Date   

Re: Yet another Chernobyl IRF510 "event" #ubitx

Don - KM4UDX
 

Haha....yes a slow learner. Some of us practice the right way, and the rest of us practice the mistakes. Hahah.


Re: Yet another Chernobyl IRF510 "event" #ubitx

Dean Souleles
 

Ooops you did it again?


Re: Yet another Chernobyl IRF510 "event" #ubitx

Don - KM4UDX
 

I learned to install the heatsinks first, then put the 510s into the board. Installing the heatsinks off board allowed me to add the thermal compound (aka heatsink goo) and then torque down the screw and nut without manhandling the board.

https://photos.app.goo.gl/mUfdDiPGNXpFPbeZA


A minor process improvement to a thoroughly unnecessary process in the first place. If you pay attention in the first place. 

Don


Yet another Chernobyl IRF510 "event" #ubitx

Don - KM4UDX
 

Turns out that large heatsinks and fan are not enough to triumph over failed power supplies, non-resonate antennas, too much current,  too long digital TX sessions, and a bit of careless operations.... 

I turn my back for a second, and for no reason at all (as my kids used to say continiously), the snowflake crybabies just had to get all "torch" on me.  Lightweights.

You're thinking (a)  "operator error?" here, and (b) will he ever learn. Easy to answer: yes and no. Hahah.

https://photos.app.goo.gl/LMLf1AHpndTPJzGe7

Question:  if the PA is on 24v, does AF's (and others)  guidance on setting the bias for 100ma each on unmodulated carrier?

Do I follow the standard process even though there are 24 not 12 volts at play?

https://www.hfsignals.com/index.php/ubitx-tuneup/

Thank you all very very much as always.

Don
(aka "the 510 death star")


Re: uBitx v5 issue

Bill Cromwell
 

Hi,

The diodes are not very likey to need replacing. Or do you live in Florida - the lightning capital of the world? An impulse from a nearby lightning strike might take the diodes (and might not). Of course, a direct hit by lightning and they won't help. But you will have bigger problems than the diodes or Q90.

73,

Bill KU8

bark less - wag more

On 11/24/20 6:22 PM, Bob Lunsford via groups.io wrote:
Would be nice to install a couple of solder terminals so the two diodes could be easily replaced. I bought 100 switching diodes from Radio Shack when they were business and have only used less than five of the batch. Switching the radio to ground by way of a switch that causes the radio input to go to ground when not being used is another form of cheap insurance.
Replacing the diodes would be much better than replacing Q90 in my book. Less trouble and faster.
Bob — KK5R
On Tuesday, November 24, 2020, 12:44:31 PM EST, Bill Cromwell <wrcromwell@gmail.com> wrote:
Hi Ted,
I am preparing to replace Q90 in my V3 and I will be installing the
diodes. I have used them in other solid state rigs in the past and a
couple of time I have had to replace them (two different radios). The
usual failure mode is for them to fail-short. It becomes obvious then
that they have failed because incoming signals pretty much vanish. In
both cases the rest of the radio was preserved. The sacrificial diodes
did their job.
I have never had any problems with radios that have those diodes
installed. Most of the caveats that have been posted here are
*speculation* about what might happen. It hasn't happened. None of the
posts have asserted that any problem has actually happened. I have two
experiences where the front ends were saved and no experiences where the
diodes caused any problems. And that is experience, not speculation.
73,
Bill  KU8H
bark less - wag more
On 11/24/20 11:40 AM, Ted via groups.io wrote:
> Would the common 1n914 serve the same purpose?   Being as common as it
> is, etc.
>
>
> Ted
> k3rta
>


Re: Firmware loading ignorance

Evan Hand
 

On Tue, Nov 24, 2020 at 03:47 PM, Bill Robbins wrote:
Also should simply load factory defaults and start over?
The KD8CEC software does not really have the "factory defaults" as far as I know.   The values that I get when resetting to them are totally wrong.  I have not worked out the logic on what is being saved.  When you first open the Memory Manager software without a file selected/loaded, the factory defaults button is greyed out.  Here is a screenshot of the Memory Manager for my v5:


73
Evan
AC9TU


Re: Firmware loading ignorance

Evan Hand
 

Bill,
Yes, that is why your uBITX is deaf, though it may be more than just the BFO.  Are you sure you used the file from the UBITXV5 folder?  My first impression is that you somehow have the other folder, the UBITXV234.  If that is the case, changing the BFO will not help, as the second IF oscillator will be wrong also.

The reason that I believe that you have the wrong file is that there are checks on the BFO to try to keep it in range.  11995000 is very far from a valid starting point of 11055500. 

Please verify that you did load the correct file.  If so then go ahead and change the BFO to a value close to 11055500 (you can try the 11054600, though that does seem low to me).

I like to use the video from Ashhar Farhan to calibrate and align the BFO.  It can be used on the v5 board, even though he states it is only for the v6,  The thing that is different is how you change the values.  The process is still the same.  With the KD8CEC software, you need to press the encoder to bring up the "yellow box" and then put it into setup mode.

Three major process steps:
1 adjust the BFO so that you can hear low tones to zero beat the reference frequency.
2 calibrate the master clock using a know AM signal
3 reset the BFO for optimum voice response and opposite sideband suppression.

http://www.na0tc.org/lib/exe/fetch.php?media=technical:rx_protect.pdf

Tuning aide:
https://www.hfsignals.com/index.php/bfo-tuning-aid/

If you are OK with the calibration, then just do the last step to center the BFO on the SSB filter.

73
Evan
AC9TU


Re: My son's V6 and other received birdies

Bob Lunsford
 

Just got a message from my son in Sacramento, CA re the birdies he received all over the place, even in his IC-730. This is to alert the group that when we get QRM in our radios, it may not be what we think it is at first so we need to keep an open mind when trying to chase down the source of such QRN.

Here is what he said:

My noise was coming from battery charger in garage. I’ll try to put beads on it to see if I can still use it. I’ll get out uBITX this weekend and check receive.

Bob — KK5R


Re: uBitx v5 issue

Bob Lunsford
 

Would be nice to install a couple of solder terminals so the two diodes could be easily replaced. I bought 100 switching diodes from Radio Shack when they were business and have only used less than five of the batch. Switching the radio to ground by way of a switch that causes the radio input to go to ground when not being used is another form of cheap insurance.

Replacing the diodes would be much better than replacing Q90 in my book. Less trouble and faster.

Bob — KK5R

On Tuesday, November 24, 2020, 12:44:31 PM EST, Bill Cromwell <wrcromwell@...> wrote:


Hi Ted,

I am preparing to replace Q90 in my V3 and I will be installing the
diodes. I have used them in other solid state rigs in the past and a
couple of time I have had to replace them (two different radios). The
usual failure mode is for them to fail-short. It becomes obvious then
that they have failed because incoming signals pretty much vanish. In
both cases the rest of the radio was preserved. The sacrificial diodes
did their job.

I have never had any problems with radios that have those diodes
installed. Most of the caveats that have been posted here are
*speculation* about what might happen. It hasn't happened. None of the
posts have asserted that any problem has actually happened. I have two
experiences where the front ends were saved and no experiences where the
diodes caused any problems. And that is experience, not speculation.

73,

Bill  KU8H

bark less - wag more

On 11/24/20 11:40 AM, Ted via groups.io wrote:
> Would the common 1n914 serve the same purpose?   Being as common as it
> is, etc.
>
>
> Ted
> k3rta
>






Re: Firmware loading ignorance

Bill Robbins
 

Also should simply load factory defaults and start over?

On 11/24/2020 2:18 PM, Evan Hand wrote:
Bill,
I should also point out that the zip archive has a text file that describes the display hardware that each of the .hex files uses.
FileNameInfo.txt

73
Evan
AC9TU


Re: Firmware loading ignorance

Bill Robbins
 

Evan:

While I have you here answer this for me. My v5 has audio but deaf for signals.  In looking at memory manager settings I see my default for USB Calibration at 11995000.  Others are at 11054600.  Is that why mine bitx is deaf?

Bill

On 11/24/2020 2:18 PM, Evan Hand wrote:
Bill,
I should also point out that the zip archive has a text file that describes the display hardware that each of the .hex files uses.
FileNameInfo.txt

73
Evan
AC9TU


Re: Firmware loading ignorance

Bill Cromwell
 

Hi Bill,

You already have the help you wanted getting new software installed. For what it's worth, updating the software does not change any of your alignment of BFO settings. You only need to do a realignment if you change the microcontroller IC on your Raduino board. Or maybe change the clock crystal.

73,

Bill KU8H

bark less - wag more

On 11/24/20 1:18 PM, Bill Robbins wrote:
I now have my ubitx20 v5 assembled.  I was working fine and I had begun the alignment process.  Then it occurred to me to load the KD8CEC firmware rather than going thru alignment twice.
I have loaded sketches previously but it has been sometime.  I followed the KD8CEC instructions (I thought).  But I get no satisfaction.
So I tried to revert to the stock firmware with no success also. I clearly am missing something.
One source of confusion is after I unzip the packages I am left with many files.  When opening Xloader I select one of the files believing that the others will follow.  Nope.
HELP!!
Bill
.


Re: Firmware loading ignorance

Jonas Sanamon
 

Hi Bill,


Unzip, and read the text file that describes which hex file you should use.

Regards
Jonas


Den tis 24 nov. 2020 kl 20:14 skrev Bill Robbins <wa8cdu@...>:

Thanks Jonas.  Can you point me to that?



Re: V6 BFO alignment problems after installing AGC

Jack Hunt
 

Thank you Tim,
I seem to have the coarse BFO alignment ok now. I'm just trying to get the frequency calibration correct now.

73s


Re: Firmware loading ignorance

Evan Hand
 

Bill,
I should also point out that the zip archive has a text file that describes the display hardware that each of the .hex files uses.
FileNameInfo.txt

73
Evan
AC9TU


Re: Firmware loading ignorance

Bill Robbins
 

Thanks Jonas.  Can you point me to that?

On 11/24/2020 1:36 PM, Jonas Sanamon wrote:
Hi Bill,

You should only upload the precompiled .hex file with xloader. Perhaps You downloaded the source code instead?

Regards, Jonas


Den tis 24 nov. 2020 kl 19:18 skrev Bill Robbins <wa8cdu@...>:
I now have my ubitx20 v5 assembled.  I was working fine and I had begun
the alignment process.  Then it occurred to me to load the KD8CEC
firmware rather than going thru alignment twice.

I have loaded sketches previously but it has been sometime.  I followed
the KD8CEC instructions (I thought).  But I get no satisfaction.

So I tried to revert to the stock firmware with no success also. I
clearly am missing something.

One source of confusion is after I unzip the packages I am left with
many files.  When opening Xloader I select one of the files believing
that the others will follow.  Nope.

HELP!!

Bill


Re: Firmware loading ignorance

Evan Hand
 

Bill,
I am most familiar with the KD8CEC firmware and would recommend loading that software using Xloader.  You will need to use the correct version that is in the uBITXV5 folder after you unzip the archive.  The correct file depends on the hardware you have.  I assume that you are using the supplied stock 1602 display.  That file would be UBITXV5_CEC_V1.200_16P.hex.  This also assumes that you have not added the second Nano to do the S meter and other signal processing.

For reference, the archive is here:
https://github.com/phdlee/ubitx/releases/tag/v1.20

you download the zip file and extract the files to a known location.

How to load the file into your uBITX Nano depends on your OS.  For Windows, you first need to work out which com port the uBITX is connected to on your computer.  Then select it after opening Xloader and set the baud to 34800.

Let us know if you need more information and provide us with any error messages that pop up.

73
Evan
AC9TU


Re: uBitx v5 issue

Evan Hand
 

Jerry,

Again, Thank You.  What you state makes sense.  When I figure out how to measure IMD with the tools that I have I will try it on my other v4 uBITX board.

73
Evan
AC9TU


Re: uBitx v5 issue

Jerry Gaffke
 

Evan,

Good to know that your back-to-back diodes present no issues with reception.
Seems a fine solution.  If incoming RF is kept below 4 volts peak-to-peak,
there should be no trouble with Q90 blowing due to Veb-max of 6v being violated.

I would not call the 1n914 obsolete, they still sell them on Mouser.
1n914's are an older part, were not spec'd as tight as the newer 1n4148, but otherwise identical.
I suspect that any parts sold as 1n914's in the last few decades come off the same line
as the 1n4148's, just slapped with different labeling.

>  There was concern about the reverse diode on the base of Q90 having a negative impact on the SSB transmission. 

I'd be surprised if this was an issue, but worth looking at if you have a way to measure IMD.
Transmit RF into Q90 should be down around 100mv rms, so currents through
a silicon diode would be measured in picoamps.
Also, we already have the base-emitter diode in there to cause distortion of large signals, 
adding a 1n4148 going the other way across that junction diode would make it symetrical, 
and may well reduce distortion rather than add to it.

Jerry, KE7ER




On Tue, Nov 24, 2020 at 03:38 AM, Evan Hand wrote:

I have done the back to back diodes on the input to my v4 board and have not noticed any negative effects on the receive capability. 


Re: New PCB available for WA2EBY linear amp #linear-amp

AndyH
 

Hi Ken,

  I like your filter board!  I've had the "it would be cool if the µBITX could change bands on the amp" thought in my head for a while but haven't gotten farther than that.  Nice work!

Leonard - you did more than that.  You've also answered frantic questions from RF noobs that helped them know for sure that their new creation was working correctly.  Thanks again, Sir!

  FWIW, this is the heat sink I'm using.  It was the closest size match I could find to the part WA2EBY specified in his article.  It's 61 x 116.8 x 38.1 mm (L x W x H).  
   https://www.mouser.com/ProductDetail/TDK-Lambda/HAF15T?qs=%2Fha2pyFadujYuVZC2e13mzcrXnoEzMiZDtNhiwH3OfQ%3D

   Andy


On Mon, Nov 23, 2020 at 01:33 PM, Ken K0KV wrote:
Andy, 
Regarding the multi-band LPF board - I needed one that was PC-controllable because I mainly operate remotely (shack is upstairs, PC is in family room).   So I designed my own board, which uses relays to switch the LPF's in and out for each band.  It can be controlled from a simple contact closure (e.g. an Alexa-controlled relay) or via digital outputs from an Arduino. 
 


Also - you're right, I should have mentioned the toroid kit - it's super convenient.  I decided not to buy it because I already had some of the cores on hand.

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