There are a number threads with the power train mods being discussed and I've lost track of where I read some comments I think between Farhan and Allison about using easily obtainable parts in the tens of thousands in the transmit chain as being a limitation on part choices.? What seems to emerging as an issue is that replacing components in the current transmit chain circuit to increase output at higher freqs is that the current architecture requires finding parts closer to the unobtanium end of the spectrum.
So my question is could this be solved by adding another amp stage allowing for lower gain at each stage but still using parts from the generic end of the spectrum?
73
Simon
VK3ELH
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Re: New VK4PLN Audio Daughter Board + BCI
I believe there are many pin-compatible replacements for the LM324 for those who want better audio noise performance. For example MC33179, MAX414 - although many through hole DIP parts are reaching end of life for manufactureres. No need to change to two dual parts.
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Hi all,
I did the same mod as Nigel G4ZA did but using FT37-43 giving 30uH? in series with R86?
and 2 ceramic disk C's 220 pF.
And? al with exact the same power output results!!
Now I see another mod by Ashar Fahran? changing C81 to 470pF.in the new uBITX.
Could I do the mod by Ashar too and will this give a better result???
Who can advise me about this?
Rob PA0RBL
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Re: New VK4PLN Audio Daughter Board + BCI
Hi Nik,
You could put the audio amp on there like a 2n3904 replacement version per the new ubitx version. Or some AGC circuitry?
Or one of the more sophisticated pop suppression circuits (admittedly not a clean installation as what you have designed here given need to link to traces on the board).
Could the SMM2167 stand vertically to conserve space for other stuff?
73
Simon
VK3ELH
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Re: boosting the power on 28 MHz
#ubitx
Depends on the regions. In Europe 10 meters are open for e-sporadic in may and June every year. Anyway many vhf and uhf transverters have the IF at 28, so I'm my opinion it is important to have it fully functional even when the band is closed.
Il 31/mag/2018 09:39, "Terry Morris" < terry.kb8amz@...> ha scritto: In the late 80's too. KB8AMZ
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Re: The new uBITX boards are here
lovely recollection of my 1st job doing optical design by using? BIG "BIBLE" LIKE 7 FIGURE LO AND SINE COSINE ETC BOOK -- WAY BACK IN 1964-65
?Thaniks Kevin
On Thu, May 31, 2018 at 12:45 PM, Kevin Luxford <kbgluxford@...> wrote: Well you will just have to fall back on your Chambers Seven Figure Mathematical tables.? Or perhaps you can get your hands on a Monroematic electric calculator or even one of those crank and shift jobs we used in Physics labs 60 years ago.
73, Kevin VK3DAP / ZL2DAP
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Re: boosting the power on 28 MHz
#ubitx
In the late 80's too. KB8AMZ
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Re: The new uBITX boards are here
Well you will just have to fall back on your Chambers Seven Figure Mathematical tables.? Or perhaps you can get your hands on a Monroematic electric calculator or even one of those crank and shift jobs we used in Physics labs 60 years ago.
73, Kevin VK3DAP / ZL2DAP
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Re: Need Clarification on uBitx v. 4 Schematic
i suppose that RD16HHF1 are to be used.? Some people experiment with RD15HVF1 too. They feel that 21 and 28 mhz performance would improve. but you might suffer poor performance at 80m band etc
On Thu, May 31, 2018 at 9:50 AM, Mike <msmith@...> wrote: Regarding the new version 4 schematic:
Do new components Q942 and Q952 connect in parallel with the IRF510's as per schematic or
are?the RD15HV's meant to be used as an?alternative to the IRF510's?
Thanks,
Mike
-Mike
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Hi Jerry,
Thanks for the additional information. I've been reading many of your explanations of the interworking of the si5351 with interest. Especially the tidbit about it using a variable delay line to implement non-integer dividers.?
Tom, wb6b
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Re: New VK4PLN Audio Daughter Board + BCI
Hi.
I'm thinking I'll make the board so it reaches all the way to the LPF relays.
One end is supported by the connector and then you can just glue a couple of 12mm stand offs on the first and last relay for the board to screw to.
Ill leaver the extra area blank for prototyping...
What would be best in the area? Me-Squares? or Through holes?
Thanks for the feedback.
73, Nick VK4PLN
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Sounds like the CEC firmware uses about the same math as the stock uBitx code: ? ?? /g/BITX20/message/37973What calibration does is to set the value of si5351bx_vcoa This is the frequency of the nominally 875mhz? oscillator inside the si5351 that is locked to the 25mhz reference crystal. So if if it is being adjusted in steps of 8750, that's in increments of 10 parts per million. As the value of si5351bx_vcoa is moved, the clk0,1,2 outputs from the si5351 get adjusted proportionally on any subsequent calls to si5351bx_setfreq() ? With an operating frequency of 7.0 mhz, each increment in that "calibration number" of 10ppm would move it by 70 hz. At 30mhz, the shift per calibration number increment is 300hz. Jerry
On Wed, May 30, 2018 at 09:11 pm, Tom, wb6b wrote:
I only know about the CEC firmware. In that case it is the offset of the 25mhz crystal. The calibration number would be 0 if the 25mhz crystal was exactly correct.
If you use the CEC uBITX Manager, the master calibration number, in the Manager, is the calibration number you zero beat on times 8,750. So, the Master Calibration can vary from zero to large values. In my case I zero beat at 18, so 18 x 8,750 = 157,500.
[For sake of completeness, I'll add that in my case the "USB Calibration" sounded best at at 11,995,655.]
?
Also, I discovered you need to turn the power off to the uBITX and back on after each attempt to calibrate. (If connected, be sure to disconnect the USB cable, too, to remove that source of power to the processor.) Otherwise, the calibration (I think it is the value of the second LO frequency) shifts farther away from center each time you repeat the calibration step.?
The calibration steps appear to be 10hz with the CEC firmware. It may be different with the factory firmware.
Tom, wb6b
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Need Clarification on uBitx v. 4 Schematic
Regarding the new version 4 schematic:
Do new components Q942 and Q952 connect in parallel with the IRF510's as per schematic or
are?the RD15HV's meant to be used as an?alternative to the IRF510's?
Thanks,
Mike
-Mike
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The standard 8-way looms are colored per resistor code, 0 - 7. These correspond to pins 1 - 8 then 9 - 16. Smaller connectors similarly color 0? onward for numbers 1 up. I don't have a ubitx so I can't comment on labelling, but I presume a close relationship to the bitx-40.
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Sorry, disregard. ubitx doesn't use the wiring looms. my bad ... :(
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Re: SDR as Waterfall display
So I¡¯ve actually done this¡ I used this SDR:? ?? which tunes down to 24 MHz.? I tapped into the uBITx IF at TP14 on the rev4 schematic¡ before the 45 MHz roofing filter so the IF spectrum is still wide banded¡ used a 5pf cap as not to load the IF.? I ran that into an IF amplifier made from a MC1350P circuit for 45 MHz right out of the app note.? The response from 1-30 MHz is not flat, so I took an analog pin from the Arduino to set the AGC on the MC1350P and developed a table that generates an AGC voltage for each band as selected that is calibrated basis a known input signal to give dBm on the waterfall.? The software I used for the spectrum display is Freq-show from here: .? It works very well.? I will post a video when my ubitx is back together (currently adding¡ yes¡ a ¡°second¡± receiver¡ ohhhhh!).? I¡¯m not an expert coder, but once this Python app can be coded into the Teensy, I think we have an all-in-one solution!
?
?
Dr. William J. Schmidt - K9HZ
?
From: [email protected] [mailto:[email protected]] On Behalf Of Ralph Mowery
Sent: Wednesday, May 30, 2018 2:43 PM
To: [email protected]
Subject: Re: [BITX20] SDR as Waterfall display
?
I have not tried it,but from the circuit description the first conversion is at 45 MHz.? I would try laying a short insulated wire near Q10.? You may even be able to tap off the emitter of q12 with a low value capacitor.?
Then tune the SDR ( I assume we are talking the about $ 15 TV dongle, but does not matter)? to around 45 MHz.??
There may be more out now, but the two that I bought a number of years ago, one goes from about 25 MHz up and the other starts at 50 some MHz.
?
?
On Wed, May 30, 2018 at 3:06 PM, brad martin <emclinux@...> wrote:
I noticed that the CEC firmware has an SDR mode but this seems to be where the audio as as well are transmitted to the SDR and handled there.? Seems to be a good method for digital or recording but is there a way to just use the SDR as a waterfall display and still have the radio function as normal (i.e. have audio come out the radio speakers)?
?
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Re: New VK4PLN Audio Daughter Board + BCI
Holes in the corners for mounting¡ of course¡
?
?
Dr. William J. Schmidt - K9HZ ?
?
From: [email protected] [mailto:[email protected]] On Behalf Of Nick VK4PLN
Sent: Wednesday, May 30, 2018 8:05 PM
To: [email protected]
Subject: [BITX20] New VK4PLN Audio Daughter Board + BCI
?
Hi Everyone.
I am working on a new board that will give a few extra features to stock uBitx.
Its an Audio board providing easy access to Audio I/O pins. (add in your own AGC board, External amplifier...)
A place for an SSM2167 Mic Pre-amp. (with filtering for feedback and shutdown on TX)
Simple 4 component PTT POP fix. (BS170)
Switchable 200hz CW filter. (LM324)
and a bonus Snap off section with a 3.5MHZ BCI filter for the RX chain.
Here is a pre-view, NOTE this is a WORK-IN-PROGRESS.
Suggestions and corrections welcome.
73 Nick VK4PLN
?
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Hi, I only know about the CEC firmware. In that case it is the offset of the 25mhz crystal. The calibration number would be 0 if the 25mhz crystal was exactly correct. If you use the CEC uBITX Manager, the master calibration number, in the Manager, is the calibration number you zero beat on times 8,750. So, the Master Calibration can vary from zero to large values. In my case I zero beat at 18, so 18 x 8,750 = 157,500. [For sake of completeness, I'll add that in my case the "USB Calibration" sounded best at at 11,995,655.]
?
Also, I discovered you need to turn the power off to the uBITX and back on after each attempt to calibrate. (If connected, be sure to disconnect the USB cable, too, to remove that source of power to the processor.) Otherwise, the calibration (I think it is the value of the second LO frequency) shifts farther away from center each time you repeat the calibration step.?
The calibration steps appear to be 10hz with the CEC firmware. It may be different with the factory firmware.
Tom, wb6b
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Re: boosting the power on 28 MHz
#ubitx
I'm constantly surprised at the interest in 10 meters. I always check 15. If its dead I go to 20. If it has anything on it I check 10 and hear nothing here in NC with a simple EFHW..
But 10 was a blast back in 1954!!? ?:)
73, Bo W4GHV since '54
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Re: The new uBITX boards are here
I proudly display my Post bamboo slide rule along with the latest in Electronic and Radio engineering texts.? The slide rule glass slide is cracked.? Overheated during a physics final exam? ;-)? Mike K5ESS ?
toggle quoted message
Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of Jerry Gaffke via Groups.Io
Sent: Wednesday, May 30, 2018 12:37 AM
To: [email protected]
Subject: Re: [BITX20] The new uBITX boards are here ? I've got a slide rule and CRC book of math tables as well, buried in a box deep in the basement.
Also an HP35, nearly worn out from a decade of use but still works, batteries long since dissintigrated.
Most smartphone and laptop calculators try to emulate the look and feel of a desktop calculator,
which I find exceeding silly.? No history.? No scripting.? Very limited.
I kick off python whenever I need to do a bit of math, be it add a bunch of numbers
or?prototype some nasty fixed point calculations.? It's as easy to use as any calculator
for the basic stuff, but can do much much more.
On Tue, May 29, 2018 at 10:03 pm, Terry Morris wrote: I still have my slide rule and books with the logrithms Allison.
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Paul Galburt - K2AYZ
Terry Morris
Nick VK4PP
K9HZ
