I need to replace one of the BC849 transistors in the VFO circuit.
I have on hand MMBT394, I assume I can use them? Looks like they have better ratings.
73
Ken VA3ABN
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Re: power for qrp-labs dds
Art,
I am assuming you are building your own;
?
I used an LM7808 ?(8v) regulator into the Nano (Arduino), and use the 5v out of the Nano to power the DDS /LCD (if you're building your own)
?
I have also used these successfully to help eliminate noise;
http://www.xppower.com/pdfs/SF_IV.pdf
to power a noisy OLED display - but they are not cheap and you need to be aware of your power requirements.
Rgds,
Darryl
?
?
On 2017-01-24 11:15 AM, Art Olson via Groups.Io wrote:
the Bitx40 uses 12v natively however the qrp-labs DDs vfo requires 5 volts. I have tried several buck converters but there is a lot of hashing (noisy) when the converter is powered on. Anyone have a suggestion as to anything I might try. If I use an external 5 volt wall wart then the problem (noise)?goes away. I don't want to have a 12 v power connection and have to run a wall wart also.
73
art
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Re: (Raduino) A Duhhh.... Moment
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Re: power for qrp-labs dds
Great suggestions. Will give it a try
Thanks
Art
Sent from my iPhone
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On Jan 23, 2017, at 7:42 PM, M Garza < mgarza896@...> wrote: Hi Art, What is wrong with using a 7805 to provide the 5 volts?? It should not create any noise.
Marco - KG5PRT?
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Re: power for qrp-labs dds
Hi Art, What is wrong with using a 7805 to provide the 5 volts?? It should not create any noise.
Marco - KG5PRT?
On Jan 23, 2017 6:15 PM, "Art Olson via Groups.Io" <olsonaj6927= [email protected]> wrote: the Bitx40 uses 12v natively however the qrp-labs DDs vfo requires 5 volts. I have tried several buck converters but there is a lot of hashing (noisy) when the converter is powered on. Anyone have a suggestion as to anything I might try. If I use an external 5 volt wall wart then the problem (noise)?goes away. I don't want to have a 12 v power connection and have to run a wall wart also. 73 art
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Re: (Raduino) A Duhhh.... Moment
Jason, The toroid is an "extra" part now.? You can keep it to go back to the original vfo or you can use the toroid for something else.
Marco - KG5PRT?
On Jan 23, 2017 6:13 PM, "Janson Sloughter" < janson@...> wrote: Ok, I see where to cap goes, totally missed that at first.? Just wondering on the 50 turn torroid now.
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Re: power for qrp-labs dds
Use a 5 volt 3 pin
regulator, powered from the 12 volt rail?
On 24/01/2017 11:15 AM, Art Olson via
Groups.Io wrote:
toggle quoted message
Show quoted text
the Bitx40 uses 12v natively however the qrp-labs DDs vfo
requires 5 volts. I have tried several buck converters but there
is a lot of hashing (noisy) when the converter is powered on.
Anyone have a suggestion as to anything I might try. If I use an
external 5 volt wall wart then the problem (noise)?goes away. I
don't want to have a 12 v power connection and have to run a
wall wart also.
73
art
|
Re: power for qrp-labs dds
Art,
I built a small board with a 7805 on it.? Haven't tested it yet.
73,? George
On 1/23/2017 6:15 PM, Art Olson via
Groups.Io wrote:
toggle quoted message
Show quoted text
the Bitx40 uses 12v natively however the qrp-labs DDs vfo
requires 5 volts. I have tried several buck converters but there
is a lot of hashing (noisy) when the converter is powered on.
Anyone have a suggestion as to anything I might try. If I use an
external 5 volt wall wart then the problem (noise)?goes away. I
don't want to have a 12 v power connection and have to run a
wall wart also.
73
art
|
Re: Different display issues
Thanks Darryl...that gives me something to check into...it's appreciated!
Jack, W8TEE
From: Darryl Harvey <darryl@...>
To: [email protected]
Sent: Monday, January 23, 2017 3:36 PM
Subject: Re: [BITX20] Different display issues
Hi Jack, I have been battling "noise clicks" for some time now in my DDS. I have tracked it to the i2c bus SDA data being injected in the power rail by my OLED display, the bitx is so sensitive it acts on this noise, my Mst3 with the exact same DDS doesn't have this problem.?
Anyway, the only way I could reduce this noise after many tests and redesigns was to put a D.C.-D.C. Isolator in the power rail for my OLED display. it didn't remove it 100%, more like around 95% - but at least it was usable.? A simple voltage regulator (7805) and associated filter caps and even chokes didn't help.?
Even though the clicks occur when moving the encoder, it was the display updates causing the noise for me. ?When I moved to a TFT or LCD display I didn't have this issue, but check that your voltage supply to the DDS is not under load, that could cause some noise on updates.
Hope this helps Darryl VK3DAZ
On 24 Jan 2017, at 6:39 am, Jack Purdum via Groups.Io < econjack@...> wrote: All:
I have my B40 with Raduino display and it works as advertised. I am now trying to add my TFT display and DDS VFO, which is a AD9850, more-or-less the same as the VFO in the Forty-9er article (March, 2016 QST). I am using a rotary encoder to change the frequency, again the same as before. The processor is a Mega 2560 Pro Mini; too many things going on for a Nano. I've used the TFT display, DDS, and Mega boards on an antenna analyzer project and had no issues. (Schematic attached, the SWR bridge is omitted.) However, on the B40, any movement of the encoder can be "heard" in the receiver audio. Also, there is a slight dimming, or flicker, of the display when rotating the encoder.?
As I've said many times before, I'm a software guy so the EE stuff leaves me not knowing where to begin. Any ideas sincerely appreciated.
Jack, W8TEE
<Figure33.jpg>
|
the Bitx40 uses 12v natively however the qrp-labs DDs vfo requires 5 volts. I have tried several buck converters but there is a lot of hashing (noisy) when the converter is powered on. Anyone have a suggestion as to anything I might try. If I use an external 5 volt wall wart then the problem (noise)?goes away. I don't want to have a 12 v power connection and have to run a wall wart also. 73 art
|
Re: (Raduino) A Duhhh.... Moment
Ok, I see where to cap goes, totally missed that at first. ?Just wondering on the 50 turn torroid now.
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Re: (Raduino) A Duhhh.... Moment
So I remove L4, and what do I do with the 50 turn toroid? ?Also, anyone know what the .01 uf cap is for that it came with?
Thanks, Janson W7TJS
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Re: Low Power - Final Amplifier on through - hole kit
Greetings all.
I started tracing my PA with Leonard's documentation.?
The first discrepancy I noticed right away.?
He had 30v pk-pk on the collector of Q1 (2n2218) and I only had 15.94v pk-pk. And the waveform is quite different. My guess is that the problem is around here. I double-checked all the component values, orientation of the 2n2218, and my solder joints. I'm still stumped.
Attached is a capture from the scope.?
My voltages at Q1 were as follows:?
Base: 1.79v Collector: 10.97v Emitter: 1.14v
And yes, I am running the entire board from a 20vDC regulated bench power supply (HP3630A), and I am feeding in 2v pk-pk at 14.00MHz from the function generator (Tektronix AFG3251).
Any insights would be much appreciated!
On Sat, Jan 21, 2017 at 6:09 PM, Jorge Luiz Fenerich <py2pvt@...> wrote: ? ? Thanks Leonard for finding this page I was needing it and I need to know also the voltages in Q1 (2N3866) if you know please pass me ok?? ? Jorge PY2PVT _._
-- Mark Baldridge 608.561.3853
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Re: Different display issues
Hi Jack, I have been battling "noise clicks" for some time now in my DDS. I have tracked it to the i2c bus SDA data being injected in the power rail by my OLED display, the bitx is so sensitive it acts on this noise, my Mst3 with the exact same DDS doesn't have this problem.?
Anyway, the only way I could reduce this noise after many tests and redesigns was to put a D.C.-D.C. Isolator in the power rail for my OLED display. it didn't remove it 100%, more like around 95% - but at least it was usable.? A simple voltage regulator (7805) and associated filter caps and even chokes didn't help.?
Even though the clicks occur when moving the encoder, it was the display updates causing the noise for me. ?When I moved to a TFT or LCD display I didn't have this issue, but check that your voltage supply to the DDS is not under load, that could cause some noise on updates.
Hope this helps Darryl VK3DAZ
toggle quoted message
Show quoted text
On 24 Jan 2017, at 6:39 am, Jack Purdum via Groups.Io < econjack@...> wrote: All:
I have my B40 with Raduino display and it works as advertised. I am now trying to add my TFT display and DDS VFO, which is a AD9850, more-or-less the same as the VFO in the Forty-9er article (March, 2016 QST). I am using a rotary encoder to change the frequency, again the same as before. The processor is a Mega 2560 Pro Mini; too many things going on for a Nano. I've used the TFT display, DDS, and Mega boards on an antenna analyzer project and had no issues. (Schematic attached, the SWR bridge is omitted.) However, on the B40, any movement of the encoder can be "heard" in the receiver audio. Also, there is a slight dimming, or flicker, of the display when rotating the encoder.?
As I've said many times before, I'm a software guy so the EE stuff leaves me not knowing where to begin. Any ideas sincerely appreciated.
Jack, W8TEE
<Figure33.jpg>
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Re: Strong stations too loud even at lowest volume
Yes, when power to Q1 is switched off, that path is linear. But I am curious how big a signal it can pass as a linear amp when that pot is at 10k. I'd guess either your mod or the pot on the rx line between the relays would work fine, and either would be about as much trouble to implement. Agreed, feature creep on the rig as shipped from hfsigs should be avoided. ?But it's built to be hackable, adding AGC (with a disable switch) to see if you like it seems a perfectly fine way to spend the day. ?Those with strong signals popping up next door now and then might welcome AGC. ?I doubt I'll need it out here.
Jerry Gaffke, KE7ER, Flora OR
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All:
I have my B40 with Raduino display and it works as advertised. I am now trying to add my TFT display and DDS VFO, which is a AD9850, more-or-less the same as the VFO in the Forty-9er article (March, 2016 QST). I am using a rotary encoder to change the frequency, again the same as before. The processor is a Mega 2560 Pro Mini; too many things going on for a Nano. I've used the TFT display, DDS, and Mega boards on an antenna analyzer project and had no issues. (Schematic attached, the SWR bridge is omitted.) However, on the B40, any movement of the encoder can be "heard" in the receiver audio. Also, there is a slight dimming, or flicker, of the display when rotating the encoder.?
As I've said many times before, I'm a software guy so the EE stuff leaves me not knowing where to begin. Any ideas sincerely appreciated.
Jack, W8TEE
|
Re: Strong stations too loud even at lowest volume
Good question Jerry. No, it just gets deaf(er). No extraneous products. With Q1 idle signals pass from C11 through R14 to C13. It would take nearly a volt to broach the barriers on the idle BJT. At that point it will distort no matter what. Certainly one could incorporate other measures but none would be so simple and effective. A FET between K2 14 and K1 12 could be controlled for AGC but that is a wee bit more work. No AGC is rather nice. Less background noise. CW is good without AGC. Beware Feature Creep!
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No shorts in the turns. I also re soldered the connections.
When I scope the transformer, I get 250mv p-p. Looks like one of the transistors is gone. I had it working for quite for weeks.
Checked my DDS setting drive source to 8ma,?crystal load to 8pf. Stuck a 50 ohm load on the o/p and I get 1.8v p-p.
73
Ken VA3ABN
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Re: Strong stations too loud even at lowest volume
I'm sure it works well enough. ?My concern is that the diode ring mixer is non-linear, but normally only the 40m signals from the antenna get passed on to the 12mhz crystal filter because the bandpass filter up front strips out everything except 40 meters. ?Now if Q1 goes non-linear, we've got all those 40m harmonics plus all the vfo harmonics mixing together, likely producing a few birdies. ?(That's just as true for those of you with carefully groomed sine waves out of the VFO, cuz the action of the mixer is very not linear.)
On Mon, Jan 23, 2017 at 08:04 am, Jerry Gaffke wrote: Does Don's trick of cutting power to Q1 make that first RX amp go non-linear, and introduce crud into the received signal? ?
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Look back at messages.? There was an email address that you send PayPay to and the serial? numbers of the boards. I just told them I needed 2 and sent the money PayPal. I put how many raduinos i needed in the comment/message box on PayPal. Got them In the mail a month or so later.? Jared
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On Jan 23, 2017, at 11:00 AM, "kq2q2000" < kq2q@...> wrote: Hello, I received a new BitX40 in December. I see that the 2017 units come with a Raduino DDS
I would like to order one or two Raduino's. How do I do that? I do not see them for sale on the webpage. Thank you, Bob? KQ2Q Danielsville, GA
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Don, ND6T
JP McGinley KA3BWP