DIGITAL FREQUENCY READOUT
MONEYSMITH
MAYBE I AM MISSING SOMETHING, BUT ARE ALL uBITX V4.3 RADIOS HAVE A ONE KHZ LOW READOUT. FOR EXAMPLE, IF I HAVE A STATION ON 7.150 SELECTED, IT READS OUT 7.149 FOR CLEAR RECEPTION. IS THIS NORMAL?
WILLIAM
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Mark Pilant
Hi William.
MAYBE I AM MISSING SOMETHING, BUT ARE ALL uBITX V4.3 RADIOS HAVE A ONEThe short answer, maybe. (I apologize if you already know the following; but for those who do not...) Digital frequency readout is only as accurate as the calibration of the sending and receiving stations. (I had a recent thread going about the Si5351 calibration.) I'm assuming you have done the recommended calibration of your uBitx. Even with a calibrated uBitx, there is likely to be some drift due to thermal heating from any number of sources: the components themselves, ambient air temperature, etc. This being said, it is probably unlikely you would see a 1 KHz drift. The other possibility is the sending station is "off", they may say they are transmitting on 7.150 MHz, but in reality they are on 7.149 MHz. Without knowing the calibration of the sending station, it is really impossible to know for certain. In the "good ol' days" of analog dials, you simply tuned for the best reception and went with that. (This is one of the reasons, back then, operating near the band edges was not recommended :-) I do it all the time with my Collins rigs: get close with the dial and then interpolate the frequency. My suggestion, if you are confident of your uBitx's calibration, is not to worry about it and enjoy the contact :-) 73 - Mark N1VQW
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MONEYSMITH
THANK YOU FOR THE COMMENTS. I HAVE LEARNED TO LIVE WITH IT. I HAVE TEST THE OFFSET WITH KNOWN STATIONS
THAT ARE ON FREQUENCY AND MY DISPLAY IS ALWAYS 1 KHZ LOW FROM THE ACTUAL. I SUPPOSE THE 1 KHZ OFFSET WORKS FOR CW AND SSB AND MAY BE THE REASON FOR THE STRANGE THING. On 11/8/2018 6:46 AM, Mark Pilant wrote: Hi William.---MAYBE I AM MISSING SOMETHING, BUT ARE ALL uBITX V4.3 RADIOS HAVE A ONEThe short answer, maybe. (I apologize if you already know the following; This email has been checked for viruses by AVG. https://www.avg.com
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MONEYSMITH
THIS IS WHAT I SEE WHEN LISTENING TO 7.128 WILLIAM W4NFR -------- Forwarded Message --------
THANK YOU FOR THE COMMENTS. I HAVE LEARNED TO LIVE WITH IT. I HAVE TEST THE OFFSET WITH KNOWN STATIONS THAT ARE ON FREQUENCY AND MY DISPLAY IS ALWAYS 1 KHZ LOW FROM THE ACTUAL. I SUPPOSE THE 1 KHZ OFFSET WORKS FOR CW AND SSB AND MAY BE THE REASON FOR THE STRANGE THING. On 11/8/2018 6:46 AM, Mark Pilant wrote: Hi William.
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Vince Vielhaber
Did you check the 25MHz calibration of the si5351? If that's off, everything will be.
toggle quoted messageShow quoted text
Also, what is the box above your uBitx (the one with the display that has PWR:0 SWR: 0.00 and RF: 0.0)? Vince.
On 11/08/2018 11:22 AM, MONEYSMITH wrote:
THIS IS WHAT I SEE WHEN LISTENING TO 7.128
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N5KBP
You need to calibrate the VFO.
-- N5KBP
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MONEYSMITH
THE BOX ABOVE THE uBITX IS MY HB DIGITAL WATT METER AND SWR BRIDGE. THANKS FOR THE REPLY.
W4NFR On 11/8/2018 1:41 PM, Vince Vielhaber wrote: Did you check the 25MHz calibration of the si5351? If that's off, everything will be.--- This email has been checked for viruses by AVG. https://www.avg.com
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RCC WB5YYM
Being 1khz off is not "normal". It needs master calibration adjusted, NOT BFO CALIBRATION. Mine is hardly ever 10 cycles off.
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MONEYSMITH
i must have a bad 25 mhz crystal? i will try to get closer to 25 mhz and see if that does the trick.
On 11/8/2018 5:19 PM, RCC WB5YYM wrote:
Being 1khz off is not "normal". It needs master calibration adjusted, NOT BFO CALIBRATION. Mine is hardly ever 10 cycles off.
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RCC WB5YYM
The crystal is not "bad"
http://www.hamskey.com/2018/05/frequency-adjustment-of-ubitx-si5351.html
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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"
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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:
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MONEYSMITH
HERE IS A PHOTO OF BOARD AND CRYSTAL. W4NFR
On 11/9/2018 9:57 AM, Mvs Sarma wrote:
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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.
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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
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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.
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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:
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Vince Vielhaber
To see the 25MHz xtal on mine I had to pull the display.
toggle quoted messageShow quoted text
Vince.
On 11/09/2018 02:42 PM, Arv Evans wrote:
Bill W4NFR
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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@michvhf.com> 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-- K8ZW https://urldefense.proofpoint.com/v2/url?u=http-3A__www.metalworkingfun.com&d=DwICaQ&c=pZJPUDQ3SB9JplYbifm4nt2lEVG5pWx2KikqINpWlZM&r=3ELgZgmTnPzGsfvQxkd1S_2NGLYM8sHTxVCQKFxhVXQ&m=mAUii3YaxPtywhZnzMLlmMvPiPtMo5OwMNFv6xTOoAo&s=IDgedOO3B8-YG4hw7NNxr0wxmz03BtHDWm_utsVqy-M&e= https://urldefense.proofpoint.com/v2/url?u=http-3A__www.hamradio.fun&d=DwICaQ&c=pZJPUDQ3SB9JplYbifm4nt2lEVG5pWx2KikqINpWlZM&r=3ELgZgmTnPzGsfvQxkd1S_2NGLYM8sHTxVCQKFxhVXQ&m=mAUii3YaxPtywhZnzMLlmMvPiPtMo5OwMNFv6xTOoAo&s=K12BpjbgtBoOSacLnf7IeEQTMo5Ptr6mMN0L6nAlw-g&e=
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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:
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