Re: BITX QSO Afternoon/Evening, Sunday, July 1, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.
calling also but nothing heard. This week unlike the last 2 weeks I have my antenna connected. Don't ask.
don, still listening
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Re: RFI from uBitx TX after AGC and other mods installed
Rick, I'm saying that you really SHOULD! A little history: I originally had a .01 uF across the input audio and well, surprise! Then Kees slipped it in on his re-make so I tried again with the same result. I sure hope that it helps Rowland, Alan, Mark and the rest. I'll try again and include that in the web pages. 73, Don
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If there is no current drain, what shows up on the LCD? Is the back light lit?
What method are you using to measure the current draw?
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Dear Michael
Thank you for your wise words. Now all I have to do is work out why there
is no current drain.
Andrew
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Re: newbee here...just made the order...antenna question on old G5RV
You wanted wise ones, but I'll jump in till one shows up.
The uBitx will want to see 50 ohms, ideally under a 2 to 1 SWR, though I suspect it will
survive most anything if you power the IRF510's from not much beyond 12v.
The G5RV antenna is not resonant, the impedance it presents will be all over the map.
You really need a tuner between it and the 50 ohm coax to the uBitx.
That ZM-2 might be sufficient, I don't really know.
The fact that you cannot adjust inductance is not a plus in my book, that could be getting?
inefficient as frequencies go up and capacitive coupling between windings gets out of hand.
It claims to be good to 15 Watts, though does not really say under what conditions that might be true.
Max power it can handle will vary considerably with operating frequency and antenna impedance.
I'm happy enough with my MFJ-949E tuner/swr/dummyload
Build quality varies on the MFJ stuff, you want to lift the lid when you get it and check the solder job.
If you want to build your own tuner, you need an SWR indicator such as Diz's Tandem Match SWR indicator:
? ??
Generally the tuner itself can be a couple tuning caps from some old tube type broadcast receiver
and a hand wound inductor with an alligator clip to tap into it somewhere, check the various handbooks on that.
For the price of the 7300, you can have a half dozen uBitx's go up in flames
and try out several MFJ tuners plus some homemade ones.?
And learn an awful lot in the process.
Jerry, KE7ER
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On Sun, Jul 1, 2018 at 12:32 pm, Don - KM4UDX wrote:
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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Re: RFI from uBitx TX after AGC and other mods installed
Don, please don't think I?was questioning the experts,
just was running out of options, suggestions,?and like I said nothing
ventured nothing gained and had tried everything else. Will always take advice
from those that have been there before! Thanks again,
?
Rick
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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
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Re: RFI from uBitx TX after AGC and other mods installed
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
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Re: RFI from uBitx TX after AGC and other mods installed
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
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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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Don, ND6T
Michael Shreeve