Date   
Re: RFI from uBitx TX after AGC and other mods installed

Rick Price
 

I think it would be eaiser to shield the little pcb with foil before moving it due to the interconnect wires.  May try that first as the pcb is very small and mounted to the back of the RF Gain pot. The PCB is fabircated like Don explained in his first description of the board. My PCB is not the Kee's kit. I'll let you know how the shielding works out.
Rick
KN4AIE



From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of John KC9OJV
Sent: Sunday, July 01, 2018 9:49 AM
To: BITX20@groups.io
Subject: Re: [BITX20] RFI from uBitx TX after AGC and other mods installed

Rick, If it's the PCB what about putting it below the ground plane in the same relative position as the suggested spot next to the RF relays?

John
KC9OJV

Re: Anyone seen an SSB xmit causing the menu to pop up?

Gwen Patton
 

I'm running on a different battery than the jump box I was using before. It should have sufficient amperage. I'll test it with my bench supply and see if it does it under those conditions. It's odd, though, I was running my bench supply in current limit mode at 1.5 and 2 amps, and it didn't exhibit this behavior. It almost seemed like the RF was getting into the Nano and triggering the menu event for some reason. Very peculiar.

It behaves precisely as if I pushed the encoder knob in to operate the menu switch. I key the mike, speak loudly into it or whistle into it, and BAM, the radio goes into menu mode and receive stops. I can get out of it by pushing the knob twice to cycle band select mode, but it's annoying. I was just wondering if someone else spotted this behavior and added ferrites or some other solution. I'll keep fiddling with it.

Re: Anyone seen an SSB xmit causing the menu to pop up?

Jack Purdum
 

Quite a while ago I was messing with some Nano code, but had my FT-1200 on, too. I grabbed the mike and answered a CQ and I remember the Nano display changing when I activated the mic. It turns out that the coax to the antenna switch passed within inches of the Nano. I put two ferrite beads on the coax and it didn't happen again. FWIW.

Jack, W8TEE

On Sunday, July 1, 2018, 11:15:07 AM EDT, Gwen Patton <ardrhi@...> wrote:


I'm running on a different battery than the jump box I was using before. It should have sufficient amperage. I'll test it with my bench supply and see if it does it under those conditions. It's odd, though, I was running my bench supply in current limit mode at 1.5 and 2 amps, and it didn't exhibit this behavior. It almost seemed like the RF was getting into the Nano and triggering the menu event for some reason. Very peculiar.

It behaves precisely as if I pushed the encoder knob in to operate the menu switch. I key the mike, speak loudly into it or whistle into it, and BAM, the radio goes into menu mode and receive stops. I can get out of it by pushing the knob twice to cycle band select mode, but it's annoying. I was just wondering if someone else spotted this behavior and added ferrites or some other solution. I'll keep fiddling with it.

Re: RFI from uBitx TX after AGC and other mods installed

Lawrence Galea
 

Did you put 100n, 10n, 1n filter capacitors  all in parallel on both input and output directly across the 78L05 leads?
.


On Sun, Jul 1, 2018 at 2:31 PM, Rick Price <rickprice48@...> wrote:
John, Don, others,
Yesterday I attached a 78L05 (TO220) directly to the back of the AGC board that is mounted to the RF gain control on the front panel. Bypassed all power leads and ran a separate power lead to the 12V regulator that powers my uBitx. In other words the AGC board had its own isolated(?) power source. Stll heard the audio when transmitting.  Beginning to think that radiated power is being absorbed by the AGC board and then recitifed and then coupled into the audio system. I also have the pop click board installed and not sure if this was a problem before it was installed. My AGC board is one I fabricated using Don's technique of cutting pcb with an x-acto knife.  I also have a AGC board made on perf board using through hole parts.  May sub that in and see if there are any changes. I eventually plan on installing the JackAl mod when it becomes available so this problem should go away for me but its beginning to become a challenge to fix.
 
Rick KN4AIE


From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of John KC9OJV
Sent: Sunday, July 01, 2018 8:05 AM
To: BITX20@groups.io
Subject: Re: [BITX20] RFI from uBitx TX after AGC and other mods installed

Don,
I spent part of yesterday applying ferrites to this and that to little success. I also tried wrapping the 5v line around the twisted pair coming from the volume pot and that did some good. This morning I was thinking about fixing a 7805 to the metal base of my case, drilling a hole in the ground plane and routing a wire through that hole to feed the AGC board. It could be driven off the 12v relay (K1?). Has anyone else had any ideas/success?

John
KC9OJV


Re: RFI from uBitx TX after AGC and other mods installed

Lawrence Galea
 

Also try putting a 100n directly across Q1 base-emitter on the AGC board.
It will cut off some of the higher AF as it would be in series with C1 to earth across the Af gain control.  
However, this would not be of any serious consequences.
If you don't want as much AF HF cut off you can try a smaller capacitor, say 10n.
I am thinking that Q1 base-emitter junction is acting as a detector and the AF is being coupled back to the AF gain control since the level is varying with the AF Gain control.
One could also add say a 10n capacitor directly on pin 7 of the TDA2822 or across the AF Gain control as an rf decoupling.
Can you try and report?


On Sun, Jul 1, 2018 at 5:33 PM, Lawrence Galea <9h1avlaw@...> wrote:
Did you put 100n, 10n, 1n filter capacitors  all in parallel on both input and output directly across the 78L05 leads?
.


On Sun, Jul 1, 2018 at 2:31 PM, Rick Price <rickprice48@...> wrote:
John, Don, others,
Yesterday I attached a 78L05 (TO220) directly to the back of the AGC board that is mounted to the RF gain control on the front panel. Bypassed all power leads and ran a separate power lead to the 12V regulator that powers my uBitx. In other words the AGC board had its own isolated(?) power source. Stll heard the audio when transmitting.  Beginning to think that radiated power is being absorbed by the AGC board and then recitifed and then coupled into the audio system. I also have the pop click board installed and not sure if this was a problem before it was installed. My AGC board is one I fabricated using Don's technique of cutting pcb with an x-acto knife.  I also have a AGC board made on perf board using through hole parts.  May sub that in and see if there are any changes. I eventually plan on installing the JackAl mod when it becomes available so this problem should go away for me but its beginning to become a challenge to fix.
 
Rick KN4AIE


From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of John KC9OJV
Sent: Sunday, July 01, 2018 8:05 AM
To: BITX20@groups.io
Subject: Re: [BITX20] RFI from uBitx TX after AGC and other mods installed

Don,
I spent part of yesterday applying ferrites to this and that to little success. I also tried wrapping the 5v line around the twisted pair coming from the volume pot and that did some good. This morning I was thinking about fixing a 7805 to the metal base of my case, drilling a hole in the ground plane and routing a wire through that hole to feed the AGC board. It could be driven off the 12v relay (K1?). Has anyone else had any ideas/success?

John
KC9OJV



Re: Ubitx and QRP Guys Multi Z Tuner #ubitx-help

Lawrence Galea
 

Are you using screened enclosures for the μbitx and tuner?


On Sun, Jul 1, 2018 at 4:14 PM, <davedt1e@...> wrote:
Never mind for now.

It would appear that the problem now occurs without the tuner hooked up.  I've got some kind of mic or mic jack problem.  I guess it's just coincidence that it started when I hooked up the tuner.  Seems a little odd though.


Re: Anyone seen an SSB xmit causing the menu to pop up?

M Garza <mgarza896@...>
 

Gwen,
I still suggest trying the ferrite on the Raduino wires.  Your issue will probably go away.

Does it happen on any frequency or just specific bands?

I doubt the power source will matter.  If you turn off the current limiting on your bench supply, it will probably do the same thing.  

Just things to try.

Good luck,

Marco - KG5PRT 

On Sun, Jul 1, 2018, 10:15 AM Gwen Patton <ardrhi@...> wrote:
I'm running on a different battery than the jump box I was using before. It should have sufficient amperage. I'll test it with my bench supply and see if it does it under those conditions. It's odd, though, I was running my bench supply in current limit mode at 1.5 and 2 amps, and it didn't exhibit this behavior. It almost seemed like the RF was getting into the Nano and triggering the menu event for some reason. Very peculiar.

It behaves precisely as if I pushed the encoder knob in to operate the menu switch. I key the mike, speak loudly into it or whistle into it, and BAM, the radio goes into menu mode and receive stops. I can get out of it by pushing the knob twice to cycle band select mode, but it's annoying. I was just wondering if someone else spotted this behavior and added ferrites or some other solution. I'll keep fiddling with it.

Re: RFI from uBitx TX after AGC and other mods installed

Don, ND6T
 

Do not place that capacitor from Q1 base to emitter. That will make a dandy blocking oscillator. Pin 7 of U1 already has a bypass (C78). It's just not shown on the schematic. Rather try hanging a big electrolytic across 5 volts to ground. Something like 100 uF, or 1,000 uF. in addition to a 10 nF (.01 uF). I haven't had to use any filtering on 5 volts other than the 1uF which is already on the Raduino. But my uBITX has a 1000 uF. on the 12 volt lead to the big board and the Raduino. I'm pretty sure that's why I have no issues. -Don

RFI problem at the encoder switch #ubitx-help

hakan.sjostrom@...
 

As soon as I speak in the microphone the display switches to "Band Select?". Both on a EFHW and a dipole antenna with low SWR. Except building RF chokes is there anything else worth trying - like a capacitor? Or a shielded wire from the encoder switch?

Re: RFI problem at the encoder switch #ubitx-help

Gordon Gibby
 

That is classic radio frequency interference. I’ve seen it in my own unit—-, so start shielding and bypassing and keep it up, until you get it stopped.

Folks who do digital communications get real good at this kind of stuff because any radio frequency interference at all and they have real problems.  You can do it too!


On Jul 1, 2018, at 13:47, "hakan.sjostrom@..." <hakan.sjostrom@...> wrote:

As soon as I speak in the microphone the display switches to "Band Select?". Both on a EFHW and a dipole antenna with low SWR. Except building RF chokes is there anything else worth trying - like a capacitor? Or a shielded wire from the encoder switch?

Re: Ubitx and QRP Guys Multi Z Tuner #ubitx-help

Doug W
 

double check you have a 4.7k resistor across Radiuno pins 2 & 3 and recheck all your ground connections
--
www.bitxmap.com

Re: RFI problem at the encoder switch #ubitx-help

hakan.sjostrom@...
 

Thanks Gordon, I've been looking around for this problem and just when I posted this I saw a similar posting from Gwen Patton just here !!
OK, I will start shielding and bypassing :-)

#uBITX #ubitx

SM6MOJ
 

Two capacitors -C210 and C216- arr missing from my uBITX motherboard.
Also, when I connect the board to 12V, the book says that the current
drain should be 100mW. But there is no current drain att all.

Can I assume that the board is fault?

Re: #uBITX #ubitx

Michael Shreeve
 

I looked at the V4 schematic and the value for both of those caps is zero. This means there are no caps installed. V3 has the same lack of capacitors. So, he isn't using them. 

On Sun, Jul 1, 2018 at 11:07 AM, SM6MOJ <andrew@...> wrote:
Two capacitors -C210 and C216- arr missing from my uBITX motherboard.
Also, when I connect the board to 12V, the book says that the current
drain should be 100mW. But there is no current drain att all.

Can I assume that the board is fault?










--
Michael Shreeve N6GRG

Re: #uBITX #ubitx

Michael Shreeve
 

Are you getting audio from the board ?

On Sun, Jul 1, 2018 at 11:54 AM, Michael Shreeve <shreevester@...> wrote:
I looked at the V4 schematic and the value for both of those caps is zero. This means there are no caps installed. V3 has the same lack of capacitors. So, he isn't using them. 

On Sun, Jul 1, 2018 at 11:07 AM, SM6MOJ <andrew@...> wrote:
Two capacitors -C210 and C216- arr missing from my uBITX motherboard.
Also, when I connect the board to 12V, the book says that the current
drain should be 100mW. But there is no current drain att all.

Can I assume that the board is fault?










--
Michael Shreeve N6GRG




--
Michael Shreeve N6GRG

Re: RFI from uBitx TX after AGC and other mods installed

Rick Price
 

John, Don Lawrence, others
Interesting Outcome! Shielding was no help, replacing pcb with perfboard agc helped a little, but back to pcb. bypass's on 78L05 were .68 on input and .1 on output still no help and removed 78Ll05. Did not try 1nf,10nf,100nf in parallel on 78L05 because I had already removed it.  Because pin 7 of U1 (TDA2822) is already bypassed with C78 did not do. Don suggested to filter the 5v supply. I get the 5 volts from the radino pin 3 (green wire) and use it for both AGC and mike preamp. Used a 470uf and .01 on the 5V no improvement.  Don suggested not to try the emitter-base capacitor because of forming a blocking oscillator. It looked to me that because the emitter was already grounded that it probably just bypass any unwanted signal to ground and not oscillate, connecting to the collector might have been another story.. What the heck nothing ventured nothing gained. Tried the .01 and turned on expecting possible oscillations of some sort. AGC off transmitting nothing as before, AGC on transmitting at full volume only occasionally get a very small occasional hint of audio coming through the speaker no oscillations of any kind. Before as soon as audio was present from the mike it started coming through and sometimes went into oscillations.  Hardly ever run at full volume so it looks like your theory and suggestion Lawrence may work. ARC still appears to work as before but will need a strong signal to verify.  Still have to experiment with a couple of different values to see what's best. Hope this spells relief with the agc on for the few of this it affects. Thanks to all for the input and suggestions.
 
Rick 
KN4AIE 



From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Lawrence Galea
Sent: Sunday, July 01, 2018 12:28 PM
To: BITX20@groups.io
Subject: Re: [BITX20] RFI from uBitx TX after AGC and other mods installed

Also try putting a 100n directly across Q1 base-emitter on the AGC board.
It will cut off some of the higher AF as it would be in series with C1 to earth across the Af gain control.  
However, this would not be of any serious consequences.
If you don't want as much AF HF cut off you can try a smaller capacitor, say 10n.
I am thinking that Q1 base-emitter junction is acting as a detector and the AF is being coupled back to the AF gain control since the level is varying with the AF Gain control.
One could also add say a 10n capacitor directly on pin 7 of the TDA2822 or across the AF Gain control as an rf decoupling.
Can you try and report?


On Sun, Jul 1, 2018 at 5:33 PM, Lawrence Galea <9h1avlaw@...> wrote:
Did you put 100n, 10n, 1n filter capacitors  all in parallel on both input and output directly across the 78L05 leads?
.


On Sun, Jul 1, 2018 at 2:31 PM, Rick Price <rickprice48@...> wrote:
John, Don, others,
Yesterday I attached a 78L05 (TO220) directly to the back of the AGC board that is mounted to the RF gain control on the front panel. Bypassed all power leads and ran a separate power lead to the 12V regulator that powers my uBitx. In other words the AGC board had its own isolated(?) power source. Stll heard the audio when transmitting.  Beginning to think that radiated power is being absorbed by the AGC board and then recitifed and then coupled into the audio system. I also have the pop click board installed and not sure if this was a problem before it was installed. My AGC board is one I fabricated using Don's technique of cutting pcb with an x-acto knife.  I also have a AGC board made on perf board using through hole parts.  May sub that in and see if there are any changes. I eventually plan on installing the JackAl mod when it becomes available so this problem should go away for me but its beginning to become a challenge to fix.
 
Rick KN4AIE


From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of John KC9OJV
Sent: Sunday, July 01, 2018 8:05 AM
To: BITX20@groups.io
Subject: Re: [BITX20] RFI from uBitx TX after AGC and other mods installed

Don,
I spent part of yesterday applying ferrites to this and that to little success. I also tried wrapping the 5v line around the twisted pair coming from the volume pot and that did some good. This morning I was thinking about fixing a 7805 to the metal base of my case, drilling a hole in the ground plane and routing a wire through that hole to feed the AGC board. It could be driven off the 12v relay (K1?). Has anyone else had any ideas/success?

John
KC9OJV



Re: BITX QSO Afternoon/Evening, Sunday, July 1, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.

John P
 

I'm calling CQ on 7277. Hearing nuttin but noise!
--
John - WA2FZW

newbee here...just made the order...antenna question on old G5RV

Don - KM4UDX
 

Finally, after a year or more of hand ringing and second guessing myself, I finally pulled the switch and ordered my uBITX! 

 

Believe it or not, it came down to the ICOM7300 or the uBITX.  I picked the uBITX because I love to solder and build, and when things are hard, they are much more satisfying when you finally get over the hill.  And what I learn with the uBITX will apply to any more complex and capable transceiver downstream. So I pulled the plug.  Should start the build in a few weeks. Also ordered the normal white plastic case from BG, and bnc to SO239 connectors, etc.

 

Questions to the wise ones: Can I hook up the uBITX my G5RV? I have a length of coax (which has a simple choke) that connects to the twinlead, which then goes to the dipole aerial WITHOUT an antenna tuner?

 

I borrowed 100W transceiver, and the G5RV worked just fine. But the 100W rig had an internal antenna turner, which I’m told the G5RV needs.  The uBITX does not have a antenna tuner…will it work well enough directly connected with the G5RV?

 

If I have to get an antenna tuner…(rats!), then I’m thinking of the ZM-2 or the like.

https://steadynet.com/emtech/zm2-kit-uhf-connectors

 

Guidance please!

 

Thank you o wise ones!

 

Don

KM4UDX

 

 

 

From: John P
Sent: Sunday, July 1, 2018 3:04 PM
To: BITX20@groups.io
Subject: Re: [BITX20] BITX QSO Afternoon/Evening, Sunday, July 1, 3PM & 7PMLocal Time, 7277 kHz in North America, 7177 kHz elsewhere.

 

I'm calling CQ on 7277. Hearing nuttin but noise!

--
John - WA2FZW

 

Re: RFI from uBitx TX after AGC and other mods installed

John KC9OJV
 

Thanks Rick- ditto on the electrolytic. I tried a 1000uF 16v electrolytic at the board and didn't notice any effect at all.

John
KC9OJV

Re: RFI from uBitx TX after AGC and other mods installed

Don, ND6T
 

Thank you!! I tried that TWICE and got this screaming tone. Perhaps the third time is in order. I wonder sometimes if I am living in an alternative universe. Goes to show that you should always question the "experts". Thank you very much for hanging in there, Rick. Good suggestion Lawrence. 73, Don