Q70, the audio pre-amp, has a really big job in the uBITX and sometimes gets overdriven by very strong signals. Plus, since i replaced the 2822 audio amp with an LM380 I've lost 8db in audio gain. ?I wondered if another transistor would improve this.
I have some 2sc945 transistors marked with the highest "beta"(AKA hfe) rating, so I took one with a 360 hfe and replaced Q70. ?I made no other component changes. ?The 2sc945 is supposed to be specially designed for audio pre-amps, so it should be good.
The results are totally positive. ?I have more AF gain, the IARU HF contest could not overload it and I did not burn myself with the soldiering iron or drop molten solder onto my bare legs. ?
If you are not needing more AF gain or not hearing any overload distortion, then this mod may not be for you. ?If you are, it works for me.
73,
Tom W1EAT
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Re: BITX QSO Afternoon/Evening, Sunday, July 15, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.
worked N2CQR Bill and WS0JM Jay around 7:30pm 2330Z tonight. very noisy conditions up here tonight too.
73 Tom VE3THR back on the BITX40 and 40M dipole.
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I'm trying to thin down the project list so I'm passing along my uBitX kit.? Ordered it in February, haven't unpacked the kit yet, never built.??
$130 delivered to your door.??
Benteman@...
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Hey Eardan and others: in short, it worked!
I applied the appropriate math as follows. For 100ppm:
875000000 / 10 000 000 * (10,000,100 - 10,000,000)? = 8750
Using the uBitx manager, My Master Calibration was already set to 138,250. So I subtracted 8750 for a total of 129,500.
I noticed that I was sill not quite dead on with WWV. I repeated the measurement and math and ended up with 127,458 for my master calibration value.
Thank you very much! I am much more on frequency now.
Best,
-Jeff AG7EW
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Re: RFI from uBitx TX after AGC and other mods installed
I built my second AGC kit board to see if that helped.? Unfortunately, after installing it, now I have zero RF power out on TX.? No RFI either :) .? I've tried CW, SSB with the mic that worked previously, and using the Tune button in WSJT-X, all of which should cause some RF.? Tried two different watt meters, both register zero.? I can hear a small signal on my IC 7610 when I transmit on the uBitx, so it seems my problem is the PA stage.
I thought maybe the header pins that I soldered and glued to the uBitx board - where the AGC board sits - could be loose, but I am getting a solid 0.0 ohm continuity check between the pins and the trace on either side of where I installed the header pins.? RX works fine, the RF gain control does what you would expect during RX mode.
I tried removing the AGC board and jumpering around the cut in the trace where I installed the header pins for the AGC board - same result.? No power out.
I also tried removing the new AGC board and reinstalling the original one, same result.? The original was giving me power out, but RFI in the headphones when I transmitted.
Maybe it's coincidental, but looks like I've broken something in the PA stage by plugging in the second AGC board kit.? Does that seem possible?? Any likely places to check?? I know, probably a dumb question.
73,
Rowland
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Re: BITX QSO Afternoon/Evening, Sunday, July 15, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.
Wasn't me! U gave up around 7:30 EDT.
--
John - WA2FZW
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Re: BITX QSO Afternoon/Evening, Sunday, July 15, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.
Got a faint answer (made out a possible WA2) at my CQ at around 8:00 p.m. DST. Was it you, John? Everything else is QRN and a lot of static crashes. -- Ion
VA3NOI
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Re: error in memory manager
When I try to use uBITX Manager Ver 0.11 with COM port set to 38400-N-8-1, the Raduino crashes and shows "db>4000000" which I assume mean that it has dropped into its micro debugger.? :-(? This is with factory default firmware which displays "uBITX v4.3" and "USB A:14.252.550" at startup.? I was hoping to use uBITX Manager to back up the current settings before trying CEC firmware.? Any ideas?
73 Mike KK7ER
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Ludwig I have measured the output of mine and the 3.3 V figure is correct when lightly loaded. ?With a 50ohm load it will be considerably less, Because the output impedance is about 1 k ohm
Now it boils down to troubleshooting whether you are using that chip correctly with proper voltages, programming,?at Cetera, or whether that chip is dead.
toggle quoted message
Show quoted text
Hello,
so does nobody have an idea, what might be wrong with my raduino? Which output levels should be generated by the SI5351 chip? The datasheet tells me, the output levels at the clock pins should be near 3.3V but mine aren't. So I wonder, which signals should
be generated by a healthy raduino?
73,
Ludwig, DM2LCT
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Re: BITX QSO Afternoon/Evening, Sunday, July 15, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.
Calling CQ on 7277. Nothing heard so far!
--
John - WA2FZW
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Hello,
so does nobody have an idea, what might be wrong with my raduino? Which output levels should be generated by the SI5351 chip? The datasheet tells me, the output levels at the clock pins should be near 3.3V but mine aren't. So I wonder, which signals should be generated by a healthy raduino?
73,
Ludwig, DM2LCT
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Re: receive works great, but no trans power,
#ubitx-help
Yes. 12.45, same as power source. Also, when i hit the PTT w/o audio, both finals have 3.8v/12.45/0 for g/d/s.? The gate goes from 0 to 3.8 when I hit the PPT.
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Re: Question about Nextion display and firmware
I suggest writing to Ian KD8CEC.? He will proved the source code for beta releases on request.
M
On Mon, 16 Jul 2018 at 6:16 AM, f1apy - Jacques < f1apy@...> wrote: Hello Bo, Many thanks for your responds, and yes, the proc is 2560, I will be very happy if you send me Hex file, I have just some questions about input/output pins for identify differents functions. vY¡¯s 73s de Jacques ¨C F1APY ? I don't think the source files for the latest CEC firmware have been released yet. I may still have an earlier version.
I think the chip you mentioned is a mega2560. If so I could send a hex file of the previous version compiled for the 2560.
If your English is bad, you should see my French . ? Buenos Dias. Bo W4GHV since '54
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Re: ND6T AGC and Click kit wiring notes
A quick answer: The AGC board is fed by a potentiometer (placed across the receive RF input). The release time may be set by a Variable Resistor placed from J1 to the ground return. Details may be obtained by visiting . Have fun! 73, Don
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Re: receive works great, but no trans power,
#ubitx-help
Have you checked the finals for 12 VDC on the tabs?
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Re: Windows Serial Port Problem
Yep, old joke always pertinent: "Windows has detected that the mouse has moved. Please reboot to verify new position."
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Re: Windows Serial Port Problem
I agree with Jack, I have some Arduino's and clones,? the main difference I have seen was price. I have windows 10 now and loaded the CH340 driver and it all works just fine.?
kn4ud
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Allen ?Merrell
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Re: Windows Serial Port Problem
I have probably purchased a 100 clones over the years and, yes, I did have some troubles initially with a few of them, but these were fixed by installing the CH340 drivers in almost every case. Also, it's a bit of a quibble, but non-Arduino boards are not counterfeits, they are second-sourced boards. Counterfeit implies something that is sold illegally as genuine when it is not. As far as I know, the entire Arduino family of boards are Open Source, which means anyone can produce them legally. What would be wrong is to put the Arduino logo on the board, as I believe that is under copyright. eBay has a Nano for sale for $24, and AliExpress has 10 of them for $25. For the difference, I'm willing to (rarely) install the drivers to make them work. I do have my Nano clones working under Win 10, so I'm not sure buying a "genuine" Nano is going to fix the poster's problem.
Jack, W8TEE
On Sunday, July 15, 2018, 3:19:48 PM EDT, Jon Titus, KZ1G <tituskz1g@...> wrote:
Windows 10 might have some driver problems, but the best bet is to buy genuine Arduino products.? People have reported many problems with knock-off "Arduino" boards.? I use genuine Arduino boards with Win 10 without difficulty.? This link at Arduino shows the differences between genuine products and counterfeits.? Yes, you'll pay a bit more, but you won't hassle with problem boards or drivers.
I have no commercial connection with Arduino or any other company.
--
Jon Titus, KZ1G
Herriman, UT USA
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Re: Windows Serial Port Problem
Windows 10 might have some driver problems, but the best bet is to buy genuine Arduino products.? People have reported many problems with knock-off "Arduino" boards.? I use genuine Arduino boards with Win 10 without difficulty.? This link at Arduino shows the differences between genuine products and counterfeits.? Yes, you'll pay a bit more, but you won't hassle with problem boards or drivers.
I have no commercial connection with Arduino or any other company.
--
Jon Titus, KZ1G
Herriman, UT USA
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AG7EW
Ion Petroianu, VA3NOI
Don, ND6T