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Re: DIGITAL FREQUENCY READOUT
Gordon Gibby
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: [email protected] <[email protected]> on behalf of Vince Vielhaber <vev@...> Sent: Friday, November 9, 2018 2:55 PM To: [email protected] 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 |
Re: DIGITAL FREQUENCY READOUT
Vince Vielhaber
To see the 25MHz xtal on mine I had to pull the display.
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Vince. On 11/09/2018 02:42 PM, Arv Evans wrote:
Bill W4NFR --
K8ZW |
Re: a simple spur fix
¿ªÔÆÌåÓýI 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: [email protected] [mailto:[email protected]] On Behalf Of Ashhar Farhan ? 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
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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Re: a simple spur fix
Excellent!
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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:
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Bitx40 Raduino question
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
Scot,
If you access this list from the website /g/BITX20/topics there is a search button toward the top.? Searching Baofeng Socket produces several hits including this gem /g/BITX20/message/46336 -- |
Re: DIGITAL FREQUENCY READOUT
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
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
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Re: DIGITAL FREQUENCY READOUT
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: |
Re: DIGITAL FREQUENCY READOUT
¿ªÔÆÌåÓýI 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"? |
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 ![]()
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Re: KD8CEC 1.095 vs 1.097 Features and S-Meter
#smeter
#ubitx
#ubitx-help
Yes...sorry for wrong spelling On Fri, Nov 9, 2018, 7:03 PM Evan Hand <elhandjr@...> wrote:
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Re: KD8CEC 1.095 vs 1.097 Features and S-Meter
#smeter
#ubitx
#ubitx-help
I believe you meant hamskey web Ian Lee web site. |
Re: KD8CEC 1.095 vs 1.097 Features and S-Meter
#smeter
#ubitx
#ubitx-help
S meter using lm358 as sensor is very simple. One more sensor version is using another Arduino. For more info refer hamsky web. On Fri, Nov 9, 2018, 12:23 AM David Posthuma <davep@...> wrote: I have been using KD8CEC's 1.095 version of the Firmware and have been very happy with it. I am using a 3.7-inch?Nextion?display. My question is two-fold: |