Date   

Re: Electronic encoder (Not rotary)

Gerard
 

Evan,
When I reflected on all this, I told myself that something is not clear between the - Power, the mass chassis and ground of the sector.
I don’t think it’s normal for me to see the noise with oscilloscope without connection to the - power, and that I don’t see them by connecting the crocodile clamp of the probe to the - power of the circuit.
There must be a loop.
Also as I said, if I connect the chassis to the - Power I get the 50htz
as a general rule you use an external alim, so no earth(?)
My question is the following and concerns security.
If you have a built-in conventional power supply (Transformer + regulation), what is the connection rule, between 220v mains ground, chassis, and the - power supply. All connected??
cdt


Re: Simple UBITX Test Set

Jerry Gaffke
 

Would be good if the standard test set did not require a $400 scope.
I'd be shooting for under $10 in parts if we expect everybody having trouble
with a uBitx to obtain it.

Curious that a broadband noise source is good enough for this.
Ideal if that is truly good enough.
We could put down pads for a $1 Si5351 and somehow drive that i2c bus
from the uBitx's Nano, perhaps bit-blasting over a couple pins usually used
by the display so we don't disturb the Raduino's Si5351.

The Si5351 in a QFN-20 is now $2 from Mouser, it has an A0 pin to 
flip the i2c address so we could use the same two wires as the Raduino's Si5351.
Perhaps some new Raduino should use the QFN-20 so we always have an extra output
for use as an RF signal source?
The QFN-20 has separate pins for each output, reducing crosstalk.

An AD8307 could be monitored using a cheap DVM, far more sensitive than a diode RF probe.
Ebay has AD8307 chips for $0.50 each if you get 10, reports are that they work fine.
Harbor Freight here in the US has suitable DVM's on sale for a dollar at times.

We also need a Nano pin to use as a standard audio source into the mike amp.
Perhaps use CW-TONE for this, though there are plenty of
other possible pins that could be temporarily borrowed.

A bunch of resistors for use as calibrated audio and RF attenuators,
and a 50 ohm dummy load.
 
Jerry, KE7ER



On Sun, Oct 25, 2020 at 12:21 PM, Gordon Gibby wrote:
Ashhar, do you think it would be worthwhile to make a small circuit board and sell that circuitry as an optional test unit?
 


Re: Simple UBITX Test Set

Scott McDonald
 

Another simple approach (for people like me that don't program well) is to just put a 2d Raduino in a breakout box.

This generates all the signals, digital and RF, you need to check full functioning of the radio's Raduino; and more importantly

when you go into the cw transmit mode, becomes a relatively high level general purpose HF signal generator reading out the frequency directly.

Considering you can get a W0EB v6.1 Raduino clone shipped for $35 US ( plus display, I think) that does all this with the 5351 already soldered on the board, it's a reasonably cost effective piece of test equipment most anyone can get running.

I use this one to check out any new software or displays before I try them on my radio.  The box pictured is just stupid overkill because of too much lockdown time on my hands, but it's been really useful as a back up signal source on other projects too.  It evolved from a blown BITX 40 Raduino over time, but a bare Raduino, basic display and some headers, pins and jumpers in a big Altoids tin will do all the same things.



Scott ka9p

-----Original Message-----
From: Jerry Gaffke via groups.io <jgaffke@...>
To: BITX20@groups.io
Sent: Sun, Oct 25, 2020 1:52 pm
Subject: Re: [BITX20] Simple UBITX Test Set

A standardized way to debug a uBitx would be a big plus for this forum.

Some kind of RF source is required that hits the operating frequencies of interest
plus the two IF frequencies would be good.
Perhaps using harmonics from a crystal oscillator is sufficient, though not always ideal.
Colorburst crystals are now archaic, but easy enough to get.
Plan B might be a $1 Si5351, plus of course an extra $10 for Nano and display and knobs.

VK4PP laid out a Raduino replacement with pads for an AD8307, though far as I know
nobody ever tried using the AD8307.     https://groups.io/g/BITX20/message/42251
That looks like a really noisy spot for the AD8307.
With proper layout (perhaps a smaller processor) this could be made to work.

Jerry, KE7ER



On Sun, Oct 25, 2020 at 09:50 AM, Scott McDonald wrote:
Jerry,
 
You're right, I think, a simple cheap standardized UBitx test set would really be a great tool, not just for a Ubitx but for anyone starting out without any RF test equipment.
 
I started down that road for a club talk last year and built a single 2N3904 oscillator with a color burst crystal that gave signals in or very close to all the HF bands except 60 meters.  
 
By juggling a few values I was getting reliable output on all those freqs at -20 dBm plus or minus probably 5 dBm, and this was reproduceable with 5 different color burst crystals (tho from the same batch).  Not enough to drive a diode ring mixer but otherwise pretty useful and consistent, I think close enough that you could count on the output being what you expected without measuring it.  
 
As an option adding a buffer with another 2N3904 would make it more useful, or maybe just use one of Diz's inexpensive new SMT HF amp kits instead of reinventing the wheel.
 
Added an IF crystal from Kits and Parts (it was for a V3) with a cap and coil to fudge it a bit and got a useful IF signal at the same level. 
 
Added a couple 50 dB Pi attenuators to give a choice of 50 over 9, S9 and a few tenths of a microvolt for signal level.  Standard resistors used that way yielded decent attenuators plus or minus 3 or 4 dB.
 
Did it on a piece of perf board using 0.1 inch headers and jumpers to switch crystals and attenuators so there were no switches or other hardware needed.
 
It was dirt cheap and pretty handy, adding the diode detector would be simple, and the attenuators possible useful with that, same for adding an audio generator.  That's got to be a 10 dollar or less project with bulk parts purchases.
 
It would make a great first build project too.  
 
If I had any board skills I would make a board and put in Osh Park... :)  But if anyone with some skills wants to collaborate on it, I'd be happy to get together, as I expect people troubleshooting with a known test kit would make the great advice you, Evan, Allison and others give on here even quicker and more powerful.  
 
73 Scott ka9p


Re: Simple UBITX Test Set

Gordon Gibby
 

Ashhar, do you think it would be worthwhile to make a small circuit board and sell that circuitry as an optional test unit?




On Oct 25, 2020, at 15:00, Ashhar Farhan <farhanbox@...> wrote:


I can document what we use at HF Signals. But , in effect it is like this ...
1. We have a dummy load (20, 1K 2/watt resistors) and an Rf sniffer with a 10K and a 50 ohms in series. the 50 ohms goes to the oscilloscope.
2. A 10 MHz crystal oscillator with a trimmer to net it exactly to 10 MHz. we calibrate it every month.
3. A zener diode biased with 1 ma of current as a noise source. it amplified by two stage of feedback amplifier and feb back to the transceiver through the dummy load through a 10pf. there are two 1N4148 back-to-back diodes to prevent high RF from entering the noise amplifiers. 
in rx mode, we can net the frequencies against the 10 Mhz oscillator.
the noise source allows us to set the BFO using the online BFO alignment tool.
on tx, we can monitor the RF to check for proper modulation.
We check it on 3.5 Mhz, 7 Mhz, 14 Mhz and 28 Mhz to exercise all the relays and LPFs.
- f

On Mon, Oct 26, 2020 at 12:22 AM Jerry Gaffke via groups.io <jgaffke=yahoo.com@groups.io> wrote:
A standardized way to debug a uBitx would be a big plus for this forum.

Some kind of RF source is required that hits the operating frequencies of interest
plus the two IF frequencies would be good.
Perhaps using harmonics from a crystal oscillator is sufficient, though not always ideal.
Colorburst crystals are now archaic, but easy enough to get.
Plan B might be a $1 Si5351, plus of course an extra $10 for Nano and display and knobs.

VK4PP laid out a Raduino replacement with pads for an AD8307, though far as I know
nobody ever tried using the AD8307.     https://groups.io/g/BITX20/message/42251
That looks like a really noisy spot for the AD8307.
With proper layout (perhaps a smaller processor) this could be made to work.

Jerry, KE7ER



On Sun, Oct 25, 2020 at 09:50 AM, Scott McDonald wrote:
Jerry,
 
You're right, I think, a simple cheap standardized UBitx test set would really be a great tool, not just for a Ubitx but for anyone starting out without any RF test equipment.
 
I started down that road for a club talk last year and built a single 2N3904 oscillator with a color burst crystal that gave signals in or very close to all the HF bands except 60 meters.  
 
By juggling a few values I was getting reliable output on all those freqs at -20 dBm plus or minus probably 5 dBm, and this was reproduceable with 5 different color burst crystals (tho from the same batch).  Not enough to drive a diode ring mixer but otherwise pretty useful and consistent, I think close enough that you could count on the output being what you expected without measuring it.  
 
As an option adding a buffer with another 2N3904 would make it more useful, or maybe just use one of Diz's inexpensive new SMT HF amp kits instead of reinventing the wheel.
 
Added an IF crystal from Kits and Parts (it was for a V3) with a cap and coil to fudge it a bit and got a useful IF signal at the same level. 
 
Added a couple 50 dB Pi attenuators to give a choice of 50 over 9, S9 and a few tenths of a microvolt for signal level.  Standard resistors used that way yielded decent attenuators plus or minus 3 or 4 dB.
 
Did it on a piece of perf board using 0.1 inch headers and jumpers to switch crystals and attenuators so there were no switches or other hardware needed.
 
It was dirt cheap and pretty handy, adding the diode detector would be simple, and the attenuators possible useful with that, same for adding an audio generator.  That's got to be a 10 dollar or less project with bulk parts purchases.
 
It would make a great first build project too.  
 
If I had any board skills I would make a board and put in Osh Park... :)  But if anyone with some skills wants to collaborate on it, I'd be happy to get together, as I expect people troubleshooting with a known test kit would make the great advice you, Evan, Allison and others give on here even quicker and more powerful.  
 
73 Scott ka9p


Re: Simple UBITX Test Set

Ashhar Farhan
 

I can document what we use at HF Signals. But , in effect it is like this ...
1. We have a dummy load (20, 1K 2/watt resistors) and an Rf sniffer with a 10K and a 50 ohms in series. the 50 ohms goes to the oscilloscope.
2. A 10 MHz crystal oscillator with a trimmer to net it exactly to 10 MHz. we calibrate it every month.
3. A zener diode biased with 1 ma of current as a noise source. it amplified by two stage of feedback amplifier and feb back to the transceiver through the dummy load through a 10pf. there are two 1N4148 back-to-back diodes to prevent high RF from entering the noise amplifiers. 
in rx mode, we can net the frequencies against the 10 Mhz oscillator.
the noise source allows us to set the BFO using the online BFO alignment tool.
on tx, we can monitor the RF to check for proper modulation.
We check it on 3.5 Mhz, 7 Mhz, 14 Mhz and 28 Mhz to exercise all the relays and LPFs.
- f

On Mon, Oct 26, 2020 at 12:22 AM Jerry Gaffke via groups.io <jgaffke=yahoo.com@groups.io> wrote:
A standardized way to debug a uBitx would be a big plus for this forum.

Some kind of RF source is required that hits the operating frequencies of interest
plus the two IF frequencies would be good.
Perhaps using harmonics from a crystal oscillator is sufficient, though not always ideal.
Colorburst crystals are now archaic, but easy enough to get.
Plan B might be a $1 Si5351, plus of course an extra $10 for Nano and display and knobs.

VK4PP laid out a Raduino replacement with pads for an AD8307, though far as I know
nobody ever tried using the AD8307.     https://groups.io/g/BITX20/message/42251
That looks like a really noisy spot for the AD8307.
With proper layout (perhaps a smaller processor) this could be made to work.

Jerry, KE7ER



On Sun, Oct 25, 2020 at 09:50 AM, Scott McDonald wrote:
Jerry,
 
You're right, I think, a simple cheap standardized UBitx test set would really be a great tool, not just for a Ubitx but for anyone starting out without any RF test equipment.
 
I started down that road for a club talk last year and built a single 2N3904 oscillator with a color burst crystal that gave signals in or very close to all the HF bands except 60 meters.  
 
By juggling a few values I was getting reliable output on all those freqs at -20 dBm plus or minus probably 5 dBm, and this was reproduceable with 5 different color burst crystals (tho from the same batch).  Not enough to drive a diode ring mixer but otherwise pretty useful and consistent, I think close enough that you could count on the output being what you expected without measuring it.  
 
As an option adding a buffer with another 2N3904 would make it more useful, or maybe just use one of Diz's inexpensive new SMT HF amp kits instead of reinventing the wheel.
 
Added an IF crystal from Kits and Parts (it was for a V3) with a cap and coil to fudge it a bit and got a useful IF signal at the same level. 
 
Added a couple 50 dB Pi attenuators to give a choice of 50 over 9, S9 and a few tenths of a microvolt for signal level.  Standard resistors used that way yielded decent attenuators plus or minus 3 or 4 dB.
 
Did it on a piece of perf board using 0.1 inch headers and jumpers to switch crystals and attenuators so there were no switches or other hardware needed.
 
It was dirt cheap and pretty handy, adding the diode detector would be simple, and the attenuators possible useful with that, same for adding an audio generator.  That's got to be a 10 dollar or less project with bulk parts purchases.
 
It would make a great first build project too.  
 
If I had any board skills I would make a board and put in Osh Park... :)  But if anyone with some skills wants to collaborate on it, I'd be happy to get together, as I expect people troubleshooting with a known test kit would make the great advice you, Evan, Allison and others give on here even quicker and more powerful.  
 
73 Scott ka9p


Re: Simple UBITX Test Set

Jerry Gaffke
 

A standardized way to debug a uBitx would be a big plus for this forum.

Some kind of RF source is required that hits the operating frequencies of interest
plus the two IF frequencies would be good.
Perhaps using harmonics from a crystal oscillator is sufficient, though not always ideal.
Colorburst crystals are now archaic, but easy enough to get.
Plan B might be a $1 Si5351, plus of course an extra $10 for Nano and display and knobs.

VK4PP laid out a Raduino replacement with pads for an AD8307, though far as I know
nobody ever tried using the AD8307.     https://groups.io/g/BITX20/message/42251
That looks like a really noisy spot for the AD8307.
With proper layout (perhaps a smaller processor) this could be made to work.

Jerry, KE7ER



On Sun, Oct 25, 2020 at 09:50 AM, Scott McDonald wrote:
Jerry,
 
You're right, I think, a simple cheap standardized UBitx test set would really be a great tool, not just for a Ubitx but for anyone starting out without any RF test equipment.
 
I started down that road for a club talk last year and built a single 2N3904 oscillator with a color burst crystal that gave signals in or very close to all the HF bands except 60 meters.  
 
By juggling a few values I was getting reliable output on all those freqs at -20 dBm plus or minus probably 5 dBm, and this was reproduceable with 5 different color burst crystals (tho from the same batch).  Not enough to drive a diode ring mixer but otherwise pretty useful and consistent, I think close enough that you could count on the output being what you expected without measuring it.  
 
As an option adding a buffer with another 2N3904 would make it more useful, or maybe just use one of Diz's inexpensive new SMT HF amp kits instead of reinventing the wheel.
 
Added an IF crystal from Kits and Parts (it was for a V3) with a cap and coil to fudge it a bit and got a useful IF signal at the same level. 
 
Added a couple 50 dB Pi attenuators to give a choice of 50 over 9, S9 and a few tenths of a microvolt for signal level.  Standard resistors used that way yielded decent attenuators plus or minus 3 or 4 dB.
 
Did it on a piece of perf board using 0.1 inch headers and jumpers to switch crystals and attenuators so there were no switches or other hardware needed.
 
It was dirt cheap and pretty handy, adding the diode detector would be simple, and the attenuators possible useful with that, same for adding an audio generator.  That's got to be a 10 dollar or less project with bulk parts purchases.
 
It would make a great first build project too.  
 
If I had any board skills I would make a board and put in Osh Park... :)  But if anyone with some skills wants to collaborate on it, I'd be happy to get together, as I expect people troubleshooting with a known test kit would make the great advice you, Evan, Allison and others give on here even quicker and more powerful.  
 
73 Scott ka9p


Audio amp + AGC + Squelch vía I2C for Raduino32

ramonlh@...
 

Buenas tardes,

I have ordered a module like this https://learn.adafruit.com/adafruit-tpa2016-2-8w-agc-stereo-audio-amplifier

The module has adjustable gain via I2C and incorporates AGC and Mute, so the idea is to test it on a V6 with ESP32 (see https://groups.io/g/BITX20/topic/76873326#82075) and have AGC and Squelch without making modifications to the circuit, only using the connectors available on the main board of the uBitx.

The second channel of the amplifier could be used to add a SA828 VHF/UHF module to the uBitx as a separate transceiver.

We will see ...

Ramón


Re: Spare 16x2 display

Bill Cromwell
 

Hi Kit,

Put in your "junk box". If you don't have a "junk box" use it to start one. You do not have so much money tied up in that spare display that you cannot afford to keep it. you can't even get a cup of coffee in a paper cup for that. When you want to start playing with microcontrollers like the Arduino (or others) remember you have it in your junk box:)

73,

Bill KU8H

bark less - wag more

On 10/25/20 1:01 PM, Kit Peters wrote:
I have a spare 16x2 display (the replacement Raduino I got from KF4FTR came with a 4 line display) sitting around. What could I do with it in the context of my uBITX?
--
Kit Peters, W0KEH
GPG public key fingerpint: D4FF AA62 AFEA 83D6 CC98 ACE5 6FAE 7E74 7F56 ED1D
Hello to any and all NSA, DEA, or other government or non-government agents reading this email.  Tell me about your life; I'll tell you about mine.


Re: Electronic encoder (Not rotary)

Gerard
 

Evan,
A little bit of reading..

https://electronics.stackexchange.com/questions/140761/arduino-how-do-i-reduce-the-noise-in-my-circuit
https://forum.arduino.cc/index.php?topic=155220.0
http://www.massmind.org/techref/noises.htm
https://www.allaboutcircuits.com/technical-articles/how-to-reduce-ground-bounce-mitigating-noise-pcb-design-best-practices/
https://thecustomizewindows.com/2018/02/capacitor-use-arduino-circuits/
https://forum.arduino.cc/index.php?topic=62065.0
https://electronics.stackexchange.com/questions/414563/reduce-noise-added-with-zener-clipper
https://translate.googleusercontent.com/translate_c?depth=1&pto=aue&rurl=translate.google.fr&sl=auto&sp=nmt4&tl=fr&u=https://electronics.stackexchange.com/questions/414563/reduce-noise-added-with-zener-clipper&usg=ALkJrhh_O_OhkHm8RmnW3f__k2s4iZ6bvw

Stop!!!

cdt


Re: Electronic encoder (Not rotary)

Gerard
 

Evan,
Here that i have made for the rotary encoder for rotation noise
solution was here at he end of page. LOL

http://ubitx.net/category/hardware/encoder/

cdt


Spare 16x2 display

Kit Peters
 

I have a spare 16x2 display (the replacement Raduino I got from KF4FTR came with a 4 line display) sitting around. What could I do with it in the context of my uBITX?

--
Kit Peters, W0KEH
GPG public key fingerpint: D4FF AA62 AFEA 83D6 CC98 ACE5 6FAE 7E74 7F56 ED1D
Hello to any and all NSA, DEA, or other government or non-government agents reading this email.  Tell me about your life; I'll tell you about mine.


Simple UBITX Test Set

Scott McDonald
 

Jerry,

You're right, I think, a simple cheap standardized UBitx test set would really be a great tool, not just for a Ubitx but for anyone starting out without any RF test equipment.

I started down that road for a club talk last year and built a single 2N3904 oscillator with a color burst crystal that gave signals in or very close to all the HF bands except 60 meters.  

By juggling a few values I was getting reliable output on all those freqs at -20 dBm plus or minus probably 5 dBm, and this was reproduceable with 5 different color burst crystals (tho from the same batch).  Not enough to drive a diode ring mixer but otherwise pretty useful and consistent, I think close enough that you could count on the output being what you expected without measuring it.  

As an option adding a buffer with another 2N3904 would make it more useful, or maybe just use one of Diz's inexpensive new SMT HF amp kits instead of reinventing the wheel.

Added an IF crystal from Kits and Parts (it was for a V3) with a cap and coil to fudge it a bit and got a useful IF signal at the same level. 

Added a couple 50 dB Pi attenuators to give a choice of 50 over 9, S9 and a few tenths of a microvolt for signal level.  Standard resistors used that way yielded decent attenuators plus or minus 3 or 4 dB.

Did it on a piece of perf board using 0.1 inch headers and jumpers to switch crystals and attenuators so there were no switches or other hardware needed.

It was dirt cheap and pretty handy, adding the diode detector would be simple, and the attenuators possible useful with that, same for adding an audio generator.  That's got to be a 10 dollar or less project with bulk parts purchases.

It would make a great first build project too.  

If I had any board skills I would make a board and put in Osh Park... :)  But if anyone with some skills wants to collaborate on it, I'd be happy to get together, as I expect people troubleshooting with a known test kit would make the great advice you, Evan, Allison and others give on here even quicker and more powerful.  

73 Scott ka9p


-----Original Message-----
From: Jerry Gaffke via groups.io <jgaffke@...>
To: BITX20@groups.io
Sent: Sun, Oct 25, 2020 10:50 am
Subject: Re: [BITX20] My son's V6

The primary selling point of the uBitx is its simplicity,
would be good to keep it that way.
The circuit improvements moving from V4 to V5 are a major win,
badly needed and no significant added complexity.

Though I would have kept the +12V for the IRF510's separate, much safer to 
debug all but the final amp of the transmitter with those IRF510's disabled.
And allows flexibility in setting the output power by adjusting the IRF510 supply voltage.
A simple way to adjust RF gain would be good.

Moving from the V5 16x2 LCD to the V6 TFT display adds lots of overhead
to the Nano's firmware.  I'd prefer the uBitx had kept the 16x2, at least as an option. 

An SWR meter and antenna tuner with a suitable dummy load for the uBitx 
might be a good accessory.  Audio and RF signal generators, a diode RF probe
(or AD8307), complete instructions to debug the rig, those would be most welcome.   
Perhaps make them all part of a single accessory?  An audio CW filter too?

Jerry, KE7ER


On Sat, Oct 24, 2020 at 05:49 PM, Bob Lunsford wrote:
Using a tuner on an antenna that is designed/dedicated to a specific band or frequency would theoretically funnel the signal to that specific frequency but it would also, theoretically, suppress received signals up and down frequency from the tuner's settings. Since it is also a good approach to getting as much power as possible from a QRP radio to the antenna by allowing the transmitter's output stage to see a much better load and lessen the complications of a mismatch, it would/should be an automatic part of the system unless weight or system complexity are concerns. It is undoubtedly a prime candidate for experimentation to see if a tuner does indeed reduce the influence of a high powered transmitter either nearby in frequency or location.
 
Thanks, Curt, for your feedback on this. Sometimes a simple solution may be best even if not a complete solution. I agree that AGC may be nice but it is not always the best or necessary. For example, on my G90 if you turn off the AGC it reveals many weak stations and even if some others come booming in, it's a small price to pay to guarantee that all stations on the [net] frequency are heard. Unless it is truly excessive in volume, of course, and this is "in the ear of the hearer."
 
Bob — KK5R


Re: Low audio output #v5

Gerard
 

see the end of this topic
https://groups.io/g/BITX20/topic/77426301?p=,,,20,0,0,0::recentpostdate,,,20,2,20,0&allview=1
I had one amplifier
I have big sound now
cdt


Re: Electronic encoder (Not rotary)

Gerard
 

Evan,
Results of the tests:
The noise remains even after disconnecting the connection and its cables of nextion
Noise still exists, but less loud if I remove the module SI5153 (For me the continuous program to turn blind)
We can clearly see that the crude corresponds when sending data (Pulses) from the arduino (leg no 26 or 27 corresponding to the TX) don't remeber
I tried to put the jumpers resistors on the legs 26, 27 >> No improvement, same if I add a small capacitor.
but it is not the same type of mounting that I had done on the encoder (review the diagram)
Pulses come at the amplifier input. Weak and drowned in background noise.
You can see them better if the oscillo is connected without ground!! back to the ground of electrical connexion 220V?

And as already said, if I connect electrical ground on power ground, you ear 50HTZ.
So for me, the signal must interfere with lines on the copper, or there’s a mass loop, not obvious to find.
I spent my afternoon on this, so I’ll look again later
cdt


Re: Low audio output #v5

Evan Hand
 

I would verify that the speaker is 8ohms and not 4.  If that is an AmateurRadioKits speaker, then I would look into an audio amp.  That is what I had to do for my v5 that I put into a 3.5" case.  Luckily it came with an audio amp.  That made a big difference AFTER I nocked the gain of the LM386 internal to the yBITX down to 20 (Pop out pins 1 and 8).  Any 1 wat or better audio amp module on Amazon or eBay would work.

The other option is to use a more efficient speaker.  I need to run now so do not have time to look up what I bought.  It was on a recommendation on this site.

73
Evan
AC9TU


Low audio output #v5

Praba Karan
 

I have noted very low audio in my ubitxv5 even at high volume. Refer attached recording taken at high volume. Sensitivity is ok.
Any troubleshooting advices?


Re: My son's V6

Jerry Gaffke
 

The primary selling point of the uBitx is its simplicity,
would be good to keep it that way.
The circuit improvements moving from V4 to V5 are a major win,
badly needed and no significant added complexity.

Though I would have kept the +12V for the IRF510's separate, much safer to 
debug all but the final amp of the transmitter with those IRF510's disabled.
And allows flexibility in setting the output power by adjusting the IRF510 supply voltage.
A simple way to adjust RF gain would be good.

Moving from the V5 16x2 LCD to the V6 TFT display adds lots of overhead
to the Nano's firmware.  I'd prefer the uBitx had kept the 16x2, at least as an option. 

An SWR meter and antenna tuner with a suitable dummy load for the uBitx 
might be a good accessory.  Audio and RF signal generators, a diode RF probe
(or AD8307), complete instructions to debug the rig, those would be most welcome.   
Perhaps make them all part of a single accessory?  An audio CW filter too?

Jerry, KE7ER


On Sat, Oct 24, 2020 at 05:49 PM, Bob Lunsford wrote:
Using a tuner on an antenna that is designed/dedicated to a specific band or frequency would theoretically funnel the signal to that specific frequency but it would also, theoretically, suppress received signals up and down frequency from the tuner's settings. Since it is also a good approach to getting as much power as possible from a QRP radio to the antenna by allowing the transmitter's output stage to see a much better load and lessen the complications of a mismatch, it would/should be an automatic part of the system unless weight or system complexity are concerns. It is undoubtedly a prime candidate for experimentation to see if a tuner does indeed reduce the influence of a high powered transmitter either nearby in frequency or location.
 
Thanks, Curt, for your feedback on this. Sometimes a simple solution may be best even if not a complete solution. I agree that AGC may be nice but it is not always the best or necessary. For example, on my G90 if you turn off the AGC it reveals many weak stations and even if some others come booming in, it's a small price to pay to guarantee that all stations on the [net] frequency are heard. Unless it is truly excessive in volume, of course, and this is "in the ear of the hearer."
 
Bob — KK5R


Re: Electronic encoder (Not rotary)

Evan Hand
 

Gerard,
I am out of suggestions on how to eliminate the clicks when the frequency changes. 

I still believe that it is coming from the Si5351 when the LO is being changed.  That could be in the runs from either of the I2C control lines, the lines to the Si5351, or the lines to the Nextion.  There is a lot of updates going on with the Nextion screen, so I doubt that it is that set of lines.  The Si5351 is changed only when there is a change in frequency or USB/LSB.  That seems to be more in line with what you are describing.

Let us know what you find.
73
Evan
AC9TU


Re: uBITX V4 assembly instructions? #v4

Evan Hand
 

Chuck,
The link that Mark has provided has clearer instruction than the original.  For comparison here is the original:
https://www.hfsignals.com/index.php/ubitx/
https://www.hfsignals.com/index.php/ubitx-wire-up/

One change that I would make on the instructions that Mark provided is to change the 5 amp fuse to another 2 amp fuse.  The mainboard will only draw 300 milliamps on its own, depending on an audio amp or other accessories added.

The other is how the protection diodes are wired.  I would move the banded end to after the fuse so that the fuse is blown instead of the diode.  Easier to replace the fuse, not the cost of the component issue.  This is especially the case if you power with a high amp supply like those in a lot of Ham shacks.

73
Evan
AC9TU


Re: Electronic encoder (Not rotary)

Gerard
 

I forgot to tell you, but I kept the same kind of connection, but obviously I changed the copper tracks accordingly. So the picture can be misleading. It’s a 5V just for the Nextion.
cdt

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