Date   

Always unpleasant noise pop T/R

Gerard
 

Hello,
Despite having modified my mounting and added some elements (Diode + resistance +capacitor) on the mosfet from the foot 25 of the arduino (T/R), I still have unpleasant noise during reception/ emission swap tests.


I looked at the oscilloscope to see how the RX and TX power supplies were switching.
I realize that, in fact, the rise in tension is almost instantaneous when we flip, but the descent in tension is not immediate, especially for part TX.
Which means that at each flip, we can have the RX powered, and again the TX for for several hundred milliseconds (Probably discharge capacitors)
So it translates as a shot of a gun or flush in the top (Each chooses. LOL)
I do not know if it is due to fat that the PA part is not cabled ?? I don't made emmision at this time.
So my question is: How to make the voltage on the TX alim drop very quickly.
Cabling resistance in parrallele on each chemical or other? A system with diodes?

Then you can say, that it is useless when we do not make a broadcast, (So no flip) but it is for the principle of finding a solution. I don’t know if the problem is 100% solved for you.

Thank you for your answers.
nb: The control of the tx/rx relay is perfect
cdt


Re: Rotary encoder

Gerard
 


Hello Barry,
thank you for the information

Datasheet here for all
https://www.bourns.com/pdfs/em14.pdf
cdt


Re: Si 5351 output power

James Lynes
 

Look at Charlie's(ZL2CTM) videos. He has good results directly driving SBL-1s and ADE-1s from the si5351.

James


Re: Suggestion for the NEW UBITX V7.

Bob Lunsford
 

The Complete kit is not just breadboard, cooking pan 'kludge' ... it is something you can show off with pride and expectation that the person you show it to will want. For the price of a well-endowed 2M rig, you get a radio that can theoretically work the world and this is not a mere idea if CW is the primary mode of operation. For me, it is possible to work hams on 75M in all states surrounding me in KY and I have worked the Caribbean and FL with QRP mobile in the past on 40M — using a hamstick. I cannot do it any day at will but it can be done.

The radio is a hit a ham club meetings because there is always someone there who has never heard of HF Signals and the uBITX radios. They grab a notepad and will no doubt look them up when they get home.

Bob — KK5R

On Wednesday, October 21, 2020, 11:10:58 AM EDT, KD2QMZ <syracusepro@...> wrote:


I love this radio kit. While I got one of the nicest cases, still out of the case for testing, experimenting etc. 
Can not compare it to anything, as its purpose is something else.

In the way that I see it, a low cost full 80-10 radio that can be used for QRP, experimenting and learning of the circuits, and to have a lot of fun with expansions such as the touch screen, etc.

Great stuff.

On Wed, Oct 21, 2020 at 9:56 AM Bob Lunsford via groups.io <nocrud222=yahoo.com@groups.io> wrote:
My son received the V6 I sent to him and told me he didn't have time to give it a thorough check out but he did check into a SSB net in Oregon from Sacramento, CA. My replacement for the V6 I sent to him is due to arrive today. I plan to use it more on the air than I did with the one I sent to my son.

Christmas is coming. $200 is not too much to spend for a gift for a ham friend or a son/daughter who may be inclined to get into ham radio. It is also an excellent Short Wave Listening receiver and who knows, once the SWLer hears some ham radio activity, his/her interests may change toward that. Just an idea.

As for a power supply, four 12V cells can be connected in series for 48V and they can be recharged individually. I'm thinking of the batteries suggested here previously (I'll have to go back to find the ones I remember that are LiOn).

Bob — KK5R

On Tuesday, October 20, 2020, 4:25:29 PM EDT, KD2QMZ <syracusepro@...> wrote:


There are 50 volts power supplies already out there for linear amplifiers and other uses. My IC-7300 cost more than 1k$ and no power supply was included.

So, let the user take care of the power supply needs as they have been doing for years.
If they want more clean power, so higher capacitance for the filters then.

As per the radio, I got V5. Didn't get the V6, but would like to see something with more power. Also, resources for the radio should be organized to guide the assembler to enhance or to provide guidance to enhance capabilities.

I love the service Farhan has given to this kits, even better than any other manufacturer, and the radio cost less than 200$.
For the amount of money, no one should expect something better then an IC-7850 or similar.

It is a great kit, great to get to learn about it, enhance and put on the air as an experimental unit.
Some do have QSO's and use it more often.

Regardless, just want to appreciate the great work Farhan has put into this, and wish something new comes out soon.

73


On Tue, Oct 20, 2020 at 3:42 PM Arv Evans <arvid.evans@...> wrote:
Farhan

It seems that the most prevalent spurious RF problem with ham equipment is that the ham equipment uses external power.  This leads many to assume that any power supply is suitable for high sensitivity radio use.  It may not be practical to include an internal power supply inside kit radios, but we probably should include power supply specifications (voltage, ripple, spurious, minimum current capability, etc.) as part of the assembly and operating instructions, and explain what these specifications mean and how to measure them.

Hans has included some built-in test equipment inside his QCX radios.  Maybe a future version of uBITX could include use of an internal ADC based multimeter that could measure power supply voltage, current, ripple, hum, as well as outputs from a built-in Stockton Bridge type measurement for RF Power (at 50 ohms), Forward power, Reflected power, antenna impedance and possibly RF received level in microvolts & S-units.  Auto-ranging instrumentation is relatively easy to do by software observation of thresholds for ADC inputs.  Of course this would probably require a section of assembly and operation instruction that explains what all of these measurements might mean and how to use the information.

After using several versions of BITX transceiver I would heartily recommend a method for reducing power for ATU or Antenna adjustments.  

The assembly and operating manual should possibly include a section showing power supply requirements and how to measure and achieve those parameters.  Having the  above-mentioned internal measuring capability could simplify measuring things like power supply ripple, hum, and power (volts * Amps).  Desktop PC power supplies are inexpensive and easily modified to provide a solid and quiet  13.8V DC at several amperes.  Wall-warts and laptop power units are rarely suitable due to having minimal RF bypassing and an unshielded plastic case.  Linear supplies should be linear regulator units with significant over-current capability.  Remember that your power supply should have a low AC impedance furnished by RF, LF, and AF bypass capacitors.  Use a scope or fast sample-and-hold circuit to check power supplies for voltage overshoot at startup.

Arv
_._



On Tue, Oct 20, 2020 at 12:01 AM Ashhar Farhan <farhanbox@...> wrote:
Tom,
That is the scheme of hf packer : switch on the boost converter only on tx.
Another approach would be to make your radio live with noisy supplies. The best case would be to make it run off 5v supplies. They are aplenty. From PC SMPS to phone chargers to the USB power banks. It is really about time we moved to 5v standard.
A 5v supply boosted to 15v and linear regulated down to 12v could internally power the radio. The transmit would boost it to 24 or 50v. An Arduino and a low cost SMPS transformer would do the trick. If someone here as experience with this, it would be a game changer.
- f

On Tue 20 Oct, 2020, 11:12 AM Tom, wb6b, <wb6b@...> wrote:
On Mon, Oct 19, 2020 at 08:02 PM, Sila wrote:
Have you noticed any problems with the power supplies?
The one I have is a similar 12V switching supply. I puts out an RF spur that drifts across 75 meters. Fortunately, in somewhat less than 15 minutes it drifts across and away from the net I check into. 

I bought a couple of these supplier 12v 30A, 360W (was mistaken on my last post that they were 300W) to have a beefier spare supply for my 3D printer. When I bought the vintage Kenwood from a local ham I decided to try the power supply on it. I was happy it worked so well. Does have a annoying fan that sometimes starts running. Most of the lower wattage supplies do not have a fan.

Here would be a great Rube Goldberg electronic project: Put a switchable capacitor in the switching regulator circuitry to shift the frequency the supply is switching on. And depending on what frequency you are receiving on, shift the power supply frequency so the spur in not on the the frequency you are working on the radio. I'm sure adding a microprocessor would be a great addition to automating this. 

I'm not above a Rube Goldberg project once and awhile. When hard dives were new and very expensive, I programmed an 8748 microprocessor to monitor the status led on a drive that was starting to have problems booting up. When the 8748 noticed the LED was flashing a certain pattern it would pull the reset down on the hard drive and repeat this cycle until the drive would finally initialize and run. 

Got another year out of that drive. By then the replacement hard drives were higher capacity and had come down significantly in price. 

Some of the supplies I see sold for amateur radio use (from HAM radio manufactures) are switching supplies. Likely are similar supplies put in a metal box with additional RF filtering. 

For boosting the power of my uBitx, I'm still tending towards using a 12v (adjusted for 13.6v) power supply and the eBay boost converts. Only enabling the boost converters when transmitting.  I'd like to keep the main supply for my uBitx at 12V (13.6V) as that gives me more ham swap meet used power supply, battery and mobile options.

Tom, wb6b


Re: Si 5351 output power

barry halterman
 

Thanks guys for all the input on this subject. I have a project that I want to build that utilize the si5351 to drive a SBL-1 or TUF-1 mixer. Will start the build.
Thanks
Barry
K3bo

On Wed, Oct 21, 2020, 11:02 AM Jerry Gaffke via groups.io <jgaffke=yahoo.com@groups.io> wrote:
Let's assume the source impedance of the Si5351 is 80 ohms, 
and the Si5351 can internally generate a 3v pk to pk square wave, so 1.5vrms.
The current through a 50 ohm load is:    i=1.5/(80+50)=0.01154 amps rms.

That's a bit more than the AN619 value of 8ma, but in the ballpark.
I would guess that evaluating the source impedance using a lighter load 
will show the source impedance dropping toward 50 ohms.
By varying the load resistor and measuring the voltage across it, we may
come up with consistent numbers for the source impedance and the voltage source.
I would do this first at fairly low frequencies, then see if it remains true at 
the frequency of interest where things may get considerably more complicated.

Power into the 50 ohm load is:    i*i*r = 0.01154*0.01154*50 = 0.006659 watts, or 6.659mw
In dBm, that would be:    10*log10(6.659) = 8.23 
With a 6dB attenuator, the 7dBm mixer is seeing 8.23-6 = 2.23 dBm
That can work fine, though might be have noticeable distortion with very strong signals.

There may be variation between Si5351's.
If some truly do limit current to 8ma, we get:   
  mw=0.008*0.008/50= 0.0032 watts,   10*log10(3.2)=5.05dbm,  mixer gets 5.05-6 = -0.5dBm

The uBitx v5 and v6 have an extra 33 ohm resistor between the Si5351 and the 6dB attenuator,
That would raise the effective Si5351 source impedance from 80 to 103 ohms, and give around 9ma.
(Or perhaps it raises the typical source impedance from 50 to 83 ohms?)
Since the Si5351 is not being asked to work so hard, it will distort less.

The fact that Farhan has found we need an attenuator between the Si5351 and the mixer
suggests to me that the source impedance of the Si5351 is not truly 50 ohms.
Without an attenuator, mixer products would come out of the mixer toward the Si5351,
and be reflected back into the mixer to mix again, creating birdies in the receiver.
I assume this was evaluated with 50 ohm coax between the Si5351 and the mixer,
or with extremely short wires.

Note that I have lots of "may", "could", "think" and "perhaps" in the above text.
Gordon is correct, this sort of armchair engineering only goes so far.
I really should do my own measurements of the Si5351 source impedance.
But I'd bet that Farhan has arrived at a good solution on the uBitx.
It keeps the circuit simple, avoiding a buffer amp between the Si5351 and the attenuator.
And does what it must to quiet down the unwanted mixer products.

Jerry, KE7ER


Re: Suggestion for the NEW UBITX V7.

MadRadioModder
 

Everyone seems to get hung up on the price of the semiconductor making the power in the amplifier, and that forces you into a bad place.  My after designing and manufacturing many amps is that the transformer cores for the input/ output/ intermediate stages (if any) and the LPFs can cost multiple times what the semiconductor devices do.  I just finished a seven band 100W amplifier using an RD100HHF1.  The RD was $21, and the cores were $37.  It still makes a heck of a 7-band amplifier for about $70 all-in.

 

My go-to parts are the RD devices as well… I like the RD100HHF1 (and have a shoebox full), but the RF70 is just as easy to design with.  With very few parts, you can make an amp that has a flat (within 1 dB) frequency response from 1-30 MHz… and that could easily be extended to 50 MHz with a small chance in the mix of the output transformer.  As long as you don’t over drive the device, they are almost indestructible. 

 

I use $18 surplus cell tower 48V supplies that are RFI free to run my amps.

 

I used to design 12V amps for my vehicles and used 2SC2879’s.  A pair would easily put out 100W and they were cheap.  Today they are extremely expensive, and quite frankly the IMD using these parts is horrible.  2SC1969’s as a 10W, 12V, $7 part works at a lower power level, but has the same IMD issues.  Now I design strictly at 48V or higher. 

 

MRM

 

From: BITX20@groups.io <BITX20@groups.io> On Behalf Of Ashhar Farhan
Sent: Tuesday, October 20, 2020 10:00 PM
To: BITX20@groups.io
Subject: Re: [BITX20] Suggestion for the NEW UBITX V7.

 

Our past experience was that save one or two brave souls, nobody bothered to run the PAs with beefier heatsinks and higher power, hence by the time we got to V6, I didn't bother to separate the PA power line the standard 12v.

Building a power amp that puts out more at higher voltage is messy. The trouble is that, a low cost, high performance device like the MRF101AN needs 50v to really shine. By next week, I will post how much it puts out at 12v. My bet is that is would just about match the venerable IRF510s at 12v. The reason for MOSFETs to behave this way is easy to fathom : the output and reverse capacitances decrease with higher voltage and the Rds drops as well, leading to better IMD.

On the other hand, nothing inexpensive works well at 12v. The best candidate for 50 watts and above is the RD70HHF1 or the RF70HVF1. They are quite expensive and mounting them is tricky.

As many in the group know I have been playing with basic SDRs and the a big challenge with them is to produce a reasonable transmitter. This is easily done with predistortion.  But unfortunately this scheme only works well with a transmitter that is simultaneously being monitored by a receiver in full-duplex that tweaks the modulating signal to reduce the IMD.

With our regular devices like, for instance the BD139, we can easily push out 10 watts of clean tx output. But really, 10 watts seems to be as far as we can go at 12v.

Please remember, although few do, it should be possible to build these radios from the scratch by a homebrewer. The parts should be generic and readily available. The performance should come from clever design and not by throwing money at it and buying expensive devices and components.

- f

 

On Wed 21 Oct, 2020, 3:57 AM Ken Hansen, <ken@...> wrote:

It is a concern, every improvement that increases cost, shrinks the market.

I bet Farhan could sketch out a tremendous radio with a beautiful case and wonderful specifications if he didn't worry about cost, but I suspect the nice ladies that assemble the radios would find themselves with significantly less work.

This project, as I understand it, was as much about creating a low-cost radio as it was to create work for a group of ladies in India.

Ken, N2VIP

> On Oct 20, 2020, at 00:23, AA9GG <paul.aa9gg@...> wrote:
>
> Unfortunately, the uBitX is just a little out of an OMs budget






Virus-free. www.avg.com

--

…_. _._


Re: Suggestion for the NEW UBITX V7.

K2ICC
 

I love this radio kit. While I got one of the nicest cases, still out of the case for testing, experimenting etc. 
Can not compare it to anything, as its purpose is something else.

In the way that I see it, a low cost full 80-10 radio that can be used for QRP, experimenting and learning of the circuits, and to have a lot of fun with expansions such as the touch screen, etc.

Great stuff.


On Wed, Oct 21, 2020 at 9:56 AM Bob Lunsford via groups.io <nocrud222=yahoo.com@groups.io> wrote:
My son received the V6 I sent to him and told me he didn't have time to give it a thorough check out but he did check into a SSB net in Oregon from Sacramento, CA. My replacement for the V6 I sent to him is due to arrive today. I plan to use it more on the air than I did with the one I sent to my son.

Christmas is coming. $200 is not too much to spend for a gift for a ham friend or a son/daughter who may be inclined to get into ham radio. It is also an excellent Short Wave Listening receiver and who knows, once the SWLer hears some ham radio activity, his/her interests may change toward that. Just an idea.

As for a power supply, four 12V cells can be connected in series for 48V and they can be recharged individually. I'm thinking of the batteries suggested here previously (I'll have to go back to find the ones I remember that are LiOn).

Bob — KK5R

On Tuesday, October 20, 2020, 4:25:29 PM EDT, KD2QMZ <syracusepro@...> wrote:


There are 50 volts power supplies already out there for linear amplifiers and other uses. My IC-7300 cost more than 1k$ and no power supply was included.

So, let the user take care of the power supply needs as they have been doing for years.
If they want more clean power, so higher capacitance for the filters then.

As per the radio, I got V5. Didn't get the V6, but would like to see something with more power. Also, resources for the radio should be organized to guide the assembler to enhance or to provide guidance to enhance capabilities.

I love the service Farhan has given to this kits, even better than any other manufacturer, and the radio cost less than 200$.
For the amount of money, no one should expect something better then an IC-7850 or similar.

It is a great kit, great to get to learn about it, enhance and put on the air as an experimental unit.
Some do have QSO's and use it more often.

Regardless, just want to appreciate the great work Farhan has put into this, and wish something new comes out soon.

73


On Tue, Oct 20, 2020 at 3:42 PM Arv Evans <arvid.evans@...> wrote:
Farhan

It seems that the most prevalent spurious RF problem with ham equipment is that the ham equipment uses external power.  This leads many to assume that any power supply is suitable for high sensitivity radio use.  It may not be practical to include an internal power supply inside kit radios, but we probably should include power supply specifications (voltage, ripple, spurious, minimum current capability, etc.) as part of the assembly and operating instructions, and explain what these specifications mean and how to measure them.

Hans has included some built-in test equipment inside his QCX radios.  Maybe a future version of uBITX could include use of an internal ADC based multimeter that could measure power supply voltage, current, ripple, hum, as well as outputs from a built-in Stockton Bridge type measurement for RF Power (at 50 ohms), Forward power, Reflected power, antenna impedance and possibly RF received level in microvolts & S-units.  Auto-ranging instrumentation is relatively easy to do by software observation of thresholds for ADC inputs.  Of course this would probably require a section of assembly and operation instruction that explains what all of these measurements might mean and how to use the information.

After using several versions of BITX transceiver I would heartily recommend a method for reducing power for ATU or Antenna adjustments.  

The assembly and operating manual should possibly include a section showing power supply requirements and how to measure and achieve those parameters.  Having the  above-mentioned internal measuring capability could simplify measuring things like power supply ripple, hum, and power (volts * Amps).  Desktop PC power supplies are inexpensive and easily modified to provide a solid and quiet  13.8V DC at several amperes.  Wall-warts and laptop power units are rarely suitable due to having minimal RF bypassing and an unshielded plastic case.  Linear supplies should be linear regulator units with significant over-current capability.  Remember that your power supply should have a low AC impedance furnished by RF, LF, and AF bypass capacitors.  Use a scope or fast sample-and-hold circuit to check power supplies for voltage overshoot at startup.

Arv
_._



On Tue, Oct 20, 2020 at 12:01 AM Ashhar Farhan <farhanbox@...> wrote:
Tom,
That is the scheme of hf packer : switch on the boost converter only on tx.
Another approach would be to make your radio live with noisy supplies. The best case would be to make it run off 5v supplies. They are aplenty. From PC SMPS to phone chargers to the USB power banks. It is really about time we moved to 5v standard.
A 5v supply boosted to 15v and linear regulated down to 12v could internally power the radio. The transmit would boost it to 24 or 50v. An Arduino and a low cost SMPS transformer would do the trick. If someone here as experience with this, it would be a game changer.
- f

On Tue 20 Oct, 2020, 11:12 AM Tom, wb6b, <wb6b@...> wrote:
On Mon, Oct 19, 2020 at 08:02 PM, Sila wrote:
Have you noticed any problems with the power supplies?
The one I have is a similar 12V switching supply. I puts out an RF spur that drifts across 75 meters. Fortunately, in somewhat less than 15 minutes it drifts across and away from the net I check into. 

I bought a couple of these supplier 12v 30A, 360W (was mistaken on my last post that they were 300W) to have a beefier spare supply for my 3D printer. When I bought the vintage Kenwood from a local ham I decided to try the power supply on it. I was happy it worked so well. Does have a annoying fan that sometimes starts running. Most of the lower wattage supplies do not have a fan.

Here would be a great Rube Goldberg electronic project: Put a switchable capacitor in the switching regulator circuitry to shift the frequency the supply is switching on. And depending on what frequency you are receiving on, shift the power supply frequency so the spur in not on the the frequency you are working on the radio. I'm sure adding a microprocessor would be a great addition to automating this. 

I'm not above a Rube Goldberg project once and awhile. When hard dives were new and very expensive, I programmed an 8748 microprocessor to monitor the status led on a drive that was starting to have problems booting up. When the 8748 noticed the LED was flashing a certain pattern it would pull the reset down on the hard drive and repeat this cycle until the drive would finally initialize and run. 

Got another year out of that drive. By then the replacement hard drives were higher capacity and had come down significantly in price. 

Some of the supplies I see sold for amateur radio use (from HAM radio manufactures) are switching supplies. Likely are similar supplies put in a metal box with additional RF filtering. 

For boosting the power of my uBitx, I'm still tending towards using a 12v (adjusted for 13.6v) power supply and the eBay boost converts. Only enabling the boost converters when transmitting.  I'd like to keep the main supply for my uBitx at 12V (13.6V) as that gives me more ham swap meet used power supply, battery and mobile options.

Tom, wb6b


Re: Rotary encoder

barry halterman
 

I use a bourns EM14 series for both my v6 and v4 ubitx. They are a little expensive but work well. You do need to connect them to 5v and ground. 
Barry

On Wed, Oct 21, 2020, 9:50 AM Evan Hand <elhandjr@...> wrote:
Gerard,
I do not have direct experience with replacing a mechanical encoder with an optical one.  You will at least need to run power to the new encoder, and verify that it outputs a low pulse rather than a high (NC vs NO type of switch).  The program for reading the encoder value is based on measuring the voltage level with a pull-up resistor (internal to the Nano).  This was done so that an analog input could be used for the connections.  Normally that would have been digital inputs.  There just are not enough digital inputs on the Nano.

So other than running the 5volt power to the encoder, and ensuring it is active low pulse output, that there are no more than 20-30 pulses per revolution, then there should not be any other changes required.

If you do go to active high, then you will need to change the logic in the Nano program.

73
Evan
AC9TU


Re: Si 5351 output power

Jerry Gaffke
 

Let's assume the source impedance of the Si5351 is 80 ohms, 
and the Si5351 can internally generate a 3v pk to pk square wave, so 1.5vrms.
The current through a 50 ohm load is:    i=1.5/(80+50)=0.01154 amps rms.

That's a bit more than the AN619 value of 8ma, but in the ballpark.
I would guess that evaluating the source impedance using a lighter load 
will show the source impedance dropping toward 50 ohms.
By varying the load resistor and measuring the voltage across it, we may
come up with consistent numbers for the source impedance and the voltage source.
I would do this first at fairly low frequencies, then see if it remains true at 
the frequency of interest where things may get considerably more complicated.

Power into the 50 ohm load is:    i*i*r = 0.01154*0.01154*50 = 0.006659 watts, or 6.659mw
In dBm, that would be:    10*log10(6.659) = 8.23 
With a 6dB attenuator, the 7dBm mixer is seeing 8.23-6 = 2.23 dBm
That can work fine, though might be have noticeable distortion with very strong signals.

There may be variation between Si5351's.
If some truly do limit current to 8ma, we get:   
  mw=0.008*0.008/50= 0.0032 watts,   10*log10(3.2)=5.05dbm,  mixer gets 5.05-6 = -0.5dBm

The uBitx v5 and v6 have an extra 33 ohm resistor between the Si5351 and the 6dB attenuator,
That would raise the effective Si5351 source impedance from 80 to 103 ohms, and give around 9ma.
(Or perhaps it raises the typical source impedance from 50 to 83 ohms?)
Since the Si5351 is not being asked to work so hard, it will distort less.

The fact that Farhan has found we need an attenuator between the Si5351 and the mixer
suggests to me that the source impedance of the Si5351 is not truly 50 ohms.
Without an attenuator, mixer products would come out of the mixer toward the Si5351,
and be reflected back into the mixer to mix again, creating birdies in the receiver.
I assume this was evaluated with 50 ohm coax between the Si5351 and the mixer,
or with extremely short wires.

Note that I have lots of "may", "could", "think" and "perhaps" in the above text.
Gordon is correct, this sort of armchair engineering only goes so far.
I really should do my own measurements of the Si5351 source impedance.
But I'd bet that Farhan has arrived at a good solution on the uBitx.
It keeps the circuit simple, avoiding a buffer amp between the Si5351 and the attenuator.
And does what it must to quiet down the unwanted mixer products.

Jerry, KE7ER


Re: Suggestion for the NEW UBITX V7.

Ashhar Farhan
 

Thanks for the kind words Bob,
I am also exploring if we can bring some jobs to USA if our volumes increase. I have been bouncing off these ideas a couple of hams in thr group.
We also want to keep the radios simple enough that someone can follow the circuit diagram. That is the secret sauce. Just look at the number of criticisms and mods here on the group! It is a testimony to the fact that people easily understand whatever is going on inside the radio. Compare this with the FT817, the circuit runs into a whole book of 30 pages!
- f

On Wed 21 Oct, 2020, 7:55 PM Bob Lunsford via groups.io, <nocrud222=yahoo.com@groups.io> wrote:
I have to voice my approval and acquiescence to this comment. After being sent to 53 countries mostly in Africa and S. America, but sadly not to India, to install foreign language labs and telephone switching system, I have seen what may be referred to as the Armpit of Africa. I have many Indian friends mostly at Fort Hood, TX and at the Univ of KY and can also see the ladies at HF Signals as being a crucial part of the success I have had with the V4 and V6. I'm sure there are many like me who "could" build a radio like this but thank my lucky stars that there are other professionals doing it for me.

I like the concept of a Basic Kit and a Complete Kit and don't see this going away. A ham friend here in my state (KY) has plans to order a V6 for his daughter to build to get a sense of accomplishment and to get her interested in Ham Radio. She is 14 years old.

Farhan is providing a service on several levels and hope his sense of satisfaction my extend to wondering about cost-effective improvements while also continuing to offer what he has now because their popularity means they are not out of vogue or considered old technology because it is a novel approach to putting an simple but affordable radio in the hands of old and new hams and for those who may lean that way. It's an outstanding and unique venture and I hope this part continues while continuing to explore ways to improve it without making it beyond consideration or merely competitive with other radios on the market.

Bob — KK5R

On Tuesday, October 20, 2020, 6:27:24 PM EDT, Ken Hansen <ken@...> wrote:


It is a concern, every improvement that increases cost, shrinks the market.

I bet Farhan could sketch out a tremendous radio with a beautiful case and wonderful specifications if he didn't worry about cost, but I suspect the nice ladies that assemble the radios would find themselves with significantly less work.

This project, as I understand it, was as much about creating a low-cost radio as it was to create work for a group of ladies in India.

Ken, N2VIP

> On Oct 20, 2020, at 00:23, AA9GG <paul.aa9gg@...> wrote:
>
> Unfortunately, the uBitX is just a little out of an OMs budget






Re: Suggestion for the NEW UBITX V7.

Bob Lunsford
 

I have to voice my approval and acquiescence to this comment. After being sent to 53 countries mostly in Africa and S. America, but sadly not to India, to install foreign language labs and telephone switching system, I have seen what may be referred to as the Armpit of Africa. I have many Indian friends mostly at Fort Hood, TX and at the Univ of KY and can also see the ladies at HF Signals as being a crucial part of the success I have had with the V4 and V6. I'm sure there are many like me who "could" build a radio like this but thank my lucky stars that there are other professionals doing it for me.

I like the concept of a Basic Kit and a Complete Kit and don't see this going away. A ham friend here in my state (KY) has plans to order a V6 for his daughter to build to get a sense of accomplishment and to get her interested in Ham Radio. She is 14 years old.

Farhan is providing a service on several levels and hope his sense of satisfaction my extend to wondering about cost-effective improvements while also continuing to offer what he has now because their popularity means they are not out of vogue or considered old technology because it is a novel approach to putting an simple but affordable radio in the hands of old and new hams and for those who may lean that way. It's an outstanding and unique venture and I hope this part continues while continuing to explore ways to improve it without making it beyond consideration or merely competitive with other radios on the market.

Bob — KK5R

On Tuesday, October 20, 2020, 6:27:24 PM EDT, Ken Hansen <ken@...> wrote:


It is a concern, every improvement that increases cost, shrinks the market.

I bet Farhan could sketch out a tremendous radio with a beautiful case and wonderful specifications if he didn't worry about cost, but I suspect the nice ladies that assemble the radios would find themselves with significantly less work.

This project, as I understand it, was as much about creating a low-cost radio as it was to create work for a group of ladies in India.

Ken, N2VIP

> On Oct 20, 2020, at 00:23, AA9GG <paul.aa9gg@...> wrote:
>
> Unfortunately, the uBitX is just a little out of an OMs budget






Re: Suggestion for the NEW UBITX V7.

Bob Lunsford
 

Just a thouht: A power diode or some in series would drop the 5V down into the livable 3.1-3.5V range. Therefore, it could be doable for both the 3.2 and 5V devices to be run from a single 5V source. Don't see why anyone would want to mix the devices for both voltage requirements unless for parts on hand or for a more enhanced/easier-to-work-with scheme.

Bob — KK5R

On Tuesday, October 20, 2020, 4:45:07 PM EDT, Arv Evans <arvid.evans@...> wrote:


Farhan

Okay, 5V might be a standard, but many modern IC's operate on 
3.2 to 3.8 volts while most older (cheaper...?) IC's operate on 5V.

Most LIPO cells charge to 4V and discharge to 3.2V.  This works 
fine for 3.2 to 3.8 volt IC's, but not so well for 5V devices.  

A myriad of boost and buck converter devices are available, but 
they cost money and add noise to the circuits.  

Backing up and re-thinking...do we really need a "standard" and 
why?  Maybe this need is defined by what the target circuitry looks 
like?  If all the IC's are 3.2V, then the target standard may be 3.2V
If all the IC's are 5V, then the target standard may be 5.0V.
If there is a mix of voltages then this may drive the design (redesign...)
to use one voltage or the other, but not a mix of voltages?  This 
now sounds like more of an economic issue than a voltage one!  
8-)

Arv
_._



On Tue, Oct 20, 2020 at 2:14 PM Ashhar Farhan <farhanbox@...> wrote:
Arv,
I am glad that you got curious about it. Most modern semiconductor devices are moving to 3.3v standard. I think 5v maybe a good, new standard.

On Wed 21 Oct, 2020, 1:26 AM Arv Evans, <arvid.evans@...> wrote:
Tom and Farhan

The idea of settling on a common battery level as standard for 
internal circuitry is an interesting one.  An internal LIPO or similar 
battery pack could be charged by an inexpensive USB or POE 
adapter.  With this the only higher voltage inside the chassis 
might be for a transmit power amplifier that would be DC isolated 
from any low-voltage circuits.  There are a number of options that 
could be evaluated if we decided to do this.

Arv
_._

On Tue, Oct 20, 2020 at 12:37 AM Tom, wb6b <wb6b@...> wrote:
On Mon, Oct 19, 2020 at 11:00 PM, Ashhar Farhan wrote:
phone chargers to the USB power banks. It is really about time we moved to 5v standard.
That's an interesting idea. Maybe have a lipo battery fill in the peak power, if the operator does not talk at 100% duty cycle.

What is interesting about USB-C is the device can negotiate with the USB-C power adaptor for higher wattage (100 wats) by requesting 20 volts at 5 amps, instead of 5 volts. 

https://www.digikey.com/en/articles/designing-in-usb-type-c-and-using-power-delivery-for-rapid-charging

The idea of cheap cost cutter suppliers making USB-C supplies, with no safety mechanisms, that may not reliably negotiate the voltage, frying my 5v USB devices with 20v worries me. Fortunately most everything is built into a chip now days and the chip manufactures still seem to follow good engineering practices. But the cost cutters will still see something to leave out to save a tenth of a penny. 

Tom, wb6b


Re: Suggestion for the NEW UBITX V7.

Bob Lunsford
 

Ken, I can see what you suggest with a jumper switch on the back, beside the higher voltage connector/s, that allows the radio to run on 12/13.8V while the higher voltage is available for the finals. Once the radio is set up, I suspect it will be left alone but if someone wanted to go out with a 12V source, simply throwing the switch would put the radio back in basic function mode with the finals provided the necessary 12V for that operating session. A DPDT switch and a steering diode would make sure the higher voltage did not get to the main board, etc., and keep the radio from being toasted with higher voltage.

Bob — KK5R

On Tuesday, October 20, 2020, 4:42:40 PM EDT, Ken Hansen <ken@...> wrote:


As a pricing exercise, I wonder what the increase would be if you shipped only one model that came with a beefier heatsink and a second power connection to optionally drive the finals to 40 watts? Those that want the higher output can figure out turning 12v into 24v, and those happy with 10 watts need for nothing and can enjoy the oversized heatsink on the finals?

The IC-705 is a 5 watt radio, unless you give it a 12v power source, then it does 10 watts.

Imagine if the uBitx was sold as a 10 watt radio, but with the addition of a voltage booster, it becomes a 40 watt radio. A 40 watt radio with an inexperienced operator and a compromise antenna would likely do much better than the same station and operator with 10 watts output...

The downside would be a (hopefully only) slightly more expensive radio, the upside would be a much more useful radio when propagation is working against you.

This all assumes the radio would still put out a clean signal and require little to no re-engineering/changes beyond a couple jumpers, a reworking of the finals wiring, and the bigger heatsink.

Just my 2¢ worth,

Ken, N2VIP

> On Oct 19, 2020, at 01:00, Ashhar Farhan <farhanbox@...> wrote:
>
> I wonder how many want higher output. The same IRF510 pair with 25v on the drains can easily push out 40 watts. They will need beefier heatsinks.
> The real is the power supply. At present a 7812 regulator can run the ubitx.






Re: Suggestion for the NEW UBITX V7.

Bob Lunsford
 

My son received the V6 I sent to him and told me he didn't have time to give it a thorough check out but he did check into a SSB net in Oregon from Sacramento, CA. My replacement for the V6 I sent to him is due to arrive today. I plan to use it more on the air than I did with the one I sent to my son.

Christmas is coming. $200 is not too much to spend for a gift for a ham friend or a son/daughter who may be inclined to get into ham radio. It is also an excellent Short Wave Listening receiver and who knows, once the SWLer hears some ham radio activity, his/her interests may change toward that. Just an idea.

As for a power supply, four 12V cells can be connected in series for 48V and they can be recharged individually. I'm thinking of the batteries suggested here previously (I'll have to go back to find the ones I remember that are LiOn).

Bob — KK5R

On Tuesday, October 20, 2020, 4:25:29 PM EDT, KD2QMZ <syracusepro@...> wrote:


There are 50 volts power supplies already out there for linear amplifiers and other uses. My IC-7300 cost more than 1k$ and no power supply was included.

So, let the user take care of the power supply needs as they have been doing for years.
If they want more clean power, so higher capacitance for the filters then.

As per the radio, I got V5. Didn't get the V6, but would like to see something with more power. Also, resources for the radio should be organized to guide the assembler to enhance or to provide guidance to enhance capabilities.

I love the service Farhan has given to this kits, even better than any other manufacturer, and the radio cost less than 200$.
For the amount of money, no one should expect something better then an IC-7850 or similar.

It is a great kit, great to get to learn about it, enhance and put on the air as an experimental unit.
Some do have QSO's and use it more often.

Regardless, just want to appreciate the great work Farhan has put into this, and wish something new comes out soon.

73


On Tue, Oct 20, 2020 at 3:42 PM Arv Evans <arvid.evans@...> wrote:
Farhan

It seems that the most prevalent spurious RF problem with ham equipment is that the ham equipment uses external power.  This leads many to assume that any power supply is suitable for high sensitivity radio use.  It may not be practical to include an internal power supply inside kit radios, but we probably should include power supply specifications (voltage, ripple, spurious, minimum current capability, etc.) as part of the assembly and operating instructions, and explain what these specifications mean and how to measure them.

Hans has included some built-in test equipment inside his QCX radios.  Maybe a future version of uBITX could include use of an internal ADC based multimeter that could measure power supply voltage, current, ripple, hum, as well as outputs from a built-in Stockton Bridge type measurement for RF Power (at 50 ohms), Forward power, Reflected power, antenna impedance and possibly RF received level in microvolts & S-units.  Auto-ranging instrumentation is relatively easy to do by software observation of thresholds for ADC inputs.  Of course this would probably require a section of assembly and operation instruction that explains what all of these measurements might mean and how to use the information.

After using several versions of BITX transceiver I would heartily recommend a method for reducing power for ATU or Antenna adjustments.  

The assembly and operating manual should possibly include a section showing power supply requirements and how to measure and achieve those parameters.  Having the  above-mentioned internal measuring capability could simplify measuring things like power supply ripple, hum, and power (volts * Amps).  Desktop PC power supplies are inexpensive and easily modified to provide a solid and quiet  13.8V DC at several amperes.  Wall-warts and laptop power units are rarely suitable due to having minimal RF bypassing and an unshielded plastic case.  Linear supplies should be linear regulator units with significant over-current capability.  Remember that your power supply should have a low AC impedance furnished by RF, LF, and AF bypass capacitors.  Use a scope or fast sample-and-hold circuit to check power supplies for voltage overshoot at startup.

Arv
_._



On Tue, Oct 20, 2020 at 12:01 AM Ashhar Farhan <farhanbox@...> wrote:
Tom,
That is the scheme of hf packer : switch on the boost converter only on tx.
Another approach would be to make your radio live with noisy supplies. The best case would be to make it run off 5v supplies. They are aplenty. From PC SMPS to phone chargers to the USB power banks. It is really about time we moved to 5v standard.
A 5v supply boosted to 15v and linear regulated down to 12v could internally power the radio. The transmit would boost it to 24 or 50v. An Arduino and a low cost SMPS transformer would do the trick. If someone here as experience with this, it would be a game changer.
- f

On Tue 20 Oct, 2020, 11:12 AM Tom, wb6b, <wb6b@...> wrote:
On Mon, Oct 19, 2020 at 08:02 PM, Sila wrote:
Have you noticed any problems with the power supplies?
The one I have is a similar 12V switching supply. I puts out an RF spur that drifts across 75 meters. Fortunately, in somewhat less than 15 minutes it drifts across and away from the net I check into. 

I bought a couple of these supplier 12v 30A, 360W (was mistaken on my last post that they were 300W) to have a beefier spare supply for my 3D printer. When I bought the vintage Kenwood from a local ham I decided to try the power supply on it. I was happy it worked so well. Does have a annoying fan that sometimes starts running. Most of the lower wattage supplies do not have a fan.

Here would be a great Rube Goldberg electronic project: Put a switchable capacitor in the switching regulator circuitry to shift the frequency the supply is switching on. And depending on what frequency you are receiving on, shift the power supply frequency so the spur in not on the the frequency you are working on the radio. I'm sure adding a microprocessor would be a great addition to automating this. 

I'm not above a Rube Goldberg project once and awhile. When hard dives were new and very expensive, I programmed an 8748 microprocessor to monitor the status led on a drive that was starting to have problems booting up. When the 8748 noticed the LED was flashing a certain pattern it would pull the reset down on the hard drive and repeat this cycle until the drive would finally initialize and run. 

Got another year out of that drive. By then the replacement hard drives were higher capacity and had come down significantly in price. 

Some of the supplies I see sold for amateur radio use (from HAM radio manufactures) are switching supplies. Likely are similar supplies put in a metal box with additional RF filtering. 

For boosting the power of my uBitx, I'm still tending towards using a 12v (adjusted for 13.6v) power supply and the eBay boost converts. Only enabling the boost converters when transmitting.  I'd like to keep the main supply for my uBitx at 12V (13.6V) as that gives me more ham swap meet used power supply, battery and mobile options.

Tom, wb6b


Re: Rotary encoder

Evan Hand
 

Gerard,
I do not have direct experience with replacing a mechanical encoder with an optical one.  You will at least need to run power to the new encoder, and verify that it outputs a low pulse rather than a high (NC vs NO type of switch).  The program for reading the encoder value is based on measuring the voltage level with a pull-up resistor (internal to the Nano).  This was done so that an analog input could be used for the connections.  Normally that would have been digital inputs.  There just are not enough digital inputs on the Nano.

So other than running the 5volt power to the encoder, and ensuring it is active low pulse output, that there are no more than 20-30 pulses per revolution, then there should not be any other changes required.

If you do go to active high, then you will need to change the logic in the Nano program.

73
Evan
AC9TU


Re: Rotary encoder

Gerard
 

Evan,
Installing an optical rotary encoder doesn’t seem that simple.
This still requires hardware changes with the addition of a splitter and/or soft changes. PB of numbers of PPM
For the moment, I will only ask this question: "Is there an optical rotary encoder possible replacement without any further modification?"

See here for exemple of post
https://groups.io/g/BITX20/topic/10293081#41319
https://groups.io/g/BITX20/topic/27394046#60812
https://groups.io/g/BITX20/topic/6188975#33650
etc

Cdt


Re: Suggestion for the NEW UBITX V7.

K2ICC
 

Great idea on the parts thing. 

Here is a high power transceiver built:

Is a Book named: Building a transceiver, authors Eamon Skelton, EI9GQ and Elaine Richards, G4LFM.

Very well explained stuff.


On Wed, Oct 21, 2020 at 12:00 AM Ken Hansen <ken@...> wrote:
Agree, I had forgotten about the third consideration, the ability to source the parts and build it yourself.

Thanks Farhan,

Ken, N2VIP

> On Oct 20, 2020, at 22:01, Ashhar Farhan <farhanbox@...> wrote:
>
> Please remember, although few do, it should be possible to build these radios from the scratch by a homebrewer. The parts should be generic and readily available. The performance should come from clever design and not by throwing money at it and buying expensive devices and components.







Re: Help Request Please with Nextion 2.8 Display

Mick
 

Hello Ted

Yes no smoke luckily and as described in my reply to Evan, my approach could have been better.
The build went fine and I had fully completed the kit and was using it on receive with the original display.
I had ordered the Nextion display when I ordered the kit from India, so I was keen to install it once I knew that I had a successful build.
No not on the air with it yet Ted.
I need to make a new front panel for the existing case and install the Kit-Projects AGC kit, which has now also arrived.

All the best Ted

73

Mick M0GWD

On 21/10/2020 01:27, Ted via groups.io wrote:
"Connecting the 4 wires to this right-angled header, for pins 1, 2 and 5 I counted from one end, and for pin 11, I counted back 4 from the other end, That would have been fine if my angled header strip had 14 pins, but mine has 15 pins."


Hi, Mick.

That's a good catch and easily missed.  I'm glad that you didn't inadvertently let the magic smoke out of the Raduino or the screen as some of us are good at doing. 

How is the rest of the build going for you? Have you had it on the air as yet? 



Ted
K3RTA


Virus-free. www.avast.com


Re: Help Request Please with Nextion 2.8 Display

Mick
 

Hello Evan

Yes good news and all is well.
My approach could have been better.
If I had snapped off my right-angle header strip to 14-pins to start with, the extraneous piece of plastic on the female header on the Nano board would have been obvious.  You live and learn.

I intend making a new front panel for the ubitx case so that the Nextion display is a nice fit.
It's a great kit and I'm really pleased with it.

Thanks Evan, all the best

Mick M0GWD


On 21/10/2020 00:43, Evan Hand wrote:
Good News!

Have fun with the new display.  I find it much easier to use then the 1602 display that came with the v5 kits.

73
Evan
AC9TU


Virus-free. www.avast.com


Re: Suggestion for the NEW UBITX V7.

Bob Lunsford
 

Excellent linked website. If used with the V6, however, a way of reducing the amp drive would be needed or it would be like driving a 4-1000 amp with an SB-220. (This was done once by a CBer with no adult supervision and the 4-1000 went west.)

I especially like that the link provides nearly every possible suggestion for using it on multiple bands even to giving coil winding specifications — and he calls it a prototype...?

Bob — KK5R

On Tuesday, October 20, 2020, 11:30:54 AM EDT, Greg Blair <j.greg.blair@...> wrote:


5441 - 5460 of 87464