Re: how to change arduino/si5351 output
Apparently, I can't git today.? I tried to make another pull-request
for Allard with just this one change, but every time I tried, it
kept getting mixed up with the existing pull request to swap
PTT_Sense and Spot, which he's already said he's not interested in.?
I'm still trying to figure that out.
Anyway.? For those who are comfortable with diff and patch, you'll
find my suggestion attached. I'm just adding somewhere near the top:
----- snip! -----
#define CLOCK_VFO (2)
----- snip! -----
Then using CLOCK_VFO everywhere si5351bx_setfreq() is called, which
appear to be around lines: 538, 543, 582, 584, and 1866.? I've made
some changes to my code, so your line numbers will be plus or minus
some from those.? But, look for something like this:
----- snip! -----
si5351bx_setfreq(2, [other stuff]
----- snip! -----
and change the "2" to "CLOCK_VFO" like:
----- snip! -----
si5351bx_setfreq(CLOCK_VFO, [same stuff]
----- snip! -----
That just makes which clock to use a "variable" (not really, but
we're splitting hairs in this context.)? If you need to change the
output to CLK1 for example, then change the #define to:
----- snip! -----
#define CLOCK_VFO (1)
----- snip! -----
Then recompile and upload.? Your Raduino will be outputting on CLK1
now.
-Mark
On 09/04/2017 02:41 PM, jrea79 via
Groups.Io wrote:
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Show quoted text
hi dale!
the si5351 remains at 40mVpp even when not connected on the
?bitx40
smitty,
can you please be more specific? but i'll try
thanks and 73!
jonathan/DV2NAH
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Re: Using a tuner with a Bitx40
Well, Ash. Yours is an alternative, and one that is a whole lot cheaper.
But I don't think it is "better". The LDG Z11 is a darn good tuner.
Both methods work well.
john
AD5YE
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Wiring/layout (was Re: New pull-request for amunters code)
A point similar to Mark's that I've noted: PTT placement. I'd venture most cabinet/housing layouts will have the PTT closely associated (if not integral with) the Mic connector/socket. Myself, I have a wire draped across the PCB from the PTT connector to the Mic connector, then intertwined (twisted) with the Mic wiring (from the as-provided Molex plug) to the (as-provided) 3.5mm stereo socket. I have PTT to Tip and Mic to Sleeve, and the companion Spkr socket similarly Spkr to Tip and Mic to Sleeve. This will end up as 2 sockets below/near the Vol control. PTT-and-Mic will work for a hand-mic along with Spkr/headphones for short overs (/ contesting?). and Spkr-and-Mic for a headset with separate (push-push toggle) PTT (mono plug?) for 'rag-chew' (or Key for CW?). Versatility and usability ... :)
So, something to consider for PCB layout of ubitx or further development?
73
Dex, ZL2DEX
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Re: limited dynamic range of the BITX40
Reducing that front end RF gain could well help.
But Henning is suggesting that there's more than 15 or 20 dB at stake here:
? > ?a dynamic range of 75 dB is possible, due to the audio preamp this range will be only 43.5 dB now!! We are loosing 31.5 dB of dynamic range!
I'm by no means an RF kind of guy. ?
But I like his argument, and I like the idea of a PIN diode attenuator for AGC between the crystal filter and modulator.
That NXP BAP64Q quad PIN diode device is $0.25 in quantity, $0.50 for a single unit from Mouser.
With that AGC in place perhaps we can leave the first RF amp as is, so the rx still works with a poor antenna.?
Jerry
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On Mon, Sep 4, 2017 at 01:12 pm, Ashhar Farhan wrote:
The bitx was sketched on a flight. I didnt know muchP about dynamic range. In retrospect, the rf amp severely compromises the dynamic range. Someone should measure the iip3 with and without the rf amp.
I thought of redoing the bitx design for Bitx40 but in the end, decided to stick to the original for it to be called a bitx.
It is a sum of many tradeoffs and lazy choices (like the LM386).
- f
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Re: how to change arduino/si5351 output
hi dale! the si5351 remains at 40mVpp even when not connected on the ?bitx40
smitty,
can you please be more specific? but i'll try
thanks and 73!
jonathan/DV2NAH
|
Re: limited dynamic range of the BITX40
Profuse thanks, Farhan! Despite those trade-offs, perhaps even because of them, the BITX concept, and the BITX40 kit, have been a 'shot in the arm' for Ham Radio! For myself, getting old and with limited finance (retiree), it has been a transition from VHF 'myopia' and an eye-opening education. The on-line community's discovery of the various 'shortcomings', and of the means of overcoming them, has been and remains a delight to this 'old fart'.
73
Dex, ZL2DEX
|
Re: New pull-request for amunters code
Mark,
Thanks for your suggestion - Understand your point to have all wires from
P1 go to the front panel, and wires from P3 to the main board. This would
certainly make wiring easier.
However please note I'm currently working on a next release v1.21 which
will have automatic keyer functionality.
For this we need yet another digital input. The "dit" contact will connect
to the existing "KEY" input (A1), the "dah" contact will connect to pin
D3. D3 is on connector P3, so we will then have yet another wire from P3
going to the front panel.
Once the keyer functionality works well, I'm planning to start a new
release cycle v2.xx which will have digital BFO. For this we will need
some extra modification and wiring which will anyway not be downward
compatible anymore to v1.xx
I believe v2 would be a good moment to rearrange the input/output pins for
easier wiring as you suggested.
For now, as long as we are still in v1.xx, I'd like to keep the pin layout
as is, so as to maintain downward compatibility.
73 Allard PE1NWL
|
Re: limited dynamic range of the BITX40
The bitx was sketched on a flight. I didnt know muchP about dynamic range. In retrospect, the rf amp severely compromises the dynamic range. Someone should measure the iip3 with and without the rf amp. I thought of redoing the bitx design for Bitx40 but in the end, decided to stick to the original for it to be called a bitx. It is a sum of many tradeoffs and lazy choices (like the LM386). - f
On 4 Sep 2017 10:11 pm, "Jerry Gaffke via Groups.Io" <jgaffke= [email protected]> wrote: I like the idea of a PIN attenuator between Q3 and C33.
Won't disturb the BPF.
The 4dB pad at R37,38,39 should help clean up impedance variations from the PIN attenuator into the demodulator.
Perhaps a single PIN diode is sufficient if Q3 can drive the varying load presented by the PIN without too much trouble.
The audio derived AGC control signal to the PIN attenuator should attack quickly, but hang around for milliseconds.
Delays through a 3khz crystal filter should be on the order of a few hundred microseconds.
I'd be surprised if that crystal filter delay made the AGC unstable when the attenuator is placed in front of the filter.
But then I'm often surprised.
Henning's insight that the audio pre-amp is severely limiting the receiver's dynamic range?
is well worth pursuing. ?
Here's an Avago app note on PIN diode attenuators: ?
And one from Skyworks: ?
An interesting part: ?
Jerry, KE7ER
?
On Mon, Sep 4, 2017 at 06:45 am, Henning Weddig wrote:
of course a RF attenautor (e.g. PIN diode in Pi configuration or even better using two diodes anti-series in the series lag and the other two in the parallel leg, see AVAGO app notes) will help.
BUT: please put this circuitry AFTER the xtal filter!!? It is of no good use to put it in front of the RF input. Not onnly because the xtal filter will give a? extra time delay which may and will cause instabilities in the closed control loop!!? ?
?
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Re: how to change arduino/si5351 output
When I checked my output from the si5351 I was seeing about 3 volts PP but this is without it hooked up to the BITX board. I suggest measuring it with it disconnected. The BITX will load this line down and you will only see about 40mv which may be normal. I was having birdies developing at 7.2mhz and I designed a tuned circuit at 4.8mhz using a toroid coil and 3 caps that brought the signal up to 5 v pp. It greatly improved the output sine wave shape and solved the interference problem. I think it has also improved the audio quality on receive and maybe the audio transmit. You may not need to change the output format on the raduino. Good luck, 73's Dale
On Mon, Sep 4, 2017 at 8:16 AM, Smitty, KR6ZY <mark-groupsio@...> wrote: I don't have the code in front of me, but look for a function near the top named something like "set_freq" Note that one of the parameters to that function is the channel number.
Then search the rest of the program for where that function is called. Note that the channel number parameter is always 2. Change that to which ever channel you intend to use instead: 1, or 0.?
Then recompile and upload. Let me know how it works for you!
-Mark On Sep 3, 2017, at 10:46 PM, jrea79 via Groups.Io < jrea79@...> wrote: hello guys!
i think i am having a problem on my si5351?
i am suspecting that it may have low output, not enough drive
it has only 40mVpp on LSB and zero on USB?
checking with a DMM, clk2 (pin6) ?has low resistance to ground
while clk1 and clk0 has high resistance to ground
I have zero programming skills,
how do I edit the sketch so that the output moves from clk2 to clk1?
btw, I am using Allard's V1.20.1
thanks and 73!
jonathan/DV2NAH
|
Re: VFO/BFO selecting outputs
Readers from the future! If you see this email but no replies, assume that it worked. :-D
It worked! I am now generating BFO from CLK0 and the BitX40 is receiving and transmitting just fine. However, when I set CLK0 to bfo_freq exactly, the IF filter was passing REALLY HIGH audio (about 1.5kHz high as we'll see).? So I adjusted bfo_freq down by 1.5kHz (after a bit of playing with it to find the right sound) which put the IF pass-band in the right place, but now the VFO dial was low by 1.5kHz? Huh? I have a working radio by keeping bfo_freq at its original value (11998000L) for the VFO frequency calculations to be correct, but setting the BFO frequency by subtracting out 1500 from the "bfo_freq" like so:
si5351bx_setfreq(0, bfo_freq-1500);
Anyone understand what's going on here?? I would expect any change in the BFO frequency to need to be applied to both the BFO and VFO calls to si5351bx_setfreq(). My intent is to add an IF shift function:? Use the A6, the one remaining analog input, with another voltage divider pot, to move the BFO/VFO +/- 500, maybe 1000Hz. I have this on my FT-920 and it can be really handy in a crowded band.
|
New pull-request for amunters code
I found the cabling much easier if I swap two pins in amunters' standard pinout, swapping PTT Sense and Spot. That makes everything from P1 go to the front panel, and everything from P3 go to the Radio board. PTT Sense is a digital input, so there's no need for it to use an Analog input pin.
Feedback/comments/questions/flames are welcome. :-)
-Mark
|
Re: VFO/BFO selecting outputs
Let's see how groups.io handles image attachments. :-)
This image shows:
- The now-socketed 12MHz crystal, my first attempt at injecting a DDS BFO. The additional lead length didn't seem to break anything. ?
- The BFO connector I added. It's turned a little bit so it can easily reach the trace going into the mixer. That blob of solder connects to the bit of trace I scraped solder mask off of.
- C106, the output coupling cap from the analog BFO, removed.
- R101 (lower right corner) removed, which removes power from the BFO.
- A 10k resistor (inside heat shrink) tied to C107 for the CW injection mod, as documented by amunter in his new software. (Unrelated to the DDS BFO mod.)
Does this help?
-Mark
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On Sep 4, 2017, at 9:59 AM, Smitty, KR6ZY <mark-groupsio@...> wrote:
How DID I? As in before? Or how am I now, as in after having read other peoples' success stories?
Before: I removed the crystal and injected CLK1 (not CLK0, but they should be equivalent) into the input of the amplifiers in the BFO. That didn't work at all: deaf receiver, birdies all over the place.
Now: I put a 2-pin header, ground pin in the "top" hole of the variable cap foot print that isn't being used, and the signal pin sticking out the side, soldered to a small section of the trace going into the mixer which I removed the solder mask.
I removed R101 to de-power the BFO circuit, and I also removed the coupling cap between the BFO and the mixer. I probably only needed to do one of these, but whatever.
Then I made a cable from RG-174 with the same 2-pin connectors that Farhhan uses on both sides. I have a stock of parts, so I just made a fresh cable, not reusing anything. There's one of these 2-pin connectors on the Raduino too.
If you do this, I encourage you to keep the polarity of the connectors the same as Farhhan uses; keep ground on the same side. It just makes it easier to not have to be critical on which cable goes where.
I have these mods made, but my laptop is borked so I haven't been able to reprogram the Raduino to enable the BFO yet. Working on that now.
-Mark
On Sep 4, 2017, at 9:09 AM, Vince Vielhaber <vev@...> wrote:
How did you couple the DDS (assuming it's CLK0) to the BitX?
Vince.
On 09/04/2017 11:55 AM, Smitty, KR6ZY wrote:
I'm looking to make the BFO-from-DDS mod too and got the
Deaf-RX-and-Birdies thing too. I was hoping you'd have some wisdom on
that. :-)
to be fair, I started this before joining this group and reading the
collected wisdom of many people who are WAY more experienced than I am,
so I tried removing the crystal and feeding CLK1 to the input of the
active section of the BFO, borrowing that idea from how the VFO is wired
up. I'll try injecting the DDS BFO directly into the mixer and see if
that solves my problems.
Readers from the future! If you see this email but no replies, assume
that it worked. :-D
--
Michigan VHF Corp.
|
Re: VFO/BFO selecting outputs
How DID I? As in before? Or how am I now, as in after having read other peoples' success stories?
Before: I removed the crystal and injected CLK1 (not CLK0, but they should be equivalent) into the input of the amplifiers in the BFO. That didn't work at all: deaf receiver, birdies all over the place.
Now: I put a 2-pin header, ground pin in the "top" hole of the variable cap foot print that isn't being used, and the signal pin sticking out the side, soldered to a small section of the trace going into the mixer which I removed the solder mask.
I removed R101 to de-power the BFO circuit, and I also removed the coupling cap between the BFO and the mixer. I probably only needed to do one of these, but whatever.
Then I made a cable from RG-174 with the same 2-pin connectors that Farhhan uses on both sides. I have a stock of parts, so I just made a fresh cable, not reusing anything. There's one of these 2-pin connectors on the Raduino too.
If you do this, I encourage you to keep the polarity of the connectors the same as Farhhan uses; keep ground on the same side. It just makes it easier to not have to be critical on which cable goes where.
I have these mods made, but my laptop is borked so I haven't been able to reprogram the Raduino to enable the BFO yet. Working on that now.
-Mark
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Show quoted text
On Sep 4, 2017, at 9:09 AM, Vince Vielhaber <vev@...> wrote:
How did you couple the DDS (assuming it's CLK0) to the BitX?
Vince.
On 09/04/2017 11:55 AM, Smitty, KR6ZY wrote:
I'm looking to make the BFO-from-DDS mod too and got the
Deaf-RX-and-Birdies thing too. I was hoping you'd have some wisdom on
that. :-)
to be fair, I started this before joining this group and reading the
collected wisdom of many people who are WAY more experienced than I am,
so I tried removing the crystal and feeding CLK1 to the input of the
active section of the BFO, borrowing that idea from how the VFO is wired
up. I'll try injecting the DDS BFO directly into the mixer and see if
that solves my problems.
Readers from the future! If you see this email but no replies, assume
that it worked. :-D
--
Michigan VHF Corp.
|
Re: limited dynamic range of the BITX40
I like the idea of a PIN attenuator between Q3 and C33.
Won't disturb the BPF.
The 4dB pad at R37,38,39 should help clean up impedance variations from the PIN attenuator into the demodulator.
Perhaps a single PIN diode is sufficient if Q3 can drive the varying load presented by the PIN without too much trouble.
The audio derived AGC control signal to the PIN attenuator should attack quickly, but hang around for milliseconds.
Delays through a 3khz crystal filter should be on the order of a few hundred microseconds.
I'd be surprised if that crystal filter delay made the AGC unstable when the attenuator is placed in front of the filter.
But then I'm often surprised.
Henning's insight that the audio pre-amp is severely limiting the receiver's dynamic range?
is well worth pursuing. ?
Here's an Avago app note on PIN diode attenuators: ?
And one from Skyworks: ?
An interesting part: ?
Jerry, KE7ER
?
toggle quoted message
Show quoted text
On Mon, Sep 4, 2017 at 06:45 am, Henning Weddig wrote:
of course a RF attenautor (e.g. PIN diode in Pi configuration or even better using two diodes anti-series in the series lag and the other two in the parallel leg, see AVAGO app notes) will help.
BUT: please put this circuitry AFTER the xtal filter!!? It is of no good use to put it in front of the RF input. Not onnly because the xtal filter will give a? extra time delay which may and will cause instabilities in the closed control loop!!? ?
?
|
Re: Auto RF Attenuator for Bitx40, Version 2
I'll try connecting a 47 ohm resistor from the other side of the capacitor that is connected to the cathode of the pin diode and see how that works. ?Yesterday, I listened to the west coast swap net all afternoon and heard everyone fine without needing to adjust the volume control. ?One station came on that is very strong, about S9 +40, and his audio was slightly distorted, but was intelligible and not louder than others. ?Everyone else sounded fine.
I've been focused on the audio compression that occurs when the stronger signals modulate the attenuation level, not the match to the BPF, so thanks for bring that up.
Jim/ND6P
?
|
Re: VFO/BFO selecting outputs
How did you couple the DDS (assuming it's CLK0) to the BitX?
Vince.
toggle quoted message
Show quoted text
On 09/04/2017 11:55 AM, Smitty, KR6ZY wrote: I'm looking to make the BFO-from-DDS mod too and got the
Deaf-RX-and-Birdies thing too. I was hoping you'd have some wisdom on
that. :-)
to be fair, I started this before joining this group and reading the
collected wisdom of many people who are WAY more experienced than I am,
so I tried removing the crystal and feeding CLK1 to the input of the
active section of the BFO, borrowing that idea from how the VFO is wired
up. I'll try injecting the DDS BFO directly into the mixer and see if
that solves my problems.
Readers from the future! If you see this email but no replies, assume
that it worked. :-D
--
Michigan VHF Corp.
|
Re: VFO/BFO selecting outputs
I'm looking to make the BFO-from-DDS mod too and got the Deaf-RX-and-Birdies thing too. I was hoping you'd have some wisdom on that. :-)
to be fair, I started this before joining this group and reading the collected wisdom of many people who are WAY more experienced than I am, so I tried removing the crystal and feeding CLK1 to the input of the active section of the BFO, borrowing that idea from how the VFO is wired up. I'll try injecting the DDS BFO directly into the mixer and see if that solves my problems.?
Readers from the future! If you see this email but no replies, assume that it worked. :-D
|
Re: Auto RF Attenuator for Bitx40, Version 2
I'm somewhat new to this, but my understanding is that if you present a mismatched load to a mixer, you'll get all kinds of spurs and birdies. So it may be working "better" at attenuating, but may also be leaking all kinds of unintended signals.?
Someone who knows more than I do: please correct/educate us if I'm wrong.?
-Mark
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On Sep 4, 2017, at 6:15 AM, Jerry Gaffke via Groups.Io < jgaffke@...> wrote: An interesting observation! Yes, as the diodes in the two "legs" of the pi conduct more, the diode in the middle is conducting less. Though he reports that the single diode circuit works better. ? Perhaps when receiving a very strong signal, the impedance mismatch adds to the attenuation, giving an overall better result. Perhaps a simple voltage follower at the output of the attenuator would help to properly drive the BFP, and the mismatch at the antenna when receiving very strong signals can be ignored. On Mon, Sep 4, 2017 at 12:49 am, Henning Weddig wrote:
in principle it is possible to use only one diode,
BUT: as your design only uses one "variable" resistor in series, the impedance will change dramatically if the attenuation starts, giving a big mismatch to the pre- and following stage.
The 3 diode att prevents this (partly, but unfortunaltely not ideally) as these diodes form a pi-type attenautor.
?
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Re: how to change arduino/si5351 output
I don't have the code in front of me, but look for a function near the top named something like "set_freq" Note that one of the parameters to that function is the channel number.
Then search the rest of the program for where that function is called. Note that the channel number parameter is always 2. Change that to which ever channel you intend to use instead: 1, or 0.?
Then recompile and upload. Let me know how it works for you!
-Mark
toggle quoted message
Show quoted text
On Sep 3, 2017, at 10:46 PM, jrea79 via Groups.Io < jrea79@...> wrote: hello guys!
i think i am having a problem on my si5351?
i am suspecting that it may have low output, not enough drive
it has only 40mVpp on LSB and zero on USB?
checking with a DMM, clk2 (pin6) ?has low resistance to ground
while clk1 and clk0 has high resistance to ground
I have zero programming skills,
how do I edit the sketch so that the output moves from clk2 to clk1?
btw, I am using Allard's V1.20.1
thanks and 73!
jonathan/DV2NAH
|
Re: BITX QSO Night, Sunday, September 3, 7pm Local Time, 7277 kHz in North America, 7177 kHz elsewhere
I was a few minutes late to the party in the Pacific time zone (got on at about 7:08), but I wasn't able to hear anything after calling CQ for about 10 minutes from CM95, near San Luis Obispo, CA. I don't know if there were any conversations before I got there, or if I was just in a skip zone.?
I may or may not be near my rig next Sunday to try again.?
-Mark
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On Sep 4, 2017, at 6:56 AM, Karl Schwab via Groups.Io < ktschwab@...> wrote: I only heard WI1B calling CQ and we worked; he was the only BITX QSO that I had or heard here in MI.? de KO8S, Karl
On Monday, September 4, 2017 9:02 AM, lostfrogsrecords <dave@...> wrote:
I had a QSO with Jerry, W0PWE in Iowa at about 6:45 CDT.? Very good signal and audio.? The Tennessee QSO party interfered with my participation in the BitX net from then on. I made a couple of TN QSO party contacts as well. (K4CTG, AB4GG)
Dave, KI4PSR
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Smitty, N6MTS
Allard PE1NWL
