Topics

Modular uBitx - "Ex: Harmonics"

Jerry Gaffke
 

The "off the rails" thing was me, not Jack.
I hope this nips the potential for another issue to argue about.

>  Well, at least everybody agrees to argue.

I rest my case.   ;-)


> Seems everyone did not understand my post.  The SDR radio does require a PC and a sound card. 
> But I meant that you could hook the STM card to that radio and there is software to decode the IQ and do psk31.


It's possible to do all the computations required for SDR
in a high end ARM processor (such as a Teensy with FP hardware).
No PC required.    OK, we can productively argue about that.

Jerry



On Thu, Aug 16, 2018 at 08:33 AM, ajparent1/KB1GMX wrote:
As to off the rails. yes, you spoke the truth.  

Arv Evans
 

One of the Rasbberry Pi versions could probably be added inside a transceiver case running Linux.  That could replace an Arduino and PC as well.  

Arv
_-_



Sent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------
From: Glenn <glennp@...>
Date: 8/15/18 11:16 PM (GMT-07:00)
To: BITX20@groups.io
Subject: Re: [BITX20] Modular uBitx - "Ex: Harmonics"

I have one of these boards.  It requires a PC plus an external sound card.

There was talk of another board to replace the PC part and display etc, but I don't think anything has come of that.
glenn vk3pe

Eric Flores <floreseric1981@...>
 


One of the Rasbberry Pi versions could probably be added inside a transceiver case running Linux.  That could replace an Arduino and PC as well.  

I was thinking along the same lines. This would open up quite a bit of possibilities with all the extra CPU power. 

I liked the suggestion from RCBoatGuy that pertains to this:

- Si5351 on main board, not on Raduino/Teensyduino/JackAl

If the Si5351 was on the mainboard, then you can use whatever you want for the CPU board and the it via the I2C interface. It would increase the hackable-ness of the uBitx.

Eric

On Thu, Aug 16, 2018 at 1:04 PM Arv Evans <arvid.evans@...> wrote:
One of the Rasbberry Pi versions could probably be added inside a transceiver case running Linux.  That could replace an Arduino and PC as well.  

Arv
_-_



Sent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------
From: Glenn <glennp@...>
Date: 8/15/18 11:16 PM (GMT-07:00)
Subject: Re: [BITX20] Modular uBitx - "Ex: Harmonics"

I have one of these boards.  It requires a PC plus an external sound card.

There was talk of another board to replace the PC part and display etc, but I don't think anything has come of that.
glenn vk3pe

W2CTX
 

No one concerned with extra power draw or noise generated by the pi?


On August 16, 2018 at 4:12 PM Eric Flores <floreseric1981@...> wrote:


One of the Rasbberry Pi versions could probably be added inside a transceiver case running Linux.  That could replace an Arduino and PC as well.  

I was thinking along the same lines. This would open up quite a bit of possibilities with all the extra CPU power. 

I liked the suggestion from RCBoatGuy that pertains to this:

- Si5351 on main board, not on Raduino/Teensyduino/JackAl

If the  Si5351 was on the mainboard, then you can use whatever you want for the CPU board and the it via the I2C interface. It would increase the hackable-ness of the uBitx.

Eric

On Thu, Aug 16, 2018 at 1:04 PM Arv Evans < arvid.evans@...> wrote:
One of the Rasbberry Pi versions could probably be added inside a transceiver case running Linux.  That could replace an Arduino and PC as well.  

Arv
_-_



Sent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------
From: Glenn < glennp@...>
Date: 8/15/18 11:16 PM (GMT-07:00)
Subject: Re: [BITX20] Modular uBitx - "Ex: Harmonics"

I have one of these boards.  It requires a PC plus an external sound card.

There was talk of another board to replace the PC part and display etc, but I don't think anything has come of that.
glenn vk3pe

 

 

Eric Flores <floreseric1981@...>
 

No one concerned with extra power draw or noise generated by the pi?

Some people might be concerned about, others may want the RPi so much that they compensate for it. With the suggestion of putting the Si5351 on the mainboard, it would leave options open for the end user.

On Thu, Aug 16, 2018 at 3:19 PM W2CTX <w2ctx@...> wrote:

No one concerned with extra power draw or noise generated by the pi?


On August 16, 2018 at 4:12 PM Eric Flores <floreseric1981@...> wrote:


One of the Rasbberry Pi versions could probably be added inside a transceiver case running Linux.  That could replace an Arduino and PC as well.  

I was thinking along the same lines. This would open up quite a bit of possibilities with all the extra CPU power. 

I liked the suggestion from RCBoatGuy that pertains to this:

- Si5351 on main board, not on Raduino/Teensyduino/JackAl

If the  Si5351 was on the mainboard, then you can use whatever you want for the CPU board and the it via the I2C interface. It would increase the hackable-ness of the uBitx.

Eric

On Thu, Aug 16, 2018 at 1:04 PM Arv Evans < arvid.evans@...> wrote:
One of the Rasbberry Pi versions could probably be added inside a transceiver case running Linux.  That could replace an Arduino and PC as well.  

Arv
_-_



Sent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------
From: Glenn < glennp@...>
Date: 8/15/18 11:16 PM (GMT-07:00)
Subject: Re: [BITX20] Modular uBitx - "Ex: Harmonics"

I have one of these boards.  It requires a PC plus an external sound card.

There was talk of another board to replace the PC part and display etc, but I don't think anything has come of that.
glenn vk3pe

 

 

Arv Evans
 

W2CTX

Interesting thought.   We already live with noise from the AVR/Arduino on 16 MHz, 12 MHz,
harmonics of these, and mixed products of those.  Yes, putting any computing device inside
the radio chassis will cause problems.  It is a trade-off for convenience and functionality versus
having a quiet receiver.  Of course if we really want a very quiet receiver we would not be using
double conversion.  Direct-conversion with phase shift methodology replacing filters could
eliminate much of the mixing products of a dual-conversion architecture. 

This does bring up the idea of having a chassis-within-a-chassis to shield the radio from
computer or computer from the radio.  Heating/cooling could be problematic, but not
insurmountable. 

Arv
_._


On Thu, Aug 16, 2018 at 2:19 PM W2CTX <w2ctx@...> wrote:

No one concerned with extra power draw or noise generated by the pi?


On August 16, 2018 at 4:12 PM Eric Flores <floreseric1981@...> wrote:


One of the Rasbberry Pi versions could probably be added inside a transceiver case running Linux.  That could replace an Arduino and PC as well.  

I was thinking along the same lines. This would open up quite a bit of possibilities with all the extra CPU power. 

I liked the suggestion from RCBoatGuy that pertains to this:

- Si5351 on main board, not on Raduino/Teensyduino/JackAl

If the  Si5351 was on the mainboard, then you can use whatever you want for the CPU board and the it via the I2C interface. It would increase the hackable-ness of the uBitx.

Eric

On Thu, Aug 16, 2018 at 1:04 PM Arv Evans < arvid.evans@...> wrote:
One of the Rasbberry Pi versions could probably be added inside a transceiver case running Linux.  That could replace an Arduino and PC as well.  

Arv
_-_



Sent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------
From: Glenn < glennp@...>
Date: 8/15/18 11:16 PM (GMT-07:00)
Subject: Re: [BITX20] Modular uBitx - "Ex: Harmonics"

I have one of these boards.  It requires a PC plus an external sound card.

There was talk of another board to replace the PC part and display etc, but I don't think anything has come of that.
glenn vk3pe

 

 

ajparent1/KB1GMX
 

Arv,

All the best radios I've built shielding was most time consuming and worth it.
Confining signals to the place needed only has been a known cure.  Often 
its the difference.

However it does not have to be mechanically complicated.

Allison 

ajparent1/KB1GMX
 

Eric,

Why should the PI be any worse than a PC in the shack.  IF anything its 
a small package and easily put in a tin pay attention to heat removal
what there is of it.

Allison

Arv Evans
 

Allison

Agreed.  Some readers have an aversion to installing a PC level board inside a radio.
I can understand, but also see the need to try it with one of the tiny but full featured PC
cards like the Raspberry Pi or Pi-Zero.  That could allow any of the Linux applications
(fldigi, etc.) to exist and run inside something like the Ubitx or one of the QRP-Labs
creations.  Using I2C and a Nextion display could provide bus-level interfaces for
many plug-in functions.  USB could host the mouse and keyboard to make a very
compact rig for field-day activities.  Shielding for such a small PC board becomes
less of a problem with these small boards.  I don't have the time, but maybe someone
will take on the challenge.

Arv
_._


On Thu, Aug 16, 2018 at 7:03 PM ajparent1/KB1GMX <kb1gmx@...> wrote:
Arv,

All the best radios I've built shielding was most time consuming and worth it.
Confining signals to the place needed only has been a known cure.  Often 
its the difference.

However it does not have to be mechanically complicated.

Allison 

ajparent1/KB1GMX
 

Arv,

I have a laptop using a Rpi3b and a 10inch screen (not touch) with a real
keyboard and mouse with a steampunk sorta look.  With a stereo usb
dongle IT runs Fldigi, gsdr and a few other useful things like Xlog under
Raspian (linux).  Noise has not been an issue.  Its mostly all wood so
its not shielded.  Power drain is pretty low with the display backlight down.

The asus Tinker board is faster and uses more power, heck 1.8GHZ,
2gb ram and all that. No Noticeable noise

Android tablets work, the smaller ones with quad cores are ok for this too
and it could be the whole front panel for a radio at cheap prices.  I have
two for that. 

Allison

Gordon Gibby <ggibby@...>
 

Regarding my external relays idea :  The Chinese boards arrived, and I believe the digikey parts also.... then I had to go to the emergency room with incredible abdominal pain that turned out to be gallbladder stone induced pancreatitis.   I’m still in the hospital,  much better, now to have the gallbladder out Monday.    

Then maybe I can get back to this and many other projects.  Group Builds of uBitx’s  at my house today had to be canceled of course.   Getting old is tough but the alternative is less desirable 

image1.jpeg

Gordon. 


On Aug 16, 2018, at 22:01, ajparent1/KB1GMX <kb1gmx@...> wrote:

Arv,

I have a laptop using a Rpi3b and a 10inch screen (not touch) with a real
keyboard and mouse with a steampunk sorta look.  With a stereo usb
dongle IT runs Fldigi, gsdr and a few other useful things like Xlog under
Raspian (linux).  Noise has not been an issue.  Its mostly all wood so
its not shielded.  Power drain is pretty low with the display backlight down.

The asus Tinker board is faster and uses more power, heck 1.8GHZ,
2gb ram and all that. No Noticeable noise

Android tablets work, the smaller ones with quad cores are ok for this too
and it could be the whole front panel for a radio at cheap prices.  I have
two for that. 

Allison

Arv Evans
 

Gordon

Those Chinese boards look pretty good. 

Hang in there.  We are all pulling for you.

Arv
_._


On Sat, Aug 18, 2018 at 7:14 PM Gordon Gibby <ggibby@...> wrote:
Regarding my external relays idea :  The Chinese boards arrived, and I believe the digikey parts also.... then I had to go to the emergency room with incredible abdominal pain that turned out to be gallbladder stone induced pancreatitis.   I’m still in the hospital,  much better, now to have the gallbladder out Monday.    

Then maybe I can get back to this and many other projects.  Group Builds of uBitx’s  at my house today had to be canceled of course.   Getting old is tough but the alternative is less desirable 



Gordon. 


On Aug 16, 2018, at 22:01, ajparent1/KB1GMX <kb1gmx@...> wrote:

Arv,

I have a laptop using a Rpi3b and a 10inch screen (not touch) with a real
keyboard and mouse with a steampunk sorta look.  With a stereo usb
dongle IT runs Fldigi, gsdr and a few other useful things like Xlog under
Raspian (linux).  Noise has not been an issue.  Its mostly all wood so
its not shielded.  Power drain is pretty low with the display backlight down.

The asus Tinker board is faster and uses more power, heck 1.8GHZ,
2gb ram and all that. No Noticeable noise

Android tablets work, the smaller ones with quad cores are ok for this too
and it could be the whole front panel for a radio at cheap prices.  I have
two for that. 

Allison

Tom, wb6b
 

The reason Raspberry Pis are so inexpensive is they take advantage of the price advantage of using basically the same processor that is used in hundreds of millions of radio transceivers, already. (smartphones) 

So, a Raspberry Pi finding its way back into another transceiver (uBITX) does not seem too far of a stretch. Not necessarily for SDR I/Q processing, but running digital modes in a small radio package is a good thing. Also, there are some audio/microphone compressor/equalizer software packages that can run under Linux that might improve your SSB transmit audio without needing to add an additional analog compressor board (albeit a second USB sound adaptor).

On the RFI noise front, I found a metal case for the Pi that will go inside the bigger transceiver case. 

I like Allison's idea of using Android tablets as a controller for the uBITX. I'm, also, looking into running a web server on my Raspberry Pi so I can operate my uBITX from either an iPhone or Android (without installing an App). Possibility borrowing a little from the web interface of OpenWebRX.  Some browsers may be capable of sending realtime audio back to the uBITX. I'm looking at the protocol that supposedly allows this. 

I've seen some commercial HF radios that let users send/receive text messages from their Smartphones. That, on Ham Radio, would certainly attract a new younger group of Amateur Radio operators to the hobby.

Tom, wb6b

 

Tom, wb6b
 

I like Gordon's add-on second set of relays idea and board. 

Just wondering if something like this relay board might do an acceptable job for someone wanting something ready made. Would follow Gordon's suggested uBITX board cuts and then wire one side of the filters to these relays. https://www.amazon.com/dp/B06XRYGM2C/

I've seen some SPST relays where the center conductor is connected to the frame (don't know if that is the case with these). That could possibility be a big issue. But, as this would only be connected to one side of the filters, and both sides are switched, due to the original relays still switching the other side, with careful choice of wiring, these might work.

---

---

Tom, wb6b

Eric Flores <floreseric1981@...>
 

Tom, you’re thinking right up my alley. I was also considering a RPi to handle digital modulation modes. 

But, I am also considering using it to run an RTL-SDR for all of the RX work and tap the signal from the 1 mixer (just off C10 and the base of Q10, and completey removing R10, R11, Q10) and send the RX strait to RTL w/ small piece of coax. The IF should be 46Mhz-75MHz (for 160-10m) right there, which is well within the range of the dongle so you wound not need a hamitup upconverter. The one issue that might prevent this is I can’t seem to get rid of a 1/2 second delay in the RTLs. 

I was also considering having a headless ubitx so I can have the radio in a shack and operate from the house, which could end up being a few hundred yards away. It would be controlled via a network connection to either another RPi or a computer (possibly via rtl_tcp for RX control, a REST API for general radio control and an RTP stream for TX voice). 

As an added plus, raspian supports Docker so each of these little services can be their own container making upgrades a breeze. 

Eric

On Sat, Aug 18, 2018 at 21:57 Tom, wb6b <wb6b@...> wrote:
The reason Raspberry Pis are so inexpensive is they take advantage of the price advantage of using basically the same processor that is used in hundreds of millions of radio transceivers, already. (smartphones) 

So, a Raspberry Pi finding its way back into another transceiver (uBITX) does not seem too far of a stretch. Not necessarily for SDR I/Q processing, but running digital modes in a small radio package is a good thing. Also, there are some audio/microphone compressor/equalizer software packages that can run under Linux that might improve your SSB transmit audio without needing to add an additional analog compressor board (albeit a second USB sound adaptor).

On the RFI noise front, I found a metal case for the Pi that will go inside the bigger transceiver case. 

I like Allison's idea of using Android tablets as a controller for the uBITX. I'm, also, looking into running a web server on my Raspberry Pi so I can operate my uBITX from either an iPhone or Android (without installing an App). Possibility borrowing a little from the web interface of OpenWebRX.  Some browsers may be capable of sending realtime audio back to the uBITX. I'm looking at the protocol that supposedly allows this. 

I've seen some commercial HF radios that let users send/receive text messages from their Smartphones. That, on Ham Radio, would certainly attract a new younger group of Amateur Radio operators to the hobby.

Tom, wb6b

 

Tom, wb6b
 

Using the RTL_SDR sounds interesting. I'd been concerned about audio delays even with using software audio filters/equalizers. Was running this by another local ham, and he suggested that some delay would likely not be an issue, as many times Hams are using the webSDR site to help hear people in a net that they can't hear directly.

I guess if I can respond to my call in a net roll call before the net control calls the next call, all is well. So, maybe a half a second is acceptable. But, at some point it will be troublesome. When I use OpenWebRX on my local network, it still will try to buffer up several seconds of audio, that is something I'd need to improve for a headless radio arrangement.  

I looked in my notes the web protocol I was looking into is called WebRTC. Supposedly it is supported by a number of browsers, now.

Docker is cool, I use it with some of my consulting clients. I just made a clone of my Pi's SD card, so when I start stringing more audio software applications together and Jack Audio stops working and it is too perplexing to get back to a known working state, I can just start again from a known system that has WSJT working and try again. At least to me, Linux has one of the most confusing audio chains imaginable. FLdigi seems to use a different audio backend than WSJT so getting both to work is requiring some work. The logic of the Linux sound support may strike me as I play with it more. 

Tom, wb6b

Gordon Gibby <ggibby@...>
 

Tom— well, that 4 relay module certainly is cheap!   And it looks like it has optically isolated controls of the relay coil’s.   That would get around the coupling back through the coil’s.   Probably even better than the inductors and bypass capacitor is that I stuck on. That little eight dollar board runs (it seems ) on 5 V, but it wouldn’t be hard to step down the TX switched voltage to 5 V to run this.   You might could just switch the input to a 5 V regulator and it might be fast enough

I would think that that’s a pretty elegant solution. Had I known about it I might have done it.

Cheers!!
Gordon
 


On Aug 19, 2018, at 05:36, Tom, wb6b <wb6b@...> wrote:

Using the RTL_SDR sounds interesting. I'd been concerned about audio delays even with using software audio filters/equalizers. Was running this by another local ham, and he suggested that some delay would likely not be an issue, as many times Hams are using the webSDR site to help hear people in a net that they can't hear directly.

I guess if I can respond to my call in a net roll call before the net control calls the next call, all is well. So, maybe a half a second is acceptable. But, at some point it will be troublesome. When I use OpenWebRX on my local network, it still will try to buffer up several seconds of audio, that is something I'd need to improve for a headless radio arrangement.  

I looked in my notes the web protocol I was looking into is called WebRTC. Supposedly it is supported by a number of browsers, now.

Docker is cool, I use it with some of my consulting clients. I just made a clone of my Pi's SD card, so when I start stringing more audio software applications together and Jack Audio stops working and it is too perplexing to get back to a known working state, I can just start again from a known system that has WSJT working and try again. At least to me, Linux has one of the most confusing audio chains imaginable. FLdigi seems to use a different audio backend than WSJT so getting both to work is requiring some work. The logic of the Linux sound support may strike me as I play with it more. 

Tom, wb6b

Jerry Gaffke
 

The desired signal at Q10 is always right around 45mhz.
Has to be, or it won't go through the 45mhz crystal filter


On Sun, Aug 19, 2018 at 01:37 AM, Eric Flores wrote:
Tom, you’re thinking right up my alley. I was also considering a RPi to handle digital modulation modes. 
 
But, I am also considering using it to run an RTL-SDR for all of the RX work and tap the signal from the 1 mixer (just off C10 and the base of Q10, and completey removing R10, R11, Q10) and send the RX strait to RTL w/ small piece of coax. The IF should be 46Mhz-75MHz (for 160-10m) right there, which is well within the range of the dongle so you wound not need a hamitup upconverter. The one issue that might prevent this is I can’t seem to get rid of a 1/2 second delay in the RTLs. 
 
I was also considering having a headless ubitx so I can have the radio in a shack and operate from the house, which could end up being a few hundred yards away. It would be controlled via a network connection to either another RPi or a computer (possibly via rtl_tcp for RX control, a REST API for general radio control and an RTP stream for TX voice). 
 
As an added plus, raspian supports Docker so each of these little services can be their own container making upgrades a breeze. 

John Brock
 

Is there a concern for how the contacts are routed on the PC board so far as RF is concerned? What about the ability of the contacts to reliably switch relatively low level signals?

John Brock

WA8US

Gordon Gibby <ggibby@...>
 

Hi John Brock I’m not sure exactly which project you were referring to, but if the external low pass filter relay project:

1. You basically want to do the wiring so the RF signal don’t get mixed into HIGHER low pass filters.   I do that by grounding the higher low pass filters when no longer in use.  On the Little board that someone pointed out the relay contacts are right there for you, so you can wire them with short or shielded wires and minimize cross talk.  You’re trying to reduce capacitance between circuits that shouldn’t know about each other

2.  You also want to avoid blow by getting around through the coil connections which are wired on both input and output of the filters and communicate by way of the DC wiring.  Decoupling bypass capacitors or  the optical coupling are good solutions for that

3.  Relays have been used to switch transmit/receive/ filter signals for a bunch of years.  My heathkits  had them.  Sometimes the Contacts get a little oxidized and less signal gets through, a bit of paper used to burnish them and they work better.   That is, if you can even get to them.  




On Aug 19, 2018, at 10:22, John Brock <brock71@...> wrote:

Is there a concern for how the contacts are routed on the PC board so far as RF is concerned? What about the ability of the contacts to reliably switch relatively low level signals?

John Brock

WA8US