Date   
Re: RFI from uBitx TX after AGC and other mods installed

alans77@...
 

Based on Rowland's results it appears that we are left with trying ferrite beads on the volume control to AGC wires or muting the speaker. Since my ICOM wired hand Mic PTT switch is SPDT with the common terminal grounded I can wire the Mic to disconnect the speaker ground on transmit.

Alan

Re: Noob tx problem #ubitx-help

davedt1e@...
 

I just wanted to update this post so that another noob isn't lead astray.

I've finally got my dummy load put together so that I could more thoroughly test the mic and transceiver and it turns out that all was not well.  On more testing, when I whistled into the mic I would get a relay clicking on and off rapidly.  The problem is that I was wiring the mic and switch together in a simple series circuit.  This is incorrect.  What got me started down the wrong path was that the plug sent with the kit was a mono plug.  Ubitx.net has a diagram showing the mic hookup....I couldn't figure out why this diagram didn't make sense to me until I realized it was for a stereo plug.

I went and bought a stereo plug,  wired it up and all is now well.

See the diagram here:   https://ubitx.net/wiring-up-the-mic-jack/

I know this is simple stuff for most of you guys,  but I didn't want to leave this thread hanging around with my incorrect conclusion.

Re: Noob tx problem #ubitx-help

davedt1e@...
 

Oh yeah,  forgot to mention that I put the orange and purple leads back in the original position on the mic jack as well.

Re: RFI from uBitx TX after AGC and other mods installed

Don, ND6T
 

Rowland, Does it go away when you unplug the power to the PA? -Don

Re: Keypad for Raduino...?

Stephanus K6NG
 

Hi,
  I have looked at this but have not yet tried them:

https://hambuilder.com/

Re: Bitx40 75KHz Spurious, How to solve it. #bitx40

Allard PE1NWL
 

Hi Akira san,

But the spurious at 75KHz was observed.
I guess you mean 75 MHz (not kHz)?

The spurious might be the multiple of 25KHz.
In that case it could be a harmonic of 25 MHz (not kHz). Perhaps it comes from the 25 MHz crystal in the Raduino?

73 Allard PE1NWL

Re: Keypad for Raduino...?

n2vdy
 

I like the idea of the resistor matrix. I might have copied it if I hadn't gone a different way already.

This little board from Sparkfun can do up to an 8x8 matrix, has debounce built in, uses I2C, and has an output that can be connected to an interrupt.

https://www.sparkfun.com/products/13601


On Mon, Jun 25, 2018 at 09:24 am, Arv Evans wrote:
Jerry

Thanks for the info.  I did a quick scan of the relevant pages. I can see several possible
uses for this device.  Maybe I missed something but it seems that  like almost all I2C
devices it is a true slave and thus does not automatically assert bus control to signal that
an event has occurred.  Possibly I would need to re-read the datasheet in detail to affirm
this if my design effort takes me in that direction.
 
Arv
_._


On Mon, Jun 25, 2018 at 10:05 AM Jerry Gaffke via Groups.Io <jgaffke=yahoo.com@groups.io> wrote:
Here's a datasheet  (sort of, you don't get the pdf):  https://pdf1.alldatasheet.com/datasheet-pdf/view/810501/TONTEK/TTP229.html
Bottom of page 8, section 3-4 describes the 2 wire interface, though not very clearly.

They say SDO is always out, SCLK is always in.
And that SCLK can be anything between 1khz and 512khz when scanning.
A pause of 2ms on SCLK resets the interface for the next scan.
They apparently have a way to just check the state of SDO occasionally to see if any key was pressed,
though I find the datasheet tough to read on exactly how this works.

The chip also implements full i2c mode, also various parallel modes,
though not clear what modes any particular keypad using the chip would support.

Jerry


On Mon, Jun 25, 2018 at 08:38 am, Robert McClements wrote:
Arv,

The TTP229 capacitive  keyboard has two pins labelled SCL and SDO but unfortunately they are not I2C.

The way that they work is SCL is clocked frequently up to 16 times and during each clock cycle SDO is
checked. If a key is pressed SDO will return a Low, the count stops and the clock count equates to
the key number. Hope that makes sense, not easy to put into words.

So this device will require the use of two digital pins.


Regards,

Bob GM4CID


Re: KD8CEC - Nextion Display - IAN questions

Michel Dupuy
 

Tank you Art
I download and test for my raduino.

Michel

Re: Keypad for Raduino...?

Arv Evans
 

n2vdy

That 1509 IO system from SparkFun looks interesting.  I have saved the data and will keep
it in mind for possible future use.
Thanks for the info.

Arv
_._

On Mon, Jun 25, 2018 at 1:30 PM n2vdy via Groups.Io <n2vdy=yahoo.com@groups.io> wrote:
I like the idea of the resistor matrix. I might have copied it if I hadn't gone a different way already.

This little board from Sparkfun can do up to an 8x8 matrix, has debounce built in, uses I2C, and has an output that can be connected to an interrupt.

https://www.sparkfun.com/products/13601

On Mon, Jun 25, 2018 at 09:24 am, Arv Evans wrote:
Jerry

Thanks for the info.  I did a quick scan of the relevant pages. I can see several possible
uses for this device.  Maybe I missed something but it seems that  like almost all I2C
devices it is a true slave and thus does not automatically assert bus control to signal that
an event has occurred.  Possibly I would need to re-read the datasheet in detail to affirm
this if my design effort takes me in that direction.
 
Arv
_._


On Mon, Jun 25, 2018 at 10:05 AM Jerry Gaffke via Groups.Io <jgaffke=yahoo.com@groups.io> wrote:
Here's a datasheet  (sort of, you don't get the pdf):  https://pdf1.alldatasheet.com/datasheet-pdf/view/810501/TONTEK/TTP229.html
Bottom of page 8, section 3-4 describes the 2 wire interface, though not very clearly.

They say SDO is always out, SCLK is always in.
And that SCLK can be anything between 1khz and 512khz when scanning.
A pause of 2ms on SCLK resets the interface for the next scan.
They apparently have a way to just check the state of SDO occasionally to see if any key was pressed,
though I find the datasheet tough to read on exactly how this works.

The chip also implements full i2c mode, also various parallel modes,
though not clear what modes any particular keypad using the chip would support.

Jerry


On Mon, Jun 25, 2018 at 08:38 am, Robert McClements wrote:
Arv,

The TTP229 capacitive  keyboard has two pins labelled SCL and SDO but unfortunately they are not I2C.

The way that they work is SCL is clocked frequently up to 16 times and during each clock cycle SDO is
checked. If a key is pressed SDO will return a Low, the count stops and the clock count equates to
the key number. Hope that makes sense, not easy to put into words.

So this device will require the use of two digital pins.


Regards,

Bob GM4CID


Re: Keypad for Raduino...?

Robert McClements
 

Arv,

Another way to drive a 16 way matrix keyboard is the inexpensive PCF8574 and PCF8574T I2C expander boards.
I have a couple of these but not made time to try them out yet.

There is however, a lot to be said for the simplicity of the analogue solution and the Robodyn module mentioned by
Mike ZL1AXG looks very practical particularly their transparent button top cap to protect the printed key legend.

73 Bob GM4CID

Re: Understanding Spurious Emissions

ajparent1/KB1GMX
 

On Fri, Jun 22, 2018 at 10:38 pm, Ashhar Farhan wrote:
It may be improper level of LO injection. On the transmit side, the mixer has _very_ strong input termination and LO termination. It will be interesting to study this. Mixers can provide endless amount of fascination or frustration depending on which side of the RF probe you are.
 
Yes they are a conundrum in three ports.  However I did explore the path of the TIA amp now working well 
and terminated it with a 6db pad... no improvement at all.  Same for the output to the filter 6db pad and
again no improvement.  In both cases there was a shift in levels of 6db and 12DB (ran both!) and no
difference in spur production.    The only thing that seems to impact the amplitude of the spur is the
port to port isolation more so than termination.  I believe it to be a alias image as it has the same
relationships.  It only shows when the relationship is such that its below filter cutoff.  

I replicated it at 45/73mhz and for experiment I did a 9mhz if, 23mhz LO  and without filtering I could
see the desired 14 and also 5mhz spur!  Its relationship is output frequency 14mhz minus IF and its
about 38db down from the desired 14mhz (two different ZLW-2 connectorized mixers).  I never noticed
a mixer spreadsheet I have from somewhere predicts it.  Likely reason I never noticed it was most
applications there is fairly strong filtering for the desired. 

I checked and it doesn't happen to the same extent with analog multiplier mixers (gilbert  cell) like
sa602 as they are not bidirectional (very high input to output isolation).

Nyquist was right.  Its the sampling behaviour of switching mixers.

Allison

 


 
. . .

Re: Bitx40 75KHz Spurious, How to solve it. #bitx40

 

Allard,

The pic attached is in 50Khz horizontal display.

Raj


At 26/06/2018, you wrote:
Hi Akira san,

But the spurious at 75KHz was observed.

I guess you mean 75 MHz (not kHz)?

The spurious might be the multiple of 25KHz.

In that case it could be a harmonic of 25 MHz (not kHz). Perhaps it comes from the 25 MHz crystal in the Raduino?

73 Allard PE1NWL

Re: Bitx40 75KHz Spurious, How to solve it. #bitx40

jj1epe@...
 

MVS Sama,

Thank you for your prompt reply.
My friend measured the spurious.
I will ask my friend to check whether cause of spurious is the power supply.

Regard,
Akira
JJ1EPE

Re: Bitx40 75KHz Spurious, How to solve it. #bitx40

jj1epe@...
 

Hi Allard san,

I am glad I can contact with you on this group too.
As Raj san mentioned, unit of the frequency of spurious is KHz.

Akira
JJ1EPE 

Re: RFI from uBitx TX after AGC and other mods installed

alans77@...
 

Can anyone specify (photo of location needed) a relay contact that is open on transmit and grounded on receive?

73,
Alan N4AYE

Re: RFI from uBitx TX after AGC and other mods installed

Don, ND6T
 

No photo but that would be K1, the relay that sits over at the left by itself. Underneath you will see one of the contacts is grounded. That's the normally open contact. The next contact down will be the normally closed contact that goes to the bandpass filter. The next contact in that line is the common one that goes to the receive line. Sorry, but my version 3 board is in a difficult case to extract from.
-Don

Re: RFI from uBitx TX after AGC and other mods installed

RowlandA
 

I don't have a separate power source for the PA - I assume to test this I'll have to cut one of the three wires going to the plug into the PCB?  I'll try it Wednesday if it will help with troubleshooting.

Thanks,
Rowland

Re: RFI from uBitx TX after AGC and other mods installed

Don, ND6T
 

I was looking for an easy test. Lifting the brown wire from the power switch sounded like it might be simple but hold off while I try to think of something else. -Don

Re: Understanding Spurious Emissions

Ashhar Farhan
 

Allison,
What is the exact math of the spur? We can swap the two local oscillators around in software. That is,  the local oscillator can be injected on the other side. Would that help?
- f

On Tue, 26 Jun 2018, 03:09 ajparent1/KB1GMX, <kb1gmx@...> wrote:
On Fri, Jun 22, 2018 at 10:38 pm, Ashhar Farhan wrote:
It may be improper level of LO injection. On the transmit side, the mixer has _very_ strong input termination and LO termination. It will be interesting to study this. Mixers can provide endless amount of fascination or frustration depending on which side of the RF probe you are.
 
Yes they are a conundrum in three ports.  However I did explore the path of the TIA amp now working well 
and terminated it with a 6db pad... no improvement at all.  Same for the output to the filter 6db pad and
again no improvement.  In both cases there was a shift in levels of 6db and 12DB (ran both!) and no
difference in spur production.    The only thing that seems to impact the amplitude of the spur is the
port to port isolation more so than termination.  I believe it to be a alias image as it has the same
relationships.  It only shows when the relationship is such that its below filter cutoff.  

I replicated it at 45/73mhz and for experiment I did a 9mhz if, 23mhz LO  and without filtering I could
see the desired 14 and also 5mhz spur!  Its relationship is output frequency 14mhz minus IF and its
about 38db down from the desired 14mhz (two different ZLW-2 connectorized mixers).  I never noticed
a mixer spreadsheet I have from somewhere predicts it.  Likely reason I never noticed it was most
applications there is fairly strong filtering for the desired. 

I checked and it doesn't happen to the same extent with analog multiplier mixers (gilbert  cell) like
sa602 as they are not bidirectional (very high input to output isolation).

Nyquist was right.  Its the sampling behaviour of switching mixers.

Allison

 


 
. . .

Re: Bitx40 75KHz Spurious, How to solve it. #bitx40

Tim Gorman
 

Your carrier is at 7.029Mhz. Did you have your mode set to CW?

If so, you aren't seeing "spurious" mixer products at 75khz, 150khz,
and 225khz. They are something else. Since their appear on both sides
of the carrier I would have called them some kind of IMD products but
I've never seen IMD go up as you move away from the carrier.

If you were in CW mode, the mixers aren't used to generate the carrier
frequency so you wouldn't see any spurious mixer products.

There is something else going on here.

Since harmonics are based on the carrier frequency the closest one you
would have would be at 14.058Mhz. It wouldn't show up on your scan.

It's very obvious that you are picking up something that is
harmonically related at multiples on both sides of the carrier.

I have to admit I'm not sure what your screen is telling me. It appears
it is scanning from 7.029Mhz to 7.049Mhz. That's only 20khz total from
screen-edge to screen-edge, not the 500khz that would be required to put
your unknown 75khz away from the carrier.

If your total scan is 20khz then your unknowns are at 3khz, 5khz, and
8khz. They wouldn't even be harmonically related.

Are you sure your "50.0KHZ/" on the screen isn't the video bandwidth or
something?

tim ab0wr

On Mon, 25 Jun 2018 00:09:11 -0700
jj1epe@... wrote:

Hi!

I built Bitx40 about 2 weeks ago.
 
I measured the spurious of Bitx40 by using the spectrum analyzer.
The level of spurious of harmonics were under 50db. So this is fine.
But the spurious at 75KHz was observed.
The spurious might be the multiple of 25KHz.
It would be much appreciated if you could advise  me the cause and
solution of this spurious of Bitx40.

In Japan, we must prove to the authority that the spurious of the
transceiver meets the criteria to obtain the certification of the
transceiver from the authority. So if i could not resolve this
spurious, I will not be able to use Bitx40 in Japan.

Thanks in advance,
Akira
JJ1EPE