Re: Do you hate to wind toroids?
I scrape with?a?box knife then burn with a torch lighter.? Works well.
I don't mind winding them but striping the enamel insulation is a real PITA,
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Re: Do you hate to wind toroids?
I don't mind winding them but striping the enamel insulation is a real PITA,
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Re: Do you hate to wind toroids?
I actually like winding toroids, something cathartic?about it.
On Thu, Aug 11, 2022 at 7:29 PM Tom Sevart < tmsevart@...> wrote: You know, winding toroids never bothered me.
--
Tom Sevart N2UHC
St. Paul, KS
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Re: Do you hate to wind toroids?
You know, winding toroids never bothered me.
--
Tom Sevart N2UHC
St. Paul, KS
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Re: sBITX transmit problem - low analog drive signal?
#sBitx
I tried making a more quantified test by driving the mic input in LSB with a signal generator with Watts set to 10 on 40 meters. What I saw was that with a 1 kHz signal at less than 8 microvolts (signal 6 divisions on scale) there was no RF out. At 9 microvolts the signal would go from 7 divisions to suddenly off the scale and the RF jump up 12 watts. It looks like I see no output or it drives to oscillation.
I do have a scope, but without info on expected signals a different locations I don't know what to do next. I am not a hardware designer. I am experienced in C/C++ on the Pi and had hoped to make software contributions.
--
? 73
??? Bob? KD8CGH
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Re: Ubitx Ver 6 need PTT circuit for Linear AMP
To bring this all to a close -? K1 relay, Pin #9 is the only pin that when PTT is activated goes to 12v.? So the anotated drawing looks like this -  --Thanks for all the help - This circuit works.? I used a high dollar digital relay that I had lying around.? KG5UMH Michael - DM93am
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Re: sBitx antenna-first warning
Is the idea to "nerf" the transmit via software if the SWR is too high ?
This could be a handy approach as it would potentially allow the sbitx to be integrated with other hardware/software such as Johan's very excellent PowerMeter.
On Thu, 11 Aug 2022 at 16:38, Ashhar Farhan < farhanbox@...> wrote: I am building a stockon add on for the sbitx. I will add a raspberry pico as the measuring device that you can plug into the usb port. - f
Another way NFETs can be destroyed is exceeding Vgs limits (voltage from gate to source).
This could be due to a long source lead to ground, or a poor ground plane.
This could be due to capacitance from the drain to the gate yanking the gate around
when the drain zips up and down some 24 volts, if the gate is not being driven by a source of low enough impedance.
An NFET designed for RF makes things easier because:
1)? The source lead is often connected to the heat sink tab, which is handy because we usually want to ground the source.
?On the IRF510, it is the drain that is connected to the heat sink tab.
2) An RF NFET is designed to have lower internal capacitances, making the gate easier to drive.
3) AN RF NFET comes with app notes describing a recommended design for an RF amp.
The IRF510 was meant for blinking automotive turn signals, does not have an app note for operation at 30 mHz.
Even when following app notes describing a well thought out design,
building an RF amp that works well can be tricky.
Jerry, KE7ER
On Thu, Aug 11, 2022 at 07:11 AM, Jerry Gaffke wrote:
I'd be more worried about shorts at the antenna, as it is excessive current (and subsequent heating) that will destroy the IRF510's.
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Re: sBitx antenna-first warning
Yes that definitely works. I will turn in car tomorrow. Thanks?
toggle quoted message
Show quoted text
On Aug 11, 2022, at 10:11 AM, Jerry Gaffke via groups.io <jgaffke@...> wrote:
?I could be proven wrong, but I doubt a zener is needed on the uBitx.? The uBitx has a forward transformer at the output which develops 24 volts (roughly) across the push-pull FET's regardless of how it is loaded.? The IRF510's have a Vds max of 100 volts. Should be fine with or without an antenna. The Bitx40 with the flyback transformer at the output is a different story, but the Miller effect is there to catch you. You do often see zener's on single NFET finals like the Birtx40 and the ones Demaw often used. /g/BITX20/message/84987I'd be more worried about shorts at the antenna, as it is excessive current (and subsequent heating) that will destroy the IRF510's. Some way of limiting current (perhaps just a fuse or polyswitch, or a wimpy power supply) might be sufficient, as it will take a second for the heat to build up enough to destroy the IRF510.? I think. Don was burning up his IRF510's when operating with 24 volts into the final.? Keep things at 12 volts and add a polyswitch if you want something reasonably bulletproof. Some RF NFETs claim to tolerate any SWR. They assume you use their circuit design recommendations and don't exceed the recommended supply voltage. Any NFET can be bulletproof if used conservatively. Any NFET can be blown away if you push things. Jerry KE7ER On Thu, Aug 11, 2022 at 06:19 AM, Anthony Good wrote:
On an aside, could a strategically placed zener diode or two on the finals prevent damage? ?Doug Demaw recommended this on NPN finals in his books.
?
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Re: callsign command not found
You can also type inside sbitx from your regular keyboard
On Thu, Aug 11, 2022, 11:00 PM James Conaway < jwc7992@...> wrote:
Okay got it. From on screen keyboard.
Thanks
On 8/11/2022 12:24 PM, James Conaway
via wrote:
Thanks Anthony, for the quick reply.
I went to terminal changed directory "cd /home/pi/sbitx"? and
get command not found.
I am 84 yr old and have not used linux in many years.
Also when I click on thes bitx icon in comes up in Ft8?? I know
I am doing something wrong.
James
On 8/11/2022 11:52 AM, Anthony Good
wrote:
If you¡¯re attempting these commands in the OS terminal, they
will not work.? You need to be in sbitx.? Also, the commands
within sbitx are case sensitive.
On Aug 11, 2022, at 12:49, James Conaway
< jwc7992@...>
wrote:
I keep getting "command not found" when
trying to enter "callsign" or "grid". Which directory
should I be in to do this?
I have done "git pull" and ./build and every thing went
fine. HELP PLEASE.
james
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Re: callsign command not found
Okay got it. From on screen keyboard.
Thanks
On 8/11/2022 12:24 PM, James Conaway
via groups.io wrote:
toggle quoted message
Show quoted text
Thanks Anthony, for the quick reply.
I went to terminal changed directory "cd /home/pi/sbitx"? and
get command not found.
I am 84 yr old and have not used linux in many years.
Also when I click on thes bitx icon in comes up in Ft8?? I know
I am doing something wrong.
James
On 8/11/2022 11:52 AM, Anthony Good
wrote:
If you¡¯re attempting these commands in the OS terminal, they
will not work. ?You need to be in sbitx. ?Also, the commands
within sbitx are case sensitive.
On Aug 11, 2022, at 12:49, James Conaway
< jwc7992@...>
wrote:
I keep getting "command not found" when
trying to enter "callsign" or "grid". Which directory
should I be in to do this?
I have done "git pull" and ./build and every thing went
fine. HELP PLEASE.
james
|
Re: callsign command not found
You need to be *within the sbitx app* to execute the commands, not a terminal. ?When the sbitx app GUI loads, run the commands in there.
toggle quoted message
Show quoted text
On Aug 11, 2022, at 13:24, James Conaway < jwc7992@...> wrote:
Thanks Anthony, for the quick reply. I went to terminal changed directory "cd /home/pi/sbitx"? and get
command not found. I am 84 yr old and have not used linux in many years. Also when I click on thes bitx icon in comes up in Ft8?? I know I
am doing something wrong. James
On 8/11/2022 11:52 AM, Anthony Good
wrote:
If you¡¯re attempting these commands in the OS terminal, they will
not work. ?You need to be in sbitx. ?Also, the commands within
sbitx are case sensitive.
On Aug 11, 2022, at 12:49, James Conaway < jwc7992@...>
wrote:
I keep getting "command not found" when trying
to enter "callsign" or "grid". Which directory should I be
in to do this?
I have done "git pull" and ./build and every thing went
fine. HELP PLEASE.
james
|
Re: callsign command not found
Thanks Anthony, for the quick reply.
I went to terminal changed directory "cd /home/pi/sbitx"? and get
command not found.
I am 84 yr old and have not used linux in many years.
Also when I click on thes bitx icon in comes up in Ft8?? I know I
am doing something wrong.
James
On 8/11/2022 11:52 AM, Anthony Good
wrote:
toggle quoted message
Show quoted text
If you¡¯re attempting these commands in the OS terminal, they will
not work. ?You need to be in sbitx. ?Also, the commands within
sbitx are case sensitive.
On Aug 11, 2022, at 12:49, James Conaway < jwc7992@...>
wrote:
I keep getting "command not found" when trying
to enter "callsign" or "grid". Which directory should I be
in to do this?
I have done "git pull" and ./build and every thing went
fine. HELP PLEASE.
james
|
Re: callsign command not found
If you¡¯re attempting these commands in the OS terminal, they will not work. ?You need to be in sbitx. ?Also, the commands within sbitx are case sensitive.
toggle quoted message
Show quoted text
On Aug 11, 2022, at 12:49, James Conaway < jwc7992@...> wrote:
I keep getting "command not found" when trying to enter "callsign" or "grid". Which directory should I be in to do this?
I have done "git pull" and ./build and every thing went fine. HELP PLEASE.
james
|
callsign command not found
I keep getting "command not found" when trying to enter "callsign" or "grid". Which directory should I be in to do this?
I have done "git pull" and ./build and every thing went fine. HELP PLEASE.
james
|
Re: Ubitx Ver 6 need PTT circuit for Linear AMP
That section of the schematic goes back to v3:  You can see that K3 and the other relays use the same part model to make the circuit board.? When things changed in the v6, the board had to change significantly.? When that was done, the model for the relays other than K1 was updated, and the correct pins were used to mark the connections. v6 schematic:  Doing the conversion, it is either pin 8 or 9 on the part model from the manufacturer.? Look at the board and see which one is grounded on that end of the relay.? It would be the other one.? Then test to verify that the pin does go to 12volts when transmitting. As always, check whatever you are given for advice that is free.? That includes anything from me ;-) 73 Evan AC9TU
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Re: Do you hate to wind toroids?
Fully wired, but abandoned because too much interference and interference. But it¡¯s beautiful.? LOL
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Re: Do you hate to wind toroids?
Hello,
I¡¯ve always made the reels by hand. It takes a little agility.
Here is the first result on a double-sided circuit.
Then the 2nd version and the 3rd...
Only for reception; but planned for emission LOL.?
cdt
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Re: sBitx antenna-first warning
Check the J1 on the digital board. There are two digital line left free and? +5v and ground. - f
On Thu, Aug 11, 2022, 9:24 PM Ken N2VIP < ken@...> wrote: That sounds like an excellent approach, while the sBitx may be viewed as a hackers/experimenters radio, all but inviting its owner to grab a soldering iron and modify the radio, a fair number of owners may not be comfortable cracking open their $300-500 radio and poking a hot sokderingbiron inside of it. Ken, N2VIP ? I am building a stockon add on for the sbitx. I will add a raspberry pico as the measuring device that you can plug into the usb port. - f Another way NFETs can be destroyed is exceeding Vgs limits (voltage from gate to source).
This could be due to a long source lead to ground, or a poor ground plane.
This could be due to capacitance from the drain to the gate yanking the gate around
when the drain zips up and down some 24 volts, if the gate is not being driven by a source of low enough impedance.
An NFET designed for RF makes things easier because:
1)? The source lead is often connected to the heat sink tab, which is handy because we usually want to ground the source.
?On the IRF510, it is the drain that is connected to the heat sink tab.
2) An RF NFET is designed to have lower internal capacitances, making the gate easier to drive.
3) AN RF NFET comes with app notes describing a recommended design for an RF amp.
The IRF510 was meant for blinking automotive turn signals, does not have an app note for operation at 30 mHz.
Even when following app notes describing a well thought out design,
building an RF amp that works well can be tricky.
Jerry, KE7ER
On Thu, Aug 11, 2022 at 07:11 AM, Jerry Gaffke wrote:
I'd be more worried about shorts at the antenna, as it is excessive current (and subsequent heating) that will destroy the IRF510's.
|
Re: sBitx antenna-first warning
That sounds like an excellent approach, while the sBitx may be viewed as a hackers/experimenters radio, all but inviting its owner to grab a soldering iron and modify the radio, a fair number of owners may not be comfortable cracking open their $300-500 radio and poking a hot sokderingbiron inside of it. Ken, N2VIP
toggle quoted message
Show quoted text
On Aug 11, 2022, at 10:38, Ashhar Farhan <farhanbox@...> wrote:
? I am building a stockon add on for the sbitx. I will add a raspberry pico as the measuring device that you can plug into the usb port. - f Another way NFETs can be destroyed is exceeding Vgs limits (voltage from gate to source).
This could be due to a long source lead to ground, or a poor ground plane.
This could be due to capacitance from the drain to the gate yanking the gate around
when the drain zips up and down some 24 volts, if the gate is not being driven by a source of low enough impedance.
An NFET designed for RF makes things easier because:
1)? The source lead is often connected to the heat sink tab, which is handy because we usually want to ground the source.
?On the IRF510, it is the drain that is connected to the heat sink tab.
2) An RF NFET is designed to have lower internal capacitances, making the gate easier to drive.
3) AN RF NFET comes with app notes describing a recommended design for an RF amp.
The IRF510 was meant for blinking automotive turn signals, does not have an app note for operation at 30 mHz.
Even when following app notes describing a well thought out design,
building an RF amp that works well can be tricky.
Jerry, KE7ER
On Thu, Aug 11, 2022 at 07:11 AM, Jerry Gaffke wrote:
I'd be more worried about shorts at the antenna, as it is excessive current (and subsequent heating) that will destroy the IRF510's.
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Re: sBitx antenna-first warning
Good deal!
On an aside, I believe I read in a post a few weeks ago that all the Pi GPIO lines are used by the sBitx? ?I haven¡¯t had time yet to study the schematic to fully understand the GPIO usage. ?Undoubtedly, hackers like me are going to need I/O lines to interface with ¡°stuff". ?Could this outboard Raspberry Pico give us some more I/O pins to work with?
73 Goody
toggle quoted message
Show quoted text
I am building a stockon add on for the sbitx. I will add a raspberry pico as the measuring device that you can plug into the usb port. - f Another way NFETs can be destroyed is exceeding Vgs limits (voltage from gate to source).
This could be due to a long source lead to ground, or a poor ground plane.
This could be due to capacitance from the drain to the gate yanking the gate around
when the drain zips up and down some 24 volts, if the gate is not being driven by a source of low enough impedance.
An NFET designed for RF makes things easier because:
1)? The source lead is often connected to the heat sink tab, which is handy because we usually want to ground the source.
?On the IRF510, it is the drain that is connected to the heat sink tab.
2) An RF NFET is designed to have lower internal capacitances, making the gate easier to drive.
3) AN RF NFET comes with app notes describing a recommended design for an RF amp.
The IRF510 was meant for blinking automotive turn signals, does not have an app note for operation at 30 mHz.
Even when following app notes describing a well thought out design,?
building an RF amp that works well can be tricky.
Jerry, KE7ER
On Thu, Aug 11, 2022 at 07:11 AM, Jerry Gaffke wrote:
I'd be more worried about shorts at the antenna, as it is excessive current (and subsequent heating) that will destroy the IRF510's.
|
Bob Benedict, KD8CGH
Gerard
