Re: zBitx +-2 MHz transmit spurs? --> SHOWSTOPPER for transmitting
I have yet measured the output voltage (after the 40 dB attenuator). Below
are the results.
Indeed, one can see a 2 MHz amplitude modulation.
That's not an aliasing artifact. Below there is a
By
WZab - SP5DAA
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#117437
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Re: zBitx touchsreen issue
The calibration screen does come up - for less than 2 seconds.
Not enough time to calibrate.
What next?
Thanks,
AC4OW, Sam Hanie
samhanie@...
gmail.com@groups.io> wrote:
By
Sam Hanie
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#117436
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Re: zBitx +-2 MHz transmit spurs? --> SHOWSTOPPER for transmitting
I don't know where R70 is on the PCB, or how accessible it might be.
Can Ashhar have someone back at the factory swap out R70 with a clock buffer and see if that reduces spurs?
- Ron
By
Ron, N6YWU
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#117435
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Re: zBitx +-2 MHz transmit spurs? --> SHOWSTOPPER for transmitting
Frank,
my measurement setup has been described already in my FIRST posting on this topic:
" Measurement with a TinySA Ultra connected via 50dB (20dB + 30dB) attenuators.
Adding another 30dB of
By
Joerg DB2OO
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#117434
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Re: zBitx +-2 MHz transmit spurs? --> SHOWSTOPPER for transmitting
The U.S. regulation is -43 dBc. ?The spur 2.5 MHz above the carrier does not get close enough to meeting that spec for me to be interested in taking more careful measurements. ?I can also hear that
By
Ron, N6YWU
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#117433
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Re: zBitx +-2 MHz transmit spurs? --> SHOWSTOPPER for transmitting
Work,
The spurs are well below -40 dbc
gmail.com@groups.io> wrote:
By
Ashhar Farhan
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#117432
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Re: zBitx touchsreen issue
Same issue as Sam. Pressing the screen while powering up and releasing shows the calibration screen with red markers in every corner. One corner has a white marker, touching it shifts the marker to
By
Wolfgang
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#117431
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Re: zBitx +-2 MHz transmit spurs? --> SHOWSTOPPER for transmitting
My zBitx arrived today. I can confirm that when working from batteries, it
produces those modulation (?) components.
73, Wojtek SP5DAA
?r., 16 kwi 2025, 17:36 u?ytkownik Joerg DB2OO via
By
WZab - SP5DAA
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#117430
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Re: zBitx +-2 MHz transmit spurs? --> SHOWSTOPPER for transmitting
Jeorg,
Please describe your set-up and monitoring cabling, antenna etc,l
Sincerely, Frank Krozel t: 1-630-924-1600 frank@...
BSEE, AASEET, FCC Lic.# PG-18-19178,
By
Frank KG9H
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#117429
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Re: zBitx +-2 MHz transmit spurs? --> SHOWSTOPPER for transmitting
I crossed checked with two different models of tinySA, and also compared against two other QRP transmitters using the same 50 dB attenuation chain at similar power levels. ?Only my zbitx showed the
By
Ron, N6YWU
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#117428
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Re: zBitx +-2 MHz transmit spurs? --> SHOWSTOPPER for transmitting
To be on the safe side, I tested it with a lab supply as well as with 18650 batteries:
Same result, the +/- 2.x MHz spurs are there with both types of power supplies!
I think the spurs are
By
Joerg DB2OO
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#117427
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Re: zBitx touchsreen issue
Power up the unit while pressing the screen with the stylus. it will bring up a calibration menu.
By
JJ - W9JES
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#117426
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Re: zBitx +-2 MHz transmit spurs? --> SHOWSTOPPER for transmitting
If the problem is related to the change of power supply voltage due to
periodically changing current consumption, the problem may persist with
battery supply.
They have non-zero internal
By
WZab - SP5DAA
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#117425
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Re: zBitx +-2 MHz transmit spurs? --> SHOWSTOPPER for transmitting
Ashhar,
Thanks for the information.
My business is Electromagnetic Compatibility for the past 40 years or so.
I have been following along on all the posts.
So many folks take their (fill in the
By
Frank KG9H
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#117424
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zBitx touchsreen issue
zBitx touchscreen no longer aligned.
When I press the macro key "F4", the terminal reports that I pressed "F1".
rev 1.06 / 3.052.
Any help appreciated.
Thanks,
AC4OW, Sam Hanie
By
Sam Hanie
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#117423
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Re: zBitx +-2 MHz transmit spurs? --> SHOWSTOPPER for transmitting
You could probe the input to the 3.3v regulator. However, this is a little
more complicated than what it appears to be.
First, I spent weeks measuring the spurs. They are all below -43dbc except
on
By
Ashhar Farhan
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#117422
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Re: zBitx +-2 MHz transmit spurs? --> SHOWSTOPPER for transmitting
GM Gordon,?
I still believe it could be a power issue - the 3.3v regulator does not appear to be properly filtered per the manufacturer Datasheet. The other possibility is that the output of the
By
Lee
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#117421
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Re: zBitx +-2 MHz transmit spurs? --> SHOWSTOPPER for transmitting
Well that tells us even more..
Not due to the power supply.
Unlikely to be produced BEFORE the crystal filter (it would screen it out)
Has to be coming in AFTER the filter
Dependent on the existence
By
Gordon Gibby KX4Z
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#117420
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Re: zBitx +-2 MHz transmit spurs? --> SHOWSTOPPER for transmitting
I tested my unit with two different sets of batteries, and saw the +-2 MHz spurs. So it's not external SMPS noise.
The spurs were there when trying to FT8, CW, and 2Tone modes, They only vanished
By
Ron, N6YWU
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#117419
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Re: Where is the line at for ZbitX's that are shipping.
Quickly is all I can say,
My Order (#3595) was place UK 1st April 2025 @ 06:24 GMT
Shipment collected Hyderabad -12:00 UTC 14th April 2025
Shipment expected by 23:59 on 17th April 2025
Actual Arrival
By
BigJonn - G8DVB
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#117418
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