Date   
Re: Transmitter Mods

Howard Fidel
 

Stamped self addressed envelope sent to my QTH.


On 6/15/2018 10:52 AM, Art Olson via Groups.Io wrote:
Howard

Would like to request the parts for the mod. What do you need from me

Art - N2AJO 


On Jun 15, 2018, at 10:27 AM, Rob Snow <rsnow@...> wrote:

Sajid,

Just to lower your anxiety I'm going to post a pic of my mods so you can see how badly it can be done and still work.  May the soldering gods have mercy on my soul for posting this with my globs of dull solder!

This was done with a flat tipped soldering iron + wick, some vodka for my shakes (I'm old) and +3.0 eye glasses.  Note that the cap on top of R87 looks like it's not connected with solder, but if you zoom in you'll see it is.  I decided not to go back in with wick to clean it up as nobody will ever see it (until now). 

If I can do it, you can.   Start with R87 and R88, they are much easier as all you need to do is hold the cap down on top (I used the pointy end of my tweezers to stab it down) and dab some solder on one of the ends to get it to hold.

73 Rob AG5OV (prepared for the wrath of the soldering gods)

<2018_06_13 19.15.00.jpg>


Re: Went Dead

Bill Watkins
 

Is there a troubleshooting guide with suggested voltages and resistance?  

Probing what I believe to be collector and emitter on the two IRF510, looking from the rear, the left shows no flow from collector to emitter,  but the right shows 37.4 from collector to emitter.

Forgive me if using wrong terms.  New learning experience.



On Jun 14, 2018, at 11:28 PM, Ashhar Farhan <farhanbox@...> wrote:

Something has shorted. take out the PA power line and check?

- f

On Fri, Jun 15, 2018 at 11:54 AM, Bill Watkins <kf7yxs@...> wrote:
Was in middle of wspr transmission. Radio went dark. Power source checks out good. When cycle off and on, display just slightly flashes. Display and raduino work fine with usb to computer.

What happened?  Where do I start?

Bill





Re: SI5351 quadrature VFO

Ashhar Farhan
 

Are you sure these work upto 290 mhz? 

Re: The BITeensio board is here. #ubitx

BruceN
 

Is the BITeensio board compatible with CEC software?  Looked on your page but didn't find and answer.  Maybe didn't look close enough.

Bruce, K4TQL

Re: uBitx has a bit too crispy / semi-distorted audio even on low signal levels #ubitx #ubitx-help

ajparent1/KB1GMX <kb1gmx@...>
 

There is distortion, sounds like clipping in the receiver due to overload
by a strong signal.

Also check to see if the Q70 mod is needed, it is listed in a different thread.

The last items is maybe the speaker itself is bad and distorting.

Allison

Re: The BITeensio board is here. #ubitx

Jim Sheldon
 

No it is not.  CEC only runs on a NANO and his I2C display is on I2C Wire 0 where our card (and software) runs on a Teensy 3.6 and uses Wire 2 for all I2C I/O. We have abandoned the NANO as too limited.

Jim

On Jun 15, 2018, at 10:41 AM, BruceN <k4tql@...> wrote:

Is the BITeensio board compatible with CEC software?  Looked on your page but didn't find and answer.  Maybe didn't look close enough.

Bruce, K4TQL

Re: The BITeensio board is here. #ubitx

Jim Sheldon
 

Hi Bruce,
Tried to answer this from my  iPAD but I don't think it sent.

NO, Ian's CEC software is NOT compatible with our BITeensio board - he handles his I2C in a totally different way than we do and his stuff will not work on our board.  Besides, we have abandoned the NANO as an MPU and are now using Teensy 3.6 MPU's so none of his stuff will run on our boards.  Our own software will, however work just fine.

Jim

------ Original Message ------
From: "BruceN" <k4tql@...>
Sent: 6/15/2018 10:41:01 AM
Subject: Re: [BITX20] The BITeensio board is here. #ubitx

Is the BITeensio board compatible with CEC software?  Looked on your page but didn't find and answer.  Maybe didn't look close enough.

Bruce, K4TQL

Re: The BITeensio board is here. #ubitx

BruceN
 

Thanks Jim for the fast reply.  Now, another question: what are the feature differences between your software and Ian's CEC software?  I'm sure I could find it somewhere but an answer from you would be a lot quicker.  I do like the idea of the Teensy for the expanded computing power.  Makes for expanding the system features more likely.

Bruce

Re: Went Dead

ajparent1/KB1GMX <kb1gmx@...>
 

They are mosfets and do not have have collector or emitter.

It looks like your probing Drain to Source and one way should be nesr open and the other
you should see the substrate diode.

IF the fets are shorted then will show near zero ohms Source to Drain. 

When you turn it on how many amps does it require?
What is the Voltage at the power supply after you turn it on?
If you disconnect the BROWN wire (power to the output transistors) does it power up?

Allison

Re: How hot is too hot? #ubitx

ajparent1/KB1GMX <kb1gmx@...>
 

Recommends or maximum of 500ma?  That seems like a very high
number and I'd expect it to be seriously bright.

The reason I ask as my 7" touch screen all total draws less than that with a
HDMI interface(video)  and USB( touch screen). 

As to 7805 heat... Keep it under 70C (168F) as the device has a thermal shutdown
and it lives longer.  

Allison

Re: How hot is too hot? #ubitx

Kees T
 

I would sure (and have) reduced the intensity of the backlight with a pot for any of those type displays. Then add a buck converter to reduce the 13.4V to about 7V for the poor ol' 5V regulator. 

73 Kees K5BCQ

Re: Went Dead

Bill Watkins
 

Did the quickest check first. When brown wire disconnected, it powers up. 

Btw, I appreciate your help very much. 

Bill
K0WHW




On Jun 15, 2018, at 12:06, ajparent1/KB1GMX <kb1gmx@...> wrote:

They are mosfets and do not have have collector or emitter.

It looks like your probing Drain to Source and one way should be nesr open and the other
you should see the substrate diode.

IF the fets are shorted then will show near zero ohms Source to Drain. 

When you turn it on how many amps does it require?
What is the Voltage at the power supply after you turn it on?
If you disconnect the BROWN wire (power to the output transistors) does it power up?

Allison

Re: How hot is too hot? #ubitx

Lawrence Galea
 

Simply add a 7808 or 7809 before the 7805
Regards
Lawrence

On Fri, Jun 15, 2018 at 7:17 PM, ajparent1/KB1GMX <kb1gmx@...> wrote:
Recommends or maximum of 500ma?  That seems like a very high
number and I'd expect it to be seriously bright.

The reason I ask as my 7" touch screen all total draws less than that with a
HDMI interface(video)  and USB( touch screen). 

As to 7805 heat... Keep it under 70C (168F) as the device has a thermal shutdown
and it lives longer.  

Allison


Re: How hot is too hot? #ubitx

Jack, W8TEE
 

Allison:

Which 7" touchscreen are you using that has that low current draw? Is that when the screen is "populated" or blank?

Jack, W8TEE

On Friday, June 15, 2018, 1:17:37 PM EDT, ajparent1/KB1GMX <kb1gmx@...> wrote:


Recommends or maximum of 500ma?  That seems like a very high
number and I'd expect it to be seriously bright.

The reason I ask as my 7" touch screen all total draws less than that with a
HDMI interface(video)  and USB( touch screen). 

As to 7805 heat... Keep it under 70C (168F) as the device has a thermal shutdown
and it lives longer.  

Allison

Re: SI5351 quadrature VFO

Jerry Gaffke
 

As I recall, Hans reported that the samples he tested did work up to 290mhz,
above which they definitely failed.

If you want to be sure, then should follow the datasheet spec.    
    https://www.silabs.com/documents/public/data-sheets/Si5351-B.pdf

Or go to a different part
    https://www.silabs.com/documents/public/data-sheets/Si5338.pdf

Datasheet says the si5351 has a vco max of 900 mhz and output msynth min of 4,
so that suggests it could do 900/4 = 225mhz. 
Datasheet also says a max output clock of 200 mhz, I'd guess beyond that
they can't guarantee proper CMOS logic levels from the driver.

To hit 290 mhz, the vco must be operating at 290*4 = 1160 mhz.
Jitter might be getting bad, as the vco loop filter is not designed for this.
Heat could also cause trouble. 

Jerry, KE7ER 


On Fri, Jun 15, 2018 at 08:31 am, Ashhar Farhan wrote:
Are you sure these work upto 290 mhz? 

Re: SI5351 quadrature VFO

Hans Summers
 

Hi Farhan

> Are you sure these work upto 290 mhz? 

According to the datasheet specification the top frequency is 200MHz. 

However if you ignore this and just configure it for higher and higher frequencies, in my test it really did seem to work fine up until 290MHz. After that the output just gives up. Other QRP Labs kit owners also verified similar maximum frequency around 300MHz.

Of course I have no idea what performance specification may be violated, or no longer guaranteed under all specified conditions, at 290MHz. The wisdom of using the chip up so far outside its specification is debatable, particularly in anything other than a one-off homebrew project. 

73 Hans G0UPL 

BITX40 and uBITX Kits missing encoders for VFO! #ubitx #bitx40

mtrager1@...
 

I unpacked both kits and cannot find the tuning encoders or the elecret mic elements!
Has this happened to anyone else?

73's Michael
n2zdb

TX Debug Steps?

W8SWG
 

I have been running my uBitX very successfully using WSJT-X for about a week and now all of a sudden I cannot make any contacts at all.  I am still receiving perfectly I do not seem to be getting out even with close contacts.  The indicator says that it is transmitting and the heat sinks warm up but still no contact.

I am a noob and have almost nothing in test equipment except for a VOM.  Anyone have any suggestions?

Re: Can't get my uBitX to transmit CW on the Dial frequency

Jerry Gaffke
 

Tim,

I'm not convinced. you can't just move the BFO to receive CW.

Assume you are receiving an upper sideband phone signal at your 7030 mhz.
The crystal filter is only allowing through that upper sideband energy between
roughly 7030.500 khz and 7032.500 khz, any residual carrier from the transmitter
is further suppressed by our 12mhz crystal filter.

Now, assume that remote transmitter switches to a CW transmission at 7030 khz.
We are now only interested in the carrier at 7030 khz, but the crystal filter is not
allowing that carrier through.  Does not matter where we place the bfo, there is
simply no signal to hear.  (Assuming our filter is perfect).

The solution is to special case the reception of a CW signal.
When receiving in upper sideband mode, we should have the receiver tuned
for a frequency 700 hz lower than that displayed in the LCD.
And when receiving in upper sideband mode, we should have the receiver tuned
for a frequency 700 hz higher than that displayed in the LCD.
The BFO can stay where it was for SSB phone reception.

Jerry, KE7ER


On Fri, Jun 15, 2018 at 07:54 am, Tim Gorman wrote:
Jerry,

On Thu, 14 Jun 2018 20:57:48 -0700
"Jerry Gaffke via Groups.Io" <jgaffke@...> wrote:
I'm not sure what you mean about shifting the BFO.
The BFO has nothing to do with transmit.
On receive, it can remain exactly where it was for SSB operation.
The original message says: "The uBITX is on CWU has a 700 Hz sidetone
set (ie offset) then the dial on the uBITX needs to be at 7.029.300
Mhz  so that it is receiving a the Flex with a 700hz audio tone."

If you are working CW at 7030 then why should you have to set the
receive frequency to 7.029.300? That just means you need to know
whether you are in CWL or CWU and do math in your head to know what
frequency you are actually listening to!

Why not just shift the BFO so the receive frequency can remain showing
7030 and you still get your 700hz tone?



And no idea what all the other software releases out there are doing.
Mine is rigged as follows

On transmit the dial shows the frequency of the CW carrier (of
course).

On receive (if RIT is not enabled) it still shows the same operating
frequency in the LCD. However, the VFO is tuned up in frequency by
however many hertz the cw sidetone is set up to be if operating in
LowerSideBand mode, and down in frequency by that many hertz if
UpperSideBand mode.
This is *exactly* what I am saying. You are doing it with the VFO. You
can do it with the BFO as well! It's why my homemade receivers always
had two BFO frequencies. It was easier to shift the BFO oscillator with
a switched-in capacitor than to try and shift the VFO frequency in an
analog vfo!

Apparently the software Michael is using utilizes neither of these
methods.

tim ab0wr

Re: Can't get my uBitX to transmit CW on the Dial frequency

Jerry Gaffke
 

And when receiving in lower sideband mode, we should have the receiver tuned
for a frequency 700 hz higher than that displayed in the LCD.


On Fri, Jun 15, 2018 at 11:54 am, Jerry Gaffke wrote:
And when receiving in upper sideband mode, we should have the receiver tuned
for a frequency 700 hz higher than that displayed in the LCD.