Re: Modifying Bitx20 to use a Si5351
I am creating the PCB myself, it it not a pre-designed one, I am just at the initial stage of re-working my original through hole design in to a surface mount one and so am removing the VFO and BFO circuitry.
I will look up the board you mentioned and see how the DDS input is implemented there - this should give a me a good idea of what components I need to remove / leave in place on my PCB.
Thanks again for the help.
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Re: Delivery Time Bitx40 (SMD)
It might take litte longer , but it would surely arrive. All the best
sarma
vu3zmv
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Ken -- You don't really need to set up a DDS BFO. The on-board BFO oscillator is strong and stable. What you probably should do is adjust the BFO frequency directly to suit your ears. (See message #19317; that is what I did with my unit). You can setup a DDS BFO as well, of course; I know you now know how to do that. --? If using a DDS, remember to disable the on-board oscillator; probably removing the BFO crystal is the simplest solution. In fact, injecting the DDS signal into where the crystal was is probably the best all-around solution as to where to do it. Mind the signal level and the frequency. Experiment for the best sound. You probably SHOULD use a DDS for the VFO. Remember to disable the on-board VFO oscillator by removing L4. john AD5YE ---In BITX20@..., <chase8043@...> wrote : I got it. I kept thinking the IF(12 MHZ) was the BFO. So it turns out my BFO is also 11.9986 MHZ.
So if I have mine start at say 7.164 MHZ, it's o/p is 11.9986 - 7.164 = 4.8346 MHZ
OK back to the DDS LPF and 20M BPF.
73 Ken
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Re: Calling CQ on 7.285 with BITX
Three stations on the BITX 40 NET ?tonight N2CQR KB9MAC W3TTT I opened with my Icom at 100 watts, then switched to the BITX at 7 watts.
I then worked W4QNW in South Carolina 550 miles / 875 km (with the BitX).? He was calling CQ DX, but 500 miles is DX for 7 watts, right?
Are we up for tomorrow?
73, Joe W3TTT
On Tue, Dec 6, 2016 at 5:11 AM, Bill Meara n2cqr@... [BITX20] <BITX20@...> wrote:
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Thanks for trying Tim.? SoCal was a bit far from NoVa for last night's conditions.? 73? Bill
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Bill at about 16:07 I called you and could hear some one respond, but I make out the call sign as the qrm was I and the signal was just above the noise in So Cal.? 73 Tim Sutton
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I got it. I kept thinking the IF(12 MHZ) was the BFO. So it turns out my BFO is also 11.9986 MHZ.
So if I have mine start at say 7.164 MHZ, it's o/p is 11.9986 - 7.164 = 4.8346 MHZ
OK back to the DDS LPF and 20M BPF.
73 Ken
On Wed, Dec 7, 2016 at 4:33 PM, Joel Caulkins caulktel@... [BITX20] <BITX20@...> wrote:
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Ken,
I set my Arduino sketch to always start on 7.268.500 so when I turn on the Radio/DDS it always displays that, of course it's only displaying that, but it's really outputting 4.730.100 to the VFO. So, 11.998.600-4.700.100 = 7.268.500. Clear as mud?
I know it gets confusing at times.
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What is displayed on your DDS? 7.000000 MHZ or 7.001400 MHZ.
73 Ken
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Re: Modifying Bitx20 to use a Si5351
<< I have not really been able to find much about where the best place is to put the signal in except for one person who seemed say they put it directly in to the mixer coils via a 0.1uF capacitor>>
Well, Farhan provided a DDS connector on the board for that purpose. Remove the existing VFO toroid to remove the VFO from the circuit.
73,
Todd K7TFC
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Re: Modifying Bitx20 to use a Si5351
Hi Todd,
Thanks for the reply, I have been reading the various
posts on this this evening and have see lots of people discussing the code (I have
written my own code for this) and seen lots of discussion about the
level of the output signals. Currently mine is set to output 8mA, but I can change it if needed.
I have not really been able to find
much about where the best place is to put the signal in except for one
person who seemed say they put it directly in to the mixer coils via a
0.1uF capacitor.
I will keep looking just in case I managed to
miss the posts where the signal injection is discussed.
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Re: Unable to pick anything up
First thought is to get the dipole off the floor. Unless you are in the 2nd story of a wood building. But generally antennas on the ground don't do much.
Does tuning it do anything? Maybe the oscillator isn't running?
On Wed, Dec 7, 2016 at 3:50 PM, chriscoel@... [BITX20] <BITX20@...> wrote:
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Hi there I got my bitx40 v3 and I have hooked up a homemade dipole, i layed it out on the floor.. powered on (did not yet hook up PA).. I get an odd noise:
I also at minimum volume am picking up 92.3mhz FM Station..?
Is there something wrong with the bitx or is this noise more related to my throw on the floor dipole? I dont have the xmit pieces setup yet, so I didnt hook up the PA.. Should I hook up the PA and that can fix it? I tried to adjust the tuning and the whole band was like this.. I did notice?
I am running on a 12v SLA battery.. into headphone jack into normal earbuds.?
Any help would be appreciated!
-- Mark Baldridge 608.561.3853
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Unable to pick anything up
Hi there I got my bitx40 v3 and I have hooked up a homemade dipole, i layed it out on the floor.. powered on (did not yet hook up PA).. I get an odd noise:
I also at minimum volume am picking up 92.3mhz FM Station..?
Is there something wrong with the bitx or is this noise more related to my throw on the floor dipole? I dont have the xmit pieces setup yet, so I didnt hook up the PA.. Should I hook up the PA and that can fix it? I tried to adjust the tuning and the whole band was like this.. I did notice?
I am running on a 12v SLA battery.. into headphone jack into normal earbuds.?
Any help would be appreciated!
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Ken,
I set my Arduino sketch to always start on 7.268.500 so when I turn on the Radio/DDS it always displays that, of course it's only displaying that, but it's really outputting 4.730.100 to the VFO. So, 11.998.600-4.700.100 = 7.268.500. Clear as mud?
I know it gets confusing at times.
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On Dec 7, 2016, at 12:58 PM, Ken Chase chase8043@... [BITX20] < BITX20@...> wrote:
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What is displayed on your DDS? 7.000000 MHZ or 7.001400 MHZ.
73 Ken
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What is displayed on your DDS? 7.000000 MHZ or 7.001400 MHZ.
73 Ken
On Tue, Dec 6, 2016 at 7:46 PM, Joel Caulkins caulktel@... [BITX20] <BITX20@...> wrote:
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I set mine to 11998.600 because that was my BFO frequency. Farhan says it should be 11998.800 YMMV. Joel Caulkins KB6QVI
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so I am at a stop point and need some help from the community. Have a bitx40v3, purchased a qrp-labs vfo. All tested and seem to be working. Could someone help by leeting me know what the IF freq should be set to.?
thanks art n2ajo
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Thanks DuWayne,
Just the info I was looking for. I think I'll build one and give it a try. I already removed the cap between pins 1 and 8 on the 386, so might have to increase gain a bit, we'll see. Joel Caulkins KB6QVI
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On Dec 7, 2016, at 11:15 AM, duwayne@... [BITX20] < BITX20@...> wrote:
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I laid out a small circuit board and built it up.? It seems to work quite well from the little I have used it.? Only thing I noticed was a decrease in total audio level.? I compensated for that by increasing the value of the capacitor between 1 and 8 on the LD386, I think I used a 4.7uF instead of the 1 uF.? Have not noticed any appreciable increase in the background noise.? Nice thing about it is you do not need to make any changes to the board, everything just gets tacked onto the volume control.? I plan on making some measurements of the audio response with and without the AGC when I get time.? But right now I am working on a si5351 VFO to get rid of the drivt problem.
DuWayne KV4QB
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Re: New BITX40v3 seams deaf on ssb phone signals
Mark
Receiving CW but having broken audio on SSB might be caused by several things
but I would start with checking the BFO frequency relative to the crystal filter
characteristic.? The BFO for USB should be 12 to 16 db down on the lower skirt
of the filter passband.?
Another possibility is that there could be something wrong with BFO injection
level (too low) which could be the case if you have replace the BFO oscillator
with a DDS or Si5351a and set its output level too low.
Same thing with incorrect LO injection levels.
It could also be something really trivial like a damaged speaker (dirt in the
air-gap or a bent frame) causing the voice coil to drag.
Arv? K7HKL
_._
On Tue, Dec 6, 2016 at 8:56 PM, 'Mark W' k3mrk1@... [BITX20] <BITX20@...> wrote:
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Someone has probably mentioned this already, but out of the box, I¡¯m not sure it tunes very far into the US phone portion of the band. ? From: BITX20@... [mailto:BITX20@...]
Sent: Tuesday, December 06, 2016 9:33 AM
To: BITX20@...
Subject: [BITX20] New BITX40v3 seams deaf on ssb phone signals ? ? I just got the new 40 m version three board in the mail three weeks ago. Very pretty packaging I might add. Unfortunately this thing seems ?not to like S9 phone signals in the extra class portion of the 40 m band. It actually doesn't like any voice signals. I can hear some strong CW stations in that portion of the band but no real voice conversations. When I kick my dipole over to any one of my other HF Rigs, ?are your booming voice signals.? The food suffered no trauma in transit that I can tell and everything seems to be fine.? ? Any ideas now? I'm thinking of throwing a signal generator on it and seeing what I got.
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I laid out a small circuit board and built it up.? It seems to work quite well from the little I have used it.? Only thing I noticed was a decrease in total audio level.? I compensated for that by increasing the value of the capacitor between 1 and 8 on the LD386, I think I used a 4.7uF instead of the 1 uF.? Have not noticed any appreciable increase in the background noise.? Nice thing about it is you do not need to make any changes to the board, everything just gets tacked onto the volume control.? I plan on making some measurements of the audio response with and without the AGC when I get time.? But right now I am working on a si5351 VFO to get rid of the drivt problem.
DuWayne KV4QB
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Re: Modifying Bitx20 to use a Si5351
There have been several recent postings on this question. The output of the 5351 can be set at different levels. Do a search of recent conversations on this reflector.
73,
Todd K7TFC
On Dec 7, 2016 8:41 AM, " kerrsmithusa@... [BITX20]" < BITX20@...> wrote:
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My first version of the Bitx20 is completed and works very well (I just made the receiver part), it was made using through hole components on individual pcbs that plugged together.
My next version is going to be surface mount (as much as possible) and use a Si5351 for the vfo and bfo.
I have now finished the coding part of this project but am wondering if I need to amplify the outputs of the Si5351 before they are fed in to the mixers?
For example, should I feed the vfo input to the first mixer through the last transistor amplifier (the one with the two 1k resistor divider at the base (Q7))?? For the bfo should this go through the transistor with a 1k in to the base and a 1k on the emitter Q9? (references are for the Ashhar Farhan, 2004 version of schematic)
Or is there a different way to do this?
Thanks for your help.
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Thanks, I'm aware of the article, what I'm asking is, who has built it and is using everyday, and how do they like it? Does it work good? I've built a lot of audio derived AGCs and some raise the background noise level so bad I end up removing them. Joel Caulkins KB6QVI
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On Wed, Dec 7, 2016 at 2:04 PM, mikewogden@... [BITX20] <BITX20@...> wrote:
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Anymore ideas on the low power problem?
Only getting milli-watts. Adjustment of the bias pot seems to have no effect on the supply current.
A loud HALLO only gets a small flicker on the power meter.
I've looked at the driver transfomers. I can't see any shorted leads Any chance of a stage by stage diagnostic aid please? I don't have ready access to a scope so DC measurements only preferred or a ?pointer towards a simple RF probe I can build.
DDS VFO ready to go.
Regards
Mike.. G4KXQ
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Has anybody built and installed farhan's AGC? Does it work well? I think it's high time I install one. Joel KB6QVI
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Modifying Bitx20 to use a Si5351
My first version of the Bitx20 is completed and works very well (I just made the receiver part), it was made using through hole components on individual pcbs that plugged together. My next version is going to be surface mount (as much as possible) and use a Si5351 for the vfo and bfo. I have now finished the coding part of this project but am wondering if I need to amplify the outputs of the Si5351 before they are fed in to the mixers?
For example, should I feed the vfo input to the first mixer through the last transistor amplifier (the one with the two 1k resistor divider at the base (Q7))?? For the bfo should this go through the transistor with a 1k in to the base and a 1k on the emitter Q9? (references are for the Ashhar Farhan, 2004 version of schematic)
Or is there a different way to do this?
Thanks for your help.
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Todd K7TFC
Joel Caulkins/N6ALT
DuWayne Schmidlkofer