PTT is usually an input to signal that the operator wants to transmit. Do you want an output to control a linear amplifier?
Does the subitx have the possibility of a PTT (one contact output)?
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Re: Needed: replacement PA transformer for sBitx (T8)
As Ashhar pointed out on another thread regarding a T8 failure, the real question is, why did it fail? So after repairing T8 I did some testing. First, power output on all bands was low¡ªabout 1 watt or less. Then one of the finals shorted. Before replacing it I removed both and tested the drivers. The voltages on the collector of Q15 on CW key down was 19V P-P on 80M, 22.5V on 40, then decreasing by band to 4V on 12 M and 2.4V on 10M. These voltages were with Drive=100 and decreased with decreasing drive, and are of appropriate frequency according to the bands.
Then the collector voltage suddenly dropped to zero with no ac. The receiver still works and goes silent on key down, and CW side tone persists, but there is zero voltage on the TX line (gate to Q10) on key down. I still see the appropriate CLK2 sine wave at the input (pin 6) of U5, but zero voltage at the output of U5, and no ac, at the output, pins1or 3, and no signal at C68 either on key down or key up.?
Then forcing the gate of Q10 to +3.3V gives a oscillation on the collector of Q15 with a DC peak about +14V (the input voltage from my linear power supply) and an rf signal of about 4-5V P-P at an unstable frequency of about 59-73 MHz. This doesn¡¯t change whether or not I press PTT (key down) on CW mode. I understand that forcing Q10 on without any proper rf to the drivers may be causing self oscillation. Please see the oscilloscope screen shot.
What should the output of U5 look like? Shouldn¡¯t there be some signal? Does the lack of signal output from this mixer on CW key down suggest that U5 failed? As it happens I already ordered and have replacement FSA3157 parts because I previously saw one burn out (U3) but that was before upgrade #2 with the T/R board, which makes U3 unnecessary. But it¡¯s an SMD part and I don¡¯t want to replace U5 it if it¡¯s working.
Thanks
Jack
N6LN
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Does the subitx have the possibility of a PTT (one contact output)?
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Re: Raspberry Pi 4 2GB vs Pi 4 8GB
I should have stated that the Sbitx running is a v1 DE that was updated to the v2 software.? There could be an issue with the update.? When the iso for the v2 software is available, I will re-run the test with that build.
73
Evan
AC9TU
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Re: Raspberry Pi 4 2GB vs Pi 4 8GB
Here are screenshots of loading using htop with the temp monitor enabled in the taskbar. With the Chrome controls on:   With Chrome off:   Memory usage never requires swap space, so there is no memory issue with Chrome and the other apps running.? There is a performance issue.? The sound becomes jittery, and the FT8 decodes become erratic. Sorry for the blurry screen blow-ups of the top windows.? I was trying to show the actual values.? The best you can do from these pictures is to note the CPU bars fill the area when running Chrome, indicating there is not enough CPU to run this setup. The DSI screen on the Sbitx is running in this setup:  The temperature stays in the low 50s C while running this test.? I should note that the top is off the Sbitx, and the room is 68degF (20degC). 73 Evan AC9TU
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Re: Raspberry Pi 4 2GB vs Pi 4 8GB
The memory?footprint of the sbitx is tiny compared to the gigabytes of ram available. I guess the chrome eats far more RAM than the sbitx does. It works even with the tiny raspberry pi zero (original). - f
On Sun, Apr 16, 2023 at 9:15?AM James French < w8iss1@...> wrote: I have had a pi4 2gb and 4gb in my raspad 3 running build-a-pi on them.
Both wsjt and fldigi (which are the primary programs I use on it) don't seem to mind either one. So I left the 4gb board in there.
Hope this little bit of input helps.
James W8ISS
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Re: Raspberry Pi 4 2GB vs Pi 4 8GB
I have had a pi4 2gb and 4gb in my raspad 3 running build-a-pi on them.
Both wsjt and fldigi (which are the primary programs I use on it) don't seem to mind either one. So I left the 4gb board in there.
Hope this little bit of input helps.
James W8ISS
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Re: Raspberry Pi 4 2GB vs Pi 4 8GB
The 2GB model has enough RAM to run the sBitx software comfortably, and to run some other applications alongside it like WSJT-X. Right now, the main time when having more RAM would be an advantage is if you want to create your own builds of the sBitx software; the development software will run better with more RAM. Aside from that, there is no compelling reason to swap the Pis.
My DE has a 4GB Pi because that's what I had on hand when I ordered it. (I bought the basic version and supplied my own Pi and display.) I'm not planning to buy the v2 (I got the opportunity to get an mcHF to use as my field rig instead; the DE will stay in the shack), but if I did I would just leave the 2GB Pi inside.
On Sat, Apr 15, 2023 at 4:43?PM HA3HZ < gyula@...> wrote: 2GB is suitable for the purpose.
But you decide:
--
Gyula HA3HZ
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Re: Cooling RPi4 in Sbitx
The specific solution will probably be implemented during operation.
--
Gyula HA3HZ
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Re: Cooling RPi4 in Sbitx
Yes ¡and even more, if Farhan did not find the reason for cooling it with additional
heatsink then I don¡¯t care, right now.?
- P
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Re: Raspberry Pi 4 2GB vs Pi 4 8GB
2GB is suitable for the purpose.
But you decide:
--
Gyula HA3HZ
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Re: Cooling RPi4 in Sbitx
Again, I think this is more of an issue if you plan for this to run for hundreds of hours and many many years. ?
For instance, I run two Winlink radio message servers at my house and they have been running 24/7/365 for six years. ?
So it¡¯s a trade-off whether it¡¯s worth it to run air conditioning a little bit in that part of the house or just accept the fact that they may quit a few years earlier.?
toggle quoted message
Show quoted text
On Apr 15, 2023, at 16:19, HA3HZ <gyula@...> wrote:
?James, I agree with you.
Unfortunately, the construction makes it difficult for me to solve the cooling for several reasons.
The heat dissipation of the heatsink shown in the previous message is also unfortunate, because it would be between two mounted PCBs. Therefore, a fan might be a better solution due to free air flow. If you really need it. I accept that it is good to have cooling, so I am looking for a favorable option.
--
Gyula HA3HZ
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Re: Cooling RPi4 in Sbitx
James, I agree with you.
Unfortunately, the construction makes it difficult for me to solve the cooling for several reasons.
The heat dissipation of the heatsink shown in the previous message is also unfortunate, because it would be between two mounted PCBs. Therefore, a fan might be a better solution due to free air flow. If you really need it. I accept that it is good to have cooling, so I am looking for a favorable option.
--
Gyula HA3HZ
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Re: Cooling RPi4 in Sbitx
Cooling is up to you to figure out if you need it.
Most of my pi's are passive cooled but not in any enclosures that restrict air flow either.
The only two exceptions here are my Raspad 3 and the pi400 keyboard. The raspad 3 has a fan built-in since it is pretty restrictive on the air flow. The pi400 keyboard has enough cooling built in as not to worry about adding a fan.
From seeing the pictures of the case for the sbitx, I'd probably see about adding a fan because of all the other heat producing elements of the system. I have no idea how much heat all the other parts produce but better to side on caution.
James W8ISS
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Re: Cooling RPi4 in Sbitx
For most transistors the data sheet gives some suggested limitations on the operating temperatures.? I have a General IRT207 Infaraed Thermometer that will tell you what the temperature of a single point
is, and they are relatively inexpensive.? They are made for measuring the temperatures of surfaces in buildings.? I am a believer in lots of heatsink area.? I tried to publish an article with infarred pictures in QST, but they decided not to publish my article.?
? ? ? 73, Dan Eggers, Radiotelegraph N7DE
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My radio has been running continuously for the last one week, this is our peak summer, with temperatures soaring to 38 c. The shack's air conditioner is in on only about 3 hours day.
It has run without problem.
- f
On Sat, Apr 15, 2023, 6:07 PM HA3HZ < gyula@...> wrote:
The question whether the RPi4 should be installed without cooling or with cooling does not let us rest.
I looked through several test descriptions, where they show measurements depending on the number of processors /
CPU frequency used and with different cooling solutions.
The point is that there can be a difference of up to 30 degrees C with or without the refrigerator.
In the state without a cooler, 85-88 degrees Celsius is also possible.
While the most effective passive cooling is 50-63 degrees Celsius.
Since I used an RPi400 so far, I have no experience, but I think that some kind of cooling is necessary.
(I don't mean the 3 small cooling surfaces)
I'd like to hear other people's opinions and experiences.
--
Gyula HA3HZ
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Raspberry Pi 4 2GB vs Pi 4 8GB
I have a sBitx DE V1 with a RSP Pi 4 8GB ram, I also have a V2 on order which will come with a RSP Pi 4 2GB. Is there any advantage to swapping the two Pi's, is 8GB going to be any better/faster than the 2GB version?
Joel
N6ALT
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Re: sBitx Audio Setup (Was: Re: [BITX20] Using an external HDMI TV Monitor)
Indeed, just like in telephony, RTP would be the way to go. WebRTC is good.. but way complex IMHO, but you are right as there as ways to bridge it to RTP, but the Web software stack is not really friendly to RTP.
Talking about Phil Karn... he is a myth, one of the greatest of all times! I like the NOS operating system he created back in the 80's. We still have the JNOS [1] descendant, which we could somehow integrate to sbitx in the future.
Anyway, concerning the discussion about audio I/O on Linux - which is not really what we really need - as we just need an API to direct access A/D and D/A converters of wolfson codec - it might be possible to tweak the wolfson driver and remove alsa all the way... the Wolfson is connected via i2c right? We could talk to it directly over i2c. I'm readind this:
I also found this tiny alsa userland library, which could be useful for embedded/tiny sBitx software stacks without any kernel / driver change:
Cheers,
Rafael
[1]
toggle quoted message
Show quoted text
On 4/15/23 19:50, Ashhar Farhan wrote: Rafael,
I would go a layer lower and use rtp (rfc 1889). This would make everything simple. I suspect that there are ways to gateway rtp to webrtc.et <> al.
Phil Karn KA9Q, who is the chief motivator for the sbitx, built his sdr system multicasting rtp traffic. It waa brilliantly simple. He multicast the entire spectrum out of the fft engine and multiple receivers could read and demodulate it simultaneously.
- f
On Sat, Apr 15, 2023, 9:55 PM Rafael Diniz <rafael@...> wrote:
IMHO, the best way to support all the use-cases for sBitx while
maintaining low latency and lower use of cpu resources is by using
alsa
ucm (use-case-manager):
Which is not another layer of software (like Jack, Pulseaudio, ESD or
Pipewire), but use an alsa configuration manager with pre-defined
profiles for each use case (and Pulseaudio, for example, honor it, in
case of used).
If latency is not an issue... then any solution will work fine if
properly set. Sorry to spam the list on this topic...
ow boy, how I miss good ol' OSS times... just open() /dev/dsp and
be happy.
Rafael
On 4/15/23 19:13, Rafael Diniz wrote:
> Btw, if you want to install Pipewire in Debian:
>
>
> Pipewire is officially unsupported in Debian 11, which sBitx v2 is
> using currently. I had some bad experiences with it tbh, and rolled
> back to using alsa directly. I strongly recommend Debian 12 if one
> wants to use Pipewire. Also bear in mind some changes in
sbitx_sound.c
> might be needed for optimum operation with Pipewire.
>
> 73's
> Rafael
>
> On 4/15/23 18:56, Rafael Diniz wrote:
>> Nope. Pipewire is an extra layer on top of the audio drivers
(ALSA).
>>
>> Rafael
>>
>> On 4/15/23 18:49, Lou KI5FTY wrote:
>>> its actually not another layer, it replaces alsa and pulse audio
>>> with a high performance audio engine.? It has a pulse and alsa
>>> connector so everything is transparent when the change is made
>>>
>>> On Sat, Apr 15, 2023 at 9:43?AM Rafael Diniz
>>> <rafael@...> wrote:
>>>
>>> ??? Another layer of audio never helps. Better stick with pure
alsa
>>> only.
>>> ??? What exactly do you need Ashhar? Alsa has plugins for almost
>>> ??? everything,
>>> ??? with different level of performance and efficiency.
Pulseaudio is
>>> ??? really
>>> ??? evil indeed...
>>>
>>> ??? Rafael
>>>
>>> ??? On 4/14/23 19:27, Ashhar Farhan wrote:
>>> ??? > If someone can show me a small bit of code that allows full
>>> duplex
>>> ??? > audio and control over mixer, I will switch to Jack or
pipewire
>>> ??? in an
>>> ??? > instant.
>>> ??? > - f
>>> ??? >
>>> ??? > On Fri, Apr 14, 2023, 7:12 PM Bill
<groups191117@...>
>>> wrote:
>>> ??? >
>>> ??? >? ? ?Pulseaudio is a bit of a dumpster fire.? Have you
considered
>>> ??? >? ? ?Pipewire instead?
>>> ??? >
>>> ??? >? ? ?All of the low-latency and connection advantages of
JACK
>>> without
>>> ??? >? ? ?the bugs and arrogance of pulseaudio.
>>> ??? >
>>> ??? >? ? ?All the cool kids are using it. :)
>>> ??? >
>>> ??? >
>>> ??? >? ? ??- Bill? N3AJ
>>> ??? >
>>> ??? >
>>>
>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>>
>>
>
>
>
>
>
|
I know its off topic - no bitx related¡
VU2TMP is now on 18072 CW with great signal. Band is opened.?
Maybe chace to work Farhan ¡;);)
- P
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Re: Cooling RPi4 in Sbitx
I think the biggest impact of getting devices to be cooler is the change in lifetime. ? An individual semiconductor device has a lifetime measured in many many many years. ? But it¡¯s a strong inverse relationship to temperature. ?
And the problem may be that we have a bunch of semi connectors in complicated systems ? ?Because the failure of a complicated device with 1 million semi conductors could be the combined risk of ANY of the 1 million failing then the chance of total device failure could be as much as 10 to the sixth greater than the risk of one failure. ?(In practice I bet you could live with an I/O ?that quit working however. but it might require both hardware and software changes to keep working)
Here¡¯s a plot that shows how strongly it¡¯s related to temperature for a single example device ?
After looking at that plot it looks like the risk to individual analog transistors is much smaller than the risk to complicated integrated circuits or processors. ? ? The article explains that in order to get meantime between failure manufacturers use elevated temperatures because otherwise indivisible semiconductor devices are just unlikely to fail before their useful marketing of sales is over¡ª so they wouldn¡¯t be able to even finish testing before the device had been superseded
So getting the temperature down by 10 or 20¡ãC might be worth it if you want the thing to keep working flawlessly for a long time. ? If your interest is much shorter lived then it might not be worth it
Gordon Kx4z
toggle quoted message
Show quoted text
On Apr 15, 2023, at 11:52, HA3HZ <gyula@...> wrote:
?I know that the testing is done with programs that use the CPU.
It can also be called an overload test.
In our case, the goal may be to avoid heat production due to long-term use.
The question is whether the center cooling surface does as much cooling as opposed to letting the air flow.
--
Gyula HA3HZ
|
Re: sBitx Audio Setup (Was: Re: [BITX20] Using an external HDMI TV Monitor)
Rafael, I would go a layer lower and use rtp (rfc 1889). This would make everything simple. I suspect that there are ways to gateway rtp to al. Phil Karn KA9Q, who is the chief motivator for the sbitx, built his sdr system multicasting rtp traffic. It waa brilliantly simple. He multicast the entire spectrum out of the fft engine and multiple receivers could read and demodulate it simultaneously. - f
On Sat, Apr 15, 2023, 9:55 PM Rafael Diniz < rafael@...> wrote: IMHO, the best way to support all the use-cases for sBitx while
maintaining low latency and lower use of cpu resources is by using alsa
ucm (use-case-manager):
Which is not another layer of software (like Jack, Pulseaudio, ESD or
Pipewire), but use an alsa configuration manager with pre-defined
profiles for each use case (and Pulseaudio, for example, honor it, in
case of used).
If latency is not an issue... then any solution will work fine if
properly set. Sorry to spam the list on this topic...
ow boy, how I miss good ol' OSS times... just open() /dev/dsp and be happy.
Rafael
On 4/15/23 19:13, Rafael Diniz wrote:
> Btw, if you want to install Pipewire in Debian:
>
>
> Pipewire is officially unsupported in Debian 11, which sBitx v2 is
> using currently. I had some bad experiences with it tbh, and rolled
> back to using alsa directly. I strongly recommend Debian 12 if one
> wants to use Pipewire. Also bear in mind some changes in sbitx_sound.c
> might be needed for optimum operation with Pipewire.
>
> 73's
> Rafael
>
> On 4/15/23 18:56, Rafael Diniz wrote:
>> Nope. Pipewire is an extra layer on top of the audio drivers (ALSA).
>>
>> Rafael
>>
>> On 4/15/23 18:49, Lou KI5FTY wrote:
>>> its actually not another layer, it replaces alsa and pulse audio
>>> with a high performance audio engine.? It has a pulse and alsa
>>> connector so everything is transparent when the change is made
>>>
>>> On Sat, Apr 15, 2023 at 9:43?AM Rafael Diniz
>>> <rafael@...> wrote:
>>>
>>> ??? Another layer of audio never helps. Better stick with pure alsa
>>> only.
>>> ??? What exactly do you need Ashhar? Alsa has plugins for almost
>>> ??? everything,
>>> ??? with different level of performance and efficiency. Pulseaudio is
>>> ??? really
>>> ??? evil indeed...
>>>
>>> ??? Rafael
>>>
>>> ??? On 4/14/23 19:27, Ashhar Farhan wrote:
>>> ??? > If someone can show me a small bit of code that allows full
>>> duplex
>>> ??? > audio and control over mixer, I will switch to Jack or pipewire
>>> ??? in an
>>> ??? > instant.
>>> ??? > - f
>>> ??? >
>>> ??? > On Fri, Apr 14, 2023, 7:12 PM Bill <groups191117@...>
>>> wrote:
>>> ??? >
>>> ??? >? ? ?Pulseaudio is a bit of a dumpster fire.? Have you considered
>>> ??? >? ? ?Pipewire instead?
>>> ??? >
>>> ??? >? ? ?All of the low-latency and connection advantages of JACK
>>> without
>>> ??? >? ? ?the bugs and arrogance of pulseaudio.
>>> ??? >
>>> ??? >? ? ?All the cool kids are using it. :)
>>> ??? >
>>> ??? >
>>> ??? >? ? ??- Bill? N3AJ
>>> ??? >
>>> ??? >
>>>
>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>>
>>
>
>
>
>
>
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John Terrell, N6LN
Shirley Dulcey KE1L
HA3HZ
Joel Caulkins/N6ALT