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Re: The new uBITX boards are here

 

Sarma, by strange coinci?ence our labs requiring all those computations were associated with wavelengths of spectral lines of substances at room temp then cooled with liquid nitrogen.

Email from Farhan confirms my version 4 is in the tender care of India Post.
73 Kevin VK3DAP / ZL2DAP

--
Kevin B. G. Luxford
kbgluxford@...
Teensy I2c on wire2 (SDA2/SCL2) #ubitx

 

Has anyone ever gotten the I2C LCD display AND the Si5351 clock chip to operate on SDA2/SCL2?? Looking to get that running on a Teensy3.6 if possible.? Any help from the group would be very much appreciated.

Jim Sheldon, W0EB
Re: Simple sound card interface #ft8

 

Thanks Doug,

I followed your instructions and was able to make several FT8 contacts yesterday. I wonder what the 1K resistors are for across the audio outputs. Can they be eliminated?

73, Dennis
W7DRW
Re: What does zero-beat sound like? #ubitx

Mike aka KC2WVB
 

Interesting, I will have to look at this at a level that is more than casual. I was thinking that one would be discriminating to the limit of zero Hz.

I do like the idea of the Nano or Uno or... serving as the measuring instrument because I am tone death too.

On Thu, May 31, 2018, 11:16 AM Jerry Gaffke via Groups.Io <jgaffke=[email protected]> wrote:
The 30x improvement by calibrating at 30mhz vs calibrating at 1mhz is not theoretical,
even if your hearing is shot.
Instead of looking for a 10hz change in tone, you are looking for a 300hz change.

The ideal might be to monitor the audio from a Nano analog pin, have it look?
for either zero-beat or a specific tone.? Especially for those like me who are tone deaf.

With FFT's on an ARM processor like the Teensy, could discriminate the carrier from
the audio tones on WWV.



On Thu, May 31, 2018 at 08:02 am, Mike aka KC2WVB wrote:
?It seems to me to be without question that if one were to allign/adjust/tune an oscillator to a precise frequency by listening for a zero beat with respect to a known reference frequency that the higher the reference frequency the greater the accuracy with respect to alignment of the oscillator. However, if done by human ear the entire procedure is only as precise as the individual's ability to detect the a a absence of low frequency audio signals. So for someone like me who has been yelled at by kid's, dogs and other assorted life forms for 63 years the theoretical may be a bit of a moot point?
?
Re: What does zero-beat sound like? #ubitx

 

On Thu, 31 May 2018 11:02:34 -0400
"Mike aka KC2WVB" <rb5363@...> wrote:

Just a thought:

It seems to me to be without question that if one were to
allign/adjust/tune an oscillator to a precise frequency by listening
for a zero beat with respect to a known reference frequency that the
higher the reference frequency the greater the accuracy with respect
to alignment of the oscillator. However, if done by human ear the
entire procedure is only as precise as the individual's ability to
detect the a a absence of low frequency audio signals. So for someone
like me who has been yelled at by kid's, dogs and other assorted life
forms for 63 years the theoretical may be a bit of a moot point?

On May 29, 2018 6:58 PM, "Jerry Gaffke via Groups.Io" <jgaffke=
[email protected]> wrote:

I have no idea what the various software releases for the uBitx are
doing. But during calibration, the BFO should be placed in the center
of the 12mhz crystal filter
so a zero beat can be heard.

Also, the accuracy of that zero beat is proportional to the frequency
of the signal.
So a zero beat to WWV at 15mhz is 15 times more accurate than a zero
beat of a 1.0mhz AM broadcast station.
The three local oscillators are each a strict ratio of the 25mhz
reference, and from post 44515
the operating frequency of a stock uBitx in LSB mode is: vfo -
(clk1-bfo)
By the distributive law of algebra, a 100ppm change in vfo, clk1 and
bfo will result in a 100ppm change in the operating frequency.

Jerry

I have used an analog voltmeter on the speaker leads to watch the beat
tone. You just watch the meter move as you tune toward zero-beat. It
will move up and down at a slower and slower pace. You can get pretty
darn close to zero-beat this way. The biggest problem is that the SSB
filter causes a drop-off at the lower frequencies making the beat tone
disappear. You kind of have to interpolate even with the meter.

If you have a third receiver you might be able to transmit a CW signal
from the ubitx against a strong external signal that is a known
frequency and use the 3rd receiver to listen to the beat tone between
the external signal and your ubitx. You can tell just how far your
calibration is off in that manner. In fact that is kind of what the
"spot" function on many older transmitters was for. You could
"zero-beat" your transmitter using a low-power output against a station
you wanted to talk to.

tim ab0wr

On Tue, May 29, 2018 at 03:38 pm, Glenn Anderson wrote:

When tuning in an AM station when your rig is listening on SSB, you
will hear a carrier tone... This will vary depending on whether you
change your frequency up or down... When you tune so that the
frequency you hear gets so low that it "disappears" then you have
"zero-beated" on the station... Most commercial rigs have a tune
button that typically is at every 25 or 100 khz on the dial...

Once you no longer hear the tone then that's when you calibrate your
dial... A good frequency on air is WWV @ 10.000Mhz...

I hope that helps,

Glenn VE3JAU
Re: looking for a ubitx board

M Garza
 

Hi Richard,
Are you interested in selling that burned up board?? I am looking for something else to experiment with.? I would be interested in the board and Raduino.

Please let me know if you are interested in selling it.

Thanks

Marco - KG5PRT

On Thu, May 31, 2018 at 9:05 AM, Richard E Neese <kb3vgw@...> wrote:
My ubitx got hit by a power surge and I am looking for a board locally before ordering from hfsignals. SO if you have a ubitx unbuilt and willing to part let me know.


Re: SDR as Waterfall display

 

This mod works great!.?

?I have been using it with a similar upconverter / dongle with the? SDR software? for several weeks--- works very well...


The tap? / place Gregory found is perfect and? ?the pictures he has taken to show exactly where to hookup made it a very easy mod...

So far it? has protected my sdr rx hardware -??My current ubitx tx outputs? range from 15 watts on 80, around 12 watts and? 10 on 20 mtrs .



Thanks Gregory!!


Joe
VE1BWV

On Wed, May 30, 2018 at 10:46 PM, K9HZ <bill@...> wrote:

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.

?

de ku4pt

?

?

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)?

?

Brad

?

--?

?

Virus-free.


Re: What does zero-beat sound like? #ubitx

 

The 30x improvement by calibrating at 30mhz vs calibrating at 1mhz is not theoretical,
even if your hearing is shot.
Instead of looking for a 10hz change in tone, you are looking for a 300hz change.

The ideal might be to monitor the audio from a Nano analog pin, have it look?
for either zero-beat or a specific tone.? Especially for those like me who are tone deaf.

With FFT's on an ARM processor like the Teensy, could discriminate the carrier from
the audio tones on WWV.



On Thu, May 31, 2018 at 08:02 am, Mike aka KC2WVB wrote:
?It seems to me to be without question that if one were to allign/adjust/tune an oscillator to a precise frequency by listening for a zero beat with respect to a known reference frequency that the higher the reference frequency the greater the accuracy with respect to alignment of the oscillator. However, if done by human ear the entire procedure is only as precise as the individual's ability to detect the a a absence of low frequency audio signals. So for someone like me who has been yelled at by kid's, dogs and other assorted life forms for 63 years the theoretical may be a bit of a moot point?
?
Re: What does zero-beat sound like? #ubitx

Mike aka KC2WVB
 

Just a thought:

?It seems to me to be without question that if one were to allign/adjust/tune an oscillator to a precise frequency by listening for a zero beat with respect to a known reference frequency that the higher the reference frequency the greater the accuracy with respect to alignment of the oscillator. However, if done by human ear the entire procedure is only as precise as the individual's ability to detect the a a absence of low frequency audio signals. So for someone like me who has been yelled at by kid's, dogs and other assorted life forms for 63 years the theoretical may be a bit of a moot point?

On May 29, 2018 6:58 PM, "Jerry Gaffke via Groups.Io" <jgaffke=[email protected]> wrote:
I have no idea what the various software releases for the uBitx are doing.
But during calibration, the BFO should be placed in the center of the 12mhz crystal filter?
so a zero beat can be heard.

Also, the accuracy of that zero beat is proportional to the frequency of the signal.
So a zero beat to WWV at 15mhz is 15 times more accurate than a zero beat of a 1.0mhz AM broadcast station.
The three local oscillators are each a strict ratio of the 25mhz reference,? ?and from post 44515
the operating frequency of a stock uBitx in LSB mode is:? ? vfo - (clk1-bfo)?
By the distributive law of algebra, a 100ppm change in vfo, clk1 and bfo will result in a 100ppm change in the operating frequency.

Jerry


On Tue, May 29, 2018 at 03:38 pm, Glenn Anderson wrote:
When tuning in an AM station when your rig is listening on SSB, you will hear a carrier tone... This will vary depending on whether you change your frequency up or down... When you tune so that the frequency you hear gets so low that it "disappears" then you have "zero-beated" on the station... Most commercial rigs have a tune button that typically is at every 25 or 100 khz on the dial...

Once you no longer hear the tone then that's when you calibrate your dial... A good frequency on air is WWV @ 10.000Mhz...

I hope that helps,

Glenn VE3JAU
Re: Heat proofing the ubitx.

 

Very nice.? This is another reason for me to get a 3d printer.? Which kind is yours??? I posted this picture before of my temperature controlled variable 20mm fan.? Not much spare room in my case which is why the fan and filter are on the outside.
--
Lee - N9LO? "I Void Warranties"

?
Re: ubitx assembly confusion, help needed

[email protected]
 

See attached photo for the pin connections on the molded-plastic 3.5 mm jacks.
--
Jon Titus, KZ1G
Herriman, UT USA

DSC04685.JPG

Re: The new uBITX boards are here

 

¿ªÔÆÌåÓý

Well this jogged my memory when I used 21 figure logs and 15 figure Sine tables . Both books about 3" thick. Cosines and tangents are calculated from the Sine tables using trig functions.


The 'calculator' was a dual hand cranked machine with both halves coupled for 28 SF.


Was in Civil engineering and setting starting points from distant trig points.?


Peter Paul Fox G8HAV
Mid-Cheshire Amateur Radio Society
5 Llandovery Close
Winsford
Cheshire CW7 1NA?

Group Controller
Dane Valley?RAYNET?
Tel: 01606553401 (H)
Tel: 07919315547 (M)

From: [email protected] <[email protected]> on behalf of Mvs Sarma <mvssarma@...>
Sent: 31 May 2018 09:15:47
To: [email protected]
Subject: Re: [BITX20] 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

Regards
MVS Sarma
?

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
Re: Need Clarification on uBitx v. 4 Schematic

 

In answer to Mike's question, the RD15*/RD16* parts are an alternative to the IRF510's.
But they are not magical, just stuffing them into the uBitx will not improve things by much,
there are a number of mods required to make good use of them.?
And considerably more mods required to address the issue of getting sufficient gain
at 30mhz from the preceding? 2n3904 stages.??

I suggest waiting for Allison and others to arrive at a good recipe?
before blindly butchering boards.

Jerry


On Wed, May 30, 2018 at 10:27 pm, Mvs Sarma wrote:
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
?

Regards
MVS Sarma
?
. . .

?

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
Re: Transmitter Mods

 

Can't find the post, but I think Allison has already answered this in the affirmative.
Could stick with the 2n3904's if gain is reduced from 16dB per stage to around 10dB.
But then need a fourth driver stage.
Allison is chasing hotter parts so it can just be a matter of replacing parts rather than adding?
extra parts, a possible manufacturing solution for hfsignals.

But an easy way to add a stage to existing boards might be to remove C84, then add a
small daughterboard to the back of the uBitx with a $1 MMIC on it to bridge the
through-hole pins from RV1-wiper to Q912-base??

Available gain at 30mhz from the 2n3904's is the big one here, but there may also be
other stuff such as board layout issues and torroid core choices, and quiescent currents
to be addressed.? Unless you are keen to help diagnose these problems, best to just
sit on your hands?till Allison and others report back.
?
Jerry


On Thu, May 31, 2018 at 04:18 am, Kelly Jack wrote:
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?
Re: uBITx For Sale #ubitx

 

do you still have the unit ?\
I would like to buy it
looking for a ubitx board

 

My ubitx got hit by a power surge and I am looking for a board locally before ordering from hfsignals. SO if you have a ubitx unbuilt and willing to part let me know.
Re: Heat proofing the ubitx.

 

I think I can blame android for the 4th paragraph.
Basically I meant to say that I had to redesign the shroud to fit the larger heatsinks and that I only have very slight warming with prolonged ft8 tx.?

A wood case fits over the bright red parts.?
73?
Dave
Re: Transmitter Mods

 

¿ªÔÆÌåÓý

I did not get good results with this mod, I found 80 meters had reduced output. It is also difficult to implement, since to remove some of the parts, you need to remove the FETs first to get to them, at least I would have had to do that.
I did another mod that was easy, and also helped, along the same idea as Ashar's. I put a small cap from the top of VR1 to the wiper. The value needed depends on where you set the pot. If the pot is set to the top end, then it won't help at all. The problem with all these transmitter mods is that we are pushing the parts to there limits, and when you design without margin, you don't get consistent results. This is kind of how we got in trouble with the original design to begin with, where the design compromises were made to keep the cost down. My original 3 part mod, which you did works fairly reliably. Allison is working on replacing the existing parts with new parts to improve the performance, which is great. I have taken a different track and am working on a new transmitter power train. The problem with that is you need a new PCB.


On 5/31/2018 6:49 AM, Rob Bleumer wrote:

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


Amazon

 

Any chance the ubitx could be offered via Amazom with the price to reflect the additional fees. The reason I ask is I have some Amazon gift cards to use up.

Tx Joe N7QPP
Re: Transmitter Mods

 

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
66341 - 66360 of 116922