May 2024 - pacsat-dev - mailman.amsat.org

Re: PA Working!
by Chris Thompson 14 May '24

14 May '24

The power was set very low for bench testing. I put an extra hard coded call to set the register in the TxTask: radio_set_power(0x020); // minimum power to test You can change that line to update the tx power for testing. As Burns said, this all needs to be connected back to commands from the ground, stored in the telemetry etc. 73 Chris On Mon, May 13, 2024, 21:34 Bob Stricklin via pacsat-dev < pacsat-dev(a)amsat.org> wrote: > Thanks Jim. > > Bob > > > On May 13, 2024, at 7:39 PM, Jim McCullers via pacsat-dev < > pacsat-dev(a)amsat.org> wrote: > > The power level is set by registers TXPWRCOEFFE0 and TXPWRCOEFFE1 (0x171 > and 0x170). > The range is 0 to 4095 (0x0fff) with 4095 representing maximum power. > > The documentation leads one to believe the relationship is linear but that > is not the case. > The power level follows a curve best described in the attached document. > See figure 1. > There is no way that I know to write an equation to set a desired level > and a table lookup is required. > The only given is 4095 (0xfff) represents max power, about +17dbm. The > low range is about -10dbm if I recall. > > Jim McCullers > WA4CWI > > > > > DCT is "Digital Command Transponder" which makes about as much sense as > IHU, but it's the Gofl name for the chip. That command can set two levels, > I think, and each pair can be set for either safe mode or non-safe. In > other words, you can set it so if golf is in safe mode, it will be either > high or low, and also if it not in safe mode, it will be high or low. I > don't remember what I did with the command on Pacsat. But look where in > MRAM that command puts a value, and then search for the MRAM name in other > places, and you can probably see what it does to change the power. > > 73, > > Burns Fisher, WB1FJ > *AMSAT**(R) **Engineering -- Flight Software* > > > On Mon, May 13, 2024 at 11:58 AM Bob Stricklin via pacsat-dev < > pacsat-dev(a)amsat.org> wrote: > > We have a functioning PA. The final level is low at this point but that > should be a matter of running things. > > The input drive level is also very low. Is there a provision in the code > to turn adjust the drive level? > I see a command "Set dct drive power” but what is dct? I hope it the name > of the AX5043 register. > Also see “SELECT DCT POWER”. What does this do? > > I hope one of your knows the combination otherwise I can start looking at > the data sheet and manual for AX5043? > > The magic here has to do with the Vbias level on the LDMOS. I just copied > the example in the data sheet and they never talk about what the Vbias > level should be. > The level also sets up the quiescent current in the LDMOS and critically > biases the device. I took out the filtering and matching and just > capacitively coupled the input and output then tuned the > Vbias. The operate point is going to be about 2.9 volts to 3.4 Volts. at > 2.8 volts the Ids through the device is 100 ma and it goes up fast from > there. We will need a Ids of about 300 to get 2W operation. > > WE need to be thinking about turning on and off the supply voltage to the > PA when we transmit. This will save a lot of battery power and a heat > reduction. > > Currently when I turn the Vbias up to about 2.9 volts I get extra > oscillation. This should be eliminated by adding matching components back > in. I have included two images of the signals with and without the > oscillation. The level of output is about -40dBm with the current setup > and it is sending packets to the ground station fine. > > Photo of my setup for spectrum analyzer testing included. Using a stack of > attenuators on transmitter. The Rx antenna is two of the clip leads > together and clipped on Rx antenna. > > One thing to look for at Hamvention would be a low cost rubber ducky > antenna for 2M and 70cm. Either dual band or two singles. If we want to > keep spending money on this we could probably use 8 of these antennas. > > Bob N5BRG > > > > > > > > > > > > <image001.jpg> > > > > <image002.jpg> > > > > <image003.jpg> > > > > > ----------------------------------------------------------- > > pacsat-dev mailing list -- pacsat-dev(a)amsat.org > View archives of this mailing list at > https://mailman.amsat.org/hyperkitty/list/[email protected] > To unsubscribe send an email to pacsat-dev-leave(a)amsat.org > Manage all of your AMSAT-NA mailing list preferences at > https://mailman.amsat.org > > <AX5043_AND9314-D_Power Analysis.PDF> > ----------------------------------------------------------- > > pacsat-dev mailing list -- pacsat-dev(a)amsat.org > View archives of this mailing list at > https://mailman.amsat.org/hyperkitty/list/[email protected] > To unsubscribe send an email to pacsat-dev-leave(a)amsat.org > Manage all of your AMSAT-NA mailing list preferences at > https://mailman.amsat.org > > > > ----------------------------------------------------------- > > pacsat-dev mailing list -- pacsat-dev(a)amsat.org > View archives of this mailing list at > https://mailman.amsat.org/hyperkitty/list/[email protected] > To unsubscribe send an email to pacsat-dev-leave(a)amsat.org > Manage all of your AMSAT-NA mailing list preferences at > https://mailman.amsat.org >

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Re: PA Working!
by Bob Stricklin 14 May '24

14 May '24

Thanks Jim. Bob On May 13, 2024, at 7:39 PM, Jim McCullers via pacsat-dev <pacsat-dev(a)amsat.org<mailto:[email protected]>> wrote: The power level is set by registers TXPWRCOEFFE0 and TXPWRCOEFFE1 (0x171 and 0x170). The range is 0 to 4095 (0x0fff) with 4095 representing maximum power. The documentation leads one to believe the relationship is linear but that is not the case. The power level follows a curve best described in the attached document. See figure 1. There is no way that I know to write an equation to set a desired level and a table lookup is required. The only given is 4095 (0xfff) represents max power, about +17dbm. The low range is about -10dbm if I recall. Jim McCullers WA4CWI DCT is "Digital Command Transponder" which makes about as much sense as IHU, but it's the Gofl name for the chip. That command can set two levels, I think, and each pair can be set for either safe mode or non-safe. In other words, you can set it so if golf is in safe mode, it will be either high or low, and also if it not in safe mode, it will be high or low. I don't remember what I did with the command on Pacsat. But look where in MRAM that command puts a value, and then search for the MRAM name in other places, and you can probably see what it does to change the power. 73, Burns Fisher, WB1FJ AMSAT(R) Engineering -- Flight Software On Mon, May 13, 2024 at 11:58 AM Bob Stricklin via pacsat-dev <pacsat-dev(a)amsat.org<mailto:[email protected]>> wrote: We have a functioning PA. The final level is low at this point but that should be a matter of running things. The input drive level is also very low. Is there a provision in the code to turn adjust the drive level? I see a command "Set dct drive power” but what is dct? I hope it the name of the AX5043 register. Also see “SELECT DCT POWER”. What does this do? I hope one of your knows the combination otherwise I can start looking at the data sheet and manual for AX5043? The magic here has to do with the Vbias level on the LDMOS. I just copied the example in the data sheet and they never talk about what the Vbias level should be. The level also sets up the quiescent current in the LDMOS and critically biases the device. I took out the filtering and matching and just capacitively coupled the input and output then tuned the Vbias. The operate point is going to be about 2.9 volts to 3.4 Volts. at 2.8 volts the Ids through the device is 100 ma and it goes up fast from there. We will need a Ids of about 300 to get 2W operation. WE need to be thinking about turning on and off the supply voltage to the PA when we transmit. This will save a lot of battery power and a heat reduction. Currently when I turn the Vbias up to about 2.9 volts I get extra oscillation. This should be eliminated by adding matching components back in. I have included two images of the signals with and without the oscillation. The level of output is about -40dBm with the current setup and it is sending packets to the ground station fine. Photo of my setup for spectrum analyzer testing included. Using a stack of attenuators on transmitter. The Rx antenna is two of the clip leads together and clipped on Rx antenna. One thing to look for at Hamvention would be a low cost rubber ducky antenna for 2M and 70cm. Either dual band or two singles. If we want to keep spending money on this we could probably use 8 of these antennas. Bob N5BRG <image001.jpg> <image002.jpg> <image003.jpg> ----------------------------------------------------------- pacsat-dev mailing list -- pacsat-dev(a)amsat.org<mailto:[email protected]> View archives of this mailing list at https://mailman.amsat.org/hyperkitty/list/[email protected] To unsubscribe send an email to pacsat-dev-leave(a)amsat.org<mailto:[email protected]> Manage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.org<https://mailman.amsat.org/> <AX5043_AND9314-D_Power Analysis.PDF> ----------------------------------------------------------- pacsat-dev mailing list -- pacsat-dev(a)amsat.org<mailto:[email protected]> View archives of this mailing list at https://mailman.amsat.org/hyperkitty/list/[email protected] To unsubscribe send an email to pacsat-dev-leave(a)amsat.org<mailto:[email protected]> Manage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.org<https://mailman.amsat.org/>

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Re: PA Working!
by Jim McCullers 14 May '24

14 May '24

The power level is set by registers TXPWRCOEFFE0 and TXPWRCOEFFE1 (0x171 and 0x170). The range is 0 to 4095 (0x0fff) with 4095 representing maximum power. The documentation leads one to believe the relationship is linear but that is not the case. The power level follows a curve best described in the attached document. See figure 1. There is no way that I know to write an equation to set a desired level and a table lookup is required. The only given is 4095 (0xfff) represents max power, about +17dbm. The low range is about -10dbm if I recall. Jim McCullers WA4CWI DCT is "Digital Command Transponder" which makes about as much sense as IHU, but it's the Gofl name for the chip. That command can set two levels, I think, and each pair can be set for either safe mode or non-safe. In other words, you can set it so if golf is in safe mode, it will be either high or low, and also if it not in safe mode, it will be high or low. I don't remember what I did with the command on Pacsat. But look where in MRAM that command puts a value, and then search for the MRAM name in other places, and you can probably see what it does to change the power. 73, Burns Fisher, WB1FJ AMSAT(R) Engineering -- Flight Software On Mon, May 13, 2024 at 11:58 AM Bob Stricklin via pacsat-dev <pacsat-dev(a)amsat.org <mailto:[email protected]> > wrote: We have a functioning PA. The final level is low at this point but that should be a matter of running things. The input drive level is also very low. Is there a provision in the code to turn adjust the drive level? I see a command "Set dct drive power” but what is dct? I hope it the name of the AX5043 register. Also see “SELECT DCT POWER”. What does this do? I hope one of your knows the combination otherwise I can start looking at the data sheet and manual for AX5043? The magic here has to do with the Vbias level on the LDMOS. I just copied the example in the data sheet and they never talk about what the Vbias level should be. The level also sets up the quiescent current in the LDMOS and critically biases the device. I took out the filtering and matching and just capacitively coupled the input and output then tuned the Vbias. The operate point is going to be about 2.9 volts to 3.4 Volts. at 2.8 volts the Ids through the device is 100 ma and it goes up fast from there. We will need a Ids of about 300 to get 2W operation. WE need to be thinking about turning on and off the supply voltage to the PA when we transmit. This will save a lot of battery power and a heat reduction. Currently when I turn the Vbias up to about 2.9 volts I get extra oscillation. This should be eliminated by adding matching components back in. I have included two images of the signals with and without the oscillation. The level of output is about -40dBm with the current setup and it is sending packets to the ground station fine. Photo of my setup for spectrum analyzer testing included. Using a stack of attenuators on transmitter. The Rx antenna is two of the clip leads together and clipped on Rx antenna. One thing to look for at Hamvention would be a low cost rubber ducky antenna for 2M and 70cm. Either dual band or two singles. If we want to keep spending money on this we could probably use 8 of these antennas. Bob N5BRG ----------------------------------------------------------- pacsat-dev mailing list -- pacsat-dev(a)amsat.org <mailto:[email protected]> View archives of this mailing list at https://mailman.amsat.org/hyperkitty/list/[email protected] To unsubscribe send an email to pacsat-dev-leave(a)amsat.org <mailto:[email protected]> Manage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.org

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Re: PA Working!
by Burns Fisher (AMSAT) 13 May '24

13 May '24

DCT is "Digital Command Transponder" which makes about as much sense as IHU, but it's the Gofl name for the chip. That command can set two levels, I think, and each pair can be set for either safe mode or non-safe. In other words, you can set it so if golf is in safe mode, it will be either high or low, and also if it not in safe mode, it will be high or low. I don't remember what I did with the command on Pacsat. But look where in MRAM that command puts a value, and then search for the MRAM name in other places, and you can probably see what it does to change the power. 73, Burns Fisher, WB1FJ *AMSAT(R) Engineering -- Flight Software* On Mon, May 13, 2024 at 11:58 AM Bob Stricklin via pacsat-dev < pacsat-dev(a)amsat.org> wrote: > We have a functioning PA. The final level is low at this point but that > should be a matter of running things. > > The input drive level is also very low. Is there a provision in the code > to turn adjust the drive level? > I see a command "Set dct drive power” but what is dct? I hope it the name > of the AX5043 register. > Also see “SELECT DCT POWER”. What does this do? > > I hope one of your knows the combination otherwise I can start looking at > the data sheet and manual for AX5043? > > The magic here has to do with the Vbias level on the LDMOS. I just copied > the example in the data sheet and they never talk about what the Vbias > level should be. > The level also sets up the quiescent current in the LDMOS and critically > biases the device. I took out the filtering and matching and just > capacitively coupled the input and output then tuned the > Vbias. The operate point is going to be about 2.9 volts to 3.4 Volts. at > 2.8 volts the Ids through the device is 100 ma and it goes up fast from > there. We will need a Ids of about 300 to get 2W operation. > > WE need to be thinking about turning on and off the supply voltage to the > PA when we transmit. This will save a lot of battery power and a heat > reduction. > > Currently when I turn the Vbias up to about 2.9 volts I get extra > oscillation. This should be eliminated by adding matching components back > in. I have included two images of the signals with and without the > oscillation. The level of output is about -40dBm with the current setup > and it is sending packets to the ground station fine. > > Photo of my setup for spectrum analyzer testing included. Using a stack of > attenuators on transmitter. The Rx antenna is two of the clip leads > together and clipped on Rx antenna. > > One thing to look for at Hamvention would be a low cost rubber ducky > antenna for 2M and 70cm. Either dual band or two singles. If we want to > keep spending money on this we could probably use 8 of these antennas. > > Bob N5BRG > > > > > > > > > > > > > > > > > > > > > ----------------------------------------------------------- > > pacsat-dev mailing list -- pacsat-dev(a)amsat.org > View archives of this mailing list at > https://mailman.amsat.org/hyperkitty/list/[email protected] > To unsubscribe send an email to pacsat-dev-leave(a)amsat.org > Manage all of your AMSAT-NA mailing list preferences at > https://mailman.amsat.org >

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PA Working!
by Bob Stricklin 13 May '24

13 May '24

We have a functioning PA. The final level is low at this point but that should be a matter of running things. The input drive level is also very low. Is there a provision in the code to turn adjust the drive level? I see a command "Set dct drive power” but what is dct? I hope it the name of the AX5043 register. Also see “SELECT DCT POWER”. What does this do? I hope one of your knows the combination otherwise I can start looking at the data sheet and manual for AX5043? The magic here has to do with the Vbias level on the LDMOS. I just copied the example in the data sheet and they never talk about what the Vbias level should be. The level also sets up the quiescent current in the LDMOS and critically biases the device. I took out the filtering and matching and just capacitively coupled the input and output then tuned the Vbias. The operate point is going to be about 2.9 volts to 3.4 Volts. at 2.8 volts the Ids through the device is 100 ma and it goes up fast from there. We will need a Ids of about 300 to get 2W operation. WE need to be thinking about turning on and off the supply voltage to the PA when we transmit. This will save a lot of battery power and a heat reduction. Currently when I turn the Vbias up to about 2.9 volts I get extra oscillation. This should be eliminated by adding matching components back in. I have included two images of the signals with and without the oscillation. The level of output is about -40dBm with the current setup and it is sending packets to the ground station fine. Photo of my setup for spectrum analyzer testing included. Using a stack of attenuators on transmitter. The Rx antenna is two of the clip leads together and clipped on Rx antenna. One thing to look for at Hamvention would be a low cost rubber ducky antenna for 2M and 70cm. Either dual band or two singles. If we want to keep spending money on this we could probably use 8 of these antennas. Bob N5BRG [cid:[email protected]] [cid:[email protected]] [cid:[email protected]]

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Re: Inductor Insertion
by Jim McCullers 12 May '24

12 May '24

Chis, Since you have Bob’s transformer mods you are good to go. Bob did a nice job on this mod, much better than what I did. Good luck, Jim McCullers WA4CWI Tha is for the pictures Bob. Do we need to make other changes as well? Is this in addition to the changes you made to the balun, or instead of them? Can you provide an updated schematic with the changes? Thanks 73 Chris On Sat, May 11, 2024, 13:20 Bob Stricklin via pacsat-dev <pacsat-dev(a)amsat.org <mailto:pacsat-dev@amsatorg> > wrote: 2 standing on there ends and on top of the capacitors. All 100 uh Bob ----------------------------------------------------------- pacsat-dev mailing list -- pacsat-dev(a)amsat.org <mailto:[email protected]> View archives of this mailing list at https://mailman.amsat.org/hyperkitty/list/[email protected] To unsubscribe send an email to pacsat-dev-leave(a)amsat.org <mailto:[email protected]> Manage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.org

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Re: Inductor Insertion
by Chris Thompson 12 May '24

12 May '24

Tha is for the pictures Bob. Do we need to make other changes as well? Is this in addition to the changes you made to the balun, or instead of them? Can you provide an updated schematic with the changes? Thanks 73 Chris On Sat, May 11, 2024, 13:20 Bob Stricklin via pacsat-dev < pacsat-dev(a)amsat.org> wrote: > 2 standing on there ends and on top of the capacitors. > All 100 uh > > Bob > > > > ----------------------------------------------------------- > > pacsat-dev mailing list -- pacsat-dev(a)amsat.org > View archives of this mailing list at > https://mailman.amsat.org/hyperkitty/list/[email protected] > To unsubscribe send an email to pacsat-dev-leave(a)amsat.org > Manage all of your AMSAT-NA mailing list preferences at > https://mailman.amsat.org >

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Inductor Insertion
by Bob Stricklin 11 May '24

11 May '24

2 standing on there ends and on top of the capacitors. All 100 uh Bob

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Log with RSSI readings
by Bob Stricklin 09 May '24

09 May '24

Log captured with all four receivers set for 145.840 to get common RSSI data. On the ground station log and the satellite log you can see for different transmission responding to a dir request. Bob

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Pacsat dev mtg 5/9/2024
by Bill 09 May '24

09 May '24

Pacsat dev mtg 5/9/2024 Thu, May 9, 2024 7:00 PM - 9:00 PM (CDT) Please join my meeting from your computer, tablet or smartphone. https://meet.goto.com/910630661 You can also dial in using your phone. (For supported devices, tap a one-touch number below to join instantly.) United States: +1 (571) 317-3112 - One-touch: tel:+15713173112,,910630661# Access Code: 910-630-661 Join from a video-conferencing room or system. Dial in or type: 67.217.95.2 or inroomlink.goto.com Meeting ID: 910 630 661 Or dial directly: 910630661(a)67.217.95.2 or 67.217.95.2##910630661 Get the app now and be ready when your first meeting starts: https://meet.goto.com/install

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