Re: SI labs generator chip which has an FM input pin
Jerry and others, I'm wondering if using the old RTTY technique of a varactor diode to pull an oscillator a few hundred Hertz for changing the Mark and Space frequencies, but actually using Audio to drive the varactor's shift (might take a bit of audio to move it far enough) and hooking that shift circuit to the master oscillator 25 (or 27) MHz crystal used for the Master Oscillator on the Si5351 might not work to FM it.? Could be worth someone experimenting with it any way.
I won't be the one doing it though as I'm far too busy with other projects here but thought I'd throw out the idea for discussion anyway.
------ Original Message ------
Sent: 4/10/2021 9:15:24 AM
Subject: Re: [BITX20] SI labs generator chip which has an FM input pin
Yes, doing digital writes to update the si5351 for FM modulation was mentioned in that old thread: ? ?? /g/BITX20/topic/6256856#34064But updating fast enough to get good audio would be a fight. ? ?? /g/BITX20/message/34362Jerry, KE7ER On Fri, Apr 9, 2021 at 08:55 PM, Ashhar Farhan wrote:
A neater way would be to read the modulating audio from an adc pin and program it to update the frequency of the si5351 very quickly. I believe usdx does that ti generate FM.
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Re: Rf it's "freezing" the Ubitx ???
Enclose the board in a metal box or make sure you have a balanced
antenna.
At 10/04/2021, you wrote:
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Hello,
i'm using a ver. 4 Ubitx with 2.8 " Nextion display, using in CW
there is a strange problem, something the radio it's "freezing"
during trasmission and i can't send no more CW and also i can listen the
sound of a strong MW transmitter near my house when it's making this
problem. I have made a short youtube video with this strange
thing:
Can be some RF getting into the Arduino Nano ??? Or the Diplay ??
73 de IW0HK Andrea
Roma
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Re: SI labs generator chip which has an FM input pin
Yes, doing digital writes to update the si5351 for FM modulation was mentioned in that old thread: ? ??/g/BITX20/topic/6256856#34064 But updating fast enough to get good audio would be a fight. ? ?? /g/BITX20/message/34362Jerry, KE7ER
On Fri, Apr 9, 2021 at 08:55 PM, Ashhar Farhan wrote:
A neater way would be to read the modulating audio from an adc pin and program it to update the frequency of the si5351 very quickly. I believe usdx does that ti generate FM.
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Hello,
Finally the problem with transmit fixed.
I have replace Q12 with a new and transmitting on ssb working perfect.
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Rf it's "freezing" the Ubitx ???
Hello,
i'm using a ver. 4 Ubitx with 2.8 " Nextion display, using in CW there is a strange problem, something the radio it's "freezing" during trasmission and i can't send no more CW and also i can listen the sound of a strong MW transmitter near my house when it's making this problem. I have made a short youtube video with this strange thing:
Can be some RF getting into the Arduino Nano ??? Or the Diplay ??
73 de IW0HK Andrea
Roma
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Justin
? I made the same choice for through hole. I built the earlier Barb variant with plug in band boards using a Si5351 module board.
--
? 73
??? Bob? KD8CGH
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Re: SI labs generator chip which has an FM input pin
In terms of? ?code for the Si570 I? note this contribution has been done so the? Hardware from SDR kits? (UK) could potentially be made open source. There are subtle diffs between the? Si 571 and 70 of course so it is only a starting ooint.? ?Personally taking the kit from? QRP Labs? and doing one of the two possible FM modifications arrived at or? three if you were to go the original A Farhan number eight fencing wire method (as attached )? as per previous post (separate thread)? ?might make a lot more sense in terms of a modern design .?
Just think a few hrs ago my head was a blank sheet of paper and now I am spinning on my seat... :-))? TEFidler?
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Re: SI labs generator chip which has an FM input pin
Geez Jerry et al you are all a bunch of very useful an busy bees.
What I have found in the meantime is that the Si571 has or had a VC pin. now? Sdr radio kits sells a full ham osc which is based on the SI 570 which is same same but different. BUT BUT
the don' t sell the Si571 part which may be a legacy part. - I have not been able to establish that yet.? I think the code for that kit is fully proprietary though so changes for? Direct on freq and then Freq - offset on? Rx would not be easy to make.? Essentially it has provisions for SSB use but that's? a different possum from an FM tcvr configuration.? BUT BUT it does say it can be used for CW which means a hoop off to the IF freq offset on Rx... anyways.. hold that thought... it is still locked up code...
The Si5351B has a special "VC" pin that you might find interesting: indeed VERY VERY interesting. as Hans summers sells a kit based on a similar part and the VC pin clearly can do FM modulation?
Ok full disclosure . Nearly every Marine VHF FM HH sold in Nz under $250 or so is generally a piece of crap.? I have been looking for a useful winter project as I have a smal sail boat,? flying fifteen and sailing in mid winter is polar bear material.
So I think you can see where this might be going.? Getting the stock standard Hans kit to move from Direct on Freq on Tx to? -10 Mhz or - 10.7Mhz offset on Rx might be a big ask - for an experienced systems programmer it might be doddle but I'm not set up for it.? Hans? Summers at Qrp labs .com? ?has a??Si5351? based kit and it is open source I believe. But it surely will not be the B model of the chip.? (that comes from my "Life is hard " theory of luck and life.
Basically this could be a 6m + 2m + Marine band Tcvr or just a marine VHF band Tcvr- the concept is very much weakware but I have got something to think about.?
any other constructive input is most welcome. BTW the SMA? here (read FCC) has put a ban on all Beo Feng / Woxun tcvrs here? (NZ) in terms of sales of new units because of spec purity issues so using one of them on a throw out every few years is not so easy.? ?And of course most would require reprogamming as they would be set for two mtr use.
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Re: SI labs generator chip which has an FM input pin
Jerry at least you did not try to take yerself out as I did once at about 14 when I decided to see what would happen if I put a 90v mini neon across the HV terminals of a motor mower and gave the starter a pull... now that's a Spark transmitter :-)) TEF?
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Re: SI labs generator chip which has an FM input pin
A neater way would be to read the modulating audio from an adc pin and program it to update the frequency of the si5351 very quickly. I believe usdx does that ti generate FM.
On Sat 10 Apr, 2021, 6:07 AM Evan Hand, < elhandjr@...> wrote: My embarrassment would be the relay-based computer science fair project that I tried to design in 6th grade.? It did work to some extent until the actual fair.? By then the relays were intermittent and timing between them made it unreliable? I know now why relays can not be used for fast calculations.
73
Evan
AC9TU
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Jerry - I ordered my last one on 3/28, it shipped on 4/3, and I received it on 4/7.? Won't be able to play with it until September, though... :-(
73,
Justin B.
KI5GKD
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Re: SI labs generator chip which has an FM input pin
My embarrassment would be the relay-based computer science fair project that I tried to design in 6th grade.? It did work to some extent until the actual fair.? By then the relays were intermittent and timing between them made it unreliable? I know now why relays can not be used for fast calculations.
73
Evan
AC9TU
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Re: SI labs generator chip which has an FM input pin
A man after my own heart!
Someday I may have to embarrass myself by describing attempts?
at building a spark gap transmitter while in early primary school.
Those encyclopedia entries were just not explicit enough.
Jerry, KE7ER
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On Fri, Apr 9, 2021 at 04:27 PM, jerry@... wrote:
Once upon a time...
I did ( well, tried to do ) 2M FM with the following setup:
* A Harvey Wells TBS-50D transmitter driven by
* A Heathkit VF-1 VFO
with
* A paper megaphone taped to it. I figured the VFO would FM enough to be "modulation"
for the TBS-50D. Which had a single 807 tube for its output stage. Frequency of the
VFO was multipled by IIRC 18. Power out was 1 or 2 watts. Never did make a contact with this setup, but it was fun trying.
- Jerry KF6VB
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-------- Original Message -------- On Apr 9, 2021, 8:00 PM, Skip Davis via groups.io < skipnc9o@...> wrote:
Jerry checkout Communication Concept¡¯s website they sell heatsinks and a copper spreader. Although the spreader may be larger than you need it can be cutdown to a usable size. You might get two equal size copper spreaders for a second amplifier project.
73, Skip, NC9O
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Jerry checkout Communication Concept¡¯s website they sell heatsinks and a copper spreader. Although the spreader may be larger than you need it can be cutdown to a usable size. You might get two equal size copper spreaders for a second amplifier project.
73, Skip, NC9O
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How does it work with KD8CEC firmware? Are the formerly known problems solved like :
- CW, the beginning of the first character being eaten ;
- harmonics level, are they below 43dB ;
- integration with Inkits enclosures for Nextion, their AGC and their digital board??and?;
- integration of an ATU like the 7x7.
73 - Pierre - FK8IH
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Re: SI labs generator chip which has an FM input pin
Once upon a time...
I did ( well, tried to do ) 2M FM with the following setup:
* A Harvey Wells TBS-50D transmitter driven by
* A Heathkit VF-1 VFO
with
* A paper megaphone taped to it. I figured the VFO would FM enough to be "modulation"
for the TBS-50D. Which had a single 807 tube for its output stage. Frequency of the
VFO was multipled by IIRC 18. Power out was 1 or 2 watts. Never did make a contact with this setup, but it was fun trying.
- Jerry KF6VB
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On 2021-04-09 16:20, Jerry Gaffke via groups.io wrote: Tim,
There's a bunch of hits for a search of "NBFM -f" in the forum.
This is probably the one you are thinking of:
/g/BITX20/topic/6256856#34020
where Farhan was modulating the 25mhz reference oscillator.
The Si5351B has a special "VC" pin that you might find interesting:
Jerry, KE7ER
On Fri, Apr 9, 2021 at 03:57 PM, Timothy Fidler wrote:
Ages back Ashan or Ashar published a whimisical schematic where he
used on of the Si labs offerings to potentially become an FM VHF as
in NBFM generator.
Does anyone recall how this was done and how far way from the
Si5351 chip is from the other chip in terms of pin out ?
Obviously I am looking if any of the existing Vfo kits is amenable
to this. The Si570 is avail in a VFO kit too but I see no evidence
that this chip has a pen that allows it to be FM modulated.
best regards, (I am sure that this is not a false memory but it may
well be some orphan Si Labs chip that is now unobtainium). THe
Marine VHF band 160 - 174 MHz is of interest to me in this matter
:-)
Tim Fidler Links:
------
[1] /g/BITX20/message/87503
[2] /mt/81981998/243852
[3] /g/BITX20/post
[4] /g/BITX20/editsub/243852
[5] /g/BITX20/leave/10189903/243852/952924773/xyzzy
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Re: SI labs generator chip which has an FM input pin
Tim,
There's a bunch of hits for a search of "NBFM -f" in the forum.
This is probably the one you are thinking of:
? ??/g/BITX20/topic/6256856#34020
where Farhan was modulating the 25mhz reference oscillator.
The Si5351B has a special "VC" pin that you might find interesting:
? ??
Jerry, KE7ER
On Fri, Apr 9, 2021 at 03:57 PM, Timothy Fidler wrote:
Ages? back Ashan? or Ashar published a whimisical schematic where he used on of the Si labs offerings to potentially become an FM VHF as in NBFM generator.
Does anyone recall how this was done and how far? way from the Si5351 chip is from the other chip in terms of pin out ?
Obviously I am looking if any of the existing Vfo kits is amenable to this.? The Si570 is avail in a VFO kit too but I see no evidence that this chip has a pen that allows it? to be FM modulated.?
best regards,? (I am sure that this is not a false memory but it may well be some orphan Si Labs chip that is now unobtainium).? THe Marine VHF band 160 - 174 MHz is of interest to? me? in this matter :-)?
Tim Fidler
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Jerry, KF6VB
> *** I wonder if the old "audio oscillator CW" trick would work?
It was used for years on the *Bitx* transceivers, but adds opportunities for distortion,
a not quite suppressed carrier, opposite sideband leakage, spurs due to mixer products.
In short, all the various troubles one might have with SSB.
Generating the CW signal at the operating frequency avoids all of this.
It would be relatively easy to add CW envelope shaping, but nobody has yet bothered
since it isn't much of an issue at QRP levels. (You would also need envelope shaping
on your audio oscillator.) ... And CW is an afterthought for the uBitx.
> *** I ordered the amp. It uses a pair of MRF300's for 600W out.
That sounds like a fun and challenging project.
Let us know how it goes, I'll be very curious.
> I recently got a little tiny spectrum analyzer
The tinySA is a very useful tool.
However, not quite enough resolution to check for IMD.
Best Regards,
Jerry, KE7ER
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On Fri, Apr 9, 2021 at 03:23 PM, jerry@... wrote:
Name here is Jerry, KE7ER.
A ham since the early 1970's.
A pleasure, Jerry!
The uBitx is a hackers delight, a brief look at this forum will tell
you that.
*** Yes, that was the primary driver. I *love* open source software and
hardware.
It is primarily an SSB rig, CW is an afterthought.
*** I wonder if the old "audio oscillator CW" trick would work?
if you want a good cheap CW rig.)
*** My TS-590 works OK for that :).
There is no QSK for CW,
*** I'm honestly not that fond of QSK. Semi-break is fine for me.
The CW keying envelope on the stock rig is rectangular,
*** Yeah, that's bad.
there will be
key clicks which would be problematic when
driving a 600W linear.
In SSB mode, IMD and various spurs can pop up if you give it too much
mike gain,
I'd want tools to monitor signal quality if boosting to 600 Watts.
Where the uBitx shines is as a learning tool.
Many in the forum have modded it, broke it, and then fixed it.
And came out the other side quite a bit smarter.
I'd be afraid to take the covers off a $1k+ HF transceiver, on the
uBitx they come already off.
The Ebay linear amps are often, well, ebayish.
*** I ordered the amp. It uses a pair of MRF300's for 600W out. The
seller ( dxworld.e ) has a Youtube video showing it being tested, with
600W out. Drive was 10W. It comes with a bank of switchable low pass
filters. This seems to be a serious vendor.
I also ordered a 50V 20A power supply. So I need to dream
up a case and a heatsink. Seller claims 80% efficiency. On the back
of the envelope that works out to 750W input, 600W out, 150W dissipated as
heat. Maybe a copper spreader coupled to a big CPU cooler?
The linear comes without the power transistors. That's OK, I can
source them from Mouser etc, and they're AMAZINGLY cheap. I have a case
from a Heathkit "Single bander" SSB transceiver, that should be just right.
If the uBITX is too dirty, I can stil use the linear with my other rigs. The
TS590 has a"power" control, and can be turned down to 5 watts.
I recently got a
little tiny spectrum analyzer - it should work fine for checking for spurious.
- Jerry KF6VB
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SI labs generator chip which has an FM input pin
Ages? back Ashan? or Ashar published a whimisical schematic where he used on of the Si labs offerings to potentially become an FM VHF as in NBFM generator.
Does anyone recall how this was done and how far? way from the Si5351 chip is from the other chip in terms of pin out ?
Obviously I am looking if any of the existing Vfo kits is amenable to this.? The Si570 is avail in a VFO kit too but I see no evidence that this chip has a pen that allows it? to be FM modulated.?
best regards,? (I am sure that this is not a false memory but it may well be some orphan Si Labs chip that is now unobtainium).? THe Marine VHF band 160 - 174 MHz is of interest to? me? in this matter :-)?
Tim Fidler
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Jim Sheldon
Raj vu2zap
Bob Benedict, KD8CGH
Skip Davis