Date   

Re: Audio bandwidth between the product detector and VOL-H

Rob French (KC4UPR)
 

Hey Evan,  thanks for the input.

I've actually previously done some DSP filtering with the Teensy, I had it communicating with the Raduino Nano via serial, to coordinates modes.  Unfortunately, I accidentally killed my Teensy by plugging things into my level shifter wrong once (I had to unplug the Teensy from the Raduino to update the Nano, otherwise the serial would interfere).

This time around, I will try using I2C to communicate between the Teensy and the Raduino (yes, I could use JackAl or something similar... JackAl is the only one that also uses the Teensy Audio Adapter, which is part of my setup). 

Anyway, yeah, I could simply do the DSP at normal audio frequencies like I did previously.  This was just some thinking for experimentation.  My uBITX is never done...

Rob
KC4UPR


Re: Receive only version?

Bob, N1KPR
 

I have not actually spec'd out the receiver yet, but can tell you that it is very sensitive and the MDS is excellent...guessing about -130dB. The one (of many) receiver controls missing is AGC for general SWLing. If I was going to build one for receive-only, I'd cut the 12V T/R relay rail and add an audio leveler to act as AGC (link below). Another definite addition would be a real RF Gain control. I'm using a 5K pot as an attenuator in the front end. And, of course, all receivers need an S-Meter. It would be a fun project for an SWLer who has some tech skills. Half the fun is building this stuff.

Go to the 3-minute mark to see the leveler

and the complete system here:

Gud signals to all,
Bob, N1KPR







NOTE Pls add backup address to your phone book: rwbetts@...

http://www.bobsamerica.com  http://www.youtube.com/n1kpr

Engineering: Where Enigma meets Paradox


On Wednesday, September 2, 2020, 8:08:08 AM EDT, Bill Cromwell <wrcromwell@...> wrote:


Hi Gerald,

Your idea really is practical. To assure your radio does not transmit
you can disconnect the CW key line and the Push to talk. You could go so
far as removing the finals but just turning the bias and drive pots all
the way down should be good - just in case it does get put into
transmit. Some day you may want to sell it to a licensed ham (or get
your own ham license). All you have to do is connect those CW and PTT
lines and set up the bias and drive.

The fact is - I do a lot more listening than transmitting even though I
am licensed. I already have a general coverage receiver but I also use
my V3 for SWL. I also use it as a signal tracer and heterodyne frequency
meter on my bench. You do not have to transmit to get some work out the
uBitX.

73,

Bill  KU8H

bark less - wag more

On 9/2/20 7:46 AM, Gerald Bramwell wrote:
> Hi all,
>
> As a SWL for a number of years and haveing found this group, I was
> wondering if a receive only version could be built as it looks like a
> very interesting project.
> 73s
> Gerald Bramwell (RS49875)
>




Re: Receive only version?

iz oos
 

Indeed, It could be. But consider that a Tecsun PL660 costa less than 100usd, is sensitive, sounds good, forse have synch detection, AGC. A ubitx receiver would be interesting but the ubitx is very convenient as a transceiver as a multiband QRP can cost 1000usd or even more.


Il mer 2 set 2020 01:46 PM Gerald Bramwell <gerald.bramwell@...> ha scritto:
Hi all,

As a SWL for a number of years and haveing found this group, I was wondering if a receive only version could be built as it looks like a very interesting project.
73s
Gerald Bramwell (RS49875)


Re: Receive only version?

Bill Cromwell
 

Hi Gerald,

Your idea really is practical. To assure your radio does not transmit you can disconnect the CW key line and the Push to talk. You could go so far as removing the finals but just turning the bias and drive pots all the way down should be good - just in case it does get put into transmit. Some day you may want to sell it to a licensed ham (or get your own ham license). All you have to do is connect those CW and PTT lines and set up the bias and drive.

The fact is - I do a lot more listening than transmitting even though I am licensed. I already have a general coverage receiver but I also use my V3 for SWL. I also use it as a signal tracer and heterodyne frequency meter on my bench. You do not have to transmit to get some work out the uBitX.

73,

Bill KU8H

bark less - wag more

On 9/2/20 7:46 AM, Gerald Bramwell wrote:
Hi all,
As a SWL for a number of years and haveing found this group, I was wondering if a receive only version could be built as it looks like a very interesting project.
73s
Gerald Bramwell (RS49875)


Ubitx audio Vogad/AGC

iz oos
 

Hello everybody, I use and SL6270 as a mic preamp/compressor. As essentially is a sort of AGC and, in my opinion, works really great at the mic input, I am thinking of adding at C222 of my ver.3. would It possibly work? The input and output impedance are about 600 ohm, It delivers about 100mv RMS and the input level can be anything between 0 and 100mv. Would 100mv enough for high impedance headsets?


Receive only version?

Gerald Bramwell <gerald.bramwell@...>
 

Hi all,

As a SWL for a number of years and haveing found this group, I was wondering if a receive only version could be built as it looks like a very interesting project.
73s
Gerald Bramwell (RS49875)


VK4PP ultimate add-on boards #ubitx

Jeroen Bastemeijer <pe1rge@...>
 

Dear all,

I was looking for information on the VK4PP ultimate add-on boards. According to VK4PP's site it would be made available. However, I'm not able to find it... Can someone give me a pointer?

The information I'm looking for are Gerbers or other design files, schematic diagram, bill of materials, etc.

Thank you, best 73 Jeroen PE1RGE


Re: Audio bandwidth between the product detector and VOL-H

Evan Hand
 

Rob,
I am not the expert on the frequency response of the audio sections of the uBITX, however the preamp should be able to handle the higher frequencies.  The issue I am sure that you will have is the transmit side.  The same BFO and product detector are used to create the transmitted signal that then goes through the SSB filter.  You will either have to use the DSP to transform the mic audio to the correct frequency so that the product detector mixer than adds the correct carrier or change the BFO in the Nano program when transmitting.  You could do some audio compression algorithms for that, it will require a second DAC or relays to feed the current mic preamp.

My question back is why not just do the DSP at the current audio frequencies?  There are audio DSP filters that can be bought to lower the bandwidth to a couple of hundred hertz for CW, so it has been done.  There are also add on boards with higher processing capabilities that can be reprogramed to what you might want to do in the DSP.  One that comes to mind is the JackAl board, though this is no longer available from QRPGuys.  There is also the Teensy upgrade to replace the Nano.  This would give you extra program and I/O space if you want to play there.

My thoughts.  WARNING, they could be wrong.
73
Evan
AC9TU


Re: Aardpen antenna

 

Hams living in the northern latitudes may improve their earthing with the help of a naked hot headed Ice borer.
It is fully described on Wikipedia.


At 02/09/2020, you wrote:
There is an much easier way. The trouble with most antennas is improper grounding. As thr coax to the antenna is suffers from bad grounding, the radio too has bad grounding. From there, it continues to the earphones and finally to the operators ears.
Solution is drastic, we can either ground it well at the antenna end or the operator end. A trick used by the early pioneers of the wild west operators is to simply keep one ear to the ground. The operator lies on the field with one ear to the ground. Depending upon the polarization needed, you can choose left or right ear. Hold the earphone to the other ear. If works best if there is moisture in the ground. A bucket of water splashed a few minutes before the contest is recommended. Change shirts frequently.Â
- f

On Wed 2 Sep, 2020, 11:29 AM Gerard, <kabupos@...> wrote:
hello,
I see the specialists
I found it strange too. LOL
Viewed well.
have a nice day
cdt


Re: Aardpen antenna

Ashhar Farhan
 

There is an much easier way. The trouble with most antennas is improper grounding. As thr coax to the antenna is suffers from bad grounding, the radio too has bad grounding. From there, it continues to the earphones and finally to the operators ears.
Solution is drastic, we can either ground it well at the antenna end or the operator end. A trick used by the early pioneers of the wild west operators is to simply keep one ear to the ground. The operator lies on the field with one ear to the ground. Depending upon the polarization needed, you can choose left or right ear. Hold the earphone to the other ear. If works best if there is moisture in the ground. A bucket of water splashed a few minutes before the contest is recommended. Change shirts frequently. 
- f

On Wed 2 Sep, 2020, 11:29 AM Gerard, <kabupos@...> wrote:
hello,
I see the specialists
I found it strange too.
LOL
Viewed well.
have a nice day
cdt


Re: Aardpen antenna

Gerard
 

hello,
I see the specialists
I found it strange too.
LOL
Viewed well.
have a nice day
cdt


Audio bandwidth between the product detector and VOL-H

Rob French (KC4UPR)
 

I have a uBITX v5 that I have been playing around with in many ways, for many months.  I'm revisiting some earlier DSP work I had done, and had a thought.

I want to try a 3rd "DSP" IF of around 16 kHz or so.  The idea with that is that:
(a) I could quash some low frequency noise and birdies,
(b) I could do some passband tuning (including width) in the DSP.

So the 2nd IF would be unchanged, but then I would lower the frequency of the BFO by 16 kHz, with the result that the desired signal at the output of the product detector would be in a ~3 kHz band from 16-19 kHz (-ish).  (I'm sure I'm missing something here...)

My question is, will the circuit from the output of the product detector, to VOL-H, support audio frequencies up to ~20 kHz with minimal loss?  I don't see any significant filtering, but at the same time, I can't imagine the circuit was originally designed intentionally to pass more than ~3 kHz, so...

The DSP would be inserted between VOL-H and the actual volume control.

Regards,
-Rob KC4UPR


Re: Serial cable to usb dongle to usb cable

Owen Vinall
 

Hi Christopher, 
Re Serial cable length.
Typical I. T. Answer I'm afraid.
Given decent cable terminated correctly and decent Line driver chips 100's of metres but the higher the baud rate or speed the shorter the distance. I believe the line driver chips/ interface in Arduino's were not designed for distance. I have plenty of info and suggestions but to keep it simple what distances are you aiming for ? Part of my job was squeezing the longest distance possible for Comms eg Rs232 on Copper via Radio links Fibre etc etc.

On Wed, 2 Sep 2020, 12:51 am Christopher Miller, <djmalak2k6@...> wrote:
Does anyone know the maximum reach of a serial cable and usb cables?

I have a pc across my bedroom and between my serial dongle and radio I would like to start getting digital modes going. Sorry for the basic questions.

KF4FTR


New TFT file for Nextion Enhanced 3.2 with CEC 1.2 #nextion

Rob French (KC4UPR)
 

Hey all,

I'm guessing no one cares much at this point (may be obsolete), but I've created an updated set of displays for use with the CEC firmware version 1.2 and a 3.2" Nextion Enhanced display.  Why?

1. The "stock" 3.2" Nextion display works on a 3.2" display, but doesn't actually scale to fill the display (I'm assuming it was just reformatted from a 2.8" display).
2. The only other suitable TFT file I could find for a 3.2" display, was made for an earlier version of the CEC firmware, so it was missing some functionality and didn't fully work.

So, voila... This one is scaled to use the full display.

https://groups.io/g/BITX20/files/3.2%20Enhanced%20Nextion%20for%20CEC%201.2/ubitx_Nextion32E_20200901.zip

I will note, I have successfully used it with the following display, which appears to be a Nextion clone.  Nextion wasn't originally in my uBITX plans, but I happened across this display for $19.99.  Sadly, it is no longer being sold at that price on Amazon, now it's up to $35.99.

Regards,
-Rob KC4UPR


Re: CW Keyboard and decoder #cw

Slurm <42irongazelle@...>
 

Just a thought ,,,There are chips that change the very fast PC keyboard scan codes to ASCII letters that are sent out of the chip as RS-232 serial.  So you could use a full size PC keyboard.  There are/were also keyboards for industry that output ASCII in RS-232 but they were very expensive at the time.

I used these chips 30 years ago for a robot project that needed real time control. It worked fine and the chip easily kept up with rapid keystrokes for 40 different one letter commands.   Wish I could recall the name of the chip we ended up with,,  but Google will know. I'm guessing you could do the scan code conversion through any chip like a basic stamp2, a very inexpensive PIC, or an Arduino, etc. 

Slurm


Re: CW Keyboard and decoder #cw

Mark Hatch
 

There is a very basic decoder in the KD8CEC software. I played with it a couple times, but there are better options.

73
Mark
AJ6CU


Re: CW Keyboard and decoder #cw

Evan Hand
 

You can always add one that is somewhat external.  There is not any room in the stock v6 Nano to do that.  There are a number of upgrades to either the Nano (Like converting to a Teensy for more memory and processor power) or offloading the display program to a Nextion display like KD8CEC did.  KD8CEC then has the option of adding a second Nano that is integrated into the total system for a number of different functions.  You can go the either Ubitx.net or Hamskey.com and browse for options on the upgrades.

The choice is yours.  There are many options, though none that do not require more hardware.  The v6 has pretty much maxed out the functions on the stock hardware.
73
Evan
AC9TU


Re: CW Keyboard and decoder #cw

Reed N
 

Once you have CAT working, fldigi can do both of those for you. If you mean to build one in, then you probably won't be able to without adding an additional microcontroller.


Reed


Re: uBITX V6 setup for digital modes #digital #ubitxv6

Evan Hand
 

Aaron,
I am sorry that you are having soo much trouble.  It really was not an issue for me using a v4 or v5 and the KD8CEC software.

Critical steps that I used.
1 - verify the com port through the Windows Device Manager.
         a - open the manager without the uBITX connected. 
         b - Verify what (if any) com ports are connected (you may not have any and the Com Port folder will not show up)
         c - Connect the uBITX to the USB port
         d - Note the com port that was just added.  this is the port you will set in the WSJT-X software
2 - Connect the Audio USB dongle.  Verify that it works through the Windows audio tests.  Note the device name
         NOTE:  I have had issues trying to use a laptop earphone port.  USB Audio dongles are very inexpensive so I would go that route.
https://smile.amazon.com/Sabrent-Aluminum-External-Adapter-AU-EMAC/dp/B00OJ5AV8I/ref=sr_1_2_sspa?dchild=1&keywords=sabrent+usb+external+stereo+sound+adapter&qid=1599006270&s=electronics&sr=1-2-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyNVhDQVhWSUo2V0tNJmVuY3J5cHRlZElkPUEwNDk4NjA1MkVDQVVVUTdIRFVJRiZlbmNyeXB0ZWRBZElkPUEwMTUwODk1MzhORU5YSkFTSTJKNCZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=
3 - Open the WSJT-X software
         a  - Setup the Radio and Audio tabs as shown in the PDF in message 
https://groups.io/g/BITX20/message/80833
         b - Test the CAT and PTT
         c - save the settings and go to the operating screen, select the band, and adjust the volume on the uBITX to the max green bar, without going into the red.  You should be decoding messages.
4 - Connect the USB audio dongle to the uBITX
5 - You will need to adjust the audio levels sent to the uBITX mic through either the speaker icon in the tray, or using the output slider on the WSJT-X software.  Here I used a power meter on the output to be the same as CW for the band you are using.  If yiou do not have a power meter, then another receiver is the only other option, and here you are looking for minimum splatter.  The last option would be to monitor the current draw of the rig on CW, then just as the power meter, adjust the audio level to be about the same.

I may have forgotten steps, but the above is what I remember doing the first time.

Hope this helps
73
Evan
AC9TU


CW Keyboard and decoder #cw

Aaron K5ATG
 

Just wondering if it would be possible to add a CW decoder or the ability to add a CW keyboard to the uBitX. 
--
'72
Aaron Scott
QRPARCI# 16443
GQRP# 16389
4SQRP # 1080

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