Topics

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

Daniel Isaza
 

Hi All,
I've been puzzled by this for a while now...
Why my uBitX doesn't transmit CW on the frequency on the dial?
I'm using Ian's CEC Firmware V1.08.
On TX the dial frequency is offset by the amount set in the "CW Tone" menu setting, so I'm really transmitting on the Dial freq. + or - the CW sidetone setting, depending on the mode (CWL or CWU) I understand that is the audio frequency of the sidetone and the audio frequency of a CW signal perfectly at Zero beat, so we need to RECEIVE a few Hz up or down to be able to hear anything on CW but I don't get why it's not transmitting on the dial frequency?
Shouldn't all these settings affect just the sidetone and the CW receiving freq? Why is it offsetting the TX freq by that amount of the sidetone? is it a bug?
What am I missing here?

Thanks
Dan.

Tom, wb6b
 

Yes, this is extremely confusing. The transmit frequency is offset by the amount of the sidetone setting. The software gives you no indication of this offset.  The simplest solution would be for the display to change to the transmit frequency when CW is key down, and the "CW" mode is displayed. At least you would know what is happening. 

In the CEC firmware, using the manager program, you can check the "Enable Adjust CW Frequency" checkbox and the transmit frequency will be displayed instead of the receive frequency.

Here is a similar thread: https://groups.io/g/BITX20/message/50224

Tom, wb6b

Daniel Isaza
 

Thanks for your reply Tom!

Been fiddling a bit more with the issue and my solution(?) was to edit the ubitx20.ino lines 504 and 508 and deleted the "+sidetone" and "-sidetone" and then proceeded to adjust the "CW RX freq" on the menu until perfect 800hz on zero beat.
That seems to fix the issue but I'm hoping to hear from Ian or someone with more experience since honestly I just understand like half of the .ino code there Hehe. dunno if I'm messing something else.

73, Dan
Hk4DEI

Daniel Isaza
 

Well, there's definitely and issue there...
Now I could get my uBitX to Transmit on the exact Dial freq changing those lines in the code.
but...
The CW RX BFO isn't getting recalled or applied or something, I mean I can get it to zero beat when adjusting it in the menu but somewhat it just revert back to where it was before when I press the PTT to save it no matter what I do. the "number" setting remains 11.997.xxx... or whatever but it just doesn't do anything to the actual CW RX freq on CW modes just when I press the PTT to save the freq shifts to where it was before, no change there on RX...

Tom, wb6b
 

The CEC code has a lot of very good options. The options do make it a bit more of a challenge to work through.  There may be more "adjustments" made elsewhere in the code. There are a number of if statements that change the frequency logic depending on a CW mode. However, I'm just beginning to work through the code myself, so have not worked through the details. 

The CEC firmware has specific CW modes, so it has more possible solutions to the transmit/receiver issue offset. The factory firmware (unless it has been updated since I tried it) does not have a specific CW mode, so that is why it seemed the simplest solution was just to display the transmit frequency when the uBITX was I the "CW" mode by virtue of "CW" being displayed while it detects the key is being used. 

Tom, wb6b

Dave de WS1ETI <docame12@...>
 

Ok, so this issue is of great interest to me. So far, CW is the only mode I've been working...and unsuccessfully at that. My uBITX is still using the factory installed firmware - I haven't changed over to the CEC ware yet. It seems no matter how I holler at received stations, they just do not hear me. My dial frequency shows the same freq as when in normal USB mode - it does not change. Would this be made simpler if I just went and loaded the CEC software?

Thanks,
Dave

Daniel Isaza
 

Yeah Tom,
I'm using CEC firmware because it solved my problem with the paddle on the original firmware, now it just works perfectly (well, the paddle...). Not to mention all the new features.

Dave, sure, that's a real problem, I haven't really used CW because of this issue, hopefully the solution is just a bit of code but that is beyond my knowledge, let's wait what will happen in future versions. The CEC firmware is amazing, Thanks Ian ! but bear in mind that it's a bit more complex than the original, I was wondering if this issue was on the original one also.

Now that I can transmit on the dial frequency I'm just going to measure the deviation in CW receive and use the RIT to zero beat and make QSO's

73, Dan.

On Sunday, June 3, 2018, 9:36:59 AM GMT-5, Dave de WS1ETI <docame12@...> wrote:


Ok, so this issue is of great interest to me. So far, CW is the only mode I've been working...and unsuccessfully at that. My uBITX is still using the factory installed firmware - I haven't changed over to the CEC ware yet. It seems no matter how I holler at received stations, they just do not hear me. My dial frequency shows the same freq as when in normal USB mode - it does not change. Would this be made simpler if I just went and loaded the CEC software?

Thanks,
Dave

Tom, wb6b
 

Hi Dave,

The CEC firmware does not totally "fix" the issue, but if you use the uBITX Manager software software it can change the CW frequency display to the transmit frequency. Just kind of moves the problem around.

If you tune the CW station so the received tone matches the sidetone when you transmit, you should be very close to the same frequency as the other station. Once you know about the transmit offset issue you can mentally subtract the sidetone setting from the displayed frequency to know where you are transmitting. The problem is, that there is no indication by looking at the display that such a thing as the transmit frequency being shifted is going on. And it is somewhat unexpected, and best I can tell undocumented.

To see how your version of the firmware is behaving you may want to go here http://www.websdr.org and see if you can find a receiver that is hearing you. Then check the frequency the waterfall shows you at. Most of these receivers' frequency calibration are fairly accurate, but try to double check to be sure.

Tom, wb6b
 


Tom, wb6b
 

Hi Daniel,

Using RIT with the CEC firmware sounds like an interesting solution. (With the transmit frequency shown on the dial)

Tom, wb6b

Dan Withers
 




On Sun, Jun 3, 2018 at 4:37 PM -0700, "Daniel Isaza via Groups.Io" <deisaza@...> wrote:

Yeah Tom,
I'm using CEC firmware because it solved my problem with the paddle on the original firmware, now it just works perfectly (well, the paddle...). Not to mention all the new features.

Dave, sure, that's a real problem, I haven't really used CW because of this issue, hopefully the solution is just a bit of code but that is beyond my knowledge, let's wait what will happen in future versions. The CEC firmware is amazing, Thanks Ian ! but bear in mind that it's a bit more complex than the original, I was wondering if this issue was on the original one also.

Now that I can transmit on the dial frequency I'm just going to measure the deviation in CW receive and use the RIT to zero beat and make QSO's

73, Dan.

On Sunday, June 3, 2018, 9:36:59 AM GMT-5, Dave de WS1ETI <docame12@...> wrote:


Ok, so this issue is of great interest to me. So far, CW is the only mode I've been working...and unsuccessfully at that. My uBITX is still using the factory installed firmware - I haven't changed over to the CEC ware yet. It seems no matter how I holler at received stations, they just do not hear me. My dial frequency shows the same freq as when in normal USB mode - it does not change. Would this be made simpler if I just went and loaded the CEC software?

Thanks,
Dave

 

I have confirmed the same thing in the CEC firmware V1.08.  The uBITX display frequency is the RX frequency not the TX frequency.

I will now explain why this is a problem.

This is not theoretical .. I tried this with my Flex-1500 with both rigs side-by-side, TXing into dummy loads. 

My Flex is transmitting on 7.030 Mhz CWU exactly (dial frequency BTW) using a 700 Hz RX offset. 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. Both stations can hear each other with a 700 Hz tone. This confirms that the uBITX dial frequency is the receive frequency not its transmit frequency.  I can also see and hear that the uBITX is transmitting on
7.030 Mhz with this dial setting.

Now I switch the Flex to CWL without changing frequency. I leave the uBitx on the same frequency (7.029.300 Mhz) and still on CWU. Both stations can still hear each other with a 700 Hz tone. Changing modes on the Flex left the TX (dial) frequency the same and only moved the RX frequency of the Flex to the other sideband (ie. the Flex RX frequency switches from 7.029.300 Mhz to 7.030.700 Mhz). 

I put back Flex back on CWU without changing frequency (ie. dial still shows 7.030 Mhz). Now switch I the uBITX from CWU to CWL. The dial frequency on 
the uBITX still shows 7.029.300 Mhz on the dial but it is now transmitting at 7.028.600 Mhz and is inaudible to the Flex which is still listening at 7.029.300 Mhz !

With any rig in CW mode, when you have a station tuned in and are listening you should be able to switch from CWL to CWU at at any time and without 
retuning and you should be able to hear the other station and he should still be able to hear you. The whole idea of switching sidebands in CW mode is to
be to use it as a means of avoiding adjacent noise. Sometimes switching from CWU to CWL will allow you to avoid QRM. 

That is only possible if the uBITX TX frequency remains fixed on CW sideband changes (CWU/CWL) and the RX frequency changes according to the sideband selected and the configured offset.  

So that means that the display frequency since it is fixed, must be the TX frequency. The RX frequency should change on switching from CWU to CWL based on a minus or plus offset from the TX frequency. 

Cheers

Michael VE3WMB 

Tim Gorman
 

Michael,

It would actually make the most sense to me if *both* the TX and RX
frequency stayed the same, only the BFO would be shifted. If you are
working CW on 7030 the both the TX and RX should show 7030! If you
change from CWL to CWU only the BFO should move. Otherwise you wind up
continually having to do math in your head to determine what frequency
you are actually listening to!It's far easier and quicker to make the
rig do that!

tim ab0wr

On Thu, 14 Jun 2018 18:19:42 -0700
"Michael Babineau" <@ve3wmb> wrote:

I have confirmed the same thing in the CEC firmware V1.08.  The uBITX
display frequency is the RX frequency not the TX frequency.

I will now explain why this is a problem.

This is not theoretical .. I tried this with my Flex-1500 with both
rigs side-by-side, TXing into dummy loads. 

My Flex is transmitting on 7.030 Mhz CWU exactly (dial frequency BTW)
using a 700 Hz RX offset. 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. Both
stations can hear each other with a 700 Hz tone. This confirms that
the uBITX dial frequency is the receive frequency not its transmit
frequency.  I can also see and hear that the uBITX is transmitting on
7.030 Mhz with this dial setting.

Now I switch the Flex to CWL without changing frequency. I leave the
uBitx on the same frequency (7.029.300 Mhz) and still on CWU. Both
stations can still hear each other with a 700 Hz tone. Changing modes
on the Flex left the TX (dial) frequency the same and only moved the
RX frequency of the Flex to the other sideband (ie. the Flex RX
frequency switches from 7.029.300 Mhz to 7.030.700 Mhz). 

I put back Flex back on CWU without changing frequency (ie. dial
still shows 7.030 Mhz). Now switch I the uBITX from CWU to CWL. The
dial frequency on the uBITX still shows 7.029.300 Mhz on the dial but
it is now transmitting at 7.028.600 Mhz and is inaudible to the Flex
which is still listening at 7.029.300 Mhz !

With any rig in CW mode, when you have a station tuned in and are
listening you should be able to switch from CWL to CWU at at any time
and without retuning and you should be able to hear the other station
and he should still be able to hear you. The whole idea of switching
sidebands in CW mode is to be to use it as a means of avoiding
adjacent noise. Sometimes switching from CWU to CWL will allow you to
avoid QRM. 

That is only possible if the uBITX TX frequency remains fixed on CW
sideband changes (CWU/CWL) and the RX frequency changes according to
the sideband selected and the configured offset.  

So that means that the display frequency since it is fixed, must be
the TX frequency. The RX frequency should change on switching from
CWU to CWL based on a minus or plus offset from the TX frequency. 

Cheers

Michael VE3WMB


Jerry Gaffke
 

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.

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.

Since I worked for years with not terribly selective receivers (no crystal filter) I prefer to tune in a CW carrier
by going for a zero beat in the audio.  In this mode, the BFO is moved to the center of the 12mhz
crystal filter passband, halfway between USB and LSB mode.  I call it ZSB. 
Then once tuned in, flip back to LSB or USB mode to operate CW.
This ZSB mode is also handy when calibrating the the 25mhz si5351 reference oscillator as per post 35235.

Jerry, KE7ER


On Thu, Jun 14, 2018 at 07:57 pm, Tim Gorman wrote:
It would actually make the most sense to me if *both* the TX and RX
frequency stayed the same, only the BFO would be shifted. If you are
working CW on 7030 the both the TX and RX should show 7030! If you
change from CWL to CWU only the BFO should move. Otherwise you wind up
continually having to do math in your head to determine what frequency
you are actually listening to!It's far easier and quicker to make the
rig do that!

Tom, wb6b
 

On the CEC firmware, and the original factory firmware when you use the PTT for SSB the transmit frequency is what is shown on the display. When you key the transmitter with the CW key the firmware changes the transmit frequency to be lower than what is on the display by the same amount as the "sidetone" frequency setting. 

For someone hearing a CW station that they would like to respond to, then, if they tuned the other station at the same tone as the sidetone they hear when transmitting, everything is great. If you were wanting to initiate an exchange at a specific frequency (like inside the lower edge of amateur band) the unexpected offset kind of sucks. 

If the display at least switched to showing the actual transmit frequency, when transmitting CW, at least people would not be kept in the dark about what the radio is doing. Basic user interface feedback. Pretty much people assume the displayed frequency is the frequency they are transmitting on, and this shift from the display is unexpected behavior.

Tom, wb6b

Jerry Gaffke
 

My code is different than most others in that there is an explicit CW mode that you select within the menu.

Without an explicit CW mode (just hit the key to send CW, hit the PTT to send SSB), the receiver must always
display the the frequency of what is normally the suppressed carrier of the SSB signal since this is 
primarily an SSB transceiver.   To hear a CW signal (which is just a carrier, in this case not suppressed),
you must tune a few hundred hz to one side somehow.  That's the source of the confusion.

The solution is an explicit CW mode as per post 44349
This also allows the PTT switch to be used as a straight key, freeing up A6 in the stock code.

Jerry
 


On Thu, Jun 14, 2018 at 08:57 pm, Jerry Gaffke wrote:
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.

 

As Tom, WB6B suggests, an important reason for displaying the TX frequency in CW modes is that you need to know that when you
hit that key that you are transmitting in-band. It is more important to know your TX frequency than your RX frequency and this is also 
the convention used on most commercial HF rigs. 

I only had the original uBITX code installed for a day but I do seem to recall that there was no explicit CW mode.  
The CEC code does have explicit CWU and CWL and as I stated, once you have a station properly tuned you should be able to toggle
back and forth between the two CW modes and still have the received station in the filter passband. There may be a slight shift in received tone
(nothing is perfect) but it should be very close.  

I also believe that what Tim AB0WR suggests regarding changing the BFO frequency is correct.
If you haven't moved the VFO the frequency it's frequency shouldn't change except to apply a +/- offset equal to the sidetone frequency on RX (the TX carrier frequency stays the same and should be the dial frequency as stated above). Switching back and forth  from CWU to CWL should change the BFO frequency (which only affects RX) to allow the switching of the selected sideband. The change in BFO frequency plus the application of the RX offset with the correct sign to the VFO determines the change in RX frequency on the CW mode change. 

If you must display the actual RX frequency as the dial frequency then it has to change when you change from CWU to CWL. Changing the TX frequency
as it currently does is incorrect.  Also I would suggest that if the dial frequency remains the RX frequency, then the display should change on TX  to show the
TX frequency (i.e. carrier frequency) and then back again on RX. 

As Allard, PE1NWL stated in an earlier posting on this same topic ... we went through pretty much the same discussion on the operation of the BITX40
and came to the conclusion that the display frequency on both CWU and CWL should be the TX (carrier frequency) and that is what Allard implemented in
his Bitx40 code. 

Cheers 

Michael VE3WMB 

 

One more thing ...

Just to simplify the discussion, what we have here are two issues :

1)  switching from CWU to CWL on CEC V1.08 incorrectly changes the TX frequency (it should remain fixed) wheres it should be the RX frequency
that moves due to the change in sign of the applied RX offset and the change to the BFO frequency to match the selected sideband. 

This is a bug. 

2) The issue of what frequency should be displayed. (Currently it is the RX frequency).

   Options are :
   
   1) Display Tx frequency - will not change on display when moving between CWU/CWL. Will not change on TX vs RX. (Recommended) 

    2) Display Rx Frequency - must change when switching CW sidebands to be accurate.
        Recommend it change to TX frequency and back when switching between TX and RX so operator knows what actual carrier TX frequency is. 

Cheers

Michael VE3WMB 


 

Tim Gorman
 

Jerry,

On Thu, 14 Jun 2018 20:57:48 -0700
"Jerry Gaffke via Groups.Io" <jgaffke=yahoo.com@groups.io> 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

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

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.