Date   
Re: Antuino support group opened -- early antuino question

Don - KM4UDX
 

Ashhar and Jerry -- thank you so much for the reply and info.  I better understand the general antuino application.  It is not a inline SWR/pwr meter, but it does a thousand other equally or more important jobs.  I'm always borrowing VNA from club members.  When I get a Antunio, I can stop being a pain in the neck to others. hahah.

P.S. I showed your email to my wife, and breathlessly exclaimed...look at this...Ashhar wrote to me!!!!  I did a little dance and told her I would never delete his email. [Obviously I need to get out more, but it is nice to have a few heroes out there, and you fit the bill. So a thousand thanks for all you've accomplished for all of us.  Okay, now I will stop sucking up. hahah.]

Don
km4udx

Re: Narrow filter for CW #ubitxcw

Curt
 

Dave

I sense we have thrown lots of choices at you.  Except for playing with IF shift, implementing an audio filter is easiest - with many low cost choices around.  Note in most respects the design architecture is very similar across v3, v4 and v5.  v5 was a larger change with a different IF selection for the SSB crystal filter. 

Many of us have rigs with 4915 kHz xtal filters made from cheap xtals.  Sounds like it could be installed in parallel with the 12 MHz filter without needing relays -- I should have thought of that - but we need a rig control to command the ubitx to 'Receive CW' to change the oscillator functions as Asher describes. 

Except in a major contest maybe, I find the audio filter is entirely sufficient with the way ubitx receive gain is distributed.  You might find CW transmit behavior a bit strange but it works fine once you are used to it. 

Curt

Re: Antuino support group opened -- early antuino question

Evan Hand
 

I have ordered my Antunio, and am waiting for delivery, anxious to try it out .  The above comment from Don raises one question for me:  Is it a VNA or SNA.  As I understand the difference is that the VNA measures the phase angle as well as the magnitude of the impedance, an SNA just measures the magnitude of the impedance.  in reading the description on the HF Signals Web Page it states SNA capabilities.

As far as output, you can get a Smith Chart from a VNA, not from an SNA.

So the question is if the hardware would support a VNA application, and and if so does the software provided have both the real and imaginary values of the impedance?

73
Evan
AC9TU

Re: Issues with ordering the BITX40

Ken
 

Could this be the Raduino link?

https://amateurradiokits.in/product/raduino-clone/

73

Ken VA3ABN

Re: Narrow filter for CW #ubitxcw

iz oos
 

I guess an audio active filter 200hz wide like the Hipermite by 4SQRP might suffice.


Il 14/ago/2019 19:59, "Curt via Groups.Io" <wb8yyy=yahoo.com@groups.io> ha scritto:
Dave

I sense we have thrown lots of choices at you.  Except for playing with IF shift, implementing an audio filter is easiest - with many low cost choices around.  Note in most respects the design architecture is very similar across v3, v4 and v5.  v5 was a larger change with a different IF selection for the SSB crystal filter. 

Many of us have rigs with 4915 kHz xtal filters made from cheap xtals.  Sounds like it could be installed in parallel with the 12 MHz filter without needing relays -- I should have thought of that - but we need a rig control to command the ubitx to 'Receive CW' to change the oscillator functions as Asher describes. 

Except in a major contest maybe, I find the audio filter is entirely sufficient with the way ubitx receive gain is distributed.  You might find CW transmit behavior a bit strange but it works fine once you are used to it. 

Curt


Re: Narrow filter for CW #ubitxcw

Evan Hand
 

I am traveling on business, so can not get at the documentation on the CEC software.  From memory I am sure that one of the control shifts the signal on the "roofing" 45 mhz filter to act as a gain control.  The filter skirts of the single crystal would be more gradual than the sharper skirts on the 12/11 mhz SSB filter.  The other is moving the BFO to change where the signal is received relative to the SSB passband.  I just do not remember which one is which without the documentation.  

Since you are moving the center of the signal across the pass band of the filter you should be able to move the signal up against one side or other of the skirt of the SSB filter to narrow the received signal.  My use of the CEC sliders has not been very precise.  To make the software work more efficiently for the operator, I would look at adding another encoder in place of the Nextion slider.  Issue is what I/O do you give up to connect it to.  Another option would be to use a switch to toggle the frequency encoder to do both frequency and IF shift.  Would be better than what I have used on the Nextion screen.  Response there is not always accurate.

Above are just ramblings.  Please take with a grain of salt.

73
Evan
AC9TU

Re: Narrow filter for CW #ubitxcw

 

I use a simple sofa beams filter in my audio chain. It works fantastic. Check it out at https://www.dxengineering.com/parts/sbm-lb-module-cw?seid=dxese1&gclid=EAIaIQobChMI1dqE3puD5AIVA9vACh1ZLg6MEAQYASABEgJYifD_BwE.

David Posthuma
WD8PUO

 


From: bitx20@groups.io on behalf of Evan Hand <elhandjr@...>
Sent: Wednesday, August 14, 2019 4:30 PM
To: bitx20@groups.io
Subject: Re: [BITX20] Narrow filter for CW #ubitxcw
 
I am traveling on business, so can not get at the documentation on the CEC software.  From memory I am sure that one of the control shifts the signal on the "roofing" 45 mhz filter to act as a gain control.  The filter skirts of the single crystal would be more gradual than the sharper skirts on the 12/11 mhz SSB filter.  The other is moving the BFO to change where the signal is received relative to the SSB passband.  I just do not remember which one is which without the documentation.  

Since you are moving the center of the signal across the pass band of the filter you should be able to move the signal up against one side or other of the skirt of the SSB filter to narrow the received signal.  My use of the CEC sliders has not been very precise.  To make the software work more efficiently for the operator, I would look at adding another encoder in place of the Nextion slider.  Issue is what I/O do you give up to connect it to.  Another option would be to use a switch to toggle the frequency encoder to do both frequency and IF shift.  Would be better than what I have used on the Nextion screen.  Response there is not always accurate.

Above are just ramblings.  Please take with a grain of salt.

73
Evan
AC9TU

Re: Antuino support group opened -- early antuino question

Jerry Gaffke
 

Evan,

Looking at the Antuino schematic, it has an AD8307 at the output of the 25mhz filter
to tell the processor the magnitude of the received signal.
Nothing to tell the processor anything about phase.
So it's an SNA (Scaler Network Analyzer), not a VNA (Vector Network Analyzer)

You might think it needs both phase and magnitude to determine the SWR of an antenna.
But no, it uses a bridge circuit, and senses the difference between what the antenna does
to the signal and what a 50 ohm resistor does to the signal.  It assumes a 50 ohm environment.  
From post    https://groups.io/g/BITX20/message/63034
  I suppose R21,R29,R16, and an antenna on P3 would form a balanced
  bridge when the antenna is 50 ohms, CLK1 is driving the antenna and the top of the bridge.
  The ADE-1 RF port sees any imbalance across the bridge.
  CLK2 into the LO port is 25mhz above (or below) CLK1.

The cheapest VNA that I am aware of is the Vector Impedance Analyzer kit that Kees sells,
toward the bottom of this webpage:     http://www.qsl.net/k5bcq/Kits/Kits.html
Some other VNA's mentioned here:  https://groups.io/g/BITX20/message/56219
But I haven't looked over what's available out there for several years.

Jerry, KE7ER



On Wed, Aug 14, 2019 at 01:14 PM, Evan Hand wrote:
I have ordered my Antunio, and am waiting for delivery, anxious to try it out .  The above comment from Don raises one question for me:  Is it a VNA or SNA.  As I understand the difference is that the VNA measures the phase angle as well as the magnitude of the impedance, an SNA just measures the magnitude of the impedance.  in reading the description on the HF Signals Web Page it states SNA capabilities.

As far as output, you can get a Smith Chart from a VNA, not from an SNA.

So the question is if the hardware would support a VNA application, and and if so does the software provided have both the real and imaginary values of the impedance?

Re: Antuino support group opened -- early antuino question

Evan Hand
 

Jerry,

Thank-you for the clarification. 

I was aware that you can measure SWR with just the scaler values, as I have built a resistor bridge based scanning SWR antenna analyzer, and purchased a cheap VNA with Smith chart capability.  I wanted to make sure that I had not missed something based on Don's mention of using the VNA capability of the Antuino  

73
Evan
AC9TU
AC9TU

Re: Antuino support group opened -- early antuino question

Doug W
 

If you're looking for a cheap VNA this might be of interest.
https://groups.io/g/antennas/topic/nanovna_cheap_vna_on/31731387

I don't consider this to be competition at all for the Antuino.
--
www.bitxmap.com

Re: Issues with ordering the BITX40

JT Croteau
 

Ken, that is the Raduino clone by Sunil.


On Wed, Aug 14, 2019, 15:26 Ken <chase8043@...> wrote:
Could this be the Raduino link?

https://amateurradiokits.in/product/raduino-clone/

73

Ken VA3ABN

Re: uBITX SSB Audio #ubitx #calibration #ssb

Dean Souleles
 

Thanks Jim!

Where were you three weeks ago?  :)

My experience exactly.

Your straightforward post will really assist new builders,

Dean
KK4DAS

another stuck relay in TX mode #ubitx #bitx20

Don - KM4UDX
 

hello all!

My beloved V4 uBITX has been working really hard and flawlessly 24/7 in wspr mode for (almost) months at a time.  The results are impressive...frequently in the top 10 worldwide 2 way spot ranking.  But all that success comes at a price. 

Now, my uBITX randomly sticks in TX mode.  If I tap the left side relay, it releases TX mode.  I learned that diagnostic technique from Dave_ K0MBT (hahah, and thank you!).  If I just reboot or turn off/on, it stays in TX mode.  But the back of the pen allways works.  So am I good to go to replace the relay? I really hate to mess with it, but my hand is forced, as they say.

Is there a prefered type/source of replacement relay? 

thank you all!!!!

Don
km4udx

Re: Issues with ordering the BITX40

Ken
 

I know but I couldn't find the original Raduino on HFsignals


On Wed, Aug 14, 2019 at 5:29 PM JT Croteau <jt.tobit@...> wrote:
Ken, that is the Raduino clone by Sunil.

On Wed, Aug 14, 2019, 15:26 Ken <chase8043@...> wrote:
Could this be the Raduino link?

https://amateurradiokits.in/product/raduino-clone/

73

Ken VA3ABN

Re: Issues with ordering the BITX40

Ken
 


On Wed, Aug 14, 2019 at 5:29 PM JT Croteau <jt.tobit@...> wrote:
Ken, that is the Raduino clone by Sunil.

On Wed, Aug 14, 2019, 15:26 Ken <chase8043@...> wrote:
Could this be the Raduino link?

https://amateurradiokits.in/product/raduino-clone/

73

Ken VA3ABN

Re: uBITX SSB Audio #ubitx #calibration #ssb

Jim Willis
 

You are welcome! Just learning myself.

Best regards,
73,

Jim

On Aug 14, 2019, at 5:33 PM, Dean Souleles <dsouleles@...> wrote:

Thanks Jim!

Where were you three weeks ago?  :)

My experience exactly.

Your straightforward post will really assist new builders,

Dean
KK4DAS

Re: Narrow filter for CW #ubitxcw

Tom, wb6b
 

On Tue, Aug 13, 2019 at 07:42 AM, MadRadioModder wrote:
I use my own coded version of this thing
That looks like a cool implementation. Is your audio bandpass filter stand alone or is it an add-on to the Sotabeams filter board?

It sounds like it is a stand alone DSP filter and display.

Is the code on GitHub or somewhere?

Tom, wb6b

Re: Narrow filter for CW #ubitxcw

Tom, wb6b
 

On Tue, Aug 13, 2019 at 05:50 AM, Jack Purdum wrote:
Inexpensive DSP is incorporated into the JackAl board.
The JackAl board looks like it is a good all in one upgrade to the uBitx. 

So it looks like, in all but the more extreme cases, people are happy with DSP audio bandpass filters. Crystal CW filters can provide some additional protection from overloading from a strong close by frequency signal.

It would seem the reason for this is, the crystal filter may filter out the strong unwanted signal while the signals are still in the first stages of the IF chain. The signals are still relatively weak at this point and the undesired signal is removed before it can get amplified to the point that overloading starts to occur. 

Tom, wb6b

Re: another stuck relay in TX mode #ubitx #bitx20

Curt
 

Don

First before we assume its a bad relay, reflow each pin and also reduce the transmit drive level. You never know the relay may be okay. I assume you tried more than one band? Make sure you don't have a small strand of wire to blame for this mishap.

Curt

Re: Narrow filter for CW #ubitxcw

Jerry Gaffke
 

The 12/11mhz crystal filter is after all IF amps on receive.
The IF amps are operating at very low signal levels, most of the gain is in the audio amps.
It's the audio pre-amp (a 2n3904 just before the volume control) that overloads first,
by a very wide margin:  https://groups.io/g/BITX20/topic/5945215
That thread is about the Bitx40, but the uBitx will have the same issue.

So, if you have a very strong CW station 500 hz away from the weak signal you are trying to hear,
the strong signal will cause audio distortion in that audio pre-amp and any audio filter
that follows the pre-amp won't be able to clean it up.

The solution is to have a choice of wide crystal filter for SSB, and narrow for CW.
But that's not a big deal for most of us, easier to implement the audio filter for CW.


Jerry, KE7ER
 
Jerry, KE7ER


On Wed, Aug 14, 2019 at 04:56 PM, Tom, wb6b wrote:
It would seem the reason for this is, the crystal filter may filter out the strong unwanted signal while the signals are still in the first stages of the IF chain. The signals are still relatively weak at this point and the undesired signal is removed before it can get amplified to the point that overloading starts to occur.