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From: Drew
Demarco
Sent: Thursday, September 19, 2024 2:24 AM
Subject: [BITX20] Max pwr on sbitx v3
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I'm confused is? the max pwr on the v3 25w or 40w
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Re: Renewed attempt to hack together a workable PA #uBITX V6
#ubitx
Will do.? The individual W8DIZ amps are very flat from 1-30 MHz. The spice model as I posted has a 0.5 dB drop from about 14 to 30 MHz for the pair. I'm cautiously optimistic, especially since this effort is based on advice from Allison.? I've finally learned enough to understand at least some of what she was trying to teach. Hihi
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73, Andy
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I'm confused is? the max pwr on the v3 25w or 40w
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I got my sBitx yesterday and got it on the air today.? I've made three contacts with it already on 30m CW, but I'm glad to hear that someone is working on the keyer. Right out of the box, the keying is very rough.
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Is there a thread here that will show me how to get this dev code, so I can try it out?
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I can post to both, but I prefer discord to an email list server.?
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With respect, Jeff, you'll not get BITX20 community review if you post something to a discord group most here don't use.? Why not post it here?
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On Tue, Sep 17, 2024 at 12:10 PM, Jeff Duce wrote:
...? I want to go over my design a couple more times and I'll probably post it on the discord for community review...
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Re: Renewed attempt to hack together a workable PA #uBITX V6
#ubitx
Please post a linearity plot when you complete it. ?
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com
email:??bill@... ?
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On Sep 18, 2024, at 2:27?PM, AndyH <awhecker@...> wrote:
? I've decided not to use the K9HZ amp due to its size, and to stick with the QRP-Labs 10 W board with it's much smaller heatsink requirement.? I'm looking for a fairly flat 10 W output from 80 to 10 that will easily fit into the existing uBITX case.
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I think I'll use two stages of slightly modified W8DIZ 2N5109/2SC5551A amps to replace the Q90 and Q911/912 stages.? The attached LTspice model is my current best guess.? The total gain is about 34 dB, with an output of about 1.6-1.65 V peak, slightly above the 1.58 V peak for a 14 dBm input to the QRP-Labs amp.? There appeared to be some gain interactions when adding the second stage - it took a couple of rounds of tweaking to get the gain back in line.? The R14/15/16 pad might need to move up from 3 dB to 4.? We'll see how well hardware mimics spice.
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73, Andy
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<2n5109_Amp_20Bb_3dBpad_transformer_2InSeries.asc>
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Re: Renewed attempt to hack together a workable PA
Sorry...I broke the thread.
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I've decided not to use the K9HZ amp due to its size, and to stick with the QRP-Labs 10 W board with it's much smaller heatsink requirement.? I'm looking for a fairly flat 10 W output from 80 to 10 that will easily fit into the existing uBITX case.
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I think I'll use two stages of slightly modified W8DIZ 2N5109/2SC5551A amps to replace the Q90 and Q911/912 stages.? The attached LTspice model is my current best guess.? The total gain is about 34 dB, with an output of about 1.6-1.65 V peak, slightly above the 1.58 V peak for a 14 dBm input to the QRP-Labs amp.? There appeared to be some gain interactions when adding the second stage - it took a couple of rounds of tweaking to get the gain back in line.? The R14/15/16 pad might need to move up from 3 dB to 4.? We'll see how well hardware mimics spice.
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73, Andy
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With respect, Jeff, you'll not get BITX20 community review if you post something to a discord group most here don't use.? Why not post it here?
?
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On Tue, Sep 17, 2024 at 12:10 PM, Jeff Duce wrote:
...? I want to go over my design a couple more times and I'll probably post it on the discord for community review...
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Re: Renewed attempt to hack together a workable PA #uBITX V6
#ubitx
I've decided not to use the K9HZ amp due to its size, and to stick with the QRP-Labs 10 W board with it's much smaller heatsink requirement.? I'm looking for a fairly flat 10 W output from 80 to 10 that will easily fit into the existing uBITX case.
?
I think I'll use two stages of slightly modified W8DIZ 2N5109/2SC5551A amps to replace the Q90 and Q911/912 stages.? The attached LTspice model is my current best guess.? The total gain is about 34 dB, with an output of about 1.6-1.65 V peak, slightly above the 1.58 V peak for a 14 dBm input to the QRP-Labs amp.? There appeared to be some gain interactions when adding the second stage - it took a couple of rounds of tweaking to get the gain back in line.? The R14/15/16 pad might need to move up from 3 dB to 4.? We'll see how well hardware mimics spice.
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73, Andy
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Re: ubitx audio amp problem discovered
I'm still playing with the subject mic amp and think I can present the best I've been able to come up with in LTspice.? This will be the version I'll build and test once I'm back from the scope rescue mission at the end of the month.? The LTspice schematic/model is attached.
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The original Q6 amp had a bit of distortion into a 1K Ohm load, with a 50 mV peak input signal resulting in +332.6 mV and -383.0 mV. The LTspice FFT showed the 10 kHz input to be at -32 dB with the 20 kHz harmonic at -58 dB.
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The attached model shows that R63 is retained, R64 changes from 1K to 130 Ω, and C62 changes from 47 uF to 0.047 uF.? This combo provides between 140 and 147 mV peak on the positive swing, and between 140-144 mV on the negative side? (it seems to vary between different spice runs. Not sure why.)? LTspice FFT shows the primary 10 kHz signal is now -20 dB and the 20 kHz harmonic is down 47 dB to -67.? The 10uF cap in the buffer provides a much better frequency response than a 1uF.
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FWIW...
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73, Andy, KG5RKP/MM
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Re: uBITX Digital Adapter Board pinouts
Sorry if this is a dumb question, but why do you need this? The ubitx already has cat control and picking off audio is not very difficult. I added a cheap sound card to mine and it does digital modes just fine.
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On Wed, Sep 18, 2024 at 10:03 AM, HA3HZ wrote:
I have another question, the text shown in the picture appears in the comment field in the wsjt-x log. I don't remember what switch I turned on at that time or what I did, but that seems like useless information. How can I remove it without having to delete it every time?
I found the answer to my question. If someone else has a similar problem, check "Special operating activity to comments" on the wsjtx/settings/reporting page, if it is marked, it must be deleted. If it is still present (like mine), you need to find the line shown in the picture in the wsjts.ini file, delete it and save it, then restart wsjtx.
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Gyula HA3HZ
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sbitx_log
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wsjt-x_log
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cqrlog_adi
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Gyula HA3HZ
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sBitx_log file import into cqrlog without GRID
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I use the sbitx device with external jtdx and cqrlog programs due to the shortcomings of the built-in FT8 program and LOG (it does not handle complex callsigns). In the past few days, I returned to using the software of the basic device and tested the software development. I made some QSOs with the basic device, which I copied to an .adif file with the sbitx_log/Export command and copied to cqrlog with the Import command.
The problem is that the data is transmitted without the GRID of the QSO station, with the GRID blank.
I have no problem using cqrlog, it does its job and I can manage the QSOs made on sbitx together.
I wonder if anyone else is experiencing a similar phenomenon?
Could this be related to the fact that one program calls the same data as GRIDSQUARE, while the other calls it SRX_STRING?
Could it be that the data is not visible because of the name difference?
There was a case when I reinstalled the cqrlog program and I imported the old data and it transferred everything without any problems.
What can be the solution?
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I have another question, the text shown in the picture appears in the comment field in the wsjt-x log. I don't remember what switch I turned on at that time or what I did, but that seems like useless information. How can I remove it without having to delete it every time?
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Gyula HA3HZ
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Re: uBITX Digital Adapter Board pinouts
So I broke out the meter. The pinout is in fact incorrect or rather does not follow the industry standard for USB connectors.? ?It *should* be (with USB header pins on the top/left of the board) from left to right, 1/2/3/4 5V/D-/D+/GND.?
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Looking at the pin side of the board with the USB connector on the top/left we actually have? 1/2/3/4 GND/5V/D-/D+.?
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I guess this is not an issue if you are soldering a wire to the pin holes but pre-made header cables will not work. I was trying to avoid soldering wires to this board in favor of the header pins. Luckily I have a stash of pre-wired 4 pin Dupont connectors. Moving the pins around is trivial. I'll just have to make sure I mark the cable correctly as I'll never remember that it's not 1-1 in 5 years time when I service the radio.
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While I was at it I mapped the DB9. Again, from the left of the header 1/6/2/7/3/8/4/9/5.
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I hope this helps someone.
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Mark
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"Jeff Duce" <jefe_de_estado@...> writes: It uses a p-type mosfet with a zener diode. I haven't bothered putting polarity protection on my sbitx yet, but my TeleLaunch rocket launch control system products that run on a nominal-12V SLA battery use the Infineon IPD068P03L3G which is a p-channel FET in an TO252 SMT package for reverse polarity protection. Nearly no drop when things are hooked up correctly since the channel on resistance is only 7 milliOhms typical. The parts are spec'ed for up to 70A at 30V, but we have a self-resetting 30A circuit breaker upstream of them. Works great. 73 - Bdale, KB0G
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I have a love hate relationship with powerpoles.? I mostly hate them.? They are missing many features that make a good connector, but seem to be heavily used in this hobby because they are cheap and can handle high current.? There's no real keying features
for multipin setups, the contact retention method is weak, there's no connector retention method, there's no strain relief for the wire in the crimp, no strain relief for wire going out of the housing... But I do use them just like everyone else, ha! (For
the same reasons, cheap and high current capability).? I haven't seen any other low cost connectors that has all those features, so we're stuck with either XT65s or powerpoles. At least XT65s are keyed. Okay, done with rant.??
What I was drawing up wouldn't rely on the connectors for reverse polarity protection.? It uses a p-type mosfet with a zener diode.? On reverse polarity, Vgs is high, shutting the mosfet which means no current flow through the mosfet.? There is also an overvolt
protection circuit, and an esd protection diode.? Overvolt protection requires a fuse to prevent damage to the power supply, but it does mean that if you accidentally plug in your radio to a 24v source, you're going to pop the fuse.? I want to go over my design
a couple more times and I'll probably post it on the discord for community review.? It will take some time to get boards made and tested, maybe 1 month or more.
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Just know that simply using Power Pole connectors is not the answer. They can still be connected with reverse polarity as they do not have keyed connectors that prevent reverse connections. A red connector will mate perfectly with a black connector and
all it takes is for someone to become confused in the rush of the moment or perhaps someone introduces a power cord they made with the red and black connectors switched from left to right and then when no one notices this, they plug in and BANG!
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Just know that simply using Power Pole connectors is not the answer. They can still be connected with reverse polarity as they do not have keyed connectors that prevent reverse connections. A red connector will mate perfectly with a black connector and all it takes is for someone to become confused in the rush of the moment or perhaps someone introduces a power cord they made with the red and black connectors switched from left to right and then when no one notices this, they plug in and BANG!
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Hey Jeff,
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I’d be interested and I bet that there would be a lot of other people would be interested.
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Robert, AG6LK?
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Platform. That’s the word I meant to say..
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Jens/HB9JOI
Dan Romanchik KB6NU
K9HZ
HA3HZ
Mark Phillips
Bdale Garbee
Gary Eldridge - KC8UD