Topics

Audio feedback during transmit? #ubitx

 

I'm having audio feedback during transmit through my external speaker.!  I have the issue even with a dummy load.  I hear my voice (distorted) on the receive side when transmitting on any band. Anyone else have this issue?
Thanks,,
Jim W0CHL

Joe
 

Plenty of builders have had this problem.   Lots of fixes.

The one I used was, I just added a small low trigger 5v relay .
I put the relay trigger across the PTT of the ubitx, so when Ptt is pressed, the low level triggers the relay.  
I feed my speaker to the  normally closed contacts so when the relay is triggered, it opens the Speaker path and connects the path to a 10 ohm resistor to gnd
Result: no Sound coming from external speaker.

Joe
ve1bwv


On Mon, Jun 18, 2018 at 7:00 PM Jim Reagan <jimreagans@...> wrote:
I'm having audio feedback during transmit through my external speaker.!  I have the issue even with a dummy load.  I hear my voice (distorted) on the receive side when transmitting on any band. Anyone else have this issue?
Thanks,,
Jim W0CHL

iz oos
 

Excellent solution, does it also remove the thump?


Il 19/giu/2018 02:44, "Joe" <joeman2116@...> ha scritto:
Plenty of builders have had this problem.   Lots of fixes.

The one I used was, I just added a small low trigger 5v relay .
I put the relay trigger across the PTT of the ubitx, so when Ptt is pressed, the low level triggers the relay.  
I feed my speaker to the  normally closed contacts so when the relay is triggered, it opens the Speaker path and connects the path to a 10 ohm resistor to gnd
Result: no Sound coming from external speaker.

Joe
ve1bwv


On Mon, Jun 18, 2018 at 7:00 PM Jim Reagan <jimreagans@...> wrote:
I'm having audio feedback during transmit through my external speaker.!  I have the issue even with a dummy load.  I hear my voice (distorted) on the receive side when transmitting on any band. Anyone else have this issue?
Thanks,,
Jim W0CHL

Joe
 

I installed one of the thump fixes which uses a 2n7000 and a resistor.

Joe
Ve1bwv


On Tue, Jun 19, 2018, 8:41 AM iz oos <and2oosiz2@...> wrote:

Excellent solution, does it also remove the thump?


Il 19/giu/2018 02:44, "Joe" <joeman2116@...> ha scritto:
Plenty of builders have had this problem.   Lots of fixes.

The one I used was, I just added a small low trigger 5v relay .
I put the relay trigger across the PTT of the ubitx, so when Ptt is pressed, the low level triggers the relay.  
I feed my speaker to the  normally closed contacts so when the relay is triggered, it opens the Speaker path and connects the path to a 10 ohm resistor to gnd
Result: no Sound coming from external speaker.

Joe
ve1bwv


On Mon, Jun 18, 2018 at 7:00 PM Jim Reagan <jimreagans@...> wrote:
I'm having audio feedback during transmit through my external speaker.!  I have the issue even with a dummy load.  I hear my voice (distorted) on the receive side when transmitting on any band. Anyone else have this issue?
Thanks,,
Jim W0CHL

ajparent1/KB1GMX
 

Simple solution was to use a mic that has enough contacts on PTT to allow interrupting the 
mic audio on receive.  

The pop and click mods usually help with audio on the speaker during tx.

Allison

 

Well, this has been interesting...  I started playing with a relay, which worked, but on the air testing with a local amateur made me wonder if "maybe" I had the radio setup improperly. He said my audio sounded "Weird and weak".
So I started using uBiTX memory manager. I read many of the calibration procedures and played with some of the calibration and BFO numbers.  Once I got the radio setup to my liking, the audio "feedback" during transmit went away!  Am I crazy, or was this part of the problem? 
Your mileage may vary,
Jim W0CHL

Tim Gorman
 

The only time I have had this problem was with a bad ground connection
between the ubitx and the chassis it was mounted in.

Could it be that you somehow fixed a bad ground while playing with the
relay?

tim ab0wr

On Wed, 20 Jun 2018 09:33:52 -0700
"Jim Reagan" <@jrprogrammer> wrote:

Well, this has been interesting...  I started playing with a relay,
which worked, but on the air testing with a local amateur made me
wonder if "maybe" I had the radio setup improperly. He said my audio
sounded "Weird and weak". So I started using uBiTX memory manager. I
read many of the calibration procedures and played with some of the
calibration and BFO numbers.  Once I got the radio setup to my
liking, the audio "feedback" during transmit went away!  Am I crazy,
or was this part of the problem? Your mileage may vary, Jim W0CHL


Mark M
 

Mine started doing it when I installed the ND6T/K5BCQ AGC board. It's not a ground issue, when I remove the board it stops. It looks to be correctly wired but I suppose I coulda fried something...it was my first real SMD assembly effort. It happens even with the board not connected to the RF path, i.e. just 5v and VOL-H connected. I suspect I screwed it up somehow. Maybe I'll assemble the second one I have and see if it works any differently.

Mark     AA7TA

 

I also have the ND6T modification in my radio, but after redoing the calibration and BFO setting, no longer have the issue.  I suppose one could add a small 5 volt relay and disable the AGC while transmitting.
Your mileage may vary,
Jim W0CHL

pat griffin
 

I have the same issue. Started with installation of agc board. I have some relatively long cables owing to use of clamshell cabinet with raduino on one side and board on another and thought that might be cause. Redid shielding grounds etc still no cigar. Finally just took 12 v from tr through v reg so agc board is only on during receive 
73 aa4pg


On Jun 22, 2018, at 7:15 AM, Jim Reagan <jimreagans@...> wrote:

I also have the ND6T modification in my radio, but after redoing the calibration and BFO setting, no longer have the issue.  I suppose one could add a small 5 volt relay and disable the AGC while transmitting.
Your mileage may vary,
Jim W0CHL

Tim Gorman
 

I have done this on two units. I bring +5v/Gnd to the board from a
7805 regulator I added in each unit for powering several add-on's
by using a tightly twisted pair of wires. Actually the twisted pair is
scavanged from a length of cat 5e cable. I've had no problem with
either unit.

tim ab0wr

On Fri, 22 Jun 2018 13:00:49 +0000
"pat griffin" <patgriffin@...> wrote:

I have the same issue. Started with installation of agc board. I have
some relatively long cables owing to use of clamshell cabinet with
raduino on one side and board on another and thought that might be
cause. Redid shielding grounds etc still no cigar. Finally just took
12 v from tr through v reg so agc board is only on during receive 73
aa4pg On Jun 22, 2018, at 7:15 AM, Jim Reagan
<@jrprogrammer<mailto:@jrprogrammer>> wrote:

I also have the ND6T modification in my radio, but after redoing the
calibration and BFO setting, no longer have the issue. I suppose one
could add a small 5 volt relay and disable the AGC while
transmitting. Your mileage may vary, Jim W0CHL



Bruce
 

Thanks for that. I had posted "uBitX SSB transmit oscillations on 40m only" but then noticed lesser sound from the speaker on higher frequencies. I do not know the "uBiTX memory manager" but it is time I learn.

Thomas Clark
 

On Mon, Jun 18, 2018 at 06:00 PM, Jim Reagan wrote:
I'm having audio feedback during transmit through my external speaker.!  I have the issue even with a dummy load.  I hear my voice (distorted) on the receive side when transmitting on any band. Anyone else have this issue?
Thanks,,
I have the same problem. It started after I added an Adafruit 2.5W audio amp in the speaker line. The audio volume is great now but the microphone. Would shielding on the audio lines help?

Daniel Conklin
 

I wasn't having that problem until I installed the AGC board.  Then, when it happened, I soldered a 10nF ceramic capacitor across the audio pot from high side to ground.  The feedback went away, but I noticed the audio has less high response.
Dan, W2DLC

Ian Reeve
 

The cap you fitted is acting as a top cut tone control so you will loose some top end clarity.you could try different values as there will be a trade off between feedback from transmission being killed and audio loosing it's top.For Ssb you only need audio between 300 hz and 3000hz.Probably the supplied speaker is not the best and you may find replacing that brings back some of the lost crispness.For me using screened wire for audio and twisting the wire harnesses has given me no issues.I put a small ferrite core on the leads to the led and screened the speaker wiring.  Ian M0IDR


From: BITX20@groups.io <BITX20@groups.io> on behalf of Daniel Conklin <danconklin2@...>
Sent: Monday, August 20, 2018 9:44:34 PM
To: BITX20@groups.io
Subject: Re: [BITX20] Audio feedback during transmit? #ubitx
 
I wasn't having that problem until I installed the AGC board.  Then, when it happened, I soldered a 10nF ceramic capacitor across the audio pot from high side to ground.  The feedback went away, but I noticed the audio has less high response.
Dan, W2DLC