Perhaps, I'll have to check that.
However, both my test sketch and the B40 sketch are using the same hardware and setting or attempting to set the same 5Mhz frequency on the AD9850.?
With that set of data and circumstances, it would seem to point to something in the B40 sketch that is overwriting or somehow messing with the output frequency on the AD9850. I'm unfamiliar with the AD9850 and the?AD9850SPI library. I'll have to do some deeper investigation.
Thanks,
-Rob (N4MN)??
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On Mon, Nov 27, 2017 at 08:03 pm, Mvs Sarma wrote:
Perhaps you are measuring harmonics, If i am right.
?try a small LPF and then check.? Reduce the gain of the counter 's pre-amplifier.
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Re: Help me understand the USB (upper side band) mod
Richie, ok so I guess the passband crystal filter is symmetric in which case it doesn't care.
Gordon, so if the receiver is decoding in USB and receives a USB signal like "..::?" (as would come from the bitx) where the lower frequency audio in the vocal range ends up on the higher end of the signal, wouldn't this lead to some strange sounding audio?
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Re: Help me understand the USB (upper side band) mod
?typo:? meanto to say,
""the filter can't tell and doesn't care whether the spectrum going through it is upper or lower sideband"
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?the filter can tell and doesn't care whether the spectrum going through it is upper or lower sideband.....
What makes it upper or lower sideband is the relative relationships between the radio frequencies that resulted from low- or high-frequency audio waveforms.
In upper sideband, the higher audio frequencies cause higher RF frequencies.
In lower sideband, the reverse occurs.
The Receiver must provide the carrier back on the proper SIDE of the received spectrum in order to mix (demodoulae) to a recognizable voice signal.
Gordon
Hey David,
I figured this out last year when I could never resolve SSB in any superhet that I built. I got a copy of EMRFD and it all came together. Here is my attempt at explaining it. First, the crystal filter should have a pass band that¡¯s only wide enough for one
sideband (about 3,000 hertz). The BFO frequency positions you on the side band you want to hear. To be in the middle of the pass band, the two BFO frequencies must be 1,500 + - from the center of the filter, which is 3,000 from each other. I hope that helps.
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Re: Help me understand the USB (upper side band) mod
?the filter can tell and doesn't care whether the spectrum going through it is upper or lower sideband.....
What makes it upper or lower sideband is the relative relationships between the radio frequencies that resulted from low- or high-frequency audio waveforms.
In upper sideband, the higher audio frequencies cause higher RF frequencies.
In lower sideband, the reverse occurs.
The Receiver must provide the carrier back on the proper SIDE of the received spectrum in order to mix (demodoulae) to a recognizable voice signal.
Gordon
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Hey David,
I figured this out last year when I could never resolve SSB in any superhet that I built. I got a copy of EMRFD and it all came together. Here is my attempt at explaining it. First, the crystal filter should have a pass band that¡¯s only wide enough for one
sideband (about 3,000 hertz). The BFO frequency positions you on the side band you want to hear. To be in the middle of the pass band, the two BFO frequencies must be 1,500 + - from the center of the filter, which is 3,000 from each other. I hope that helps.
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Re: Help me understand the USB (upper side band) mod
Hey David,
I figured this out last year when I could never resolve SSB in any superhet that I built. I got a copy of EMRFD and it all came together. Here is my attempt at explaining it. First, the crystal filter should have a pass band that¡¯s only wide enough for one sideband (about 3,000 hertz). The BFO frequency positions you on the side band you want to hear. To be in the middle of the pass band, the two BFO frequencies must be 1,500 + - from the center of the filter, which is 3,000 from each other. I hope that helps.
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Hi Allard
at A2 I measure 2V and can not find any short to ground.
Next thing I will try to wire a resitor from A2 to +5V and see what happens - comming back.
Thanks
Gert
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Help me understand the USB (upper side band) mod
So, as I understand it, a SSB signal is where half of an AM signal and the carrier are suppressed. For illustrative purposes, I'll draw a full AM signal like ..::||::.., where || is the carrier and the dots are the upper and lower parts of the signal envelope.?
Ok, so a normal LSB signal should look like "..:: " and USB should look like " ::..".
The USB mod for the Raduino appears to simply change the output frequency be 1500 hz lower. So really, we're transmitting a LSB signal at an offset, which means instead of " ::.." we get "..:: " in the air. Wouldn't this cause problems on the receivers end? I'm assuming their RX filtering would be expecting most of the signal near the carrier, not on the other end.?
For a "true" USB mode, would we need a different filter circuit to suppress the lower side band? I'm still pretty new to this and learning more everyday, please spare no detail in any explanation :)
-David
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Re: Just want a USB switch
?Getting it to do upper side band isn't that terribly difficult, a small mod or two in the raduino sketch will do it ---- but it is just as easy to upload one of Allards' sketches and then it handles the calibration much better and everything else.? ?
I am kinda using his 1.24 sketch and happily modifying that for my purposes.? ?
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Yes. She's 9. We just want a pushbutton to switch from LSB to USB and back again.
So, that's what I'd like to figure out how to do. I've got a heatsink for the final and removed C91 and c92
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Re: Just want a USB switch
Btw, we are building it inside a Hello Kitty or Frozen lunchbox for her
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Re: Just want a USB switch
Yes. She's 9. We just want a pushbutton to switch from LSB to USB and back again.
So, that's what I'd like to figure out how to do. I've got a heatsink for the final and removed C91 and c92
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Re: First real try at 80 meters using QRPKITS 80M low pass filter
That heatsink only 1cm thick but works OK I like to look after the pa I waiting on a kit from EA3GCY called ILER-17+ dds? Going to put it on 15,12,10m its my new winter project chris
On 28 Nov 2017 14:40, "chris gress" < Chrisg0wfh@...> wrote: Yep feel free I have built 3 sets all the same looking I had the dds programmed for me so no credit for them. Chris
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Re: Just want a USB switch
Maybe not enough coffee but at first I though you meant something like this...
And did I read that correctly?? Your daughter is nine years old?
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Re: Just want a USB switch
No but,
If you want any of the features that Allards sketch provides then go for it.
You could add some components to the BFO and have USB.
Raj
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At 28-11-2017, you wrote: Do I really have to use Allard's sketch for this one single mod? I just want a switch to go from LSB to USB.
Thank you
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Re: First real try at 80 meters using QRPKITS 80M low pass filter
Yep feel free I have built 3 sets all the same looking I had the dds programmed for me so no credit for them. Chris
On 28 Nov 2017 14:36, "chris gress" < chrisg0wfh@...> wrote: Cool it worked I upgraded my heatsinks on my pa,s I have added photo the pa never gets hot?
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Re: First real try at 80 meters using QRPKITS 80M low pass filter
?with THAT huge heat sink.....it is no wonder it never gets hot!!!
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Cool it worked I upgraded my heatsinks on my pa,s I have added photo the pa never gets hot?
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Re: First real try at 80 meters using QRPKITS 80M low pass filter
Cool it worked I upgraded my heatsinks on my pa,s I have added photo the pa never gets hot?
On 28 Nov 2017 14:23, "chris gress" < Chrisg0wfh@...> wrote: OK let's see if this works? Photo showing 8watts powered at 12v Photo showing 13watts powered at 13,5v In to 50ohm dummy load?
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Re: First real try at 80 meters using QRPKITS 80M low pass filter
?VERY COOL!!!!? ?Thanks for the schematic!!!? (and the rig looks nice too)
Now can I have permission to publish that on our ARES web site at qsl.net/nf4rc???
THANKS!!
Gordon?
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OK let's see if this works?
Photo showing 8watts powered at 12v
Photo showing 13watts powered at 13,5v
In to 50ohm dummy load?
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This may be a stupid question. I'm just getting into the bitx40. Actually, I've only been a ham about 3 months. My daughter is 9 and wants the bitx40 fir talking and FT8. She's a tech, but taking her general this weekend.
I removed C91 and C92. I took apart an old power supply and swiped the heatsink for the final. From what I understand, all that needs to be changed is a + to a - to go from 19 to 12 and be on USB.
Do I really have to use Allard's sketch for this one single mod? I just want a switch to go from LSB to USB.
Thank you
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Re: First real try at 80 meters using QRPKITS 80M low pass filter
OK let's see if this works? Photo showing 8watts powered at 12v Photo showing 13watts powered at 13,5v In to 50ohm dummy load?
On 28 Nov 2017 14:00, "chris gress" < Chrisg0wfh@...> wrote: OK I don't have PC I see if I can do it with my phone chris
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Re: First real try at 80 meters using QRPKITS 80M low pass filter
OK I don't have PC I see if I can do it with my phone chris
On 28 Nov 2017 13:48, "Gordon Gibby" < ggibby@...> wrote:
Would you be able to scribble down a portion of the schematic, putting the original capacitors etc in black, and your changes? for 60 meters?in RED or some other color, and then take a photo with a cell phone camera and post it here for posterity?? ?That
might help out other people......
Gordon?
I need to correct one thing it should be 100pf on L7 not 470pf sorry chris
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Rob Cox (N4MN)
Arvo W0VRA
Raj vu2zap
