Date   

Re: Simple UBITX Test Set

Jerry Gaffke
 

All the RF sections of the receiver except the demodulator could be
checked out by driving the BFO from CLK#0 into the antenna jack.
Need a pretty serious attenuator, of course.

Perhaps remove the series cap from CLK#0 on the Raduino, then
short CLK#0 on the main board to ground to make it possible to measure
12mhz energy going into the demodulator without having the AD8307
be overwhelmed by BFO energy.

Better would be a fourth output from a $2 QFN-20 Si5351 on the Raduino
for the signal generator.
Then you can just shut down CLK#0 using the i2c bus. 
No hardware mods required.

Jerry, KE7ER



On Mon, Oct 26, 2020 at 09:57 AM, Jerry Gaffke wrote:
But debug could be done by using one of the three
Sit5351 outputs as a signal generator, and somewhat crippling the rig.  For example, use
CLK#2 into the first mixer as our signal generator, injecting 45mhz into the first RX IF amp.
And use an AD8307 to measure RF power at the various stages between there and the
demodulator, varying the frequency of the three oscillators as necessary to measure 
filter passbands, plotting the result to a host computer using the Arduino IDE's Serial Plotter.
  https://groups.io/g/BITX20/message/32630
Then use the BFO at CLK#0 as the signal source, injecting it into the antenna port,
see if the signal arrives in the 45mhz IF amp at the expected power level, sweep the spectrum
to verify the 30mhz LPF is working properly.


Re: Electronic encoder (Not rotary)

Arv Evans
 


On Sun, Oct 25, 2020 at 8:24 PM Bob Lunsford via groups.io <nocrud222=yahoo.com@groups.io> wrote:
You are right. ALL grounds must be tied back to the service ground [rod]. Merely driving a ground rod in the ground near the radio room and tying everything to it is not per Code. A run of copper wire of the prescribed wire size must be run from that radio room ground back to the service ground to be acceptable to the Code. This is per a friend who designs large industry electrical systems.

Bob — KK5R

On Sunday, October 25, 2020, 10:13:17 PM EDT, Evan Hand <elhandjr@...> wrote:


Gerard,
The correct grounding depends on the intent.  For safety, all grounds are to be at the same level.  A potential difference can be dangerous.  In large buildings that requires running new ground rods in the immediate area and tying all power ground connections to that grid.  Extrapolating that to your case, all should be at the same ground potential by bonding altogether.   I suspect that the oscilloscope is not grounded to the same point as the mains to the uBITX.  You can measure that with a good DMM on AC volts.

For the RF side of things, it is important to have a good solid earth ground close to the antenna and to have that ground also run into the shack.

Above are what I remember from my industrial power days.
73
Evan
AC9TU


Re: Simple UBITX Test Set

Jerry Gaffke
 

Jim,

A few posts back I was suggesting that we make use of
the Raduino's Nano to drive an Si5351 on the test set board for use as a signal source.
A 4th output allows the rig to remain operational, with all three local oscillators from
the Raduino's Si5351 running normally.  A Raduino with a $2 QFN-20 Si5351 having
a fourth output for use as a signal generatore would be very nice.

But debug could be done by using one of the three
Sit5351 outputs as a signal generator, and somewhat crippling the rig.  For example, use
CLK#2 into the first mixer as our signal generator, injecting 45mhz into the first RX IF amp.
And use an AD8307 to measure RF power at the various stages between there and the
demodulator, varying the frequency of the three oscillators as necessary to measure 
filter passbands, plotting the result to a host computer using the Arduino IDE's Serial Plotter.
  https://groups.io/g/BITX20/message/32630
Then use the BFO at CLK#0 as the signal source, injecting it into the antenna port,
see if the signal arrives in the 45mhz IF amp at the expected power level, sweep the spectrum
to verify the 30mhz LPF is working properly.

A similar scheme for checking out the transmitter.
Transmitter debug needs a calibrated source of audio into the mike amp,
a 1khz square wave out of a Nano IO pin would be fine.
From there on out, just read power levels off the AD8307.
Sweep CLK#2 far enough to verify that the transmit LPF's are working.

Fine with me if serious troubleshooting occasionally involves cutting a trace now and then.
Easy enough to patch back into those 1206 pads with a soldering iron.
But having jumpers across test points would be great, a trace between the pins on the
back of the board would allow units to go out without those jumpers (or pins) installed.

No need to assume the uBitx is mostly functional.
You would need a working Raduino (or Raduino like test set), which could be had cheaply.

If everything seems dead, could verify that the Si5351 is up by monitoring each of the four channels
on a borrowed $20 SW receiver.  Once the receiver is up, calibrate by zero beating a SW AM station.

Beyond the Raduino, a diode RF probe might be a good enough detector but
an AD8307 into a Nano analog pin would be much better.  
An AD8307 chip is $0.50 on ebay, here's a complete module that looks pretty good:
    https://usa.banggood.com/0_1600M-75-15dBm-Power-Meter-Logarithmic-Detection-AD8307-Module-p-1613155.html
Would be very cool if an AD8307 chip could be already available on the Radino, or perhaps
on a quiet part of the uBits.  Also appropriate attenuators for the AD8307 input and the signal generator output.

For audio debug, perhaps one of the ADC channels of the Nano could be used along with
the Arduino IDE's Serial Plotter, making a cheap low bandwidth oscilloscope.



The Antuino is also a good debug tool, as Farhan has pointed out.
Especially if a complete test procedure for the uBitx were written up with the Antuino in mind.

As is a Nanovna plus TinySA.
Accumulating tools like that is relatively expensive,
but a good investment for those serious about learning what's going on here.

But we can't expect everybody to spend an extra $100 when their uBitx fails.
Would be best if we could make better use of the Raduino as a debug aid.

Jerry, KE7ER



On Mon, Oct 26, 2020 at 03:17 AM, Tom, wb6b wrote:
On the subject of the test set. Would it be possible to add some jumper plugs to break the circuits at critical points or jumper across parts of the circuits and test points to the uBitx and produce a sketch that could be loaded into the Raduino for the express purpose of alignment and troubleshooting, assuming the uBitx is mostly functional. The idea would be to allow the built-in Raduino to be a signal generator for one section of the uBitx at a time, and possibility use a simple DVM and a RF detector probe to verify passband and centering of filters and such. You may still want an accurate signal source to verify the final frequency calibration. That could just be a simple xtal oscillator. 


Re: Simple UBITX Test Set

Dean Souleles
 

I built a signal generator using a spare AD-9850 Direct Digital Synthesizer that I had and an 16x2 LCD.  It produces a clean sine wave from DC-daylight.  That and a step attenuator produce any signal I need for testing.   I used it extensively while building my homebrew 40 SSB transceiver.




Blog post with demo, bill of materials and link to the sketch are here:

https://kk4das.blogspot.com/2020/10/homebrew-signal-generator-arduino-and.html

Let me know if anyone decides to build it.

73, 
Dean
KK4DAS


Re: Electronic encoder (Not rotary)

Gerard
 

Evan, Bob,

Meanwhile, I think I finally found what I was looking for to replace the rotary encodeur  , with an UP DOWN encoder with 2 buttons +  ADD a 3rd to validate. It seems cool to me, instead of getting tired of the fingering. LOL

you can simulate with LTspice

https://electronics.stackexchange.com/questions/231803/rotary-encoder-to-2-buttons

If someone want to test?
cdt


Re: V6 TX on 15 and 20 meters

Chuck Eglhaut
 

I have a SWR meter and Antenna Tuner attached to the rig. The Antenna is an end fed and I have the Balan about 4 ft away from the rig. I had this problem from the beginning. But I work 80 and 40 meters everyday no problem . But was trying work CQ Worlld Wide DX contest and 15 meters was the band to be on.
 One person I talked with said maybe my antenna is not matched to 50 ohms.

73 Chuck


Re: Electronic encoder (Not rotary)

Gerard
 

Evan, Bob,
Test made with an other power without earth connexion.
it's the same. Click when digit change.

last test to do, pull resistor and diviser with capacitors on line TX, RX.

cdt


Re: Simple UBITX Test Set

Bob Lunsford
 

The scan on my Xiegu G90 also has multiple scans and repeats until you punch the Quit button. There are two scan options for Fast and Slow, also.

A Tune of the radio then another scan to see the results is often amazing. I suspect that if the analyzer is used the same way looking into a tuner, first in Bypass and then after tuning, you would see the same thing.

I'm also assuming that if you push the knob, it brings up the menus. Seems "logical" to me... {;->

Bob — KK5R


On Monday, October 26, 2020, 6:39:34 AM EDT, Raj vu2zap <rajendrakumargg@...> wrote:


Bob,

you have to use the tuning knob to scroll through the menu, set the center freq and span.
then highlight plot and press the encoder knob to start the plot. In the older version it a
single scan but newer one does continuos scan just like an expensive spectrum analyser.

If I need to measure the freq, then I would feed the signal and do a sweep. Then center
the cursor on the peak and get a reading.. not very accurate but will do on many an
occasion. Error will be a few KHz.. the width of the IF filter in the antuino.

It works on VHF with no problems and is usable to 500MHz.

The main thing is hackable.. change what you want in hardware and software.

Raj

P.S we have an antuino group on groups.io

At 26/10/2020, you wrote:
>Thanks, Raj. I'm still wondering if you press the word "plot" on the screen or if there's a button on the case that is not visible. If you press "plot" on the screen, it must be sensitive to the finger's capacitance and goes to the plotting the signal. Regardless, I'm wondering if you "measure [frequency] indirectly in power mode," is it very accurate? Considering the many decimal places shown on the screen, I'm guessing it's pretty accurate. I see it's measuring in the HF range but does it also work at 2M for measuring, for example, the SWR of an antenna?
>
>It's a box full of capabilities and must be of value when added to the tools in one's station. I'm very interested. I no longer buy a car on the basis of a sales brochure and also want to know as much as possible when buying test equipment.
>
>Thanks again for your very helpful feedback.
>
>Bob — KK5R







Re: Simple UBITX Test Set

 

Bob,

you have to use the tuning knob to scroll through the menu, set the center freq and span.
then highlight plot and press the encoder knob to start the plot. In the older version it a
single scan but newer one does continuos scan just like an expensive spectrum analyser.

If I need to measure the freq, then I would feed the signal and do a sweep. Then center
the cursor on the peak and get a reading.. not very accurate but will do on many an
occasion. Error will be a few KHz.. the width of the IF filter in the antuino.

It works on VHF with no problems and is usable to 500MHz.

The main thing is hackable.. change what you want in hardware and software.

Raj

P.S we have an antuino group on groups.io

At 26/10/2020, you wrote:
Thanks, Raj. I'm still wondering if you press the word "plot" on the screen or if there's a button on the case that is not visible. If you press "plot" on the screen, it must be sensitive to the finger's capacitance and goes to the plotting the signal. Regardless, I'm wondering if you "measure [frequency] indirectly in power mode," is it very accurate? Considering the many decimal places shown on the screen, I'm guessing it's pretty accurate. I see it's measuring in the HF range but does it also work at 2M for measuring, for example, the SWR of an antenna?

It's a box full of capabilities and must be of value when added to the tools in one's station. I'm very interested. I no longer buy a car on the basis of a sales brochure and also want to know as much as possible when buying test equipment.

Thanks again for your very helpful feedback.

Bob — KK5R


Re: Electronic encoder (Not rotary)

Gerard
 

Evan ,Bob,
Evan, I checked the earth ground  of the oscilloscope, it’s well grounded. For the power outlets, both are on the same connection.
I checked my home made power supply I built. I see actually  the radiator screwed on the chassis, the - Power is connected on it, so also on the ground of the 220V which explains the phenomenon with the oscilloscope.
I looked on the net, in fact with a power supply with a transformer, it is considered that this one makes the "galvanic" isolation. In these cases, my -Power may not need to be connected to the ground chassis, so to the ground 220v.
On your Ubitx, in theory you must use an external 12v power supply.
I thing you use this type This is called a double isolation power supply, so 2 wires for power, so no earth.
I have a cutting-out power supply from an old sattelite receiver, I’ll run a test with it to see...
see picture before power was put in the chassis.
Radiotor is connecting on -Power under the pcb with screws.
Nb: I have implanted on the power supply, a temperature sensor and the mounting that goes with it, to avoid that the fan does not run constantly. it works very well. see >>> fan Ubitx (Little CI)

for conclusion, i think an expert will said us, that to do exactly.
cdt


Re: Simple UBITX Test Set

Tom, wb6b
 

On Sun, Oct 25, 2020 at 05:34 PM, Jerry Gaffke wrote:
They also have this for $3.99, if you can wait for a boat from China:
Jerry,

Thanks for pointing those out. I just ordered some for my parts supply. Looks like the price is a 50% off promo price. 
For just a little more in shipping, less Than $0.50, it can ship Banggood Express, that is supposedly faster than Air. Still 15-20 days though.

Of course, I ended up buying some other things like a $1.99 stereo audio amp board and an 8 relay board (Might be good for switching between several pre-tuned matching networks at my antenna. A cheap remote "auto" match for multi band operation on one antenna.) And a tiny OLED display module to remind me that bigger displays are easier to read. 

On the subject of the test set. Would it be possible to add some jumper plugs to break the circuits at critical points or jumper across parts of the circuits and test points to the uBitx and produce a sketch that could be loaded into the Raduino for the express purpose of alignment and troubleshooting, assuming the uBitx is mostly functional. The idea would be to allow the built-in Raduino to be a signal generator for one section of the uBitx at a time, and possibility use a simple DVM and a RF detector probe to verify passband and centering of filters and such. You may still want an accurate signal source to verify the final frequency calibration. That could just be a simple xtal oscillator. 

Tom, wb6b


V7 Suggestion

Bob Lunsford
 

I know that programming is limited to code limits but this would be a nice V7 attribute, to me anyway...

When going to Split, an option on the screen would be "A = B" or, in other words, the operating frequency could be copied to VFO "B" in case you only wanted move the second/transmit VFO only a small distance. I normally leave mine at some AM Broadcast frequency so I can go to a broadcast station almost instantaneously but this would give the option to go immediately to the VFO "A" frequency where it could be used for transmitting in VFO "B" while allowing the operator to tune in a station better, for example, while not moving the transmit frequency. I know that RIT can do the same but this would help not make the mistake of leaving the RIT engaged and also give more flexibility on receive.

When selecting Split, then, one could put the two VFO's on the same frequency and not have to dial in the same frequency of VFO "A"  which for me would be a saving of time. The code would only refer to another line where the frequency of VFO "A" is listed and would "probably" only require one line of additional code. (Don't quote me, I'm not a code writer...)

Bob — KK5R


Re: Simple UBITX Test Set

Bob Lunsford
 

Thanks, Raj. I'm still wondering if you press the word "plot" on the screen or if there's a button on the case that is not visible. If you press "plot" on the screen, it must be sensitive to the finger's capacitance and goes to the plotting the signal. Regardless, I'm wondering if you "measure [frequency] indirectly in power mode," is it very accurate? Considering the many decimal places shown on the screen, I'm guessing it's pretty accurate. I see it's measuring in the HF range but does it also work at 2M for measuring, for example, the SWR of an antenna?

It's a box full of capabilities and must be of value when added to the tools in one's station. I'm very interested. I no longer buy a car on the basis of a sales brochure and also want to know as much as possible when buying test equipment.

Thanks again for your very helpful feedback.

Bob — KK5R

On Monday, October 26, 2020, 1:12:05 AM EDT, Raj vu2zap <rajendrakumargg@...> wrote:


Bob,

It has SMA connectors two of them. One output and one input.

When you press plot, it plots on its own screen. No PC required. No touch screen.

No freq. counter but you can measure indirectly in power mode.

It comes fully complete in a metal box..

Raj


At 26/10/2020, you wrote:
This looks very interesting. One specification was not shown, however. In the Antuino write-up, you show it reading the SWR but also shown is the frequency readout. It then acts as a frequency counter, right? How accurate is it in that mode?

I'm considering getting one. Is it a kit or built and in a box? What kind of connectors does it have? Also, you mention in the write-up "by clicking on the Plot button" so does this mean that the unit works with a computer or is it possibly a touch-screen so you can tap the screen like with the V6...?

Hope you do not mind my questions.

Bob — KK5R

On Sunday, October 25, 2020, 11:30:46 PM EDT, Ashhar Farhan <farhanbox@...> wrote:


Jerry,
We do sell a test set, it is called Antunio!
Except for the dummy load, the Antuino is really all you need to align any HF radio set. It can be used to test any radio well into UHF range as well as individual filters, including duplexers, amplifiers, mixers, etc. It can also measure input or output impedance match, antenna vswr and even act as a vtvm.
End of the plug.
- f



On Mon 26 Oct, 2020, 4:02 AM Jerry Gaffke via groups.io, <jgaffke=yahoo.com@groups.io > wrote:
Page 6 has the test set Allen mentioned:  https://www.qrparci.org/qqsample/qqsample.pdf

A 7.050mhz crystal oscillator with an attenuator suitable for checking out a 40m receiver.
And a 50 ohm dummy load for the transmitter.

That would definitely be better than nothing at all for debugging a uBitx,
but hardly sufficient.

Could tell if the receiver works on 40m.
And could drive the uBitx power amp to check it out on 40m as well
if you do away with the cute trick of using one connector for
both signal generator and dummy load.

Jerry, KE7ER


On Sun, Oct 25, 2020 at 02:25 PM, Allen Hill wrote:
Check out the TX/RX test circuit in January 2015 issue of QRP Quarterly on page 6 (shared by K1MBO).
Very simple and low cost.
This particular issue is the free download from their website.

QRPARCI.ORG

73
KI4QCK


Re: Simple UBITX Test Set

 

Bob,

It has SMA connectors two of them. One output and one input.

When you press plot, it plots on its own screen. No PC required. No touch screen.

No freq. counter but you can measure indirectly in power mode.

It comes fully complete in a metal box..

Raj


At 26/10/2020, you wrote:
This looks very interesting. One specification was not shown, however. In the Antuino write-up, you show it reading the SWR but also shown is the frequency readout. It then acts as a frequency counter, right? How accurate is it in that mode?

I'm considering getting one. Is it a kit or built and in a box? What kind of connectors does it have? Also, you mention in the write-up "by clicking on the Plot button" so does this mean that the unit works with a computer or is it possibly a touch-screen so you can tap the screen like with the V6...?

Hope you do not mind my questions.

Bob — KK5R

On Sunday, October 25, 2020, 11:30:46 PM EDT, Ashhar Farhan <farhanbox@...> wrote:


Jerry,
We do sell a test set, it is called Antunio!
Except for the dummy load, the Antuino is really all you need to align any HF radio set. It can be used to test any radio well into UHF range as well as individual filters, including duplexers, amplifiers, mixers, etc. It can also measure input or output impedance match, antenna vswr and even act as a vtvm.
End of the plug.
- f



On Mon 26 Oct, 2020, 4:02 AM Jerry Gaffke via groups.io, <jgaffke=yahoo.com@groups.io > wrote:
Page 6 has the test set Allen mentioned:  https://www.qrparci.org/qqsample/qqsample.pdf

A 7.050mhz crystal oscillator with an attenuator suitable for checking out a 40m receiver.
And a 50 ohm dummy load for the transmitter.

That would definitely be better than nothing at all for debugging a uBitx,
but hardly sufficient.

Could tell if the receiver works on 40m.
And could drive the uBitx power amp to check it out on 40m as well
if you do away with the cute trick of using one connector for
both signal generator and dummy load.

Jerry, KE7ER


On Sun, Oct 25, 2020 at 02:25 PM, Allen Hill wrote:
Check out the TX/RX test circuit in January 2015 issue of QRP Quarterly on page 6 (shared by K1MBO).
Very simple and low cost.
This particular issue is the free download from their website.

QRPARCI.ORG

73
KI4QCK


Re: Simple UBITX Test Set

Bob Lunsford
 

This looks very interesting. One specification was not shown, however. In the Antuino write-up, you show it reading the SWR but also shown is the frequency readout. It then acts as a frequency counter, right? How accurate is it in that mode?

I'm considering getting one. Is it a kit or built and in a box? What kind of connectors does it have? Also, you mention in the write-up "by clicking on the Plot button" so does this mean that the unit works with a computer or is it possibly a touch-screen so you can tap the screen like with the V6...?

Hope you do not mind my questions.

Bob — KK5R

On Sunday, October 25, 2020, 11:30:46 PM EDT, Ashhar Farhan <farhanbox@...> wrote:


Jerry,
We do sell a test set, it is called Antunio!
Except for the dummy load, the Antuino is really all you need to align any HF radio set. It can be used to test any radio well into UHF range as well as individual filters, including duplexers, amplifiers, mixers, etc. It can also measure input or output impedance match, antenna vswr and even act as a vtvm.
End of the plug.
- f



On Mon 26 Oct, 2020, 4:02 AM Jerry Gaffke via groups.io, <jgaffke=yahoo.com@groups.io> wrote:
Page 6 has the test set Allen mentioned:  https://www.qrparci.org/qqsample/qqsample.pdf

A 7.050mhz crystal oscillator with an attenuator suitable for checking out a 40m receiver.
And a 50 ohm dummy load for the transmitter.

That would definitely be better than nothing at all for debugging a uBitx,
but hardly sufficient.

Could tell if the receiver works on 40m.
And could drive the uBitx power amp to check it out on 40m as well
if you do away with the cute trick of using one connector for
both signal generator and dummy load.

Jerry, KE7ER


On Sun, Oct 25, 2020 at 02:25 PM, Allen Hill wrote:
Check out the TX/RX test circuit in January 2015 issue of QRP Quarterly on page 6 (shared by K1MBO).
Very simple and low cost.
This particular issue is the free download from their website. 

QRPARCI.ORG

73
KI4QCK


Re: Simple UBITX Test Set

Ashhar Farhan
 

Jerry,
We do sell a test set, it is called Antunio!
Except for the dummy load, the Antuino is really all you need to align any HF radio set. It can be used to test any radio well into UHF range as well as individual filters, including duplexers, amplifiers, mixers, etc. It can also measure input or output impedance match, antenna vswr and even act as a vtvm.
End of the plug.
- f



On Mon 26 Oct, 2020, 4:02 AM Jerry Gaffke via groups.io, <jgaffke=yahoo.com@groups.io> wrote:
Page 6 has the test set Allen mentioned:  https://www.qrparci.org/qqsample/qqsample.pdf

A 7.050mhz crystal oscillator with an attenuator suitable for checking out a 40m receiver.
And a 50 ohm dummy load for the transmitter.

That would definitely be better than nothing at all for debugging a uBitx,
but hardly sufficient.

Could tell if the receiver works on 40m.
And could drive the uBitx power amp to check it out on 40m as well
if you do away with the cute trick of using one connector for
both signal generator and dummy load.

Jerry, KE7ER


On Sun, Oct 25, 2020 at 02:25 PM, Allen Hill wrote:
Check out the TX/RX test circuit in January 2015 issue of QRP Quarterly on page 6 (shared by K1MBO).
Very simple and low cost.
This particular issue is the free download from their website. 

QRPARCI.ORG

73
KI4QCK


Re: Simple UBITX Test Set

Jerry Gaffke
 

I think new board designs should consider the Si5351 in a QFN-20 package.
Last time I looked, the MSOP-10 package that everybody uses now (including the Raduino)
was around $1, all the QFN-20 variants were $10.  But the QFN-20's are now $2 on Mouser.

The QFN-20 has the following advantages over the usual MSOP-10:
  8 outputs instead of 3.   So could have signal generator outputs for testing on the uBitx.
  4 VDDO pins to supply power to the outputs instead of 1, reducing crosstalk
 
In the QFN-20 packages, you have the following choices:
  The Si5351A-B-GM has an A0 pin to select between a couple i2c chip addresses
  The Si5351B-B-GM has a VC control pin into a digital VCXO at the PLLB position.
  The Si5351C-B-GM has a CLKIN pin that takes an external reference between 10mhz and 100mhz,
    perhaps from a GPS module.  The A and B parts are spec'd only for use with a 25 to 27mhz crystals.

The SSEN pin (spread spectrum enable on Si5351A and Si5351B) is likely not of much interest to a ham.
The INTR pin (interrupt the host on loss of lock,  Si5351C only) might be of interest, 

Unfortunately, the QFN-20 has the same 0.5mm pin pitch as the MSOP-10, which is pretty tight.
The QFN-20 only has one ground pad, which is the large center square pad, could be accommodated
by drilling a large plated through hole, and soldering that big pad from the back of the board.
Or you could use solder paste and a toaster oven.

AN619 for the Si5351 says max VCO is 900mhz, output msynth of 4, so that suggests a max output of 225mhz.
But the datasheet does show 200mhz max as KE1L states, which is pretty fast for a CMOS output buffer.
Hans Summers, G0UPL of QRP-Labs found he could press the internal VCO up toward 1200mhz
to give an output of around 290mhz before it pooped out. 
Some versions of the Nanovna firmware try to run it at 300mhz max, but not all Si5351 parts can do this.

Hans found he could accurately lock two of the outputs in quadrature down to about 3.5mhz.

Some good discussions of the nitty gritty details around the Si5351:
https://groups.io/g/BITX20/message/51935
https://groups.io/g/qrptech/topic/53562857#324

Jerry, KE7ER


Re: Electronic Test Device

Bob Lunsford
 

This has some promise if modified for use with our transceivers. However, it also shows in the circuit some possibilities for a simple design for a test oscillator. For example, R1 & R2 in the schematic could be a simple 1K or 500 Ohm pot with the wiper going to the output jack.

Bob — KK5R


Inline image



Re: memory manager

Evan Hand
 

N8KZ worked out a spreadsheet to use with KD8CEC Memory Manager for calibration.

https://groups.io/g/BITX20/message/72183

I have not tried it, just passing on the information.

73
Evan
AC9TU


Re: Electronic encoder (Not rotary)

Bob Lunsford
 

You are right. ALL grounds must be tied back to the service ground [rod]. Merely driving a ground rod in the ground near the radio room and tying everything to it is not per Code. A run of copper wire of the prescribed wire size must be run from that radio room ground back to the service ground to be acceptable to the Code. This is per a friend who designs large industry electrical systems.

Bob — KK5R

On Sunday, October 25, 2020, 10:13:17 PM EDT, Evan Hand <elhandjr@...> wrote:


Gerard,
The correct grounding depends on the intent.  For safety, all grounds are to be at the same level.  A potential difference can be dangerous.  In large buildings that requires running new ground rods in the immediate area and tying all power ground connections to that grid.  Extrapolating that to your case, all should be at the same ground potential by bonding altogether.   I suspect that the oscilloscope is not grounded to the same point as the mains to the uBITX.  You can measure that with a good DMM on AC volts.

For the RF side of things, it is important to have a good solid earth ground close to the antenna and to have that ground also run into the shack.

Above are what I remember from my industrial power days.
73
Evan
AC9TU

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