In your last post, you say: ? "The actual VFO output is doing as it should according to the scope and frequency counter" By that, do you mean that you measured the frequency, and verified it is at 5mhz? ?If so, then the only way I see for it to be on USB is if the BFO got moved, perhaps by adding capacitance at C103. ?If that's the case, then either restore the BFO to where it was out of the box (move it back up in freq by about 3khz), or move your VFO to 19mhz (no offset, 19mhz as measured with the scope at the VFO output). Jerry
On Wed, Feb 8, 2017 at 11:43 am, Jerry Gaffke wrote:
Did you use your scope to check the frequency coming out of the VFO? ?I'm betting it is up at 19mhz, not 5mhz. ?
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If you want another Pic to try I'm happy to post you mine.? It's redundant anyway.
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Rob G4NQX
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It doesn't work on the mode pins then ??? Must admit instructions are confusing, one table says 9 & 14 and 9 & 15.? Next table says 9 only then 9 & 15 if that makes sense.? If you have it wrong it will do a cw shift of about? point 75kHz only.? 750Hz in other words.
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Rob G4NQX
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Marc, OK, back to your original post: > ?I've recently built a SDR kits VFO (3.5 to 160 MHz) .. It's working fine, But when I connect it to my BITX-40 the LSB is flipped to USB ..I've put the IF as 12.0 MHz and the VFO range is 4.8 -5 MHz .. To cover 7.0 -7.200 ... Any ideas why it flips the Sideband ??
Let's get this straight. ?The Bitx40 worked correctly out of the box at 7mhz on LSB, using either an analog VFO or the Raduino. ?You disabled the original VFO (removed L4, unplugged any Raduino) and plugged in your SDR Kits VFO into the Bitx40's DD51 connector. ?Didn't mess with the BFO. ?And now the Bitx40 is tuning 40 meters as before, except you are on USB? ? You said that "the VFO range is 4.8-5 MHz". ?Did you use your scope to check the frequency coming out of the VFO? ?I'm betting it is up at 19mhz, not 5mhz. ?Might be less confusing to just tell the VFO an offset of zero, then set the VFO freq to 5mhz. ?See if that gives you 7mhz LSB operation.?
Jerry?
?Wed, Feb 8, 2017 at 10:55 am, Marc Jones wrote:
Hi, I've tried IF frequencies of 19 MHz , 26 MHz, 12 MHz ... Basically any frequency I could think of .. None of them work the ?BITX-40 on LSB, The frequency of 19 MHz results in basically a dead radio, No RX At all , Same goes for 26 MHz, It's a strange one, This SDR kits VFO works fine, It looks good on the scope and goes upto 160 MHz easily.. But it just won't work on the BITX-40 .. ?
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Hi Rob, Yes the IF has to be on the high side, Also the ?selectable modes ?doesn't work, Not on my version anyway ...Ive tried ?12 MHz +- a few kHz, I've tried 19 +- a few kHz, I've also tried 26 MHz +- a few kHz, Plus every other frequency from 3.5 MHz to over 30 MHz... It's not having it, Whether there a fault with the SDR kits VFO I have I really couldn't say, The actual VFO output is doing as it should according to the scope and frequency counter , If there's a fault with the coding somehow I really couldn't say ... Either way though, I've given up on the Piece of junk for now, It's been put in my parts bin for a later date, It would come in handy for use as a signal generator but not for the use as a VFO as I intended ...
Regards?
On Wed, 8 Feb 2017 at 19:07, G4NQX <tasmod@...> wrote: The SDR Kits VFO is based upon an si570 chip and a pic controller. Typically 250MHz upper frequency although the one I had did 295MHz. I couldn't get rid of the tuning clicks on mine (early) think they fixed that now. They are generated by the 570 because it has limited range before resetting? tuning jump. I wasn't able to get on with it, so cut off the si570 and transformer part then used a Nano plus code.
I seem to remember it has LSB USB selectable at 1.5kHz either side. The IF offset had to be on the high side. That's all I remember.
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Rob G4NQX
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Ok. Downloaded the manual. According to instructions for latest firmware 4.19
IF offset to 12MHz.. On J2 ----
Ground pin 9? for LSB? Ground pin 9 and 15 for USB
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Rob G4NQX
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Sorry, that should have read positive IF only.?? I've looked for my notes but can't find them. I remember I wasn't impressed with it for the price.
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Rob G4NQX
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The SDR Kits VFO is based upon an si570 chip and a pic controller. Typically 250MHz upper frequency although the one I had did 295MHz. I couldn't get rid of the tuning clicks on mine (early) think they fixed that now. They are generated by the 570 because it has limited range before resetting? tuning jump. I wasn't able to get on with it, so cut off the si570 and transformer part then used a Nano plus code.
I seem to remember it has LSB USB selectable at 1.5kHz either side. The IF offset had to be on the high side. That's all I remember.
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Rob G4NQX
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Hi, I've tried IF frequencies of 19 MHz , 26 MHz, 12 MHz ... Basically any frequency I could think of .. None of them work the ?BITX-40 on LSB, The frequency of 19 MHz results in basically a dead radio, No RX At all , Same goes for 26 MHz, It's a strange one, This SDR kits VFO works fine, It looks good on the scope and goes upto 160 MHz easily.. But it just won't work on the BITX-40 ..
On Wed, 8 Feb 2017 at 14:14, Ashhar Farhan <farhanbox@...> wrote: If you set the VFO frequency to 26 MHz, the sideband is automatically inverted. You will not need to move the BFO from LSB to USB for 14 MHz.
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Oh, right. ?You're on 20m, not 40m. ?Return the VFO to wherever the heck it was. ?(Around 2mhz, I assume.) Jerry
On Wed, Feb 8, 2017 at 10:32 am, Jerry Gaffke wrote: you could return the VFO to 5mhz as it was, ?
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Do you have a scope? The signal at T2 should be around 1.6 volts peak to peak. I found that at the higher frequencies, C91 and C92 were attenuating the signal from the SI5351.
This occurred when setting up for 20m with 26 MHZ - 11.99860 MHZ.
73
Ken VA3ABN
On Wed, Feb 8, 2017 at 1:29 PM, Marc Jones via Groups.Io <gw0wvl@...> wrote: I've tried using a 19.0 MHz IF from the SDR kits VFO I have, It results in a Dead BITX-40 .. No RX no TX . On Wed, 8 Feb 2017 at 17:41, Lawrence Macionski via Groups.Io QUOTE- "If you set the VFO frequency to 26 MHz, the sideband is automatically
inverted. You will not need to move the BFO from LSB to USB for 14 MHz".
Then if that is true then setting the VFO frequency to 19Mhz? (19-12=7) will invert- (USB) for 7Mhz? Then enabling Digital modes?? Something the Raduino could do? Advise.... de W8LM -KANSAS
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USB is already in the Raduino software, just not implemented.
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Rob G4NQX
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That's not a 26mhz "offset". ? You want zero offset, set the VFO for 26 mhz going out. I have no idea if your VFO can emit 26mhz. If that fails, you could return the VFO to 5mhz as it was, and add a variable cap at C103 to bring down the frequency by 3khz or so. ?Not sure how much capacitance would be required, I assume well under 100pf. ?
On Wed, Feb 8, 2017 at 10:14 am, Marc Jones wrote:
Offset set to 26.000 MHz results in a dead BITX-40. ?
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I've tried using a 19.0 MHz IF from the SDR kits VFO I have, It results in a Dead BITX-40 .. No RX no TX .
On Wed, 8 Feb 2017 at 17:41, Lawrence Macionski via Groups.Io <am_fm_radio@...> wrote: QUOTE- "If you set the VFO frequency to 26 MHz, the sideband is automatically
inverted. You will not need to move the BFO from LSB to USB for 14 MHz".
Then if that is true then setting the VFO frequency to 19Mhz? (19-12=7) will invert- (USB) for 7Mhz? Then enabling Digital modes?? Something the Raduino could do? Advise.... de W8LM -KANSAS
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Offset set to 26.000 MHz results in a dead BITX-40... No RX, No TX ... I'm really not getting anywhere with this SDR kits VFO.. I've tried Putting in numerous frequencies for the IF , ?None result in ?a 7 MHz Frequency that is on LSB .?
On Wed, 8 Feb 2017 at 17:41, Lawrence Macionski via Groups.Io <am_fm_radio@...> wrote: QUOTE- "If you set the VFO frequency to 26 MHz, the sideband is automatically
inverted. You will not need to move the BFO from LSB to USB for 14 MHz".
Then if that is true then setting the VFO frequency to 19Mhz? (19-12=7) will invert- (USB) for 7Mhz? Then enabling Digital modes?? Something the Raduino could do? Advise.... de W8LM -KANSAS
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Should read: ? ?assuming you can easily set that VFO to 19mhz.
On Wed, Feb 8, 2017 at 10:12 am, Jerry Gaffke wrote:
assuming you can easily set that VFO to 26mhz. ?
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Yes, a 19mhz vfo will move a Bitx40 from LSB to USB. ?And your simplest solution, assuming you can easily set that VFO to 26mhz. ?Should just work. Another way is to drive the BFO from a spare Si5351 channel so you can move the carrier down few khz to where the filter lets through the upper sideband, leave the VFO where it's at. ?A somewhat more intuitive approach, and allows the BFO to be centered in the crystal filter passband for debug or CW. ?Requires a change to the Raduino code, and a wire from the Si5351 into the BFO, but I think eventually this is the best way forward. Jerry
On Wed, Feb 8, 2017 at 09:41 am, Lawrence Macionski wrote: setting the VFO frequency to 19Mhz? (19-12=7) will invert- (USB) for 7Mhz? ?
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QUOTE- "If you set the VFO frequency to 26 MHz, the sideband is automatically
inverted. You will not need to move the BFO from LSB to USB for 14 MHz".
Then if that is true then setting the VFO frequency to 19Mhz? (19-12=7) will invert- (USB) for 7Mhz? Then enabling Digital modes?? Something the Raduino could do? Advise.... de W8LM -KANSAS
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Scratch build traffic will be pretty rare going forward with the availability of the Bitx40, not sure banning it would gain much. ?What little scratch build traffic we get is generally well informed and to the point, most of the fluff here is enthusiastic new Bitx40 owners. ?The Bitx40 is meant to be hacked, will have various bands and analog/si5351 vfo's just like scratch builds. ?Subject line should identify what you got if not a standard issue Bitx40. ?Would be nice to archive all that decade of old photos and files at some point, have a system going forward to make stuff easier to find. ?Before word gets out and this Bitx40 thing really takes off. No strongly held opinions here. ?I did mention the possibility of a new Bitx40 group in a previous post as one possible way to get around the clutter in files/photos. ?But the few extra posts don't strike me as burden, so long as they are clear about what they got.
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Marc Jones