Can't get FT8 working correctly. #3
Comments
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Here are a few hints:
1. Make sure the output of your soundcard is turned up to maximum volume.
You may also want to fit a jumper onto JP6 (this will involve temporarily
removing the LCD). The radio measures the audio frequency from the sound
card. It can be a square wave, so it's ok to have it distorted. It's not
like a normal transceiver where an overdriven input creates harmonics.
2. The mode is not actually used in Ext mode, it is just set to CW to
force the SSB code to turn off. The code below it takes control of the
frequenc
3. When you are in CW mode, the BFO is set to 667 Hz below the selected
VFO frequency so that the CW creates a beat of 667 Hz (the sidetone
frequency). So for example, if you tune 14074000 Hz, and you are in CW
mode, before the Ext mode is selected, you should hear a faint signal from
the BFO of 14074000 Hz - 667 Hz = 14073333 Hz. Once the Ext mode is
selected, the BFO should be at 14074000 Hz. That's why it is jumping up by
about 700 Hz.
4. When the soundcard sends a tone, for example 1.2 kHz, the radio should
transmit a frequency of 14074000 + 1200 Hz = 14075200 Hz. If this is not
the case then there is something wrong.
Check these things and see if that helps.
73,
Dan
KW4TI
When external control mode is selected, the BFO should increase to
2. The operation in Ext mode doesn't depend on the selected mode.
…On Sat, Oct 21, 2023 at 11:24 AM larryl719 ***@***.***> wrote:
Hi,
First, I'd like to say Thanks! This is a very interesting radio and was
easy to assemble and play with. I have built a full set of band boards and
am starting to put it to use.
Maybe I'm missing something (that would be great!) but when I'm trying to
get it to operate on FT8, I see a couple of things happening:
1.
I need to use EXT mode to control the transceiver and it says it is
the way to do it.
When I enter EXT mode and the words "EXT Mode" appear and then go
away, I can hear the frequency of the receiver shifting. My measurements
seem to indicate a move of about 700Hz. If I keep the radio tuned to
14.074, my audio output ends up 700Hz too high, and in many cases, it's
above the audio passband of the signal so that no one can hear me. Tuning
lower might be the answer but then there appears to be another issue.
(below)
When exiting EXT mode, the frequency returns to the original value. I
only really figured this out by using another radio to monitor my
transmission and see that my signal was above the audio passband used for
FT8.
2.
When transmitting FT8 signals in EXT mode (and possibly shifting the
frequency), I notice that it sounds "choppy" with some additional
"artifacts" on the signal; normal FT8 signals tend to sound very smooth.
When I use "Tune" mode in WSJTX, the signal is very clean and sounds
normal. (My X6100 shows the audio spectrum on the display and there are
"lobes" at lower amplitude under the main signal. Also, the signal sounds
very different on the X6100 than other FT8 signals.)
3.
In the manual there are instructions (In the EXT mode description) to
tune to the upper sideband (14.074) when doing FT8. This is the normal way
of doing FT8, so that's not unusual. But, in looking at the code (and
watching what happens), when EXT mode has been activated the mode is
changed to CW and stays there. While I don't think that is an issue
exactly, I was wondering why change it and whether it might be related to
the above problems in some way.
4.
I'm sorry to say I haven't tested out the other modes like SCAMP or
RTTY mostly because 10m is really open so far this year and I'm having a
great time making QRP contacts on 10m all over the world. That has also
meant that I've spent a lot of time trying to get a bit more power out at
10m (with "normal" builds of the boards I'm getting about 0.5W out). IF
everything else was working well, I'd enjoy the challenge of the QRP
contacts at 0.5W, but so far the issues above are keeping me from making
contacts.
If there is anything I can do or try, please let me know, I'd be happy to
help. I haven't tried reprogramming the radio yet because I wanted to spend
more time with the original design before I mess with it in any way.
Thanks again!
Larry, WB6JSO ***@***.***)
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I've gotten some pictures of the results... With the RFBitBanger in EXT mode, tuned to 14074 and using WSJTX to "TUNE" at 2000 Hz (and later at 1000Hz), the signal received on the X6100 showed a strong signal at about 2700 Hz and at 1700 Hz. BTW, the radio was in CW mode when I put it into EXT mode (I figured using SSB didn't make sense since it would change anyway.). I'm wondering if the 667Hz is being added twice. (or on top of the actual frequency) I hope this helps, |
|
Just to be sure, are you using the latest build from the RFBitBanger code
repository? If not, could you upload the new code and see if that helps?
73,
Dan
KW4TI
…On Sun, Oct 22, 2023 at 12:35 AM larryl719 ***@***.***> wrote:
I've gotten some pictures of the results...
With the RFBitBanger in EXT mode, tuned to 14074 and using WSJTX to "TUNE"
at 2000 Hz (and later at 1000Hz), the signal received on the X6100 showed a
strong signal at about 2700 Hz and at 1700 Hz. BTW, the radio was in CW
mode when I put it into EXT mode (I figured using SSB didn't make sense
since it would change anyway.). I'm wondering if the 667Hz is being added
twice. (or on top of the actual frequency)
[image: IMG_20231021_214236]
<https://user-images.githubusercontent.com/36279690/277146385-8525e59c-be5d-4900-9f62-7af420862c35.jpg>
[image: IMG_20231021_214151]
<https://user-images.githubusercontent.com/36279690/277146435-5ec80a8e-7bc4-4688-96e1-c84c6b7a26fc.jpg>
[image: vlcsnap-2023-10-21-22h24m32s605]
<https://user-images.githubusercontent.com/36279690/277146879-accb60a3-781a-47e0-8304-ad51989efa27.png>
I hope this helps,
Larry
WB6JSO
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BTW, I tested the FT8 again yesterday on the RFBitBanger ext mode and I was
able to make 6 or 7 contacts on 20 meters, so I'm a little baffled as to
what's going on.
73,
Dan
KW4TI
…On Sun, Oct 22, 2023 at 6:53 AM Daniel Marks ***@***.***> wrote:
Just to be sure, are you using the latest build from the RFBitBanger code
repository? If not, could you upload the new code and see if that helps?
73,
Dan
KW4TI
On Sun, Oct 22, 2023 at 12:35 AM larryl719 ***@***.***>
wrote:
> I've gotten some pictures of the results...
>
> With the RFBitBanger in EXT mode, tuned to 14074 and using WSJTX to
> "TUNE" at 2000 Hz (and later at 1000Hz), the signal received on the X6100
> showed a strong signal at about 2700 Hz and at 1700 Hz. BTW, the radio was
> in CW mode when I put it into EXT mode (I figured using SSB didn't make
> sense since it would change anyway.). I'm wondering if the 667Hz is being
> added twice. (or on top of the actual frequency)
> [image: IMG_20231021_214236]
> <https://user-images.githubusercontent.com/36279690/277146385-8525e59c-be5d-4900-9f62-7af420862c35.jpg>
> [image: IMG_20231021_214151]
> <https://user-images.githubusercontent.com/36279690/277146435-5ec80a8e-7bc4-4688-96e1-c84c6b7a26fc.jpg>
> [image: vlcsnap-2023-10-21-22h24m32s605]
> <https://user-images.githubusercontent.com/36279690/277146879-accb60a3-781a-47e0-8304-ad51989efa27.png>
>
> I hope this helps,
> Larry
> WB6JSO
>
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> Reply to this email directly, view it on GitHub
> <#3 (comment)>,
> or unsubscribe
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Also, did you calibrate the frequency using WWV? The instructions are in
the manual. If not, since it's not using a TCXO, the frequency could be
off by as much as several hundred Hz.
73,
Dan
KW4TI
…On Sun, Oct 22, 2023 at 6:54 AM Daniel Marks ***@***.***> wrote:
BTW, I tested the FT8 again yesterday on the RFBitBanger ext mode and I
was able to make 6 or 7 contacts on 20 meters, so I'm a little baffled as
to what's going on.
73,
Dan
KW4TI
On Sun, Oct 22, 2023 at 6:53 AM Daniel Marks ***@***.***> wrote:
> Just to be sure, are you using the latest build from the RFBitBanger code
> repository? If not, could you upload the new code and see if that helps?
>
> 73,
> Dan
> KW4TI
>
> On Sun, Oct 22, 2023 at 12:35 AM larryl719 ***@***.***>
> wrote:
>
>> I've gotten some pictures of the results...
>>
>> With the RFBitBanger in EXT mode, tuned to 14074 and using WSJTX to
>> "TUNE" at 2000 Hz (and later at 1000Hz), the signal received on the X6100
>> showed a strong signal at about 2700 Hz and at 1700 Hz. BTW, the radio was
>> in CW mode when I put it into EXT mode (I figured using SSB didn't make
>> sense since it would change anyway.). I'm wondering if the 667Hz is being
>> added twice. (or on top of the actual frequency)
>> [image: IMG_20231021_214236]
>> <https://user-images.githubusercontent.com/36279690/277146385-8525e59c-be5d-4900-9f62-7af420862c35.jpg>
>> [image: IMG_20231021_214151]
>> <https://user-images.githubusercontent.com/36279690/277146435-5ec80a8e-7bc4-4688-96e1-c84c6b7a26fc.jpg>
>> [image: vlcsnap-2023-10-21-22h24m32s605]
>> <https://user-images.githubusercontent.com/36279690/277146879-accb60a3-781a-47e0-8304-ad51989efa27.png>
>>
>> I hope this helps,
>> Larry
>> WB6JSO
>>
>> —
>> Reply to this email directly, view it on GitHub
>> <#3 (comment)>,
>> or unsubscribe
>> <https://github.com/notifications/unsubscribe-auth/AKFIJZBLHLQZK6B3HYXGB2LYASWC3AVCNFSM6AAAAAA6KH2CVSVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMYTONZUGAYDANZUG4>
>> .
>> You are receiving this because you commented.Message ID:
>> ***@***.***>
>>
>
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Thanks Dan, I am running the code delivered with this first production run. (1.0?) I will take a look at the newer code and try that. I am one of "those people" who often load the latest right away and I've had my share of bricking things, so I decided to hold back this time and test the actual release first. (I have been itching to try reloading it... :-) I did calibrate it once on WWV but wasn't confident that it had all come out right, so I backed it out. My first attempt did give me something like 300Hz and, lacking confidence ( I get a fair amount of noise on WWV at times), I figured I'd see how things worked otherwise first. I'll go redo that and try the later code. I'll let you know what I find out. The fact that it's working great for you makes me feel much more confident, thanks! Larry |
|
Dan, Success! The issue was the calibration. I redid it with WWV a couple of times but did have a lot of noise. I finally realized that I could set the frequency to match what I wanted to see on 14.074 FT8 and then calibrate that. I'm now within Hertz of where it needs to be. My XTAL calibration is 25001602 Hz, so it was off a bunch. I don't know if it can help anyone else, but what I did was:
I made three contacts on 20m at about 4W and 1 on 10m with 1.5W. Now I can really play with it. Thanks so much for your help, |
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Hi,
First, I'd like to say Thanks! This is a very interesting radio and was easy to assemble and play with. I have built a full set of band boards and am starting to put it to use.
Maybe I'm missing something (that would be great!) but when I'm trying to get it to operate on FT8, I see a couple of things happening:
I need to use EXT mode to control the transceiver and it says it is the way to do it.
When I enter EXT mode and the words "EXT Mode" appear and then go away, I can hear the frequency of the receiver shifting. My measurements seem to indicate a move of about 700Hz. If I keep the radio tuned to 14.074, my audio output ends up 700Hz too high, and in many cases, it's above the audio passband of the signal so that no one can hear me. Tuning lower might be the answer but then there appears to be another issue. (below)
When exiting EXT mode, the frequency returns to the original value. I only really figured this out by using another radio to monitor my transmission and see that my signal was above the audio passband used for FT8.
When transmitting FT8 signals in EXT mode (and possibly shifting the frequency), I notice that it sounds "choppy" with some additional "artifacts" on the signal; normal FT8 signals tend to sound very smooth. When I use "Tune" mode in WSJTX, the signal is very clean and sounds normal. (My X6100 shows the audio spectrum on the display and there are "lobes" at lower amplitude under the main signal. Also, the signal sounds very different on the X6100 than other FT8 signals.)
In the manual there are instructions (In the EXT mode description) to tune to the upper sideband (14.074) when doing FT8. This is the normal way of doing FT8, so that's not unusual. But, in looking at the code (and watching what happens), when EXT mode has been activated the mode is changed to CW and stays there. While I don't think that is an issue exactly, I was wondering why change it and whether it might be related to the above problems in some way.
I'm sorry to say I haven't tested out the other modes like SCAMP or RTTY mostly because 10m is really open so far this year and I'm having a great time making QRP contacts on 10m all over the world. That has also meant that I've spent a lot of time trying to get a bit more power out at 10m (with "normal" builds of the boards I'm getting about 0.5W out). IF everything else was working well, I'd enjoy the challenge of the QRP contacts at 0.5W, but so far the issues above are keeping me from making contacts.
If there is anything I can do or try, please let me know, I'd be happy to help. I haven't tried reprogramming the radio yet because I wanted to spend more time with the original design before I mess with it in any way.
Thanks again!
Larry, WB6JSO (wb6jso@hotmailDOTcom)
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