newbee here...just made the order...antenna question on old G5RV
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. ? Guidance please! ? Thank you o wise ones! ? Don KM4UDX ? ? ?
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From: John PSent: Sunday, July 1, 2018 3:04 PM To: [email protected]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!
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John - WA2FZW
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Re: BITX QSO Afternoon/Evening, Sunday, July 1, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.
I'm calling CQ on 7277. Hearing nuttin but noise!
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John - WA2FZW
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Re: RFI from uBitx TX after AGC and other mods installed
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?
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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?
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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.?
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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?
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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?
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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 :-)
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double check you have a 4.7k resistor across Radiuno pins 2 & 3 and recheck all your ground connections
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That is classic radio frequency interference. I¡¯ve seen it in my own unit¡ª-, 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!
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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?
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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?
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Re: RFI from uBitx TX after AGC and other mods installed
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
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Re: Anyone seen an SSB xmit causing the menu to pop up?
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.
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Are you using screened enclosures for the ¦Ìbitx 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.
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Re: 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?
.
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Re: RFI from uBitx TX after AGC and other mods installed
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
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
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Re: Anyone seen an SSB xmit causing the menu to pop up?
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.
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Re: Anyone seen an SSB xmit causing the menu to pop up?
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.
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Re: RFI from uBitx TX after AGC and other mods installed
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
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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
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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.
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Yes, I have seen similar phenomena. In
my case my CW wires to my key were too close to my 50 watt linear.
Your tuner is probably radiating a lot of RF.
Howard
On 7/1/2018 9:24 AM, davedt1e@... wrote:
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Hope this is an
appropriate topic for the board.
Just built he QRP Guys Multi Z tuner and hooked it up to the
Ubitx.? The Ubitx goes straight into TX on power up.? I was very
careful in building the tuner and don't think I made any
errors.
The antenna is a horizontal loop cut a bit over 40 meters and fed
with ladder line.
The Ubitx behaves normally when using a dummy load or with loop
hooked up for receive.
No balun is currently attached.
Any ideas as to what's happening?
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Michael Shreeve
Don, ND6T
Gwen Patton