Topics

ubitx schematic cleanup #ubitx

Evan Hand
 

Not sure who is the correct person to send this to in a private email, so created a new thread for all to see.

When I first started on the ubitx journey, I was often confused by the differences between what was on the published schematic and what was actually provide.  Currently there are 2 that I am aware of:
1 - Q942 and Q952 do not exsist, and I am not sure would work as shown (most times you need some sort of resistor or other feedback to keep 2 parallel active devices sharing the load).  Regardless, they are not there
2 - C210 and C216 also do not exist (though at least they do have a 0 as the value}.

I know that these are minor points, however there is enough things to learn without having to verify that the schematic is in fact what is on the board.

This should not take that much effort, as it is just removing the components from the original and saving a new PDF.

The above are my opinions only
73
Evan
AC9TU 

Curt
 

Evan

thanks for many thoughtful and useful posts here to this list.  they certainly have helped me.  

the 2 different PA's are alternatives (one of our local builders questioned the same thing).  I have no clue why the designer left them there even in v5 -- but it does keep us on our toes.  I haven't researched those caps -but I would imagine there is a place for them in the layout - for those making modifications.  

As you know Farhan I trust stays quite busy - otherwise we would not be blessed to have a ubitx.  What might seem small to us may not fit into his schedule.  

Glad to journey with you.  I hope to report when my ubitx gets measured it passes spurious, and I am toying with a couple of the AGC circuits (I now realize I may have installed them wrong - yes when the style of the schematic, that leaves off the off-board components confuses me!)

73 Curt WB8YYY

Ted
 

I'll wager those extra final section reservations will accommodate a pair of 
 RD15HVF1, subject to checking pinout. I know they have 2 of the leads reversed as compared with the IRF510's.  The former are true RF devices and are rated to do well at 12v.

I'll let the class know how that works out, when my pair come in and I shove them into a version 5 board.




Ted
K3RTA

Evan Hand
 

Ted,
Thank-you for pointing that out.  I understand now that this is an alternate device, however I would have preferred not showing two devices in parallel on the schematic, with the pin out labeled by the device.  Rather, put the pin out in a table with letters on the schematic that are resolved by the device and pin assignments in the table that lists the alternative devices.  That is what I have seen in alternate device choices.  Regardless, are there any plans by HR Signals to provide boards with the RD15HV1 parts?  If not, then the schematic should represent the version that is being provided.  In other words, put the correct PDF on the HF Signals web page so we know what we are getting.

My opinion.
73
Evan

MadRadioModder
 

The boards (and I’m sure the Gerber files) so both parts… so why wouldn’t the schematic?  Everyone who passes a ham test knows you don’t use both parts together.

 

MRM

 

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Evan Hand
Sent: Saturday, February 23, 2019 1:31 PM
To: BITX20@groups.io
Subject: Re: [BITX20] ubitx schematic cleanup #ubitx

 

Ted,
Thank-you for pointing that out.  I understand now that this is an alternate device, however I would have preferred not showing two devices in parallel on the schematic, with the pin out labeled by the device.  Rather, put the pin out in a table with letters on the schematic that are resolved by the device and pin assignments in the table that lists the alternative devices.  That is what I have seen in alternate device choices.  Regardless, are there any plans by HR Signals to provide boards with the RD15HV1 parts?  If not, then the schematic should represent the version that is being provided.  In other words, put the correct PDF on the HF Signals web page so we know what we are getting.

My opinion.
73
Evan


Virus-free. www.avg.com

--

…_. _._

Evan Hand
 

MadRadioModder,

First thing is you are entitled to your opinion, as I am entitled to mine.

With that understanding,
1 - At first I was confused on the schematic, and I have passed my US Extra exam, so your assumption on Everyone is off by at least one.  I thought that it was an option to add the second devices in parallel.  I had to ask the question to get the correct answer. 
2 - The diagram is very congested in that area of the schematic.  I had difficulty in just reading the second value of the device, and the pin out numbers were so mixed in with the nonessential wires so as they were hard to read with my 60+ year old eyes.
3 - Though I have not done much in Amateur radio for over 30+ years, I am an engineer and have been dealing with schematics for electronics for all of those years and then some.
4 - The alternate parts are not provided by HF Signals, so not sure why they are even there on the documentation from them.

I appreciate the comments against my idea of cleaning up the schematic (Again thank-you Curt and Ted,  I continue to learn from both of you),  If you are stating that this is common for amateur radio documentation, then I will stand corrected.  In the work that I have done, this type of ambiguity is not acceptable.

I do not appreciate the derogatory comments.  If the intent is to prove that you are better then me, then fine, I concede that point in only the current acceptability of current radio documentation standards, assuming you are correct (still only your opinion at this point).

This is not the first time that I am trying to make it easier for others new to the ubitx journey.  Obviously I had worked out that both parts were not there, or would not have mentioned it.

Again, My Opinions.  I will continue to state them in as reasonable a fashion as I can.  I started a separate thread just so any one not interested can mute the thread, or me individually, if they so desire.  I reserve that right as well.

73
Evan
AC9TU 

 

Evan,

The missing transistors are for alternate use of RDD series. You remove the IRFs and replace with RDD16.
RDD pin outs are different so you have been provided alternate holes on PCB.

The missing caps places are there if you want to put them in to compensate for flattening the power. Options only!

Raj

At 23-02-19, you wrote:
Not sure who is the correct person to send this to in a private email, so created a new thread for all to see.

When I first started on the ubitx journey, I was often confused by the differences between what was on the published schematic and what was actually provide. Currently there are 2 that I am aware of:
1 - Q942 and Q952 do not exsist, and I am not sure would work as shown (most times you need some sort of resistor or other feedback to keep 2 parallel active devices sharing the load). Regardless, they are not there
2 - C210 and C216 also do not exist (though at least they do have a 0 as the value}.

I know that these are minor points, however there is enough things to learn without having to verify that the schematic is in fact what is on the board.

This should not take that much effort, as it is just removing the components from the original and saving a new PDF.

The above are my opinions only
73
Evan
AC9TU

Evan Hand
 

Thank-you Raj for the details. 

Would still like to see the HF Signals web pages updated, at least to the current shipping version and handle the v4 as archive like v3.

73
Evan
AC9TU

MadRadioModder
 

Well I didn’t want to be so obvious to say you may consider reading through the history of the development of the alternate PA transistors in the forum.  This is a support group but it only works if you read what has happened previously so you are “up to speed”.  That will probably clear up 99%+ of your confusion.

 

MRM

 

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Evan Hand
Sent: Saturday, February 23, 2019 6:38 PM
To: BITX20@groups.io
Subject: Re: [BITX20] ubitx schematic cleanup #ubitx

 

MadRadioModder,

First thing is you are entitled to your opinion, as I am entitled to mine.

With that understanding,
1 - At first I was confused on the schematic, and I have passed my US Extra exam, so your assumption on Everyone is off by at least one.  I thought that it was an option to add the second devices in parallel.  I had to ask the question to get the correct answer. 
2 - The diagram is very congested in that area of the schematic.  I had difficulty in just reading the second value of the device, and the pin out numbers were so mixed in with the nonessential wires so as they were hard to read with my 60+ year old eyes.
3 - Though I have not done much in Amateur radio for over 30+ years, I am an engineer and have been dealing with schematics for electronics for all of those years and then some.
4 - The alternate parts are not provided by HF Signals, so not sure why they are even there on the documentation from them.

I appreciate the comments against my idea of cleaning up the schematic (Again thank-you Curt and Ted,  I continue to learn from both of you),  If you are stating that this is common for amateur radio documentation, then I will stand corrected.  In the work that I have done, this type of ambiguity is not acceptable.

I do not appreciate the derogatory comments.  If the intent is to prove that you are better then me, then fine, I concede that point in only the current acceptability of current radio documentation standards, assuming you are correct (still only your opinion at this point).

This is not the first time that I am trying to make it easier for others new to the ubitx journey.  Obviously I had worked out that both parts were not there, or would not have mentioned it.

Again, My Opinions.  I will continue to state them in as reasonable a fashion as I can.  I started a separate thread just so any one not interested can mute the thread, or me individually, if they so desire.  I reserve that right as well.

73
Evan
AC9TU 


Virus-free. www.avg.com

--

…_. _._

tdelozie
 


Hi Evan,
 I have seen questions similar to yours and others which can take a little work to find the answer. To hopefully help, I created a page on the wiki for this group with links to the various versions as well as known errata. It is open to anyone group membership to update or add to.

https://groups.io/g/BITX20/wiki/Ubitx-Schematics

I don't know exactly how or when HFSignals will reorganize their website with the launch of v5, but I trust they will provide an acceptable way to view info from the various versions.

I hope this is helps,
Tom - KF5NWC

Jerry Gaffke
 

You can spend a week looking at thousands of posts debating how to get the uBitx PA to behave.
And wind up being more confused than when you started.
Most of the trouble in getting RF power out is due to issues other than the use of that IRF510 FET. 
(Looked down on by some, I guess because it was designed for use in automotive turn signals.)

Namely:  
    Gain stages from IF on through the power amp are all trying for about 16dB, and failing miserably on the upper bands
    Transformers are not optimal
    The 10W PA is on the same PC board as some very low level IF amps, feedback is inevitable
    Not enough drive into the IRF510 gates to overcome the capacitive load there on the upper bands
    
Going to RD15**/RD16** devices can help that last issue, but that won't help much.

A better bet might be to buy the excellent PA kit from QRP labs:  https://qrp-labs.com/linear.html
Can give a flat 26dB gain from 3 to 30 mhz, 10W out, roughly 200 ohms in and 50 ohms out.
    https://groups.io/g/QRPLabs/message/30760
Note that it uses the $0.50 IRF510's.

At any rate, I agree with Evan.
If whoever's maintaining documentation up on hfsignals could find the time to correct errors
and show some history and add some needed information as pointed out here in the forum,
it would make success for thousands of *Bitx* owners considerably more likely.

Jerry, KE7ER



On Sat, Feb 23, 2019 at 08:52 PM, MadRadioModder wrote:

Well I didn’t want to be so obvious to say you may consider reading through the history of the development of the alternate PA transistors in the forum.  This is a support group but it only works if you read what has happened previously so you are “up to speed”.  That will probably clear up 99%+ of your confusion.

 

Jerry Gaffke
 

The QRPlabs 10W PA kit is not a bolt-on solution for the uBitx.
I don't think anybody has posted how to use this with a uBitx.
But doing so would be considerably easier than addressing all the issues
with the uBitx PA if you are going after a flat response from 3 to 30 mhz.

Swapping to the RD15HV FET's on the uBitx might improve power out
on the upper bands some, but hardly seems worth the trouble.
 
Jerry


On Sun, Feb 24, 2019 at 08:26 AM, Jerry Gaffke wrote:
A better bet might be to buy the excellent PA kit from QRP labs:  https://qrp-labs.com/linear.html
Can give a flat 26dB gain from 3 to 30 mhz, 10W out, roughly 200 ohms in and 50 ohms out.
    https://groups.io/g/QRPLabs/message/30760
Note that it uses the $0.50 IRF510's.

Evan Hand
 

Jerry,

Good page to find ubitx schematics. I am sure there will be those who apriciate you effort.  As I had stated earlier, this topic was not for my benefit, rather the new to ubitx journey. 

Thank-you!

73
Evan
AC9TU

Jerry Gaffke
 

You need to thank Tom for assembling those schematics:
    https://groups.io/g/BITX20/message/65671

Tom describes the Minima as the first uBitx,
but it was different enough that I'd just call it the Minima.
Here's the description of the Minima, and the mailing list where it was discussed
    http://www.phonestack.com/farhan/minima.html
    https://www.freelists.org/archive/minima
The Minima had it's issues, few managed to get it to work very well.

The first version of the uBitx was presented here:
    https://groups.io/g/BITX20/message/22888
    http://www.phonestack.com/farhan/ubitx/ubitx.html
and discussed extensively in this BITX20 forum.
It is recognizably similar to what is shipped now, primary change was going to
four transmit LPF's instead of just two, the push-pull IRF510's were not balanced enough
to sufficiently suppress the second harmonic.

The next time a schematic was presented, it was the v3 uBitx.
That is the first uBitx that got shipped out as a kit.


The Bitx40 is worth mentioning.
It came out as a kit in India, early 2016 I believe,
originally with an analog VFO and through hole parts.
Then moved to surface mount parts. 
You can read up on how this happened by looking at old posts in this forum.

In December of 2016, hfsignals added the Raduino to the Bitx40,
giving it a much more stable VFO through the magic of the si5351.
   https://groups.io/g/BITX20/message/19177

Neither the Bitx40 or the Raduino has changed since then.
The Raduino shipped with a new uBitx is the same as one on a Dec 2016 Bitx40
except for a different connector on the bottom and different firmware.

This forum was started back in 2004 to discuss the original Bitx20
    https://groups.io/g/BITX20/message/2
    http://www.phonestack.com/farhan/bitx.html
from which the Bitx40 design evolved.
There are many many variations on the Bitx20, including several successful commercial kits such as this:
    https://www.qrpkits.com/bitx20a.html

Throughout all of this, it's clear that Farhan is driving for a minimalist design that has just enough 
parts to get on the air properly.  There are many other designs that may have more features,
but wind up with far more parts.  The *Bitx* is ideal for experimenters, giving a starting point.
If you want all those features you can then add them once you have the basic rig working.

And of course, Farhan's projects go beyond HF transceivers:
    http://www.phonestack.com/farhan/

Jerry, KE7ER



On Sun, Feb 24, 2019 at 01:07 PM, Evan Hand wrote:
Jerry,

Good page to find ubitx schematics. I am sure there will be those who apriciate you effort.  As I had stated earlier, this topic was not for my benefit, rather the new to ubitx journey. 

Thank-you!

73
Evan
AC9TU

Laurence Oberman
 

Thank you to Tom and to all who make this Ubitx journey for us the
most satisfying way to participate in Ham Radio
73
Laurence Oberman
KB1HKO

On Sun, Feb 24, 2019 at 5:30 PM Jerry Gaffke via Groups.Io
<jgaffke=yahoo.com@groups.io> wrote:

You need to thank Tom for assembling those schematics:
https://groups.io/g/BITX20/message/65671

Tom describes the Minima as the first uBitx,
but it was different enough that I'd just call it the Minima.
Here's the description of the Minima, and the mailing list where it was discussed
http://www.phonestack.com/farhan/minima.html
https://www.freelists.org/archive/minima
The Minima had it's issues, few managed to get it to work very well.

The first version of the uBitx was presented here:
https://groups.io/g/BITX20/message/22888
http://www.phonestack.com/farhan/ubitx/ubitx.html
and discussed extensively in this BITX20 forum.
It is recognizably similar to what is shipped now, primary change was going to
four transmit LPF's instead of just two, the push-pull IRF510's were not balanced enough
to sufficiently suppress the second harmonic.

The next time a schematic was presented, it was the v3 uBitx.
That is the first uBitx that got shipped out as a kit.


The Bitx40 is worth mentioning.
It came out as a kit in India, early 2016 I believe,
originally with an analog VFO and through hole parts.
Then moved to surface mount parts.
You can read up on how this happened by looking at old posts in this forum.

In December of 2016, hfsignals added the Raduino to the Bitx40,
giving it a much more stable VFO through the magic of the si5351.
https://groups.io/g/BITX20/message/19177

Neither the Bitx40 or the Raduino has changed since then.
The Raduino shipped with a new uBitx is the same as one on a Dec 2016 Bitx40
except for a different connector on the bottom and different firmware.

This forum was started back in 2004 to discuss the original Bitx20
https://groups.io/g/BITX20/message/2
http://www.phonestack.com/farhan/bitx.html
from which the Bitx40 design evolved.
There are many many variations on the Bitx20, including several successful commercial kits such as this:
https://www.qrpkits.com/bitx20a.html

Throughout all of this, it's clear that Farhan is driving for a minimalist design that has just enough
parts to get on the air properly. There are many other designs that may have more features,
but wind up with far more parts. The *Bitx* is ideal for experimenters, giving a starting point.
If you want all those features you can then add them once you have the basic rig working.

And of course, Farhan's projects go beyond HF transceivers:
http://www.phonestack.com/farhan/

Jerry, KE7ER



On Sun, Feb 24, 2019 at 01:07 PM, Evan Hand wrote:

Jerry,

Good page to find ubitx schematics. I am sure there will be those who apriciate you effort. As I had stated earlier, this topic was not for my benefit, rather the new to ubitx journey.

Thank-you!

73
Evan
AC9TU

tdelozie
 

I've updated the page with corrections suggested by Jerry. Having watched the projects for years (time flies) it is fun to look back through the changes. feel free to update/correct it.
https://groups.io/g/BITX20/wiki/Ubitx-Schematics
tom KF5NWC