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Re: a simple spur fix

 

Ashhar:

 

You give the number of turns necessary, and the core IDs, but what is the gauge of wire used???

 

David A Posthuma, WD8PUO

1 (616) 283-7703

 

From: BITX20@groups.io <BITX20@groups.io> On Behalf Of Ashhar Farhan
Sent: Friday, November 09, 2018 10:35 AM
To: bitx20@groups.io
Subject: [BITX20] a simple spur fix

 

so, there is one spur fix that is now consistently working for me.

among rhe solutions, i was looking for one that would be easy to apply.

first, the distortion in the 45 mhz amp is creating harmonic distortion. so a 0.3uh in series with a 10 pf is used across TP13 (output of the 45 MHz IF amp going to the front end mixer). 8 turns on T30-6 gives you 300nh.

second, there is a cross talk inside the Si5351 where the 12 mhz from the bfo leaks into the local oscillator. A 5uh in series with a 47 pf across C202 of the LPF will suppress it. 35 turns on T30-6 gives you 5uh.

- f

 


Re: DIGITAL FREQUENCY READOUT

Evan Hand
 

The Si5351 is on the back side of the board in the first picture, between the display and the board that the ATmeg board plugs into.  The board with the plug is the Raduino board.


On Fri, Nov 9, 2018 at 2:27 PM MONEYSMITH <w4nfr@...> wrote:

THIS BOARD HAS A MEGA328P CHIP. I HAVE NO INFORMATION ON THE BOARD.

I FOUND NO SI5351A CHIP?

PHOTOS ATTACHED.

W4NFR

On 11/9/2018 11:42 AM, Arv Evans wrote:
Bill W4NFR

The picture you provided is the back side of an Arduino Nano board.  The crystals on this PCB
have nothing to do with the transmitting frequency of your transceiver.  The SI5351a frequency
synthesizer is a small 10-pin MSOP IC, or 20-pin QFN IC.  It should be clearly labeled on the
top as an Si5351A device.  Do you have a picture of the Raduino board with its Si5351A chip
and crystal?

Arv  K7HKL
_._


On Fri, Nov 9, 2018 at 11:20 AM MONEYSMITH <w4nfr@...> wrote:

HERE IS A PHOTO OF BOARD AND CRYSTAL.

W4NFR

On 11/9/2018 9:57 AM, Mvs Sarma wrote:
OMG. acidentally crept in perhaps .
could you please share a  photo please, !!!!!

regards
sarma
 vu3zmv

On Fri, Nov 9, 2018 at 10:50 PM MONEYSMITH <w4nfr@...> wrote:

I OPENED UP MY uBITX  AND TOOK A LOOK AT THE S1535A BOARD. THE CRYSTAL HAS 20.0 STAMPED ON IT INSTEAD OF 25.0 MHZ?

On 11/8/2018 5:59 PM, RCC WB5YYM wrote:
The crystal is not "bad" 
http://www.hamskey.com/2018/05/frequency-adjustment-of-ubitx-si5351.html



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Re: a simple spur fix

Brian L. Davis
 

10pf series with .3uhy - resonant about 91 MHz
47pf series with 5.0uhy resonant about 10.4 MHz
Is this correct?
Brian - WA5RDG


Re: DIGITAL FREQUENCY READOUT

MONEYSMITH
 

THIS BOARD HAS A MEGA328P CHIP. I HAVE NO INFORMATION ON THE BOARD.

I FOUND NO SI5351A CHIP?

PHOTOS ATTACHED.

W4NFR

On 11/9/2018 11:42 AM, Arv Evans wrote:
Bill W4NFR

The picture you provided is the back side of an Arduino Nano board.  The crystals on this PCB
have nothing to do with the transmitting frequency of your transceiver.  The SI5351a frequency
synthesizer is a small 10-pin MSOP IC, or 20-pin QFN IC.  It should be clearly labeled on the
top as an Si5351A device.  Do you have a picture of the Raduino board with its Si5351A chip
and crystal?

Arv  K7HKL
_._


On Fri, Nov 9, 2018 at 11:20 AM MONEYSMITH <w4nfr@...> wrote:

HERE IS A PHOTO OF BOARD AND CRYSTAL.

W4NFR

On 11/9/2018 9:57 AM, Mvs Sarma wrote:
OMG. acidentally crept in perhaps .
could you please share a  photo please, !!!!!

regards
sarma
 vu3zmv

On Fri, Nov 9, 2018 at 10:50 PM MONEYSMITH <w4nfr@...> wrote:

I OPENED UP MY uBITX  AND TOOK A LOOK AT THE S1535A BOARD. THE CRYSTAL HAS 20.0 STAMPED ON IT INSTEAD OF 25.0 MHZ?

On 11/8/2018 5:59 PM, RCC WB5YYM wrote:
The crystal is not "bad" 
http://www.hamskey.com/2018/05/frequency-adjustment-of-ubitx-si5351.html



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Re: Transmit Problem

William R Maxwell
 

Ooops, hit the wrong key. Yes, 100 nF.


Re: Need Source for Baofeng Mic Sockets

Scot McMath
 

Thanks Doug!


Re: DIGITAL FREQUENCY READOUT

Gordon Gibby <ggibby@...>
 

look in your software and see what frequency is set for the crystal.
use a script that puts the oscillator right on a known frequency (best to use the crystal frequency)
calculate how far off it is, calculte the real crystal frequency
adjust your software.

or use the calibration method specific to the firmware you have chosen, if you aren't able to do the above.

All mine have been 3-4 kilohertz off from the crystals "stated"' frequency. Putting in the correct constant for the effective true oscillation frequency of the crystal clock is a huge step toward having accurate frequencies. Then set your BFO if needed.

This is really a short-kit and you have to apply some of your "ham-smarts" to make things work correctly.
Because you studied and passed a ham radio license exam, you're one of the few people who are enabled to make such changes to your own amateur radio gear! Take advantage and develop your knowledge and skills!!!

Gordon


________________________________________
From: BITX20@groups.io <BITX20@groups.io> on behalf of Vince Vielhaber <vev@...>
Sent: Friday, November 9, 2018 2:55 PM
To: BITX20@groups.io
Subject: Re: [BITX20] DIGITAL FREQUENCY READOUT

To see the 25MHz xtal on mine I had to pull the display.

Vince.



On 11/09/2018 02:42 PM, Arv Evans wrote:
Bill W4NFR

The picture you provided is the back side of an Arduino Nano board. The
crystals on this PCB
have nothing to do with the transmitting frequency of your transceiver.
The SI5351a frequency
synthesizer is a small 10-pin MSOP IC, or 20-pin QFN IC. It should be
clearly labeled on the
top as an Si5351A device. Do you have a picture of the Raduino board
with its Si5351A chip
and crystal?

Arv K7HKL
_._


On Fri, Nov 9, 2018 at 11:20 AM MONEYSMITH <w4nfr@...
<mailto:w4nfr@...>> wrote:

HERE IS A PHOTO OF BOARD AND CRYSTAL.

W4NFR

On 11/9/2018 9:57 AM, Mvs Sarma wrote:
OMG. acidentally crept in perhaps .
could you please share a photo please, !!!!!

regards
sarma
vu3zmv

On Fri, Nov 9, 2018 at 10:50 PM MONEYSMITH <w4nfr@...
<mailto:w4nfr@...>> wrote:

I OPENED UP MY uBITX AND TOOK A LOOK AT THE S1535A BOARD. THE
CRYSTAL HAS 20.0 STAMPED ON IT INSTEAD OF 25.0 MHZ?

On 11/8/2018 5:59 PM, RCC WB5YYM wrote:
The crystal is not "bad"
https://urldefense.proofpoint.com/v2/url?u=http-3A__www.hamskey.com_2018_05_frequency-2Dadjustment-2Dof-2Dubitx-2Dsi5351.html&d=DwICaQ&c=pZJPUDQ3SB9JplYbifm4nt2lEVG5pWx2KikqINpWlZM&r=3ELgZgmTnPzGsfvQxkd1S_2NGLYM8sHTxVCQKFxhVXQ&m=mAUii3YaxPtywhZnzMLlmMvPiPtMo5OwMNFv6xTOoAo&s=Kc0Z75Apkcl8tA9B-xNE9Ip0f0Sgpei-_xfrvVKO9r0&e=


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Re: DIGITAL FREQUENCY READOUT

Vince Vielhaber
 

To see the 25MHz xtal on mine I had to pull the display.

Vince.

On 11/09/2018 02:42 PM, Arv Evans wrote:
Bill W4NFR

The picture you provided is the back side of an Arduino Nano board. The
crystals on this PCB
have nothing to do with the transmitting frequency of your transceiver.
The SI5351a frequency
synthesizer is a small 10-pin MSOP IC, or 20-pin QFN IC. It should be
clearly labeled on the
top as an Si5351A device. Do you have a picture of the Raduino board
with its Si5351A chip
and crystal?

Arv K7HKL
_._


On Fri, Nov 9, 2018 at 11:20 AM MONEYSMITH <w4nfr@...
<mailto:w4nfr@...>> wrote:

HERE IS A PHOTO OF BOARD AND CRYSTAL.

W4NFR

On 11/9/2018 9:57 AM, Mvs Sarma wrote:
OMG. acidentally crept in perhaps .
could you please share a photo please, !!!!!

regards
sarma
vu3zmv

On Fri, Nov 9, 2018 at 10:50 PM MONEYSMITH <w4nfr@...
<mailto:w4nfr@...>> wrote:

I OPENED UP MY uBITX AND TOOK A LOOK AT THE S1535A BOARD. THE
CRYSTAL HAS 20.0 STAMPED ON IT INSTEAD OF 25.0 MHZ?

On 11/8/2018 5:59 PM, RCC WB5YYM wrote:
The crystal is not "bad"
http://www.hamskey.com/2018/05/frequency-adjustment-of-ubitx-si5351.html


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Re: a simple spur fix

MadRadioModder
 

I wondered about the cross-talk in the Si5351.  There have been a number of papers written on it being problematic… to the point of suggesting using only one channel of the Si5351 but multiple parts if you need more frequencies.  Channel separation in some cases is only in the 30ish dB range…

 

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Ashhar Farhan
Sent: Friday, November 9, 2018 9:35 AM
To: bitx20@groups.io
Subject: [BITX20] a simple spur fix

 

so, there is one spur fix that is now consistently working for me.

among rhe solutions, i was looking for one that would be easy to apply.

first, the distortion in the 45 mhz amp is creating harmonic distortion. so a 0.3uh in series with a 10 pf is used across TP13 (output of the 45 MHz IF amp going to the front end mixer). 8 turns on T30-6 gives you 300nh.

second, there is a cross talk inside the Si5351 where the 12 mhz from the bfo leaks into the local oscillator. A 5uh in series with a 47 pf across C202 of the LPF will suppress it. 35 turns on T30-6 gives you 5uh.

- f

 


--

…_. _._


Re: DIGITAL FREQUENCY READOUT

Arv Evans
 

Bill W4NFR

The picture you provided is the back side of an Arduino Nano board.  The crystals on this PCB
have nothing to do with the transmitting frequency of your transceiver.  The SI5351a frequency
synthesizer is a small 10-pin MSOP IC, or 20-pin QFN IC.  It should be clearly labeled on the
top as an Si5351A device.  Do you have a picture of the Raduino board with its Si5351A chip
and crystal?

Arv  K7HKL
_._


On Fri, Nov 9, 2018 at 11:20 AM MONEYSMITH <w4nfr@...> wrote:

HERE IS A PHOTO OF BOARD AND CRYSTAL.

W4NFR

On 11/9/2018 9:57 AM, Mvs Sarma wrote:
OMG. acidentally crept in perhaps .
could you please share a  photo please, !!!!!

regards
sarma
 vu3zmv

On Fri, Nov 9, 2018 at 10:50 PM MONEYSMITH <w4nfr@...> wrote:

I OPENED UP MY uBITX  AND TOOK A LOOK AT THE S1535A BOARD. THE CRYSTAL HAS 20.0 STAMPED ON IT INSTEAD OF 25.0 MHZ?

On 11/8/2018 5:59 PM, RCC WB5YYM wrote:
The crystal is not "bad" 
http://www.hamskey.com/2018/05/frequency-adjustment-of-ubitx-si5351.html



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Re: a simple spur fix

Jerry Gaffke
 

Excellent!

So no second 45mhz filter, no surface mount inductors at L5,L7,  L1,L2,L3,L4 ?

TP13 is not shown in the v3 schematics, only in the v4 schematics.
I assume these mods work will work on the v3 boards too.
TP13 is the node at T2-pin3 in the first mixer.
I assume "across TP13" means that we add the cap and inductor in series from that node to ground.
Will be interesting to see if it matters where we physically place it, at T2-pin3 would be nice
because it could be added to the bottom of the board directly to the ground plane.

The second series cap and inductor get placed across C202, in the middle of the 30mhz low pass filter
on the far left side of the schematic.
So just leave C202 as it was, but add the cap and inductor from
the through hole pin for L2 (or L3) to the ground plane.

Will be interesting to see how picky we have to be about those inductors.
If we're lucky, they can be most any small surface mount inductor.

Jerry, KE7ER


On Fri, Nov 9, 2018 at 07:35 AM, Ashhar Farhan wrote:
so, there is one spur fix that is now consistently working for me.
among rhe solutions, i was looking for one that would be easy to apply.
first, the distortion in the 45 mhz amp is creating harmonic distortion. so a 0.3uh in series with a 10 pf is used across TP13 (output of the 45 MHz IF amp going to the front end mixer). 8 turns on T30-6 gives you 300nh.
second, there is a cross talk inside the Si5351 where the 12 mhz from the bfo leaks into the local oscillator. A 5uh in series with a 47 pf across C202 of the LPF will suppress it. 35 turns on T30-6 gives you 5uh.
- f


Bitx40 Raduino question

Tim KF7VUT
 

Im trying to upload new firmware to the bitx40 and the arduino isn't recognized by the comp the red light comes on but no where in the device manager.  I know it isn't a cable because it recognizes the uBitx and another nano just fine.  The bitx40 rx with no problem but i haven't tx yet.  So as i am a novice with the arduino my question is to the experts: before I begin to TRY and unsolder the existing arduino and solder in a new, is there something im missing that could be causing the comp to not recognize the Nano?

hope that isn't to confusing..

thanks
73 Tim
KF7VUT


Re: Need Source for Baofeng Mic Sockets

Doug W
 

Scot,
If you access this list from the website https://groups.io/g/BITX20/topics there is a search button toward the top.  Searching Baofeng Socket produces several hits including this gem https://groups.io/g/BITX20/message/46336
--
www.bitxmap.com


Re: DIGITAL FREQUENCY READOUT

Evan Hand
 

Allison is correct as usual, on further inspection, there is another crystal on the other side of the Nano board.  I can not read the stamped information on the units that I have, even worse that the CH340 crystal.

Still, not the source of the frequency offset error.


Re: DIGITAL FREQUENCY READOUT

ajparent1/KB1GMX <kb1gmx@...>
 

Are you sure that in not the crystal for the CH340 USB to serial?

All the Nanos I have the MPU crystal is on the front (side where the atmel MEGA328P many legged chip is).

The likely cause of the 1khz offset is likely either BFO incorrectly set, or cumulative error in the math.
From memory the frequencies calculated and displayed are based on 5351 output frequencies and
would match the Zero beat frequency (if cal in correct) and do mot match the filter center channel
frequency.

Allison


Re: DIGITAL FREQUENCY READOUT

Evan Hand
 

That looks like an Arduino Nano board, not the Raduino in a uBitx. I checked one of my spares and noted what could be taken as 20 J stamped in the crystal, though I thought the Nano was clocked at 16 mHz.I opened my second pack of three, they were stamped ZOG as far as I could tell with a bright light and magnifying lens.  That is some mighty small print.

When I checked on line the top end for the ATMega328p is 20 mHz, so it could be a 20 mHz crystal.

Here are pictures of a Raduino board with the ATMega328p Nano plugged in.


Re: DIGITAL FREQUENCY READOUT

MONEYSMITH
 

HERE IS A PHOTO OF BOARD AND CRYSTAL.

W4NFR

On 11/9/2018 9:57 AM, Mvs Sarma wrote:
OMG. acidentally crept in perhaps .
could you please share a  photo please, !!!!!

regards
sarma
 vu3zmv

On Fri, Nov 9, 2018 at 10:50 PM MONEYSMITH <w4nfr@...> wrote:

I OPENED UP MY uBITX  AND TOOK A LOOK AT THE S1535A BOARD. THE CRYSTAL HAS 20.0 STAMPED ON IT INSTEAD OF 25.0 MHZ?

On 11/8/2018 5:59 PM, RCC WB5YYM wrote:
The crystal is not "bad" 
http://www.hamskey.com/2018/05/frequency-adjustment-of-ubitx-si5351.html



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Need Source for Baofeng Mic Sockets

Scot McMath
 

Want to use a Baofeng mic on my BitX40 but have not been able to find sockets for the cabinet. Anyone know of where I could get them?
Thanks, Scot WB7AVU


Re: DIGITAL FREQUENCY READOUT

MVS Sarma
 

OMG. acidentally crept in perhaps .
could you please share a  photo please, !!!!!

regards
sarma
 vu3zmv


On Fri, Nov 9, 2018 at 10:50 PM MONEYSMITH <w4nfr@...> wrote:

I OPENED UP MY uBITX  AND TOOK A LOOK AT THE S1535A BOARD. THE CRYSTAL HAS 20.0 STAMPED ON IT INSTEAD OF 25.0 MHZ?

On 11/8/2018 5:59 PM, RCC WB5YYM wrote:
The crystal is not "bad" 
http://www.hamskey.com/2018/05/frequency-adjustment-of-ubitx-si5351.html



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Re: DIGITAL FREQUENCY READOUT

MONEYSMITH
 

I OPENED UP MY uBITX  AND TOOK A LOOK AT THE S1535A BOARD. THE CRYSTAL HAS 20.0 STAMPED ON IT INSTEAD OF 25.0 MHZ?

On 11/8/2018 5:59 PM, RCC WB5YYM wrote:
The crystal is not "bad" 
http://www.hamskey.com/2018/05/frequency-adjustment-of-ubitx-si5351.html



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