|
Success! Maybe there's more that can be done at Q6, but it is
MUCH improved with a 10k resistor to ground at the output of C51.
Still Could be multiple causes, so still worth experimenting. I'll
dig the scope out and see.
There's a ground point very near C1, so you can scrape the
coating off of that and bridge a 10k chip resistor across the two.
Photos enclosed.
John K0JD
On 12/21/2017 11:55, Jerry Gaffke via
Groups.Io wrote:
toggle quoted message
Show quoted text
But
Q70 gets powered up on RX, and Q6 gets powered up on TX.
That power switching is really disruptive.
Might leave them both powered up, then the DC bias resistor should
work fine, if you somehow kill the microphone
But given what we got, I'm leaning toward the FET clamp on rx
audio.
Reducing the size of C52 on Q70 might help get the pop over with
quickly.
In addition to the audio pop in the phones on rx, the uBitx may
have the Bitx40's? carrier burst on tx.?
? ??/g/BITX20/message/33707
Allard has been fixing some of this with delays in firmware.
If we can get by without a special interrupt library in the code,
the sketch will be much easier to
understand, add features to, and port to other processors.?
So I'd prefer to fix the rx pop and tx burst with hardware hacks.
Jerry, KE7ER
|
Is there a similar mod for the bitx40? I'm assuming by "pop" you mean the PTT pop issue?
-David, K4DBZ
On Thu, Dec 21, 2017 at 1:29 PM John Seboldt K0JD < k0jd-l@...> wrote:
Success! Maybe there's more that can be done at Q6, but it is
MUCH improved with a 10k resistor to ground at the output of C51.
Still Could be multiple causes, so still worth experimenting. I'll
dig the scope out and see.
There's a ground point very near C1, so you can scrape the
coating off of that and bridge a 10k chip resistor across the two.
Photos enclosed.
John K0JD
On 12/21/2017 11:55, Jerry Gaffke via
Groups.Io wrote:
But
Q70 gets powered up on RX, and Q6 gets powered up on TX.
That power switching is really disruptive.
Might leave them both powered up, then the DC bias resistor should
work fine, if you somehow kill the microphone
But given what we got, I'm leaning toward the FET clamp on rx
audio.
Reducing the size of C52 on Q70 might help get the pop over with
quickly.
In addition to the audio pop in the phones on rx, the uBitx may
have the Bitx40's? carrier burst on tx.?
? ??/g/BITX20/message/33707
Allard has been fixing some of this with delays in firmware.
If we can get by without a special interrupt library in the code,
the sketch will be much easier to
understand, add features to, and port to other processors.?
So I'd prefer to fix the rx pop and tx burst with hardware hacks.
Jerry, KE7ER
|
The corresponding place is C115 in the BitX40. Looks like the
circuit is similar enough that the other issues we're pursuing
would apply.
This isn't a total fix but for one component it sure helps.
John K0JD
On 12/21/2017 12:31, David Arthur
wrote:
toggle quoted message
Show quoted text
Is there a similar mod for the bitx40? I'm assuming
by "pop" you mean the PTT pop issue?
-David, K4DBZ
On Thu, Dec 21, 2017 at 1:29 PM John Seboldt K0JD
< k0jd-l@...>
wrote:
Success! Maybe there's more that can be done at Q6, but
it is MUCH improved with a 10k resistor to ground at the
output of C51. Still Could be multiple causes, so still
worth experimenting. I'll dig the scope out and see.
There's a ground point very near C1, so you can scrape
the coating off of that and bridge a 10k chip resistor
across the two. Photos enclosed.
John K0JD
On
12/21/2017 11:55, Jerry Gaffke via Groups.Io wrote:
But Q70 gets powered up on RX, and
Q6 gets powered up on TX.
That power switching is really disruptive.
Might leave them both powered up, then the DC bias
resistor should work fine, if you somehow kill the
microphone
But given what we got, I'm leaning toward the FET clamp on
rx audio.
Reducing the size of C52 on Q70 might help get the pop
over with quickly.
In addition to the audio pop in the phones on rx, the
uBitx may have the Bitx40's? carrier burst on tx.?
? ??/g/BITX20/message/33707
Allard has been fixing some of this with delays in
firmware.
If we can get by without a special interrupt library in
the code, the sketch will be much easier to
understand, add features to, and port to other
processors.?
So I'd prefer to fix the rx pop and tx burst with hardware
hacks.
Jerry, KE7ER
|
"Success! Maybe there's more that can be done at Q6, but it is MUCH improved with a 10k resistor to ground at the output of C51. Still Could be multiple causes, so still worth experimenting. I'll dig the scope out and see.
There's a ground point very near C1, so you can scrape the coating off of that and bridge a 10k chip resistor across the two. Photos enclosed.?
John K0JD"
Very cool....!!!
If you are putting it at the output of C51 you might be able to have similar effect with a 10K from the top lug of the volume control to the bottom (ground) lug.??
Gordon
toggle quoted message
Show quoted text
Success! Maybe there's more that can be done at Q6, but it is MUCH improved with a 10k resistor to ground at the output of C51. Still Could be multiple causes, so still worth experimenting. I'll dig the scope out and see.
There's a ground point very near C1, so you can scrape the coating off of that and bridge a 10k chip resistor across the two. Photos enclosed.
John K0JD
On 12/21/2017 11:55, Jerry Gaffke via Groups.Io wrote:
But Q70 gets powered up on RX, and Q6 gets powered up on TX.
That power switching is really disruptive.
Might leave them both powered up, then the DC bias resistor should work fine, if you somehow kill the microphone
But given what we got, I'm leaning toward the FET clamp on rx audio.
Reducing the size of C52 on Q70 might help get the pop over with quickly.
In addition to the audio pop in the phones on rx, the uBitx may have the Bitx40's? carrier burst on tx.?
? ??
Allard has been fixing some of this with delays in firmware.
If we can get by without a special interrupt library in the code, the sketch will be much easier to
understand, add features to, and port to other processors.?
So I'd prefer to fix the rx pop and tx burst with hardware hacks.
Jerry, KE7ER
|
John, where you show the resistor from C51 to ground in the picture should have no effect.? According to the schematic AND my measurements, that side of C51 is already grounded through M1 on the latest schematic.? You might re-check your logic on this one?
Jim - W0EB
|
Or change to a lower value pot, like maybe 5k.
Vince.
toggle quoted message
Show quoted text
On 12/21/2017 02:40 PM, Gordon Gibby wrote: "Success! Maybe there's more that can be done at Q6, but it is MUCH
improved with a 10k resistor to ground at the output of C51. Still Could
be multiple causes, so still worth experimenting. I'll dig the scope out
and see.
There's a ground point very near C1, so you can scrape the coating off
of that and bridge a 10k chip resistor across the two. Photos enclosed.
John K0JD"
Very cool....!!!
If you are putting it at the output of C51 you might be able to have
similar effect with a 10K from the top lug of the volume control to the
bottom (ground) lug.
Gordon
------------------------------------------------------------------------
*From:* [email protected] <[email protected]> on behalf of John Seboldt
K0JD <k0jd-l@...>
*Sent:* Thursday, December 21, 2017 1:24 PM
*To:* [email protected]
*Subject:* [BITX20] SUCCESS, uBITX pop reduction with ONE added component
Success! Maybe there's more that can be done at Q6, but it is MUCH
improved with a 10k resistor to ground at the output of C51. Still Could
be multiple causes, so still worth experimenting. I'll dig the scope out
and see.
There's a ground point very near C1, so you can scrape the coating off
of that and bridge a 10k chip resistor across the two. Photos enclosed.
John K0JD
On 12/21/2017 11:55, Jerry Gaffke via Groups.Io wrote:
But Q70 gets powered up on RX, and Q6 gets powered up on TX.
That power switching is really disruptive.
Might leave them both powered up, then the DC bias resistor should
work fine, if you somehow kill the microphone
But given what we got, I'm leaning toward the FET clamp on rx audio.
Reducing the size of C52 on Q70 might help get the pop over with quickly.
In addition to the audio pop in the phones on rx, the uBitx may have
the Bitx40's carrier burst on tx.
/g/BITX20/message/33707
<>
Allard has been fixing some of this with delays in firmware.
If we can get by without a special interrupt library in the code, the
sketch will be much easier to
understand, add features to, and port to other processors.
So I'd prefer to fix the rx pop and tx burst with hardware hacks.
Jerry, KE7ER
--
Michigan VHF Corp.
|
It only has a resistive path to ground in receive, via the relay
in receive through the volume control. In transmit it's lifted,
and the end of the capacitor can float up, waiting to pop when
it's re-energized. Maybe.
There is an improvement, so it's *part* of the possible fix.
Certainly a quick fix that did something.
On 12/21/2017 14:14, Jim Sheldon wrote:
toggle quoted message
Show quoted text
John, where you
show the resistor from C51 to ground in the picture should have no
effect.? According to the schematic AND my measurements, that side
of C51 is already grounded through M1 on the latest schematic.?
You might re-check your logic on this one?
Jim - W0EB
|
Not sure why that would help, since there's no capacitor on that
side to keep drained.
The rest of the noise is probably transients from switching on Q6
for transmit.? I think that MOSFET grounding approach is the best
long term solution.
John K0JD
On 12/21/2017 13:40, Gordon Gibby
wrote:
toggle quoted message
Show quoted text
"Success! Maybe there's more that can be done at Q6, but it is
MUCH improved with a 10k resistor to ground at the output of
C51. Still Could be multiple causes, so still worth
experimenting. I'll dig the scope out and see.
There's a ground point very near C1, so you can scrape the
coating off of that and bridge a 10k chip resistor across the
two. Photos enclosed.?
John K0JD"
Very cool....!!!
If you are putting it at the output of C51 you might be able to
have similar effect with a 10K from the top lug of the volume
control to the bottom (ground) lug.??
Gordon
|
Sorry, OM. I didn't notice anything after installing this smd part. Still a pop when starting and finishing tx, but I'll get used to it.
As Microsoft states "Windows have no bugs, they're properties".
Kai, OH3WE
|
I heard it called " it
is a new Feature"!
Mike, WA6ISP
On 3/28/2018 6:34 AM, Kai Nilakari
wrote:
Sorry, OM. I didn't
notice anything after installing this smd part. Still a pop when
starting and finishing tx, but I'll get used to it.
As Microsoft states "Windows have no bugs, they're properties".
Kai, OH3WE
--
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID "MotDog@..."
Mike@...
|
Jim Sheldon