Re: ubitx spurs? Added LPF
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Re: ubitx spurs? Added LPF
Ok, I have mounted the LPF filter in a Manhattan style without any glue so I had more flexibility in positioning the toroids, which are very light. I am not sure I understood your spreadsheet. The filter was assumed to reduce some spurs above the 17m band. I'd tuned at 28mhz you should see a 17mhz spur quite attenuated than without this filter (28+17=45mhz). At 21mhz the spur at 28mhz should be attenuated (21+24=45mhz), so on and so forth for any frequency above the 17m band. You show spurs that are not related in this way.
Il 13/apr/2019 11:55, "John Sutter" < jds@...> ha scritto:
Well, that didn't go well.
Looking at it, the two toroids on the left are a little close.
I have a layer of grounded copper foil between
the PCB and the filter (insulated of course).
I might rebuild the filter lying flat.
It looks like I only have 40m and 30m for SSB now.
Input is 1KHz 50mv p-p.
Harmonics on CW follow the spur tables.? Only 80m is not usable
there.
Before
After
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Re: ubitx spurs? Added LPF
Well, that didn't go well.
Looking at it, the two toroids on the left are a little close.
I have a layer of grounded copper foil between
the PCB and the filter (insulated of course).
I might rebuild the filter lying flat.
It looks like I only have 40m and 30m for SSB now.
Input is 1KHz 50mv p-p.
Harmonics on CW follow the spur tables.? Only 80m is not usable
there.
Before
After
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Re: ubitx v5 down: IRF510 heatsink very hot immediately after turning on the radio
#ubitx-help
#ubitx
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I use this ,from {Pacific Electret Microphone kit.Works great Dale/ka5who
On Fri, Apr 12, 2019 at 2:03 PM Curt M. < Kc3hjp@...> wrote: I bought a new old stock Cobra CB mic for $5 and gutted it.? I used the original switch that came with the mic and used the element that came with the uBitx kit and put a 4 pin mic connector on the cord.? I get good audio reports with the stock element.
Curt M.
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Re: Standalone signal analyzer
Update: success with the signal analyzer install! I have moved into my new shack, but no antenna feed through? yet. So will test tomorrow. A lot accomplished today! Waiting on the new bc645 microphone, received the agc kit yesterday! One step at a time. Loving this journey! Breaking out the dummy load tomorrow for testing.
73,
Kelly K5AID?
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Re: Standalone signal analyzer
I thought about that but I wanted to reduce the stress off that 7805 on the raduino, so I added the buck converter to run the display and the extra nano. I have loaded the signal analyzer software on the nano. I have updated the firmware on the raduino to add the signal analyzer with a nextion display and now have the ability to upgrade the raduino firmware, externally. Progress!?
73,?
Kelly K5AID?
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Re: Standalone signal analyzer
Total current would not be even 1 amp, more like 100 ma.? Should not be a problem.? I do know that Dr Lee ran all of the devices off of the same Raduino supply, just added a heat sink.
73
Evan
AC9TU
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Re: ubitx v5 down: IRF510 heatsink very hot immediately after turning on the radio
#ubitx-help
#ubitx
I just thought of another possible problem, Q74 might be shorted.? This would follow the symptom of the injected audio at the volume control not getting to the earphones.
I had feedback is and though that Q74 was the culprit, so did a ohms measurement at TP21 both on receive and transmit (without power to the finals).? Should vary from a couple of hundred ohms to the value of the volume pot (10k if I remember correctly).? I did not have any issues with measuring the resistance while powered.? All but the side tone are dc isolated by capacitors, and there is a 220k ohm resistor in that line.
73
Evan
AC9TU
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Re: ubitx v5 down: IRF510 heatsink very hot immediately after turning on the radio
#ubitx-help
#ubitx
If you have access to a frequency counter or an oscilloscope I would next check the 3 clock signals coming from the Raduino to the uBitx board.?
If you measure approximately 45 MHz- dial setting in Mhz on clock#2, approximately 56 or 34 Mhz on clock#1 and the BFO frequency (11.0555 MHz on my rig) on clock#0, then the Raduino is good.? This can be checked with the Raduino removed from the rig and powered by a micro or mini USB cable depending on? the plug on the Nano in the Raduino.? You do need the display connected to the Raduino so you know what the frequency is.? You should connect the digital control connector as well.? Then measure the clock signals on the pins that would plug into the uBitx main board.
If the Raduino checks outs, then you will need to start doing static voltage tests on the active devices in the rig.
4 main differences between the v3 and the v5 uBitx
1 - First IF after the first mixer transistors were changed, so the static readings for that stage may be different
2 - The SSB crystal frequency was changed from 12 MHz to 11.059 MHz? This means the clock 2 and clock 0 frequences will be different
3 - The audio section was based on a different audio IC than the LM386
4 - The output LPF scheme was changed.
The last change would not affect the receiver.
I believe that there were other changes to improve key click and receiver audio muting.
Above are just suggestions.? I have both v4 and v5 boards, though not v3.
73
Evan
AC9TU
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Re: New siglent on the way
Thank you guys, but I already had a series of adapters, series of of BNC attenuators, a 6 dB N rated at 2 watts and heathkit Cantenna ?with a homemade attenuator and now a commercial 50 W dummy load with a 30 DB tap
On Apr 12, 2019, at 13:20, Jerry Gaffke via Groups.Io < jgaffke@...> wrote:
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Show quoted text
Correction:
The 2000 ohm 3 Watt resistor is Mouser 283-2.0K-RC
On Fri, Apr 12, 2019 at 09:29 AM, Jerry Gaffke wrote:
Forty 2000 ohm resistors in parallel can dissipate 120 Watts,? Mouser 283-20K-RC
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HERE IS A cap (CHEAP AS POSSIBLE) WAY TO CONNECT UbITX OUTPUT TO A SCOPE, METER, FREQUENCY COUNTER OR SPECTRUM ANALYZER
This utube sight has several videos on DIY test gear and dozens on radio repair.
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Some are looking for dummy ;load for uBitx here is watts up
W8TEE designed this dummy load and published it on a webpage (which now seems inactive.) and QST magazine
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Re: Raduino with a different SDR?
I use gqrx on my Ubuntu laptop. I've written several Perl and wxPerl applications that use the UDP interface to implement various scanner functions. The UDP interface implements a subset of the rigctl protocol.
I understand that the RPi should have the add-on heat sinks when running this application.
James
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Standalone signal analyzer
Hi guys it's Kelly I'm thinking of trying to add to Standalone signal analyzer to my ubitx. I have added a buck converter from 12 volts down to 5.1 volts at 3A. I currently have it successfully powering the nextion display. I am thinking I could run the nano for the signal analyzer off the same 5v 3A source without too much loading?? If anyone has any thoughts, I would appreciate it.?
73,
Kelly K5AID?
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I bought a new old stock Cobra CB mic for $5 and gutted it. ?I used the original switch that came with the mic and used the element that came with the uBitx kit and put a 4 pin mic connector on the cord. ?I get good audio reports with the stock element.
Curt M.
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Re: ubitx v5 down: IRF510 heatsink very hot immediately after turning on the radio
#ubitx-help
#ubitx
Hi Evan, I created a small test amplifier on a breadboard to test the uBitx LM386 in isolation. It still works fine. It was an interesting learning experience to build this test circuit: https://photos.app.goo.gl/geLNimcdm4BWw3Av6 With or without antenna I can not hear anything other than noise and a slight clicking noise when I tune to different frequencies. I can increase/decrease the volume of the noise with the volume potentiometer. This probably means the RX problem is located somewhere before the audio amplifier. I did find a 'uBitx diagnostic guide' (written for the uBitx v3, is there a version for the uBitx v5?). I will try to determine how much of this guide is still applicable to the uBitx v5: /g/GCBG/attachment/105/0/uBitxTroubleshooting%20manuala.pdf-jens
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Re: New siglent on the way
Correction:
The 2000 ohm 3 Watt resistor is Mouser 283-2.0K-RC
toggle quoted message
Show quoted text
On Fri, Apr 12, 2019 at 09:29 AM, Jerry Gaffke wrote:
Forty 2000 ohm resistors in parallel can dissipate 120 Watts,? Mouser 283-20K-RC
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Re: Raduino with a different SDR?
Could simply replace the Nano clone on the Raduino with a Raspberry Pi Zero.
Easier to keep all software on one processor, no need to communicate with another processor.?
Would need to port the uBitx Arduino sketch over to C on the Pi Zero, but that should be easy enough.
A high speed morse keyer might be off by a few milliseconds now and then due to
interrupts and Linux housekeeping, but I doubt most of us would notice.
Jerry, KE7ER
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On Fri, Apr 12, 2019 at 02:04 AM, Dexter N Muir wrote:
The RasPi has heaps of GPIO too - I'm wondering if the likes of a 'zero' could take some of the 'control ' and display functions from the Raduino? Would/could I^2C tie them? There must be a heap of non-critical stuff not? absolutely dependent on the microprocessor immediacy? A zero-W could give Internet remote ops too! (or has that already been thrashed and trashed?)
73
ZL2DEX
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Re: New siglent on the way
I'm not so sure there is much point in buying a special high power 20dB attenuator.
Even at 10 Watts, a 20dB attenuator would be rather expensive.
You probably already have a 50 ohm dummy load suitable for use with your transmitter.
If you plan to work on your transmitter at all, you should have a dummy load.??
A 12 Watt 50 ohm dummy load could be built with four 3 Watt 200 ohm resistors in parallel.
You can get ten such resistors for one dollar from Mouser,? part number 283-200-RC
Forty 2000 ohm resistors in parallel can dissipate 120 Watts,? Mouser 283-20K-RC
To reduce transmitter power by a power ratio of 100), must reduce the voltage by a factor of? sqrt(100) = 10.
So add a 450 ohm resistor from the top of your 50 ohm dummy load into your 50 ohm step attenuator,?
The step attenuator must be capable of dissipating 100 milliwatts if the transmitter is giving 10 Watts.
The 50 ohm step attenuator sees a voltage that is reduced by a factor equal to its 50 ohms divided by
the total resistance of that leg, or 50/(450+50) = 0.10, which is a factor of 10 as computed above.
The transmitter will see 50 ohms in parallel with (450+50) ohms, or 50*500/(50+500) = 45.5 ohms,
close enough for government work.? Could correct this 10% error by making your dummy load
look like 55.55 ohms instead of 50 ohms by adding a 1/8 Watt 5.55 ohm resistor in series with it.?
(The 5.55 ohm resistor only sees 1/10'th of the transmitter's voltage, so only 1/100'th of the power.)
Kees has a kit available for a step attenuator at a good price, kit number 13 here:
? ??
Jerry, KE7ER
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On Fri, Apr 12, 2019 at 04:51 AM, Raj vu2zap wrote:
Congrats, you will learn a lot from an analyser.
You will also need some attenuators and dummy load type power attenuators.
A 30db power attenuator rated for more than 100W will suffice even for commercial rigs. For uBitx and such
25W should do.
You will also need optionally a variable attenuator, one that has 0-9db and 0-90db steps. With this you can
set any power input to 0dbm at the SA input.
Raj
What I use is similar to this one below and this is fixed after the big dummy attenuator below. This brand will be expensive.
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Raj vu2zap
