like the bitx40 or bitx20. The performance is kuch superior. 

On Tue 24 Sep, 2019, 1:29 AM Lawrence Galea, <9h1avlaw@...> wrote:
Thanks all for your feedback
Regards
Lawrence

On Mon, Sep 23, 2019 at 8:35 PM Jerry Gaffke via Groups.Io <jgaffke=yahoo.com@groups.io> wrote:
If building a new board for external low pass filters, 
could spend an extra $0.50 on a processor to interpret serial commands from the Raduino.
If wires kept short could use the i2c bus, pin count impact on the Raduino is a minus 3
since this frees up the TXA,TXB,TXC pins.
And perhaps include a tandem match style SWR detector out there, 
communicates back to the Raduino over that same serial bus.

None of the communications out to this LPF board need speed,
this LPF board is a better choice for i2c than the display.

Not that I feel any real need for 10 LPF's.  
The 4 we have on the uBitx adequately cover the WARC bands.
Putting the corner frequencies closer to the top edge of each band
would allow better attenuation of harmonics, but in some jurisdictions at least
the v5 uBitx meets regulatory requirements.
Sufficient in my book for a QRP rig.
Actually, 20/40/80m is sufficient in my book for an $129 SSB transceiver.

There were several reports in this forum of Raduino clones being built
that had more IO pins.  Moving to an Arm blue pill would seem ideal
for a Raduino upgrade.  W3JDR got most of the way there:
    https://groups.io/g/BITX20/topic/19284407

I'd much prefer something like that for getting extra pins for tasks where
execution time is a consideration, serial access over i2c is awfully slow.

If doing a Raduino clone, address these issues of the current Raduino:
    No reverse polarity protection for the 12v supply
    No protection for the IO pins that go off board, please add 100 or 1000 ohm series resistors.
    Avoid having Raduino oscillators create birdies in the receiver
    Perhaps improve si5351 drive power to 7dBm,  have optional second si5351 to avoid crosstalk?
Might be a good project for some engineering student.
Jonathan, you still out there?

Jerry, KE7ER

On Mon, Sep 23, 2019 at 10:05 AM, ajparent1/KB1GMX wrote:
On Mon, Sep 23, 2019 at 08:34 AM, Lawrence Galea wrote:
Farhan.
Did you ever think of making available a raduino with switching for every one of the 10 HF bands so that one could use external BPFs instead of the ones on the board or perhaps a program for those who want to change the original software to do so?
Or is there any programmer on this list who is willing to do it?
Thanks to all
Likely no as its too great a change to the Raduino and the ubitx.

The existing version is at best good for 8 bands if one uses TXA,TXB,TXC as 
a binary band select along with an external decoder chip like 74138 (3-8 decode).

If one is willing a ground up build and a improved raduino-like approach would be doable.
The trick with the Nano is using a I2C display to free up pins and readjusting what pins are
used where.

Allison

Jonathan Kayne, KM4CFT
 

Thanks for all the information regarding the building of the uBITX. I am more so curious about how the RF trace layout was done. I previously built the mcHF to master SMD soldering, and I found that one of the bands didn't work because RF wasn't going through a trace for some reason. I had to solder a piece of wire to fix it. What it essentially meant is that trace layout on a PCB is a little more complex with RF.
Also, it would give me more KiCad design experience. I mean, my school pays for these types of projects, so personal projects I can go all out really.

Thanks,
-Jonathan, KM4CFT

Lawrence Galea
 

The inductance of the strip together with its capacitance to the board could have formed a series resonant circuit shorting your RF.


On Fri, Sep 27, 2019 at 5:27 PM Jonathan Kayne, KM4CFT <jzkmath@...> wrote:
Thanks for all the information regarding the building of the uBITX. I am more so curious about how the RF trace layout was done. I previously built the mcHF to master SMD soldering, and I found that one of the bands didn't work because RF wasn't going through a trace for some reason. I had to solder a piece of wire to fix it. What it essentially meant is that trace layout on a PCB is a little more complex with RF.
Also, it would give me more KiCad design experience. I mean, my school pays for these types of projects, so personal projects I can go all out really.

Thanks,
-Jonathan, KM4CFT