Re: Carrier Null revisited
grossly testing my rig tonight (with a receiver right near it) I can hear some carrier also but it doesn't move the SWR or power needle at all on a cheap SWR meter, and whistling I can get several watts (like 60% upscale movement of the meter). So the carrier is many dB below the SSB, just maybe not oodles of dB lower. both of my 2 bitx40's have the combined diode with no adjustment. ________________________________________ From: [email protected] < [email protected]> on behalf of Keith VE7GDH <ve7gdh@...> Sent: Monday, October 30, 2017 9:05 PM To: [email protected]Subject: Re: [BITX20] Carrier Null revisited Grayson KJ7UM wrote... > I can¡¯t even find the dual diode on the board or > where R105 used to be. See the hand drawing that I posted. I marked them D15 / D16 like in the drawing, even though it is a dual-diode in one package. I think Dexter said it is labeled D20 now. I didn't pop the lid to look. I wouldn't be too hasty in removing the diodes though before checking it out a bit further. -- 73 Keith VE7GDH
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Re: Carrier Null revisited
Grayson KJ7UM wrote... I can¡¯t even find the dual diode on the board or
where R105 used to be. See the hand drawing that I posted. I marked them D15 / D16 like in the drawing, even though it is a dual-diode in one package. I think Dexter said it is labeled D20 now. I didn't pop the lid to look. I wouldn't be too hasty in removing the diodes though before checking it out a bit further. -- 73 Keith VE7GDH
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Re: Carrier Null revisited
The dual-diode is labelled D20 on the board, and it's inside the triangle formed by the pads for a large version of the Pot - which is depicted. D20 is obscuring the wiper pad for the smaller (standard) version of the pot, which is the same style as R136 the Tx drive pot. The whole shebang sits next to the toroid (that looks like a 6-pin IC) bottom-left on the Wire Up picture on hfsigs site.
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Re: Board Layout Drawing?
Grayson KJ7UM wrote¡ Is there a drawing someplace that shows component placement on the board? Attached is a very crude hand-drawn component placement drawing. It doesn¡¯t show every part, but has the transistors etc. marked, so it might be enough to direct you to the right vicinity. Let me know if the resolution is too low. -- 73 Keith VE7GDH
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Re: Carrier Null revisited
On Mon, Oct 30, 2017 at 01:58 pm, Grayson Evans wrote:
So i heard about the diode/pot replacement, but I can¡¯t even find the dual diode on the board or where R105 used to be.
My own board is nearly one year old and it still has the balance pot installed. Could you perhaps make a photo of this area on your BitX board and share it with us? I'm sure someone in this group will be able to identify the dual diode for you. 73 Allard PE1NWL
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Re: Need picture of 8 pin connector
Thank you all for your help.?
Bill?
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Re: Need picture of 8 pin connector
The 8-pin connector on the *Raduino* attaches through to the A lines of the *Arduino*. On <http://www.hfsigs.com/bitx40v3_circuit.html>, at the Bottom of the page is the explanation: it's the CONTROLS connector. Note that the numbering there is reversed, but in order (with a gap or two). A0 is the right-most, and the A numbers increase leftwards. The plug as supplied with loom wiring has the wires color-coded per the Resistor color code: 0 is black, 1 is brown ... Yellow and green are +5 and 0V, taking the A4 and A5 places, purple (I call it violet, it's my NZ Post Office loom-colour naming, just like grey is slate ...) is to A7. The other 'looms' are similarly coded, but the colors are as per the diagram *minus one*! Pin 1 has the black (0) wire ... It's logical, with a bit of mental arithmetic.
73 de ZL2DEX
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Re: Need picture of 8 pin connector
BTW, one easy way to remember the colours:
It's just the same as the colour code as used on resistors:
0 - black
1 - brown
2 - red
3 - orange
4 - yellow
5 - green
6 - blue
7 - violet
73 Allard PE1NWL
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On Mon, October 30, 2017 22:52, Allard PE1NWL wrote:
pin A2 noramally has the red wire (not shown on the picture)
73 Allard PE1NWL
On Mon, October 30, 2017 22:46, W4YAH@... wrote:
I need a picture of the 8 pin connector so I can re-attach the wires to
calibrate my BITX40.??
THANKS,??
BILL, W4YAH
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Re: Need picture of 8 pin connector
pin A2 noramally has the red wire (not shown on the picture)
73 Allard PE1NWL
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On Mon, October 30, 2017 22:46, W4YAH@... wrote: I need a picture of the 8 pin connector so I can re-attach the wires to
calibrate my BITX40.??
THANKS,??
BILL, W4YAH
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Need picture of 8 pin connector
I need a picture of the 8 pin connector so I can re-attach the wires to calibrate my BITX40.?
THANKS,?
BILL, W4YAH?
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Re: Carrier Null revisited
I agree. ?I should have written down the levels. ?I will do that when I get home tonite and post it. ?
I am just grounding the PTT line to key it, no microphone attached.?
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On Oct 30, 2017, at 2:44 PM, Gordon Gibby < ggibby@...> wrote:
I think we need some numbers here. What is the gentleman's peak output, measured and whatever method he has, either watts, or even a relative reading on some swr or other indicator....
Exactly how is he "keying" the machine, does he mean he is closing the push to talk?
What is the output (on the same measurement system as above) when there is no audio mic signal??
At least then we would have some idea of whether his carrier level is zero, five, 10, or more DB below his peak output.
"A lot" it's just terribly vague.....
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Re: Carrier Null revisited
I will definitely try this.
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I remember that Farhan posted something a while back that said if you are driving the PA too hard you will see some carrier.
Decrease the PA drive (RV136) a bit and it should go away.?
Michael VE3WMB?
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Re: Carrier Null revisited
So i heard about the diode/pot replacement, but I can¡¯t even find the dual diode on the board or where R105 used to be.
I am keying the transmitter into a dummy load and monitoring with a scope. ? I am also listening on a Collins receiver with its antenna disconnected. ?The carrier seems way to high but I didn¡¯t write down the exact voltage on the scope. ?The receiver across the room shows an S9 with no antenna, but the metal enclosure on the BiTX is open, so a lot of signal escaping. ?
Also, the audio sounds terrible from the little crystal mic. ?I injected a 20mV 400 cycle tone into the mic input just to see if it was the mic. ?The tone also sounds terrible. ?Sounds like the tone is modulated with another low frequency (I checked DC supply and its clean).
I was going to do some signal following with the scope, but I have a heck of a time trying to identify where the components are on the board. ?In another post I asked if anyone has a board layout drawing. There is one somewhere but not on Farhans site.
Thanks KJ7UM Grayson
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On Oct 30, 2017, at 2:28 PM, Jerry Gaffke via Groups.Io < jgaffke@...> wrote:
Most of these seem to have the carrier pretty well suppressed without adjustment.
The change to the dual-diode bat54s was made to avoid the need for such an adjustment,
since the two schottky diodes in that package are on the same die and at the same temperature,?
thus well matched. ?Unfortunately, the two diodes in the bat54s are joined where the bitx40 schematic?
shows the 100 ohm pot, so the pot won't work with the bat54s. ?There are other diode arrays
where they are on the same die but have the two diodes separated out.
Schottky or a standard 1n4148 silicon diode both seem to work fine.
Should be easy enough to remove the bat54s and add back in a couple diodes and a 100 ohm pot,
if that's what you want. ?Though my guess is that there may be something else wrong here.
Exactly how are you measuring the carrier level on your transmissions?
Yes, you will be able to hear it on a receiver in the same area, but it typically is not strong enough
to be of any concern.
Jerry
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Re: Carrier Null revisited
I think we need some numbers here.
What is the gentleman's peak output, measured and whatever method he has, either watts, or even a relative reading on some swr or other indicator....
Exactly how is he "keying" the machine, does he mean he is closing the push to talk?
What is the output (on the same measurement system as above) when there is no audio mic signal??
At least then we would have some idea of whether his carrier level is zero, five, 10, or more DB below his peak output.
"A lot" it's just terribly vague.....
Sent from my iPhone
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>From:?Grayson
Evans
>Date: Mon, 30 Oct 2017 12:35:00 EDT?
>Just finished building out a new BITX40 board. Works, but there is a LOT of carrier when keyed (no mic installed).?
I remember that Farhan posted something a while back that said if you are driving the PA too hard you will see some carrier.
Decrease the PA drive (RV136) a bit and it should go away.?
Michael VE3WMB?
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Re: Carrier Null revisited
>From:?Grayson Evans>Date: Mon, 30 Oct 2017 12:35:00 EDT?>Just finished building out a new BITX40 board. Works, but there is a LOT of carrier when keyed (no mic installed).?
I remember that Farhan posted something a while back that said if you are driving the PA too hard you will see some carrier. Decrease the PA drive (RV136) a bit and it should go away.?
Michael VE3WMB?
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Re: Carrier Null revisited
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Re: Carrier Null revisited
Most of these seem to have the carrier pretty well suppressed without adjustment.
The change to the dual-diode bat54s was made to avoid the need for such an adjustment,
since the two schottky diodes in that package are on the same die and at the same temperature,
thus well matched. ?Unfortunately, the two diodes in the bat54s are joined where the bitx40 schematic
shows the 100 ohm pot, so the pot won't work with the bat54s. ?There are other diode arrays
where they are on the same die but have the two diodes separated out.
Schottky or a standard 1n4148 silicon diode both seem to work fine.
Should be easy enough to remove the bat54s and add back in a couple diodes and a 100 ohm pot,
if that's what you want. ?Though my guess is that there may be something else wrong here.
Exactly how are you measuring the carrier level on your transmissions?
Yes, you will be able to hear it on a receiver in the same area, but it typically is not strong enough
to be of any concern.
Jerry
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On Mon, Oct 30, 2017 at 11:09 am, Grayson Evans wrote:
Exactly. ?I haven¡¯t worked on a SSB rig that did not include a carrier null adjustment. Kind of surprised.
?
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Re: Carrier Null revisited
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Exactly. I haven?€?t worked on a SSB rig that did not include a carrier
null adjustment. Kind of surprised.
On Oct 30, 2017, at 1:59 PM, Allard PE1NWL <pe1nwl@...> wrote:
I guess what he means is that when he keys the PTT, he has some
rest-carrier (even when no mic is installed, so without modulating).
73 Allard PE1NWL
On Mon, October 30, 2017 17:45, Vince Vielhaber wrote:
You have carrier? Did you add the CW mod? (10K resistor)
Vince.
Just finished building out a new BITX40 board. Works, but there is a
LOT
of carrier when keyed (no mic installed).
I take it from previous posts that the diodes and null pot (R105) were
removed. Dont exist on my board.
This is inconvenient. How the heck is a builder supposed to fix
carrier
null with no null, AND no way to adjust the BFO frequency.
Did cost reduction make this board useless for adjustments?
--
Michigan VHF Corp.
--
Michigan VHF Corp.
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Re: Carrier Null revisited
I understand that. But if there's voltage on that resistor, whether or
not it's connected to the raduino, there will be carrier. That's how my
tune mod works - key the mic or press ptt. Audio not required.
Vince.
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I guess what he means is that when he keys the PTT, he has some
rest-carrier (even when no mic is installed, so without modulating).
73 Allard PE1NWL
On Mon, October 30, 2017 17:45, Vince Vielhaber wrote:
You have carrier? Did you add the CW mod? (10K resistor)
Vince.
Just finished building out a new BITX40 board. Works, but there is a
LOT
of carrier when keyed (no mic installed).
I take it from previous posts that the diodes and null pot (R105) were
removed. Dont exist on my board.
This is inconvenient. How the heck is a builder supposed to fix
carrier
null with no null, AND no way to adjust the BFO frequency.
Did cost reduction make this board useless for adjustments?
--
Michigan VHF Corp.
--
Michigan VHF Corp.
|
Re: Carrier Null revisited
Exactly. ?I haven¡¯t worked on a SSB rig that did not include a carrier null adjustment. Kind of surprised.
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On Oct 30, 2017, at 1:59 PM, Allard PE1NWL < pe1nwl@...> wrote:
I guess what he means is that when he keys the PTT, he has somerest-carrier (even when no mic is installed, so without modulating).73 Allard PE1NWLOn Mon, October 30, 2017 17:45, Vince Vielhaber wrote:
You have carrier? ?Did you add the CW mod? ?(10K resistor)
Vince.
Just finished building out a new BITX40 board. ?Works, but there is a
LOT
of carrier when keyed (no mic installed).
I take it from previous posts that the diodes and null pot (R105) were
removed. ??Dont exist on my board.
This is inconvenient. ?How the ?heck is a builder supposed to fix
carrier
null with no null, AND no way to adjust the BFO frequency.
Did cost reduction make this board useless for adjustments?
--
??Michigan VHF Corp. ?? ??
??????????????
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Allard PE1NWL
BillBolen