Re: Reverse Polarity Protection.
I far prefer the approach below as you are not crow-baring voltages, blowing fuses, shorting diodes, and letting smoke escape: ? ? 
More elegant solution. ?
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From: [email protected] [mailto:[email protected]] On Behalf Of Jerry Gaffke via Groups.Io
Sent: Wednesday, March 27, 2019 12:08 PM
To: [email protected]
Subject: Re: [BITX20] Reverse Polarity Protection. ? The PFET reverse polarity protection is not a bad choice if you need the minimum possible voltage drop.
But it's easy to goof up.? Some schematics for this on the web show the PFET
placed backwards, and thus offering zero protection from reverse polarity.
At power up, the intrinsic reverse diode conducts from drain to source, till the source is Vgs above the gate.
At that point, what is hopefully an enhancement mode PFET starts to conduct, reducing the voltage drop
between drain to source from a diode drop to that incurred by the current through Rds-on.
For a uBitx, I'd recommend instead a diode (most anything capable of dealing with 500ma)
in series with the main 12v into the board at P1 pin 1 (which also protects the Raduino).
We can afford a slight voltage drop there, and this is much easier to understand.
The 12v into PA-PWR on P1 pin 2 for the IRF510's can be a direct connection, since a reverse voltage
on PA-PWR will cause the IRF510's to conduct through their intrinsic reverse diode.
If there is no fuse then some easily repaired board traces (and/or L8,, L9) will blow,
but not your IRF510's.? Diode protection here is ok if you insist, but you will need
a fairly hefty diode, and the diode drop will reduce transmit power by a bit.
A 3 Amp fuse between the power supply and uBitx is highly recommended.
Without reverse protection into the main board, the Raduino can fry because
the ancient LM7805 on the Raduino does not block a negative voltage.
There are newer regulators such as the LM2940 that do.
Replacing the protection diode recommended above with an LM2940T-12,
gives protection for reverse battery voltage, it will also protect the rig
from excessive battery voltage.? (PA-PWR should not go through an LM2940T,
as that will draw too much current.)?
Jerry, KE7ER
But many people who use don't understand how it works, and often circuits found on the web show the FET backwards.
for this scheme show the FET in backwards.
On Wed, Mar 27, 2019 at 04:30 AM, Tom, wb6b wrote: Here is an interesting link to a mosfet reverse polarity protection circuit. I found this mentioned in a post on this group from about a year ago.
Tom, wb6b
-- …_. _._
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Update after using the uBitx for about 2 weeks:
Listening to SSB voice was possible for strong signals after setting IF shift to 3000
(CEC firmware)
1) interference from the KGO AM station is now gone
2) it is possible to listening to strong SSB signals (I use the
to get an idea of where a strong signal can be found and then tune the uBitx to that
frequenc. S9+ SSB signals at Half Moon Bay can generally be heard by the
uBitx in Silicon Valley).
-jens (KM6ZJV)
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Re: Reverse Polarity Protection.
The PFET reverse polarity protection is not a bad choice if you need the minimum possible voltage drop.
But it's easy to goof up.? Some schematics for this on the web show the PFET
placed backwards, and thus offering zero protection from reverse polarity.
At power up, the intrinsic reverse diode conducts from drain to source, till the source is Vgs above the gate.
At that point, what is hopefully an enhancement mode PFET starts to conduct, reducing the voltage drop
between drain to source from a diode drop to that incurred by the current through Rds-on.
For a uBitx, I'd recommend instead a diode (most anything capable of dealing with 500ma)
in series with the main 12v into the board at P1 pin 1 (which also protects the Raduino).
We can afford a slight voltage drop there, and this is much easier to understand.
The 12v into PA-PWR on P1 pin 2 for the IRF510's can be a direct connection, since a reverse voltage
on PA-PWR will cause the IRF510's to conduct through their intrinsic reverse diode.
If there is no fuse then some easily repaired board traces (and/or L8,, L9) will blow,
but not your IRF510's.? Diode protection here is ok if you insist, but you will need
a fairly hefty diode, and the diode drop will reduce transmit power by a bit.
A 3 Amp fuse between the power supply and uBitx is highly recommended.
Without reverse protection into the main board, the Raduino can fry because
the ancient LM7805 on the Raduino does not block a negative voltage.
There are newer regulators such as the LM2940 that do.
Replacing the protection diode recommended above with an LM2940T-12,
gives protection for reverse battery voltage, it will also protect the rig
from excessive battery voltage.? (PA-PWR should not go through an LM2940T,
as that will draw too much current.)?
Jerry, KE7ER
But many people who use don't understand how it works, and often circuits found on the web show the FET backwards.
for this scheme show the FET in backwards.
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On Wed, Mar 27, 2019 at 04:30 AM, Tom, wb6b wrote:
Here is an interesting link to a mosfet reverse polarity protection circuit. I found this mentioned in a post on this group from about a year ago.
Tom, wb6b
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Re: Shaking my head in disbelief....
Kelly
Apparently there are a few Arduino NANO boards becoming available with the micro-USB
connector.?
Arv _._
Bill, I am leaning that way now... I noticed? the raduino has the mini usb connector. Time to go scrounge up a cable, and get to work. I'm going to load the fw for stock display? then try the Nextion enhanced display.
73,
Kelly K5AID?
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Re: Shaking my head in disbelief....
Thanks Curt.. I channeled my inner "chop cut rebuild" last night. I heard Massachusetts last night .. heard cw and then I felt good when I heard strong cw. I reworked the encoder board, added a provision for internal batteries,? added a connection to chassis ground and added the internal speaker. Much more stable...audio. I twisted like signal wires... now just uploaded my cec firmware...good there. Now doing the nextion display and stopping. For a good while. To rest and enjoy the fruits of this labor.
Nextion display tested also 3.5...looks ok on their test s w
NX4832K035_011
Thank you Curt & everyone who gave advice!
73,
Kelly K5AID?
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Bill? i get? the? down load? but its? not? like? the? sample? file? that? kd8cec? has? on his? site? upgrading? ?Iam? useingxloader? and? says its? doing the? uploading but? nothing? there? ?his? test? ?ubitx__20_org? works? ?good? ?but? onlt? ver .02? thats? my? problem? i have? tried? evrything? ?tnx? don? W0DJK
Did he post the source somewhere?? Github perhaps? ? ? ? Try
Bill K9JUI ? On 3/27/2019 7:13 AM, Don Klier wrote: Can? anyone? send me the? right link? for the new? ver? 5 kd8cec? ?new system? thanks in advance? I have? tried 3 different and? they all fail? ?Don W0DJK
--
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Re: Board Map/Layout, Test Points? (V5)
Regarding the PCB layout for the Bitx40 and uBitx, post 35123 from Farhan states:
"the gerber had to be provided under restrictive copyright for hfsigs due to some legal twist, as the only 'asset' of hfsigs."
In post 36079, Farhan states:
"?wish somebody else does it! the circuits, the software, everything is open source. HFsigs owns nothing except the domain name and the pcb gerber files. even the content is open source. it would be even more fun for us to sit back and watch others do it."
??
So if you have a major beef with hfsignals,?
just kit up your own version of the uBitx, ????,? make millions of dollars.
Jerry, KE7ER
? ??
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On Wed, Mar 27, 2019 at 03:00 AM, Gordon Gibby wrote:
In this day and age, that would be somewhat like demanding he give up corporate intelligence knowledge. ?Layout is a valuable commodity.
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IF there was the documentation trail that you desire, the board price would would go up tremendously!? ?Creating the baseline documentation, and maintaining it from there, is a never-ending task that goes way beyond the capabilities of free labor.? The best way to describe the BITX/uBITX is a user supported, "work-in-progress".
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Re: Shaking my head in disbelief....
Kelly
I suggest getting your rig working well before updating firmware.?
Fix the volume control?? It might not be broken.?
Are you listening on speaker or headphones?? The ubitx is known for having low audio drive.? And remember there is no AGC.? Using headphones, you will likely find the need to increase volume to about 3/4ths full to receive the weakest signals, particularly on CW.? Also on CW, note with the rather wide bandwidth there is much more noise until you use an audio filter.? This could be what you are dealing with?? Note for the very loud signals you may be running at about 5% or less on the volume control.?
Do take more data before concluding anything - possibly your ubitx is operating normal.? If you are a speaker guy, an external speaker amplifier could help.? A simple AGC might be in your future also.?
Glad you might have things working.?
Curt
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Sure we all get there sometimes!? Deciding a particular path is not for I.? It happens.?
uBITX is certainly a different paradigm.? there is less focus on instructions since one mostly connects up wires, and it was never intended for a particular enclosure.? the menu system is mostly intuitive - and note its 'merely' for the initial firmware.? keep in mind many in the world cannot, or chose not to, afford something like the KX3.? the uBITX is the easiest path for many ops in many places.?
I am thinking that that the testing and alignment on the uBITX could be more thorough - but note this requires more funds to purchase, a possible obstacle for some.? Its easy to be a critic when we may live in a different culture, yet somethings aren't so different.?
I think the largest uBITX challenge may be lack of a kit to address the spurious.? I sense the supplier has put as much 'value' into the main board as possible, maybe.? If v5 still has some harmonics, I still suggest a daughter board hosting relays as perhaps the best solution.? On the 45 MHz to RF spurs on transmit - I don't yet possess a solution.? The little filter used on v5 isn't enough (see 12m especially).? A second sharp xtal filter in the transmit path certainly works, but it my case it wrecks 40m CW.? All this is part of the journey - meanwhile my uBITX is clean on CW, and okay on SSB up through 20m.? Progress!?
The world is a better place just having the uBITX option.?
73 Curt
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Hello Sir
While I fully understand the frustration, if time is an issue then yes
buying the KX3 was a bargain.
There are statistically many more happy Ubitx owners than unhappy ones
so the project is a success Sir.
The learning opportunities and ability to customize outweigh the negatives.
Please note, I am not downplaying any of the folks that have had
issues and have been frustrated with the efforts needed to get the
units fully functional, but many more have had them work out of the
box.
I have 3 units, the V4 gave me issues and turned out to be a Mic
socket hardware issue for SSB. The two new V5's worked right out the
box.
How can we help
Kindly
73
KB1HKO
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On Wed, Mar 27, 2019 at 10:53 AM A Kiddoo <kt0tt.ham@...> wrote:
Time for a break. I drank the uBITX koolaide and have been fighting with that thing for almost a month now. The instructions and available data on the project is a total mess. There is no instruction manual or step by step how-to, just a conglomeration of comments by experiments. Assembly is easy but calibration is nothing short of luck. There appears to be as many outcomes as experimenters. The low quality of parts may affect the tolerance values resulting in a quite unpredictable result. Add to that the simplicity of design with dual circuit functions and the possibility for errors compounds. So unless someone derives a solution in the near future I will be looking for a new sucker at a hamfest this summer. Fine example of 'If it sounds too good to be true it isn't'. uBITX makes my KX3 look like a bargain if my time has any value.
My board (147/2) arrived with one lead on L8 not through the board and no solder residue in the hole or pad. If this board passed ‘testing’ I really question production procedures.
I not asking for ’try this or try that’ but a book or guide with specific proven instructions. So for now uBITX sits in a box, in the basement waiting for a second chance.
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This might not be the device for you my friend.
To calibrate mine, I simply commanded the digital synthesizer to go to The frequency of its internal oscillator ?crystal, measured the frequency error, and put in appropriate correction into the software.?? But I was drawn to it because I know how to program?
Others can use different mechanisms, but it certainly isn’t the rig for everyone!
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?
Time for a break. I drank the uBITX koolaide and have been fighting with that thing for almost a month now. The instructions and available data on the project is a total mess. There is no instruction manual or step by step how-to,
just a conglomeration of comments by experiments. Assembly is easy but calibration is nothing short of luck. There appears to be as many outcomes as experimenters. The low quality of parts may affect the tolerance values resulting in a quite unpredictable
result. Add to that the simplicity of design with dual circuit functions and the possibility for errors compounds. So unless someone derives a solution in the near future I will be looking for a new sucker at a hamfest this summer. Fine example of 'If it sounds
too good to be true it isn't'. uBITX makes my KX3 look like a bargain if?my time has any value.
?
My board (147/2) arrived with one lead on L8 not through the board and no solder residue in the hole or pad. If this board passed ‘testing’ I really question production procedures.
?
I not asking for ’try this or try that’ but a book or guide with specific proven instructions. So for now uBITX sits in a box, in the basement waiting for a second chance.
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Thanks for your input Chris. ?My background was originally device drivers and sockets starting with Unix Version 7 - Then Unix System III - and then finally Unix System V. Lots of Kernel work. ?Lots of protocol development too X.25 etc. I use a Mac and I had fits at first getting the IDE to talk to the Nano Clone. ?Lots of driver installing and uninstalling. ?But once it works - it seems to stay stable. ?I hope he is able to solve his comm problem.?
73 John N6API - CFO #043
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I also keep getting many compile errors on the V5..
--
W0KFL / Tom Raber
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?
Time for a break. I drank the uBITX koolaide and have been fighting with that thing for almost a month now. The instructions and available data on the project is a total mess. There is no instruction manual or step by step how-to, just a conglomeration of comments by experiments. Assembly is easy but calibration is nothing short of luck. There appears to be as many outcomes as experimenters. The low quality of parts may affect the tolerance values resulting in a quite unpredictable result. Add to that the simplicity of design with dual circuit functions and the possibility for errors compounds. So unless someone derives a solution in the near future I will be looking for a new sucker at a hamfest this summer. Fine example of 'If it sounds too good to be true it isn't'. uBITX makes my KX3 look like a bargain if?my time has any value.
?
My board (147/2) arrived with one lead on L8 not through the board and no solder residue in the hole or pad. If this board passed ‘testing’ I really question production procedures.
?
I not asking for ’try this or try that’ but a book or guide with specific proven instructions. So for now uBITX sits in a box, in the basement waiting for a second chance.
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Re: Board Map/Layout, Test Points? (V5)
You’re quite welcome. ? It’s only my guess
On Mar 27, 2019, at 10:09, ronmhauser via Groups.Io < ronmhauser@...> wrote:
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Ah, I get it, that is a good reason.? Thanks for the insight.?
73
--Ron
K0EIA
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Did he post the source somewhere?? Github perhaps? ? ?
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From: [email protected] [mailto:[email protected]] On Behalf Of Bill
Sent: Wednesday, March 27, 2019 6:37 AM
To: [email protected]
Subject: Re: [BITX20] ubitx 5 board? Try Bill K9JUI ? On 3/27/2019 7:13 AM, Don Klier wrote: Can? anyone? send me the? right link? for the new? ver? 5 kd8cec? ?new system? thanks in advance? I have? tried 3 different and? they all fail? ?Don W0DJK
-- …_. _._
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Gary
indeed, first examine whether the BFO calibration is off - I think I see enough data (including my v4) that HFSignals does not align the BFO.? if all is okay here, then ...
[it would help a lot if HFSignals would list a 'default' BFO setting in the instructions!? maybe a v5 builder reading this will share their BFO setting]
my best guess is you have a connection issue somewhere.? (I certainly have made a bad solder joint before, and sometimes they are even attached!)
I would first check all the wires you installed, including insure you don't have a stray piece of wire causing a short across the RF.? Or it could be an audio issue also.?
A much smaller possibility - check more than one band in case it were an issue with board mounted filters or relays.?
Hang in their patiently - I sense its something simple.?
Curt
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Re: Board Map/Layout, Test Points? (V5)
Ah, I get it, that is a good reason.? Thanks for the insight.?
73
--Ron
K0EIA
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Actually, Linux (and Unix) DO use device drivers. You just don't
typically have to deal with installing them.
I was a device driver writer for HP-UX in a previous life.
Chris Shaker
On 3/26/2019 3:25 PM, Pat Anderson
wrote:
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I understand what you are saying, and would agree
if I were using Windows or Mac. I am pretty confident it is not
a problem on my computer end...Linux does not use "drivers" the
way Windows and Macs do - everything going out a USB port in
Linux goes out using the dialout device, /dev/tty. When the user
is a member of the dialout group, and there is an FTDI or
Prolific (even counterfeit) chip on the other end, a
/dev/ttyUSB0 device is created, which is then made read/write
with chmod. Linux is remarkably un-fussy about what the chip is.
Whatever the chip in the Raduino is, it does not seem my
computer is not having a problem with it.
Whatever the chip is in the Raduino is, /dev/tty is?
recognizing it and creating the USB device on? the computer.
The IDE knows the USB device is there, and I am making it
read/write, which has always worked for everything else.
Thanks for the input though. I think I may j just set this
aside for a while and come back to it later.
If
you are unable to upload ANY code to the processor - it is
likely a problem with the serial port and/or driver on your
computer.? This issue is always a black eye with new setups.?
Some Arduino boards use FTDI devices and others use CHD
devices.? It seems that most of the Chinese clones are using
CHD340/341 devices. ? HTH
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MadRadioModder
A Kiddoo
Chris Shaker, KJ7BLE