Re: Fixed: cw latency and wsjtx/flidigi sidetone
Unfortunately this update didn't fix the issues.
?
First, IambicB is still broken, I put Ron Carr's fix in a PR.
?
Second, when I took the radio out and attached it to a EFRW, through a tuner, on several bands I had significant RFI issues, they keyer did not work well at all. The second time with the same antenna I had put a ferrite on the keyer cable and that fixed that issue. I had no problems at home.
?
But for the main issue, I agree with Gordon. With modifying what's happening in the polling loop it is possible to make responsiveness to the key work better. It's not perfect, when I call cq using paddles again and again, at 25 wpm I get about one error every 5 times so quite noticeable, but at 20 wpm it's very infrequent, and I blame any errors on my keying.?
?
Erik - n2epe
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Re: Fixed: cw latency and wsjtx/flidigi sidetone
Ah, THANKS, Steven!? ? page 3:? "? Processor: Broadcom BCM2710A1, quad-core 64-bit SoC"
Then there really is no obvious reason that the same fix that worked for the sBitx, that was subsequently employed in the 64-bit code version as well, and has been verified as working in the zBitx software....shouldn't be strongly considered for release to the larger group of purchasers.? ?After all, they were assured the unit works for all modes, right?? ? ?
Thank you for straightening that out.??
Before this goes much further, we should correct the record. The Pi Zero 2W does not have a single core processor. It has a quad core of the Pi 3B+ era, but with half the memory of that board. Thus the zBitx should not suffer the single core bottleneck issues that were described earlier in the thread.?
Steven, AC1RZ 73
On Mon, Apr 14, 2025 at 03:20 Gordon Gibby KX4Z via <docvacuumtubes= [email protected]> wrote: Ron, thanks for taking the time to write such a nice explanation!
I guess the real question is "what is the distribution of delays caused by operating system housekeeping operations on a single core processor?"
?
I posit that in order to be considered "acceptable" a CW product must be able to send every single dot or dash, and more than HALF of each dot.? ?Without any studies to prove it, I suspect that most CW operators (copying in their own head) will be able to tolerate an "dot" that is shortened by less than "half" of its normal time unit.? ?But MISSING a dot is unforgiveable because it changes the code symbol to either nonsense or incorrect.
?
Apparently the length of a "dot" at 24wpm is on the order of 28 milliseconds (I looked that up, so I could be wrong)
?
We can tolerate no more than 10 milliseconds or so of delay or failure to respond.? ?Can a single core Linux raspberry provide that response more than 95% of the time?
?
We have another piece of evidence.
?
Erik (and at least one other) have already taken the revised code, which not only has fantastic interrupt-driven response to the paddle, but crucially ALSO has sped-up polling to DO SOMETHING in response to the detected changed state of the paddle --- and with this sped-up polling (20X sped up) -- they uniformly report that it "works".? ? ?In fact, they were quite positive about its acceptability.
?
So this would suggest that the bottleneck is NOT the uncontrollable operating system overhead, but is instead the every-20th-tic response pointed to time and time again by Mike Johnshoy and others.? ??
?
This is quite testable.? ? The number of ticks that go by, before anything is DONE in response to a noted change in state of the paddles, can be set to any number between 0 and 20 and users can report whether they consider the code "useable"? ? We already have two datapoints:
?
@20 tick polling:? ?we have multiple reports it is considered UN-useable
@? 1 tick polling:? ?we have at least two reports that it is considered "GOOD"
?
So wouldn't it seem reasonable that the operating system is NOT the bottleneck, and that the code itself IS the problem here?? ?We are not talking difficult code.? ?It is only a line or two of changes.? ?I made the change in my own 32-bit version in moments and my sBitx Version 2's immediately worked "useably" - in fact, excellently.? ? I don't have a zbitx on which to try, but many many others do.? ? I'm unclear why this research hasn't been furthered to allow understanding of exactly what is needed for an excellent product.
?
73,
?
Gordon KX4Z
?
?
|
Re: Should I start with uBITX, sBITX or zBITX?
Gerry,
Thanks a lot for the detailed suggestions, especially as you own all three versions.
I did not know that there is a 12V version of 807! I thought that all vacuum tubes need high voltage. I had wondered how the early car radios worked from batteries.
Regarding the filters and all, getting them here would be tough, though not impossible.
Maybe i will wait till sBITX v4 reviews are out and then decide.
Hope to meet you on air some?time soon.
73
Jon, VU2JO
Jon
I would say the uBit is probably the easiest of the lot for a new
user to use, although it lacks some of the features of the SDRs.?
It's a much less expensive radio than the sBit.? Since you say you
won't be operating portable, and you do have a resonant antenna
system, you can get away with just an AC power supply and a key to
start with.? You might be able to build a suitable power supply,
or buy something ready made.? I'm in Canada, so I don't know what
it's like to get things locally in India.? It's easy to add a few
features later to the radio, after you get familiar with it.? The
ones I would suggest are a memory keyer, an audio filter, and an
AGC system.? The uBit isn't really designed to handle some of the
more modern things like FT8, etc., just plain old CW and SSB.? It
may be possible to use these with a sound card and a computer.? I
haven't tried this.
With either of the SDRs, you are looking at updates, especially
with the zBit, as it is quite new.? You won't have this issue with
the uBit.
I have all 3 of these radios, so I do have some experience.
Sotabeams has a good audio filter at a cost of about ?25.00, plus shipping.?
Hamcrafters (K1EL) has the K16-EXT keyer, although at the moment
his situation is unsettled, as things are uncertain in the USA
with some of the president's ideas on international trade.? A
lot of his raw materials are imported.? Both of these can be
built into the uBit, although the keyer has some practice
features that make it very useful on its own.
Your comments about 807 tubes
bring back over half a century of memories with 1625s (the 12
volt version of the 807) and WWII surplus equipment.? I used a
1625 in my first transmitter, back in 1970.
Gerry Sherman
On 2025-04-13 23:45, Jon via
wrote:
I do not have a BITX yet, but have been closely following
the discussions on the group.
My experience in homebrewing was a few decades back, of a
VU2VWN QRP with BD 139 final and a 3 x 807 vacuum tube TX
running about 120W DC input.
That means I have not meddled with any radio circuit for
the past few decades.
Which one should I start with: uBITX, sBITX or zBITX?
As of now, I have no option for portable operations. Only a
fan dipole for 40-10m and a dipole for 80m.
Hoping to receive your valuable suggestions.
73
Jon, VU2JO
|
Re: Fixed: cw latency and wsjtx/flidigi sidetone
Before this goes much further, we should correct the record. The Pi Zero 2W does not have a single core processor. It has a quad core of the Pi 3B+ era, but with half the memory of that board. Thus the zBitx should not suffer the single core bottleneck issues that were described earlier in the thread.?
Steven, AC1RZ 73
On Mon, Apr 14, 2025 at 03:20 Gordon Gibby KX4Z via <docvacuumtubes= [email protected]> wrote: Ron, thanks for taking the time to write such a nice explanation!
I guess the real question is "what is the distribution of delays caused by operating system housekeeping operations on a single core processor?"
?
I posit that in order to be considered "acceptable" a CW product must be able to send every single dot or dash, and more than HALF of each dot.? ?Without any studies to prove it, I suspect that most CW operators (copying in their own head) will be able to tolerate an "dot" that is shortened by less than "half" of its normal time unit.? ?But MISSING a dot is unforgiveable because it changes the code symbol to either nonsense or incorrect.
?
Apparently the length of a "dot" at 24wpm is on the order of 28 milliseconds (I looked that up, so I could be wrong)
?
We can tolerate no more than 10 milliseconds or so of delay or failure to respond.? ?Can a single core Linux raspberry provide that response more than 95% of the time?
?
We have another piece of evidence.
?
Erik (and at least one other) have already taken the revised code, which not only has fantastic interrupt-driven response to the paddle, but crucially ALSO has sped-up polling to DO SOMETHING in response to the detected changed state of the paddle --- and with this sped-up polling (20X sped up) -- they uniformly report that it "works".? ? ?In fact, they were quite positive about its acceptability.
?
So this would suggest that the bottleneck is NOT the uncontrollable operating system overhead, but is instead the every-20th-tic response pointed to time and time again by Mike Johnshoy and others.? ??
?
This is quite testable.? ? The number of ticks that go by, before anything is DONE in response to a noted change in state of the paddles, can be set to any number between 0 and 20 and users can report whether they consider the code "useable"? ? We already have two datapoints:
?
@20 tick polling:? ?we have multiple reports it is considered UN-useable
@? 1 tick polling:? ?we have at least two reports that it is considered "GOOD"
?
So wouldn't it seem reasonable that the operating system is NOT the bottleneck, and that the code itself IS the problem here?? ?We are not talking difficult code.? ?It is only a line or two of changes.? ?I made the change in my own 32-bit version in moments and my sBitx Version 2's immediately worked "useably" - in fact, excellently.? ? I don't have a zbitx on which to try, but many many others do.? ? I'm unclear why this research hasn't been furthered to allow understanding of exactly what is needed for an excellent product.
?
73,
?
Gordon KX4Z
?
?
|
Re: Fixed: cw latency and wsjtx/flidigi sidetone
Ron, thanks for taking the time to write such a nice explanation!
I guess the real question is "what is the distribution of delays caused by operating system housekeeping operations on a single core processor?"
?
I posit that in order to be considered "acceptable" a CW product must be able to send every single dot or dash, and more than HALF of each dot.? ?Without any studies to prove it, I suspect that most CW operators (copying in their own head) will be able to tolerate an "dot" that is shortened by less than "half" of its normal time unit.? ?But MISSING a dot is unforgiveable because it changes the code symbol to either nonsense or incorrect.
?
Apparently the length of a "dot" at 24wpm is on the order of 28 milliseconds (I looked that up, so I could be wrong)
?
We can tolerate no more than 10 milliseconds or so of delay or failure to respond.? ?Can a single core Linux raspberry provide that response more than 95% of the time?
?
We have another piece of evidence.
?
Erik (and at least one other) have already taken the revised code, which not only has fantastic interrupt-driven response to the paddle, but crucially ALSO has sped-up polling to DO SOMETHING in response to the detected changed state of the paddle --- and with this sped-up polling (20X sped up) -- they uniformly report that it "works".? ? ?In fact, they were quite positive about its acceptability.
?
So this would suggest that the bottleneck is NOT the uncontrollable operating system overhead, but is instead the every-20th-tic response pointed to time and time again by Mike Johnshoy and others.? ??
?
This is quite testable.? ? The number of ticks that go by, before anything is DONE in response to a noted change in state of the paddles, can be set to any number between 0 and 20 and users can report whether they consider the code "useable"? ? We already have two datapoints:
?
@20 tick polling:? ?we have multiple reports it is considered UN-useable
@? 1 tick polling:? ?we have at least two reports that it is considered "GOOD"
?
So wouldn't it seem reasonable that the operating system is NOT the bottleneck, and that the code itself IS the problem here?? ?We are not talking difficult code.? ?It is only a line or two of changes.? ?I made the change in my own 32-bit version in moments and my sBitx Version 2's immediately worked "useably" - in fact, excellently.? ? I don't have a zbitx on which to try, but many many others do.? ? I'm unclear why this research hasn't been furthered to allow understanding of exactly what is needed for an excellent product.
?
73,
?
Gordon KX4Z
?
?
|
Re: Should I start with uBITX, sBITX or zBITX?
On Sun, Apr 13, 2025 at 04:45 PM, Jon wrote:
VU2JO, Jon
Contact me, With the email with your detail
Madhu, N6QIP
|
Re: sBitx v3 - next final MOSFET killed
Very simple: ?data sheet, p2 . ? Guaranteed “no destroy” at SWR up to 20:1 any phase angle.?
?
?
73,?
?
Gordon Kx4z?
?
?
|
Re: sBitx v3 - next final MOSFET killed
If you haven't noticed by now, HF Signals doesn't care if some people are unhappy with the product.
Profit and sales come from the fact that you can produce things cheaply.
For those who are bothered by this, there is the possibility to correct and modify the product according to their own taste.
The design can be quite diverse due to the diversity of components.
Things that have been proven in practice and work well can be sold at a higher price, against which those with little money would fall away from the product.
Now here some people say that they would pay, but the majority are probably happy with it being cheap and then modifying it.
This is a rubber bone that you can always chew on!
So don't stop, because development is driven forward by more people discussing it.
I see the problem in that no one likes to invest in uncertainty, but some people expect HF Signals to risk their money.
I also have an opinion about sBitx, the only difference between us is that I use the device, while many of you just buy it as a shelf decoration for your many devices.
Here's the point.
--
Gyula HA3HZ
|
John,
We haven't received your email. Can you resend it to sales at hfsignals dot com??
To answer your question, we are working on bringing out the V4 as soon as we can. We don't have an exact date on when the sBitx V4 will become available and we will announce this on the group and by email to those who had mailed us.?
?
73,
Ragav
|
Re: sBitx v3 - next final MOSFET killed
Cool… just let me know.? I have enough parts for about another 300 kits.? I’ve sold more than 1,200 to date. ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton – J68HZ Soufriere, St. Lucia W.I. Rent it: ? Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. ? email:? bill@... ? ?
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From: [email protected] <[email protected]> On Behalf Of Michael Bales via groups.io
Sent: Sunday, April 13, 2025 7:22 PM
To: [email protected]
Subject: Re: [BITX20] sBitx v3 - next final MOSFET killed? Good, I need to get another 20w kit from you soon. I've been bouncing it between the v3 and my radioberry v2. I eventually found the j7 connection that I missed before, so I could take the signal from there. -------- Original message -------- Date: 4/13/25 6:37 PM (GMT-05:00) Subject: Re: [BITX20] sBitx v3 - next final MOSFET killed And how is that working out for you? ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton – J68HZ Soufriere, St. Lucia W.I. Rent it: ? Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. ? email:? bill@... ? ? ? Such is the nature of using MOSFETS not designed for RF amplifiers.? I got so sick of the PA failures with my v3, I built one of K9HZ 20w PA boards and just bypassed the entire PA section of the v3. -------- Original message -------- Date: 4/12/25 11:39 AM (GMT-05:00) Subject: [BITX20] sBitx v3 - next final MOSFET killed My sBitx v3 has killed next final MOSFET. Again, as previously, only one was dead: However, this time the failure wasn't caused by overheating (the fan was cooling the heatsink and its temperature was ca 30 C) but by SWR. I was operating my device remotely via WiFi in FT8 mode, and my ATU got crazy. Unfortunately, I could only see the increase of SWR on my laptop, and the connection got broken. I couldn't cease the transmission immediately. When I reached the sBitx, it already showed the output power 0W. Well, when replacing them, I have exchanged the mica insulators with AlN ones. Let's see how long is it going to survive now. BTW. Is it possible to replace IRF510 with other MOSFETs (maybe more expensive, but offering higher maximum voltage and better power at 28 MHz)?
--
Mike - K8MCB?
--
Mike - K8MCB?
|
Re: sBitx v3 - next final MOSFET killed
“But the RD product is only guaranteed up to an SWR of 20 to one” ??? Oh… how did you come to that conclusion? ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton – J68HZ Soufriere, St. Lucia W.I. Rent it: ? Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. ? email:? bill@... ? ?
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From: [email protected] <[email protected]> On Behalf Of Gordon Gibby KX4Z via groups.io
Sent: Sunday, April 13, 2025 7:20 PM
To: [email protected]
Cc: [email protected]
Subject: Re: [BITX20] sBitx v3 - next final MOSFET killed? I can’t claim to be an RF engineer. But the RD product is only guaranteed up to an SWR of 20 to one. ?Looks like it has much lower input C ?so easier to drive. ? However, its drain source voltage limit is 50 V whereas the IRF 510 and IRF 520 ?are 100 V. On RF parts, the Mosfet is going for eight dollars each, so I think you’d be looking at $15 higher price at least. Because there’s two of them. Again, I’m not an RF engineer!!?
On Apr 13, 2025, at 20:15, Michael Bales via groups.io <mikebales73@...> wrote:
? It's been mentioned before, repeatedly. I agree. I would gladly pay the extra $5 it would cost to go with rd16hhf mosfets. You can have a SOLID 20 watts up into 10m, and not worry about blowing one if you look at it the wrong way.? -------- Original message -------- Date: 4/13/25 7:50 PM (GMT-05:00) Subject: Re: [BITX20] sBitx v3 - next final MOSFET killed I would rather pay a little more for a better output transistor than save a dollar or two on the cost.? Perhaps HFS could take note of this. Gerry On 2025-04-13 21:15, Michael Bales via groups.io wrote: Such is the nature of using MOSFETS not designed for RF amplifiers.? I got so sick of the PA failures with my v3, I built one of K9HZ 20w PA boards and just bypassed the entire PA section of the v3. -------- Original message -------- Date: 4/12/25 11:39 AM (GMT-05:00) Subject: [BITX20] sBitx v3 - next final MOSFET killed My sBitx v3 has killed next final MOSFET. Again, as previously, only one was dead: However, this time the failure wasn't caused by overheating (the fan was cooling the heatsink and its temperature was ca 30 C) but by SWR. I was operating my device remotely via WiFi in FT8 mode, and my ATU got crazy. Unfortunately, I could only see the increase of SWR on my laptop, and the connection got broken. I couldn't cease the transmission immediately. When I reached the sBitx, it already showed the output power 0W. Well, when replacing them, I have exchanged the mica insulators with AlN ones. Let's see how long is it going to survive now. BTW. Is it possible to replace IRF510 with other MOSFETs (maybe more expensive, but offering higher maximum voltage and better power at 28 MHz)?
--
Mike - K8MCB?
--
Mike - K8MCB?
|
Re: sBitx v3 - next final MOSFET killed
On this subject…. As a person who designs and sells inexpensive electronics… one learns very quickly that your designs must be robust and forgiving… or they break easily and end up relegated to a junk pile.? So, a PA must be able to tolerate mistakes without failing (with an open or shorted antenna), without over-heating, and be inexpensive.? ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton – J68HZ Soufriere, St. Lucia W.I. Rent it: ? Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. ? email:? bill@... ? ?
toggle quoted message
Show quoted text
From: [email protected] <[email protected]> On Behalf Of Michael Bales via groups.io
Sent: Sunday, April 13, 2025 7:15 PM
To: [email protected]
Subject: Re: [BITX20] sBitx v3 - next final MOSFET killed? It's been mentioned before, repeatedly. I agree. I would gladly pay the extra $5 it would cost to go with rd16hhf mosfets. You can have a SOLID 20 watts up into 10m, and not worry about blowing one if you look at it the wrong way.? -------- Original message -------- Date: 4/13/25 7:50 PM (GMT-05:00) Subject: Re: [BITX20] sBitx v3 - next final MOSFET killed I would rather pay a little more for a better output transistor than save a dollar or two on the cost.? Perhaps HFS could take note of this. Gerry On 2025-04-13 21:15, Michael Bales via groups.io wrote: Such is the nature of using MOSFETS not designed for RF amplifiers.? I got so sick of the PA failures with my v3, I built one of K9HZ 20w PA boards and just bypassed the entire PA section of the v3. -------- Original message -------- Date: 4/12/25 11:39 AM (GMT-05:00) Subject: [BITX20] sBitx v3 - next final MOSFET killed My sBitx v3 has killed next final MOSFET. Again, as previously, only one was dead: However, this time the failure wasn't caused by overheating (the fan was cooling the heatsink and its temperature was ca 30 C) but by SWR. I was operating my device remotely via WiFi in FT8 mode, and my ATU got crazy. Unfortunately, I could only see the increase of SWR on my laptop, and the connection got broken. I couldn't cease the transmission immediately. When I reached the sBitx, it already showed the output power 0W. Well, when replacing them, I have exchanged the mica insulators with AlN ones. Let's see how long is it going to survive now. BTW. Is it possible to replace IRF510 with other MOSFETs (maybe more expensive, but offering higher maximum voltage and better power at 28 MHz)?
--
Mike - K8MCB?
--
Mike - K8MCB?
|
Re: Fixed: cw latency and wsjtx/flidigi sidetone
There's one big difference between the SBitx and zBitx. ?
The number of ARM processor cores in the Pi 3B or 4 or 5 is greater than one. ?Whereas the Pi Zero 2 W only has only one ARM processor core.
?
On zBitx, which uses a Pi Zero 2 with a single core, the non-real-time Linux OS kernel is guaranteed to interrupt the polling loop process periodically, and maybe do some random Linux housekeeping or run other processes.
?
I just ssh'd into my zBitx and listed running processes. ?There were 150 processes listed, and 8 to 12 of these process were continually getting measurable CPU time. ?The sbitx process was barely getting 60% of CPU time. ?Which means 40% of the time, it's likely suspended instead of polling, and thus potentially missing key input changes during suspension. ?Polling in a tighter loop has almost no effect on the duration the polling loop spends inactively sleeping while the CPU is busy elsewhere.
?
The SBitx runs on a multicore processor. ?The OS dispatch will often run on a different processor core than the sbitx polling thread. ?Thus one can often get away with polling, as there's a far higher probability that other lower priority processes will run on other cores, and not cause the polling loop to be suspended.
?
Any real-time low-latency goals or software design has to take the above design constraints into account. ?The pin interrupt handlers likely won't miss pin events if those handlers are written correctly. ?But a user processes have to assume it was just woken from many milliseconds of sleep at random time, and could have missed lots of stuff. ?If you write code that can recognize it missed a dit while sleeping, it might handle that dit a bit late, but at least it won't miss that dit completely.
?
Another possibility is to use a real-time Linux kernel patch, and run the CW keyer at real-time priority. ?But real-time coding has lots of restrictions (deterministic max run time, no memory management, no unbounded time OS calls, etc.). ?Using Core Audio for low latency audio (live music performances) on an iPhone has similar hard real-time restrictions. ?So I've had to learn (the hard way).
?
73, Ron, N6YWU
|
Re: Should I start with uBITX, sBITX or zBITX?
Jon
I would say the uBit is probably the easiest of the lot for a new
user to use, although it lacks some of the features of the SDRs.?
It's a much less expensive radio than the sBit.? Since you say you
won't be operating portable, and you do have a resonant antenna
system, you can get away with just an AC power supply and a key to
start with.? You might be able to build a suitable power supply,
or buy something ready made.? I'm in Canada, so I don't know what
it's like to get things locally in India.? It's easy to add a few
features later to the radio, after you get familiar with it.? The
ones I would suggest are a memory keyer, an audio filter, and an
AGC system.? The uBit isn't really designed to handle some of the
more modern things like FT8, etc., just plain old CW and SSB.? It
may be possible to use these with a sound card and a computer.? I
haven't tried this.
With either of the SDRs, you are looking at updates, especially
with the zBit, as it is quite new.? You won't have this issue with
the uBit.
I have all 3 of these radios, so I do have some experience.
Sotabeams has a good audio filter at a cost of about ?25.00, plus shipping.?
Hamcrafters (K1EL) has the K16-EXT keyer, although at the moment
his situation is unsettled, as things are uncertain in the USA
with some of the president's ideas on international trade.? A
lot of his raw materials are imported.? Both of these can be
built into the uBit, although the keyer has some practice
features that make it very useful on its own.
Your comments about 807 tubes
bring back over half a century of memories with 1625s (the 12
volt version of the 807) and WWII surplus equipment.? I used a
1625 in my first transmitter, back in 1970.
Gerry Sherman
On 2025-04-13 23:45, Jon via groups.io
wrote:
toggle quoted message
Show quoted text
I do not have a BITX yet, but have been closely following
the discussions on the group.
My experience in homebrewing was a few decades back, of a
VU2VWN QRP with BD 139 final and a 3 x 807 vacuum tube TX
running about 120W DC input.
That means I have not meddled with any radio circuit for
the past few decades.
Which one should I start with: uBITX, sBITX or zBITX?
As of now, I have no option for portable operations. Only a
fan dipole for 40-10m and a dipole for 80m.
Hoping to receive your valuable suggestions.
73
Jon, VU2JO
|
Re: Should I start with uBITX, sBITX or zBITX?
Well, it's not 'designed' for transverter use, but I suppose it could be used to 'drive' a transverter, but you may need to go inside the radio to make it work (bring out a Key/PTT connection, for example)...
One thing to realize, these radios have minimal support from HF Signals after sales. The radios do not have robust warranties like the 'big boys' offer, but you are protected against DOA, manufacturing defects, etc, but this is billed as a radio for hackers, and as such you may be expected to provide your own repair service after the sale. That said, HF Signals is very supportive, their policies are described here:
?
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On Apr 13, 2025, at 19:37, Jon via groups.io <vu2jo0@...> wrote:
? Ken,
Thanks a lot for the valuable information.
I have no plans for portable operations,?at least in the foreseeable future!
From your discussion, the best option for me will be to wait for sBITX v4.
I have not used Raspberry Pi yet, but I am interested in trying it out.
I think sBITX has a little more output, which will be useful for me as a second HF radio. Currently I use an FT-710 purchased last year.
Does sBITX also allow transverter options? Currently I have an IC-2730 which I use for FM repeaters and LEO satellites.
73
Jon, VU2JO.
Jon,
Please tell us a bit more about your plans for the radio.
The zBitx is a pocket sized version of the sBitx. The zBitx has lower output power, a smaller screen, but for the most part runs the same software.
If you want a radio to carry to a remote spot and operate, the zBitx may be the best choice.
If you want a radio to operate from a home QTH, the sBitx might be better (I'd encourage you to wait for the v4 version that is planned, it will have a better, higher-resolution display).
If you want to save money and operate a more basic radio the uBitx might be a better fit, you can buy a board kit and fashion your own case for it, if you like.
BUT, if you want to tinker with the electronics, I'd suggest considering the sBitx or the uBitx, the zBitx would be very challenging to work on the hardware, in my opinion, based on size if nothing else.
If you want to tinker with the software, the zBitx or sBitx would probably be your best bet, since they are based on the popular Raspberry Pi computer board, the software is more accessible, again, in my opinion.
I hope this helps, good luck! Ken, N2VIP ? I do not have a BITX yet, but have been closely following the discussions on the group.
My experience in homebrewing was a few decades back, of a VU2VWN QRP with BD 139 final and a 3 x 807 vacuum tube TX running about 120W DC input.
That means I have not meddled with any radio circuit for the past few decades.
Which one should I start with: uBITX, sBITX or zBITX?
As of now, I have no option for portable operations. Only a fan dipole for 40-10m and a dipole for 80m.
Hoping to receive your valuable suggestions.
73
Jon, VU2JO
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Re: Should I start with uBITX, sBITX or zBITX?
On Sun, Apr 13, 2025 at 07:37 PM, Jon wrote:
Does sBITX also allow transverter options? Currently I have an IC-2730 which I use for FM repeaters and LEO satellites.
?
73
?
Jon, VU2JO.
?
My build has extended operability for use with a transverter on 10 meters. I'd go for the sBitx platform. Much better than the other offerings.
?
?
-JJ
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Re: Should I start with uBITX, sBITX or zBITX?
Ken,
Thanks a lot for the valuable information.
I have no plans for portable operations,?at least in the foreseeable future!
From your discussion, the best option for me will be to wait for sBITX v4.
I have not used Raspberry Pi yet, but I am interested in trying it out.
I think sBITX has a little more output, which will be useful for me as a second HF radio. Currently I use an FT-710 purchased last year.
Does sBITX also allow transverter options? Currently I have an IC-2730 which I use for FM repeaters and LEO satellites.
73
Jon, VU2JO.
Jon,
Please tell us a bit more about your plans for the radio.
The zBitx is a pocket sized version of the sBitx. The zBitx has lower output power, a smaller screen, but for the most part runs the same software.
If you want a radio to carry to a remote spot and operate, the zBitx may be the best choice.
If you want a radio to operate from a home QTH, the sBitx might be better (I'd encourage you to wait for the v4 version that is planned, it will have a better, higher-resolution display).
If you want to save money and operate a more basic radio the uBitx might be a better fit, you can buy a board kit and fashion your own case for it, if you like.
BUT, if you want to tinker with the electronics, I'd suggest considering the sBitx or the uBitx, the zBitx would be very challenging to work on the hardware, in my opinion, based on size if nothing else.
If you want to tinker with the software, the zBitx or sBitx would probably be your best bet, since they are based on the popular Raspberry Pi computer board, the software is more accessible, again, in my opinion.
I hope this helps, good luck! Ken, N2VIP ? I do not have a BITX yet, but have been closely following the discussions on the group.
My experience in homebrewing was a few decades back, of a VU2VWN QRP with BD 139 final and a 3 x 807 vacuum tube TX running about 120W DC input.
That means I have not meddled with any radio circuit for the past few decades.
Which one should I start with: uBITX, sBITX or zBITX?
As of now, I have no option for portable operations. Only a fan dipole for 40-10m and a dipole for 80m.
Hoping to receive your valuable suggestions.
73
Jon, VU2JO
|
Re: Should I start with uBITX, sBITX or zBITX?
Jon,
Please tell us a bit more about your plans for the radio.
The zBitx is a pocket sized version of the sBitx. The zBitx has lower output power, a smaller screen, but for the most part runs the same software.
If you want a radio to carry to a remote spot and operate, the zBitx may be the best choice.
If you want a radio to operate from a home QTH, the sBitx might be better (I'd encourage you to wait for the v4 version that is planned, it will have a better, higher-resolution display).
If you want to save money and operate a more basic radio the uBitx might be a better fit, you can buy a board kit and fashion your own case for it, if you like.
BUT, if you want to tinker with the electronics, I'd suggest considering the sBitx or the uBitx, the zBitx would be very challenging to work on the hardware, in my opinion, based on size if nothing else.
If you want to tinker with the software, the zBitx or sBitx would probably be your best bet, since they are based on the popular Raspberry Pi computer board, the software is more accessible, again, in my opinion.
I hope this helps, good luck!
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Show quoted text
On Apr 13, 2025, at 6:45?PM, Jon via groups.io <vu2jo0@...> wrote:
? I do not have a BITX yet, but have been closely following the discussions on the group.
My experience in homebrewing was a few decades back, of a VU2VWN QRP with BD 139 final and a 3 x 807 vacuum tube TX running about 120W DC input.
That means I have not meddled with any radio circuit for the past few decades.
Which one should I start with: uBITX, sBITX or zBITX?
As of now, I have no option for portable operations. Only a fan dipole for 40-10m and a dipole for 80m.
Hoping to receive your valuable suggestions.
73
Jon, VU2JO
|
Re: Fixed: cw latency and wsjtx/flidigi sidetone
Ron, you seem to know a lot more about that than I do. ?When we changed the polling on the SBitx ?it fixed the problem completely. Can you explain why that worked so well??
Gordon kx4z?
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On Apr 13, 2025, at 18:55, Ron, N6YWU via groups.io <ron.nicholson@...> wrote:
? Is the CW fix time-stamping the key closures in the interrupt handlers? ?If not, you will miss dits, as the code can't tell which key closed first, or if it missed a key closure, via polling of a global variable from a process running on a preemptive non-real-time kernel on a single core processor. ?Every time the Linux OS process dispatcher ticks, your code will have very long gaps in its polling loop. ?With IO pin time stamps, the code has enough information available to see whether it handled that time stamped event or not, and in the correct order. ?Making it much harder to miss dits.
?
The other way to solve the problem might be a hardware change. ?Poll the key inputs with one of the Pi Pico state machines, and have the Pico generate the dot dash timing.
?
73, Ron, n6ywu
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Re: sBitx v3 - next final MOSFET killed
Good, I need to get another 20w kit from you soon. I've been bouncing it between the v3 and my radioberry v2. I eventually found the j7 connection that I missed before, so I could take the signal from there.
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-------- Original message --------
From: K9HZ <bill@...>
Date: 4/13/25 6:37 PM (GMT-05:00)
Subject: Re: [BITX20] sBitx v3 - next final MOSFET killed
And how is that working out for you?
?
?
Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ
?
Owner - Operator
Big Signal Ranch – K9ZC
Staunton, Illinois
?
Owner – Operator
Villa Grand Piton – J68HZ
Soufriere, St. Lucia W.I.
Rent it:
?
Moderator: North American QRO Group at Groups.IO.
Moderator: Amateur Radio Builders Group at Groups.IO.
?
email:?
bill@...
?
?
?
Such is the nature of using MOSFETS not designed for RF amplifiers.? I got so sick of the PA failures with my v3, I built one of K9HZ 20w PA boards and just bypassed the entire PA section of the v3.
-------- Original message --------
Date: 4/12/25 11:39 AM (GMT-05:00)
Subject: [BITX20] sBitx v3 - next final MOSFET killed
My sBitx v3 has killed next final MOSFET. Again, as
previously, only one was dead:
However, this time the failure wasn't caused by overheating (the fan was cooling the heatsink and its temperature was ca 30 C) but by SWR.
I was operating my device remotely via WiFi in FT8 mode, and my ATU got crazy. Unfortunately, I could only see the increase of SWR on my laptop, and the connection got broken. I couldn't cease the transmission immediately. When I reached
the sBitx, it already showed the output power 0W.
Well, when replacing them, I have exchanged the mica insulators with AlN ones. Let's see how long is it going to survive now.
BTW. Is it possible to replace IRF510 with other MOSFETs (maybe more expensive, but offering higher maximum voltage and better power at 28 MHz)?
--
Mike - K8MCB?
-- Mike - K8MCB?
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HA3HZ
K9HZ