The only thing I would worry about with that power supply is, it is a switch mode supply and they tend to put out a lot of hash on the HF frequencies.?
Joel
N6ALT
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Hi
I have been very happy with my ubitx v6.1 and i am using a yaesu power supply with 25 amps but i was thinking about a small power supply that would be more portable.
I bought the 3 amp version of this power supply for my tivo roamio and it works great and i saw they have this 5 amp supply. It works with a 2.1 mm plug and center is positive.
I wonder if anyone has any thoughts regarding this power supply ?
thanks
David W9PH
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Re: sbitx v3 circuit and performance details
Joel -- leave a few for me!! Ashhar has found great solutions.? ? I'm sorry to see the power go down slightly, but I'm guessing the purity got even better.? ?This radio continues to improve!
I hope to box mine up when I get back home in several days.? ? I'll order the TVS diodes and add them later.? ? Make copies of my operating chip and start installing V3 software.
Gordon KX4Z
On Sun, Nov 19, 2023 at 2:50?PM Joel Caulkins/N6ALT < caulktel@...> wrote: Buy 10 and get them for $0.53 each!
Joel
N6ALT
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Re: sbitx v3 circuit and performance details
Buy 10 and get them for $0.53 each!
Joel
N6ALT
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Re: sbitx v3 circuit and performance details
Digikey has 134,000 of those diodes, and they are dirt cheap.? ?$0.64
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Re: strange behaviour of IRF MOSFETs
Just a question, how hot do the 2219As run?
Also the BFR105, how hot?
--
Allison
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Please use the forum, offline and private will go to bit bucket.
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Re: sBitx V2 FT8 Problems
Ashhar,
I was thinking of renaming the sbitx library to sbitxv3. I then cloned it from git.
I copied the necessary files and tested what it does.
I just launched gtk ui. I made some connections, which my automatic saved in a Log file.
At the end of the first connection, he deleted the contents of the qso window.
In the next one, what he saved in a log file, he did not delete, because there was no reply to my R-xx message.
Then I tried the LOG>> button and it worked. I started the WEB and qso is listed twice.
According to them, the microSD card (San Disk Ultra 32GB) could be faulty?
Now I keep the sbitxv3 folder. There might be a bad sector. Just guessing.
--
Gyula HA3HZ
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Re: sbitx v3 circuit and performance details
Farhan,
Would there be any benefit to installing the Transient suppressor diodes if I choose to just keep my PA section using the IRFZ24N FETs?
Joel
N6ALT
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Re: sbitx v3 circuit and performance details
Great work as usual.? ?Providing the VOLTAGES is a great step for folks experiencing "issues" Congrats.
I think I will stick with the existing MOSFETS but I'll look into the transient suppressor you suggest.? ?Thanks! Gordon KX4Z
On Sun, Nov 19, 2023 at 7:55?AM Ashhar Farhan < farhanbox@...> wrote: I have included rf voltages at various points to make it easier for folks to troubleshoot the PA chain. - f
I completed a comprehensive test of sbitx v3 using IRF510s and all the modifications and performance figures are in a document. To put it in a nutshell, the IRF510 PA provides 25 watts upto 10 MHz, 20 Watts to 21 Mhz, and 10 watts on 28 MHz. The power chain is very resilient and useful even for other projects. You can read the details on? The complete circuit diagram?(it is same as v2 except for a few resistors) is on?
- f
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Re: strange behaviour of IRF MOSFETs
What may be forgotten and not checked is maybe the power drop is the driver(s) and prior stages.
Lets assume the gain of the finals is stable but the drive power falls...might the driving source be the cause?
Seems real RF parts also behave wrong.
I do a lot of work with "real RF" parts? and they will behave badly as well if provoked.
To the rest yes good heat sinking helps and bias feedback is desirable to support?
reliability.? Especially when the operating conditions are not optimal like high SWR
or sustained high power.
--
Allison
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Please use the forum, offline and private will go to bit bucket.
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Re: sbitx v3 circuit and performance details
I have included rf voltages at various points to make it easier for folks to troubleshoot the PA chain. - f
I completed a comprehensive test of sbitx v3 using IRF510s and all the modifications and performance figures are in a document. To put it in a nutshell, the IRF510 PA provides 25 watts upto 10 MHz, 20 Watts to 21 Mhz, and 10 watts on 28 MHz. The power chain is very resilient and useful even for other projects. You can read the details on? The complete circuit diagram?(it is same as v2 except for a few resistors) is on?
- f
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sbitx v3 circuit and performance details
I completed a comprehensive test of sbitx v3 using IRF510s and all the modifications and performance figures are in a document. To put it in a nutshell, the IRF510 PA provides 25 watts upto 10 MHz, 20 Watts to 21 Mhz, and 10 watts on 28 MHz. The power chain is very resilient and useful even for other projects. You can read the details on? The complete circuit diagram?(it is same as v2 except for a few resistors) is on?
- f
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Re: sBitx V2 FT8 Problems
Ashhar,
I use a mouse cursor to select. The cursor is in the middle in state I, then the result is correct.
Other. Log input from the keyboard still doesn't work for me.
When it doesn't automatically create a log, I try to enter it and OK, there is nothing in the log.
I repeated this by rebooting and entering the data again, then OK and I still don't see any data in the log.
--
Gyula HA3HZ
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Re: sBitx V2 FT8 Problems
The correct line is selected on mouse up, not mouse down. So slide the finger to the target line and lift the finger.
On Sun, Nov 19, 2023, 1:04 PM HA3HZ < gyula@...> wrote: FT8 works well with V3.
The problem for me is that it is difficult to select the line you want to reply to with the mouse cursor on the 7" screen.
You can read the change from v2 to v3 as I did.
One option is to enlarge the screen with the magnifier that I also use for soldering.
Another is the HDMI monitor. No picture was taken of the latter, but the magnifying glass is here.
--
Gyula HA3HZ
ps.: in reality, there is no such distortion in the picture. the camera sees differently.
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Re: strange behaviour of IRF MOSFETs
I have noticed this even on LDMOS. i dropped AFT05MP075, a 75 watts LDMOS transistor in place of the IRFs. In this setup, there are no thermal pads. The LDMOS is directly soldered onto a small copper block that was bolted to the heatsink. That too exhibited this behaviour.? I also (dangerously) tried tweaking the bias while the output reduced, during transmission to see if the output level can be re established with bias change. That didn't work either. - f
On Sun, Nov 19, 2023, 1:51 PM K9HZ < bill@...> wrote: Whow about real RF transistors?
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it:
email:??bill@... ? On Nov 18, 2023, at 10:45 AM, Joel Caulkins/N6ALT <caulktel@...> wrote:
?Farhan,
I know you have always preferred the IRF510s, but have you considered the IRF530s? I have noticed that most of the cheap Chinese Linear amps use them to get a good 45-50 watts. I just bought a Micro 50 Plus amp that uses a set of 530s. From all the research I have done on the amp, it seems that it is pretty stable and reliable as long as we don't exceed 50 watts. Might work great for a steady 40 watts on the V3.
Joel
N6ALT
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Re: strange behaviour of IRF MOSFETs
Whow about real RF transistors?
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com
email:??bill@... ?
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On Nov 18, 2023, at 10:45 AM, Joel Caulkins/N6ALT <caulktel@...> wrote:
?Farhan,
I know you have always preferred the IRF510s, but have you considered the IRF530s? I have noticed that most of the cheap Chinese Linear amps use them to get a good 45-50 watts. I just bought a Micro 50 Plus amp that uses a set of 530s. From all the research I have done on the amp, it seems that it is pretty stable and reliable as long as we don't exceed 50 watts. Might work great for a steady 40 watts on the V3.
Joel
N6ALT
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Re: strange behaviour of IRF MOSFETs
Most prominently exhibited by those poorly designed amplifiers that do not account for thermal effects to bias related voltages. ?
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com
email:??bill@... ?
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On Nov 18, 2023, at 12:36 PM, ajparent1/kb1gmx <kb1gmx@...> wrote:
?Farhan,
You didn't specify where or details.? This is the revised sBitx or some proto?
What the bias when cold and after immediately after a keydown session?
While my amps do not exhibit this, I've seen it in others especially when??
heating is an issue.? ?
Examples are the usual Ebay "70" watt amps?and similar copies.
--
Allison
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Please use the forum, offline and private will go to bit bucket.
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Re: strange behaviour of IRF MOSFETs
After I modified the output stage circuit at SBitx v2, I only now had the opportunity to test it in reality. There were several reasons for this, I didn't have a usable antenna, which is important. After switching to v3, I tried the device on the air for the first time. I replaced the AlN insulators when it was first discussed here on the forum. I also used a very small amount of Arctic Sliver 5 additive on both sides of the ceramic insulator. This is the weakest link in the heat conduction used here. I find that in long-term FT8 use, the heatsink on the back is approx. 40 degrees, then the current consumption decreases compared to the start. So the regulation takes place so that the output power decreases slightly (according to the instrument, about 1W). I use the device from 12.5V with a current limit of 6.00 Amps. I replaced the IRFZ24Ns once. Since this is from early production, it ran for some reason during setup. The point is that so far I am satisfied with the heat conduction, I have made about 50 connections with the freshly made top-fed delta loop antenna. I scaled it to 7MHz and it has good parameters at 7-14-21 MHz. I would like to thank Ashar for his persistent work. The design is well developed for visual and usability reasons. I didn't take a picture for this topic, but you can find them in another topic. -- Gyula HA3HZ
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Joel Caulkins/N6ALT
HA3HZ
K9HZ