After watching the video in the first link below, I think this is a primo way to go. The video is excellent, in fact, at least in my opinion. However, this generates another question: If I install the AGC board from kit-projects, does it need to be place in the input path to help the AGC board work better or as designed? If it can go on the output path, the added filter board can be placed just to the left of the AGC board but it in the input path, then it has to be inserted some other way such as mounted vertically in the diagonal land going between the mounted AGC board and the relay just to the upper right of the AGC board.
Any thoughts on this? Two of the AGC boards are due in here on Tuesday, one for me and one for my son in Sacramento. The video at nearly the end shows a small, doable board that could be mounted vertically with one lead directly to the board and the other from the filter board down to the signal path (assuming the land is cut between the two connections). I hope I have created an easy-to-understand visual image from my mind to your.
Bob ¡ª KK5R
On Sunday, November 15, 2020, 7:45:25 AM EST, Gary Rindfuss <rindfussg@...> wrote:
Kit-projects sells a uBitx broadcast filter kit on the web page where they sell their agc board. It requires you to wind 3 tiny torroids but it works well.? There is another design you can build yourself that uses axial inductors it works well too. I have used one of each. The info on that is here:
On Sun, Nov 15, 2020, 5:28 AM Gerard < kabupos@...> wrote: Hello,
The other time when I did a search on E.. Y, with the keyword Ubitx, I came across this.
A filter, but I don¡¯t know any more...
cdt
|
Good suggestion, Evan. I just called my son and he said he's too busy at the moment to go back and check but I forwarded your message to him to check this. I have heard that some super-duper toasters can also generate RF signals. The FCC apparently hasn't addressed this kind of unwanted signal generation ¡ª yet!
I also suggested to him that when he hears such signals to disconnect the antenna to at least get an idea if it's coming in as a transmitted signal but if a super-strong carrier is being generated at some unknown frequency, it could be some non-linear element in the signal path that is generating the harmonics (assuming they are harmonics) but this just helps isolate the signal/s from being generated in the V6 itself.
Let's hope that disconnecting the antenna is a useful part of the diagnosis. However, this still does not eliminate the possibility of it coming in over the power lines, either generated in the grid or more locally.
Mysteries have so many possibilities.
I'll let the forum know whatever my son may find out. He's a good ham with years of experience as a ham (since the mid-70's) but works as a contractor supervisor in Sacramento, CA and does not have all that much time for hobbying these days.
Bob ¡ª KK5R
On Sunday, November 15, 2020, 4:26:26 AM EST, Evan Hand <elhandjr@...> wrote:
Bob,
I would agree with Gary's suggestion to add the Broadcast Band high pass filter.??
I had a similar experience to your son's one afternoon.? All of a sudden I had birdies all over the band.? Turned out that my wife had started our new high-efficiency washer at that time.? When the washer stopped (30+ minutes later), the noise went away.? It could be that there is an appliance being run in the area that is generating a lot of noise.? Switching to battery power did not eliminate the problem so it was not just power line related.
I would have him try again and see if the problem persists.
73
Evan
AC9TU
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Re: Follow-up Antuino question
On Sun, Nov 15, 2020 at 01:43 PM, Arv Evans wrote:
Since H&P only corrects HF frequency during each cycle of the LF clock
there is a possibility of overshoot if the delta-C is too large.?
Hi Arv, This is good information you supplied while I was slowly working on my last message. So, the Huff and Puff method may introduce a constantly varying low frequency phase shift. That makes sense. In Hans' design he refers to using Huff and Puff in his xtal oven frequency adjustment method. But, because it uses a full microprocessor to generate the up and down voltage pulses, it may really be more of a sample and hold arrangement as a DAC. Not limited to correcting only when the phase delta reaches a certain point. I'll need to see what he did in his software. Tom, wb6b
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Re: Follow-up Antuino question
toggle quoted message
Show quoted text
On Sun, Nov 15, 2020 at 4:13 AM Gareth Evans via <headstone255= [email protected]> wrote: Bore da, Arv!
Sut dych chi?
(Dw i'n dysgu siarad Cymraeg!)
Related? There are teeming millions of we of the Evans clan!
On Sat, Nov 14, 2020 at 09:56 PM, Arv Evans wrote:
> Gareth Evans
>
> We have the same last name...are we related?? ?8-)
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Re: Follow-up Antuino question
This is an clever way to use an AVR chip to stabilize a 10mhz oscillator without a pre-scalier. Just use the 10mhz oscillator as the main CPU clock.
Here is a GPS stabilized frequency reference by Hans doing that.
Faster AVR chips above 20mhz could also work, but this simpler and provides the microprocessor with a very accurate clock, to boot.
If I use a similar design to making a GPS disciplined frequency standard, I might use a processor chip that has a digital to analog converter to do the crystal oscillator fine tuning. But the huff and puff is a DAC (a slow one) and may be as good as a "real" DAC for this application. Probably would not try to use PWM as a DAC in this case, as there may be a residual ripple at the PWM frequency.?
Somewhere I have an old crystal oven similar to what Hans used in his project. I'll need to see if it has a voltage input to adjust the frequency. Bought the xtal oven 20 years ago for a frequency counter project. So, after only 20 years the oven may finally end up in a project.?
If the oven is fixed frequency, but has a hole that can be uncovered to re-calibrate the frequency, maybe I'll move it so it is at the correct frequency is at a lower temperature than the thermostat setting in the oven and vary the temperature of the oven by controlling the heater voltage to keep it on track this the GPS 1 PPS reference. But, otherwise use Hans' design.?
Off to the garage to rummage through the many old boxes of junk (fine scientific radio apparatus) that has somehow resisted the sands of time.
Tom, wb6b
?
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Re: Follow-up Antuino question
Jerry
I suppose that in a very broad description one could say that H&P is a PLL. Just depends on how deep one wants to go into what the tiny gears are? doing deep inside.??
Arv ?
It's been lots of years since I have looked at huff-and-puff oscillator stabilization.
What I wrote in that last post is incorrect, there's more going on here.
Jerry, KE7ER
On Sat, Nov 14, 2020 at 06:08 PM, Jerry Gaffke wrote:
This may be an alternate way of looking at what you are proposing.
I suspect you are describing a phase-locked-loop.
And that yes, you have tried it.
There's a phase-frequency-detector inside the Si5351.
The VCO in the Si5351 can be pulled anywhere between 600 and 900 mhz
(and quite a bit beyond, actually).
But if instead of that VCO we have a VFO that is first manually tuned very near the
target frequency, the error detection will have far less work to do.?
And the output will have far less jitter.
Jerry, KE7ER
?
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Re: Follow-up Antuino question
Tom, wb6b
Using H&P to "stabilize"? a 10 MHz VFO or crystal oscillator with a low? frequency clock derived for GPS or WWV sounds interesting.? Way back? when we were playing with H&P, I did something similar but used the 60 Hz? mains as a reference clock.? That proved that using the mains as a? reference is not really a good idea.? Large current loads going?on and off? cause significant frequency shifts in mains.? I even visited a local mains power? hydro-electric generating station to see how mains frequency is controlled. They have a flow control system that uses a GPS clock for a frequency? reference.? This allows the mains frequency to move up or down by several? Hz but still maintains an average 60 Hz so our clocks are usually accurate.
Since H&P only corrects HF frequency during each cycle of the LF clock there is a possibility of overshoot if the delta-C is too large.? This stabilizes? for average frequency but at the same time it can introduce phase and? frequency jitter at the LF rate.
Very?low LF clock frequencies are interesting because the sampling rate can? become so slow that it actually allows frequency drift to occur, between? phase comparison samples.
It is possible to run the LF clock much faster. There are some examples of? this FAST H&P on Hans web site.
Your idea of H&P stabilization with an LF clock derived from GPS or WWV? is intriguing, but remember that H&P is never really stable.? It just holds? the HF part very close to some multiple of the LF clock.? Think of H&P as a? frequency multiplier that holds an HF signal close to some multiple of the LF? reference frequency.? It has jitter (frequency shift) but that is very slow and? is based on the LF reference frequency.
Arv _._
On Sat, Nov 14, 2020 at 8:27 PM Tom, wb6b < wb6b@...> wrote: On Sat, Nov 14, 2020 at 06:08 PM, Jerry Gaffke wrote:
But if instead of that VCO we have a VFO that is first manually tuned very near the
target frequency,
So it seems the Huff and Puff method is for providing the final little bit of frequency stabilization to a VFO that is already adjusted to oscillate very close to the desired frequency. Would the Huff and Puff method be one of the preferred ways to fine adjust the frequency of a 10mhz crystal oscillator to make a DIY GPS disciplined frequency reference?
Tom, wb6b
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Re: S-Meter Pin A7 Location V6
Hi Mick,
? ?I received a V6.2 ?BITX about 6 weeks ago and confirm that my 'digital' connector looks like yours with the wires cut.
? ?You can use a small probe or small straight/minus screwdriver to push the tab on the side of the connector to remove/replace the cut wire on your existing connector.
? ? On the V6 radios, A7 from the Arduino comes out on pin 8 of the connector, same as my V3 and Evan's photo.? Here's the Raduino schematic for reference.? You're working on the 'mate' for the 'Controls1' connector:??
? ?Cheers and 73, Andy
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On Sun, Nov 15, 2020 at 03:23 PM, Mick wrote:
Hello Evan
You're becoming my mentor - very much appreciated.
I assume then that the numbering of that plug starts at A-Zero one end (Black) though to A7 Purple at the other end.
My encoder arrived pre-wired with the purple, blue, green and orange wires cut off - please see photo.
The kit arrived with spare wired plugs though, so it's easier if I use the spare 8-way plug and just re-wire the encoder.
That leaves me with the other wires including the purple A7 wire to use as I wish.
If there is someone with a Version 6 ubitx I would appreciate confirmation, though it looks spot on Evan.
Thanks Evan, all the best? 73? Mick M0GWD
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Re: S-Meter Pin A7 Location V6
Hello Evan You're becoming my mentor - very much appreciated. I assume then that the numbering of that plug starts at A-Zero one end (Black) though to A7 Purple at the other end. My encoder arrived pre-wired with the purple, blue, green and orange wires cut off - please see photo. The kit arrived with spare wired plugs though, so it's easier if I use the spare 8-way plug and just re-wire the encoder. That leaves me with the other wires including the purple A7 wire to use as I wish. If there is someone with a Version 6 ubitx I would appreciate confirmation, though it looks spot on Evan. Thanks Evan, all the best? 73? Mick M0GWD 
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Re: Follow-up Antuino question
H&P is not a phase locked loop in the sense that we usually consider it.?? There is no "lock" situation involved.? As Farhan mentioned, H&P continuously? detects whether one edge of an HF cycle leads or follows an edge of an LF? reference cycle.? A single D-type FF is used as a comparator to generate a steering? voltage with a relatively long time constant until the next edge comparison happens.?? This occurs?at the LF rate.? The FF is always flipping back and forth at the LF rate unless an edge match keeps it from flipping or flopping.? One of the "Q"? outputs of the FF drives the steering voltage.? If it drives off frequency instead? of on-frequency you only need to use the opposite 'Q' output to change the? steering voltage so it tunes the other direction.? This fact that the correction is only? applied at the?LF rate is what makes it also control the tuning step size.
There are several other ways to implement H&P.? I have not mentioned them? here but they are covered in the QRP-labs web page section on H&P stabilizers.
It is also possible to count VFO frequency with a PIC or pre-scaled arduino input and use the processor to generate scaled steering voltage for either stabilization? and/or tuning of the VFO frequency.? While this is not H&P it is also relatively? easy to implement if you can handle a bit of programming.? It is another way? to get linear VFO output over the VFO tuning range, or over some translated? range.? If you measure both BFO and VFO the microprocessor can be made? to display actual frequency or actual frequency with calculated offsets for? various transmission or receive modes.
Arv _._
This may be an alternate way of looking at what you are proposing.
I suspect you are describing a phase-locked-loop.
And that yes, you have tried it.
There's a phase-frequency-detector inside the Si5351.
The VCO in the Si5351 can be pulled anywhere between 600 and 900 mhz
(and quite a bit beyond, actually).
But if instead of that VCO we have a VFO that is first manually tuned very near the
target frequency, the error detection will have far less work to do.?
And the output will have far less jitter.
Jerry, KE7ER
On Sat, Nov 14, 2020 at 05:39 PM, Ashhar Farhan wrote:
I was expecting Arv to write in about H&P schemes. Between him and Hans, there is all we know about how this scheme works.
The challenge of Huff and Puff is that it needs a very stable oscillator to begin with. It should have very minimal wobble (short term drift). The drift between two correction pulses should be less than its step size. That is not difficult to obtain.
The inherent drawback of H&P is that the oscillator is always being pushed up or down from the central frequency between two cycles. This can have a disastrous effect on digital modes.
There is probably another way to fix this. It is to use two flip flops as parallel mixers, each is fed the clock pulse that is 90 degrees out of phase from the other (imagine it to be a phasing receiver). Noe, the combined DC output of the two will indicate if we have drifted above, below or stayed on the frequency. I haven't tried this, but I am guessing that this will work. In the professional literature it is called a phase frequency detector.
- f
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Re: Follow-up Antuino question
If you have a uBitx and wish to experiment with sine waves instead of square,
perhaps add a low pass filter to each of the three Si5351 clocks.
The VFO at CLK2 would need to select from multiple filters if targeting?
more than one band.?
I'm assuming we select USB vs LSB by moving the BFO a few khz
instead of moving the second LO at CLK1 by 11+11=22mhz.
I'm not yet convinced that a sine wave will give significantly better
reception than a square wave
Jerry, KE7ER
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Show quoted text
On Sun, Nov 15, 2020 at 11:23 AM, Arv Evans wrote:
My comments were in response to someone's complaint about Si5351a outputs?
being square waves.? With H&P the VFO can be a linear output.??
?
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Re: Follow-up Antuino question
Farhan
It is possible to reverse the H&P design by dividing the VFO down to LF and letting? it be synched with a very stable HF reference (WWVB or GPS or TCO).? Result is? the same when derived steering voltage is then applied to the HF part of the VFO.
My comments were in response to someone's complaint about Si5351a outputs? being square waves.? With H&P the VFO can be a linear output.??
Arv _._
On Sat, Nov 14, 2020 at 6:39 PM Ashhar Farhan < farhanbox@...> wrote: I was expecting Arv to write in about H&P schemes. Between him and Hans, there is all we know about how this scheme works. The challenge of Huff and Puff is that it needs a very stable oscillator to begin with. It should have very minimal wobble (short term drift). The drift between two correction pulses should be less than its step size. That is not difficult to obtain. The inherent drawback of H&P is that the oscillator is always being pushed up or down from the central frequency between two cycles. This can have a disastrous effect on digital modes. There is probably another way to fix this. It is to use two flip flops as parallel mixers, each is fed the clock pulse that is 90 degrees out of phase from the other (imagine it to be a phasing receiver). Noe, the combined DC output of the two will indicate if we have drifted above, below or stayed on the frequency. I haven't tried this, but I am guessing that this will work. In the professional literature it is called a phase frequency detector. - f
This H&P jitter may not matter much if it isn't very frequent.
If it's a second or two between updates and the frequency slews
at a reasonable rate after an update, the "jitter" should be
no more objectionable than when manually making slight adjustments.
Jerry, KE7ER
On Sat, Nov 14, 2020 at 01:56 PM, Arv Evans wrote:
H&P stabilization is interesting because by default it sets the tuning?
step size as well as holding frequency drift to around 1 Hz, sometimes?
less.? However it does introduce its own type of slow jitter.?
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Re: For Sale : uBITx 6.0 full kit
Sold.?
73
--
Jean-Fran?ois M¨¦nard?
Jeff | VA2SS
Envoy¨¦ ¨¤ partir de mon appareil mobile.?
Sent from my mobile device.
|
Re: Follow-up Antuino question
There are lots of variants to doing a Huff and Puff.
EMRFD shows a very basic example on pages 4.5 and 4.7.
In this design, the frequency is constantly bouncing somewhere
between two frequencies that are 40hz apart.?
If the VFO is stable enough, one could slow down the loop filter between
the Huff and Puff detector and the varactor diode in the VFO, such that it
takes a minute or two (instead of under a second) before a change in
VFO frequency causes a significant change to the varactor correction voltage.
This would make the output frequency much more stable, but would take some time
to settle in after you manually tune the VFO.
The advantage of Huff and Puff is that you can make the VFO lock to
discrete steps without having to reprogram the dividers with each frequency change
as you would on a standard PLL.? Where a standard PLL will lock only to one specific?
frequency, a Huff and Puff might lock to any frequency that is an even multiple?
of 100 Hz. I doubt you could borrow a phase-frequency-detector directly
from a PLL design and have it work in a Huff and Puff.
Tom would almost certainly be better off with a standard PLL design
for his GPS stabilized crystal reference oscillator.
Huff and Puff isn't used a lot these days.? If you have a microcontroller in
the rig (such as the Nano on the Raduino), it's fairly easy to program the dividers
on a PLL device.? This will generally give a more stable output.? A PLL can allow
more resolution (much smaller steps) when choosing the output frequency.
Take the above with a large grain of salt.
I am no expert on either Huff and Puff or PLL's.
Jerry, KE7ER
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Show quoted text
On Sat, Nov 14, 2020 at 08:33 PM, Jerry Gaffke wrote:
It's been lots of years since I have looked at huff-and-puff oscillator stabilization.
What I wrote in that last post is incorrect, there's more going on here.
Jerry, KE7ER
Hide quoted text
?
On Sat, Nov 14, 2020 at 06:08 PM, Jerry Gaffke wrote:
This may be an alternate way of looking at what you are proposing.
I suspect you are describing a phase-locked-loop.
And that yes, you have tried it.
There's a phase-frequency-detector inside the Si5351.
The VCO in the Si5351 can be pulled anywhere between 600 and 900 mhz
(and quite a bit beyond, actually).
But if instead of that VCO we have a VFO that is first manually tuned very near the
target frequency, the error detection will have far less work to do.?
And the output will have far less jitter.
Jerry, KE7ER
?
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For Sale : uBITx 6.0 full kit
Hi,
I have for sale my uBITx 6.0 full kit for sale. I purchased it last spring. I just assembled it to make sure it was working, then it is now collecting dust on the shelf since that time.
I unfortunately not having enough time to spend with it that justify having one.
Items: uBITx 6.0 full kit (black enclosure), microphone, screen pencil, etc... see webpage for all included items
I would like to have 100$ USD + shipping via PayPal
Best 73.
--
Jean-Fran?ois M¨¦nard?
Jeff | VA2SS
Envoy¨¦ ¨¤ partir de mon appareil mobile.?
Sent from my mobile device.
|
Re: S-Meter Pin A7 Location V6
Mick, I do not have a v6 kit, so not sure about the following: A7 is the Purple wire coming off of the Raduino digital connector to goes to the encoder.? In one picture that I have seen of the encoder, the purple wire has been trimmed back.? You may need to pull that pin and insert another one crimped to a longer wire. Here is a picture from HFSignals that shows the encoder connector:  A7 is the purple wire that is unconnected, wrapped around the other wires. AGAIN, I do NOT have a v6, so you may want to wait for someone to post a picture of their uBITX. 73 Evan AC9TU
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S-Meter Pin A7 Location V6
Good afternoon all
I have just installed the kit-projects AGC board and read in the instructions to connect to pin A7 for the S-meter.
Please can someone confirm the location of pin A7?
Is it the pin 7 on the same header strip where I've connected the 4 wires that go the nextion display, or somewhere else?
An image showing pin A7 would be great if someone has one.
Many thanks
73
Mick M0GWD
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Richard,
The name of the group is BITX20, not uBITX.? It is really for homebrewing as well as the kits that came out of that effort.? Feel free to continue to post if you so choose.? We are all interested in the type of experimentation that you are doing.? I can speak for myself that I learn with all of the questions and answers on bidirectional transceiver work that is being done.
Have fun with the build!
73
Evan
AC9TU
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Evan, again thank you
I think this will be my last post on the subject as this is a uBITX group, not a Homebrew group.....
I think a *simple* fix involves both hardware and software.
Since I already have USB and LSB oscillators, I do not need the 57 / 33 MHz output of CLK1
I can change both these values to 27 MHz,? combine with the CLK2 in a mixer and put through a bandpass filter.
I will then have the correct IF? I need.
Since I will be using a Nextion, there will? be free pins on the Raduino / Nano.
I can put is some simple code to switch? on my USB or LSB oscillators.
I will also have to tweak the output filter code as I have 8 output filters, not 4.
Problem:? the rest of the CEC goodies will not be functional in my radio.? Thanks sadly OK
I may report back if successful, so others can play with their Raduinos as well.
Thanks a gain and best to all
Richard? VA3NDO
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I also used this on the antenna input for a while before I built my own filter. It worked ok. Definitly killed the AM interference. Their may have been some slight attenuation of the transmitted signal since its in both the Tx? and Rx path.? But I didn't notice it much.?
On Sun, Nov 15, 2020, 5:28 AM Gerard < kabupos@...> wrote: Hello,
The other time when I did a search on E.. Y, with the keyword Ubitx, I came across this.
A filter, but I don¡¯t know any more...
cdt
|
Bob Lunsford