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Re: uBitx V4 Audio extremely quiet and other needed mods#ubitx
It is Nice , but take precaution to power TDA2822 only with 6V dc by using 7806 only for powering TDA2822. Secondly, never use mono 3.5mm plug in the stereo 3.5mm socket provided for speaker. ?The device would fail. Never plug head / ear phones when RIG is ON. All the best On Mon, Mar 4, 2019 at 7:01 PM Playthatbeat Mrdj <playthatbeat303@...> wrote: Got my TDA2822 in the post, and installed it. I put it on the rear of my case, and fed it with the speaker leads from the audio board that comes with Sunil's case, then i have the output switchable between internal speaker and a minijack for an external speaker. MUCH better. The original drive was so feeble (V4 board) that it's just perfect as input to the TDA2822. I did it like this as i am happy enough with the audio levels i have for digital modes, so this only comes into play for speaker use. |
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Re: uBitx V4 Audio extremely quiet and other needed mods#ubitx
Got my TDA2822 in the post, and installed it. I put it on the rear of my case, and fed it with the speaker leads from the audio board that comes with Sunil's case, then i have the output switchable between internal speaker and a minijack for an external speaker. MUCH better. The original drive was so feeble (V4 board) that it's just perfect as input to the TDA2822. I did it like this as i am happy enough with the audio levels i have for digital modes, so this only comes into play for speaker use.
At full tilt it does not distort, which is a clear win over the stock audio circuit. Great little mod.. |
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Re: Encoder
Hello All I have one (5 volt) of these but I don't know how to wire it on my uBitx v5 please help ! Many thanks. 73' Olivier Le?sam. 2 mars 2019 ¨¤?22:15, ajparent1/KB1GMX <kb1gmx@...> a ¨¦crit?: I have two of those and its 5v for the leds and it works well. |
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Re: Pseudo-Sine?
I mean, sure, but you could also put some filtering on a couple of si5351 outputs to get them to be sine waves, then mix them to get higher frequencies with the kind of control (and yeah, a bandpass filter afterwards.) I've been thinking about doing that for a few rig restorations; it seems a common thing people are doing now to replace old unobtainium VFOs.. -a On Sun, 3 Mar 2019 at 16:58, Dexter N Muir <dexy@...> wrote: I glimpsed an article a while back that said the SI5351 could be driven well beyond HF. If that could be 120MHz, let's fantasize: |
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Re: Pseudo-Sine?
If you were to produce the correct sine values for each point, you are describing a DDS.? If your samples are fast enough, this might push harmonics out - but in the case of a 30MHz carrier (call this Fw, for the wanted frequency) and 120MHz sample rate (call this Fs, for the sample rate), you only have 4 samples per cycle? These 4 samples would be [0, 1, 0, -1] - or apply a DC offset if you choose.? This resulting waveform will result in energy at: Fw (this is good!) (Fs - Fw) (Not good - this is identical to the third harmonic!) Fs (sample rate, also fourth harmonic) (Fs + Fw) (fifth harmonic) (2Fs - Fw) (seventh harmonic) ...and so on. Overall, you would need significantly more samples/waveform to improve upon the 3rd harmonic spur - but I suppose if you varied your samples/waveform as you lowered in frequency, this could actually push out unwanted energy.? Of course, building a discrete DDS DAC and keeping it clean, waveform-wise, isn't easy... 73, Josh, KB8NYP On Sun, Mar 3, 2019 at 7:58 PM Dexter N Muir <dexy@...> wrote: I glimpsed an article a while back that said the SI5351 could be driven well beyond HF. If that could be 120MHz, let's fantasize: |
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Re: How many schematics exist for uBITX
#bitx40help
Do us a favor and include the schematic you are working from.? Then we don't
have to repeatedly query and guess. Allison |
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Re: Pseudo-Sine?
Sure you can go though all that effort and replace the odd harmonics with
even ones that are harder to filter.? Also the added switching. Or just include a series wide band pass pass filters?the sequence can then be half octave or about 5 -6 filters for all of 1.5 to 30. Cleans up the square enough to make it easier to filter and helps with the SSB TX spurs. Allison |
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Re: How many schematics exist for uBITX
#bitx40help
Jon
Q13?? Please notice the designer numbers the transistors in groups -- so they are not consecutive except within a group.? as you look at the schematic you will see that the numbers begin with Q10, then after Q12 the next number maybe Q20.? its just a style to easily ID the subcircuits.?? make sure you have wired in the 4.7k resistor that is needed off-board for CW operation.? the sidetone in the stock unit is quite loud.? check things out using headphones to see what is working.? with v4 there isn't a lot of audio to drive a speaker.? if your receiver is working with headphones, that is a good sign.? a full sized antenna is needed for good receive -- purposely receive gain is scarce to keep the dynamic range very high.?? its a fine rig - be patient to figure it out and make sure all is wired correct.? there is a brief delay in keying CW.? very important - with one 4.7k resistor installed it will only work with a straight key.? to use a paddle, two different value resistors must be placed in each line from the paddle - this is documented somewhere on the web.?? 73 Curt |
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Pseudo-Sine?
I glimpsed an article a while back that said the SI5351 could be driven well beyond HF. If that could be 120MHz, let's fantasize:
120MHz is within the capabilities of an up/down counter. Let's say 0-1-2-3-2-1-0... Now use those logic levels to drive resistive dividers to a common output: Pseudo-sine! (somewhere between square and triangle, with a bit of filtering, more effective approaching 30MHz: the step-frequency is 120MHz, easily filtered out). Different counts could serve different bands or ranges, with the 120 clock varying as required to give finer frequency control. Add the present filtering and you're closer to Sine drive to the finals :) What say? 73 Dex, ZL2DEX |
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Re: Version 5 board 10 meter SSB Spur Test
#ubitx
¿ªÔÆÌåÓýAdjusting the BFO did the trick. For my v5 the BFO is set at 11.055.3Both v3 the BFO is at 11.996.1 One v4 is at 11.996.7 Thanks! On Mar 3, 2019, at 6:47 PM, Gordon Gibby <ggibby@...> wrote:
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Re: Version 5 board 10 meter SSB Spur Test
#ubitx
Gordon Gibby
¿ªÔÆÌåÓýLook at the receiver output of the background galactic white noise using the waterfall of ANY digital protocol. ?It should fall off under 500 Hz. ??
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Re: AF Diode voltage
Jon,
You are welcome.? I did not include the code snippets to do anything other than let you know the default frequencies.? The thing to watch for is that the frequencies are very important for the sensitivity of the rig, and later you could find that the carrier suppression is not what it should be.? None of that is software, other than if set wrong, it could appear as not enough volume when it is the BFO puts the audio into the skirts of the crystal filters. Good luck 73 Evan AC9TU |
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Re: AF Diode voltage
TP12, 15, & 18 are near and under the pcb that carries the raduino. I'm planning on rigging an 750Hz audio signal to the mic connection and start my signal trace from there. I have to stop hit or miss troubleshooting hoping for a luck guess and start at the beginning and go to the end to where the signal stops.
Thanks for your help. Jon S |
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Sending perfect CW via PC
WPX CW contest is approaching... I had still one unsoluted issue with my ver. 3 ubitx (with still the original firmware). Sending perfect CW via a contest program. The ubitx likes clean contacts to send correct CW, even with a vertical key or paddles. My CW optoisolated interface plus a Keyall interface were not enough. I have now added a small relay in between the ubitx and the Keyall. I have tried up to 35wpm and seems great to me. I think I may be ready for the CW WPX :) |
Olivier Grand
Terry Morris
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