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Re: Raduino clicking when microphone is connected or keying CW.
#ubitx-help
#radiuno
Jim
i would do some probing with a continuity checker (like your DVM) to see what is what with your construction.? if rig goes into transmit when plugging in your microphone, somehow it is making a connection to ground.? the matter at hand is there needs to a common connection between the mic audio return, and the unswitched end for PTT -- to allow suitable current flow for each function.? if you can tell which microphone connection is attached to the 'braid' this may solve your issue.? or try reversing PTT and ground in the wiring.? now if somehow in your microphone wiring both PTT and common are simultaneously connected - then you would have a short in your microphone wiring.? 73 Curt |
Re: Power supply
The spec's say that the Eventek switcher has "ripple and noise" of "0.5% V P-P", so 0.005*12 = 60mv P-P at 12v out.
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The MFJ4230MV has "ripple and noise < 100mv", that may be rms, definitely worse than the Eventek. The Tekpower says "CV < 1mv rms", so more than an order of magnitude better than the other two. The MFJ4230MV has the worst spec of the bunch, but works fine with my Swan 100MX. Depends on the frequency components of that noise, better not radiate stuff above 1mhz. Assumes the high gain audio amps in the receiver reject supply voltage noise. About the best you can do is try it and see. I've never tried the MFJ4230MV on my uBitx. On Sat, Nov 24, 2018 at 09:00 AM, Jerry Gaffke wrote:
Here's a cheaper one, this one is a switcher so is probably (but not necessarily if they did it right) noisier: |
Re: Raduino clicking when microphone is connected or keying CW.
#ubitx-help
#radiuno
I am currently in the same situation.? I have a simple lapel mic and every time I plug it in the rig goes into transmit mode, it's almost like there's a short.? I've attached the diagram from the BitX40 but it's not quite what I'm looking for.? Is there a good diagram for the uBitX Mic jack with PTT?? The diagrams I've seen don't specify if you're seeing the top or the bottom of the connector. I've attached photos, probably too many, and hopefully someone from this awesome group and point out my error Thanks, Jim? AE0BZ On Fri, Nov 23, 2018 at 7:45 AM KN4IYL <kn4iyl@...> wrote:
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3.5mm stereo socket diagram.jpg
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uBitX-Mic.jpg
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Re: To shield or not to shield, that is the question.
Well when we build a radio into a metal box, then attach several wires to it, that can compromise the shielding. And cut a large opening for a display its not as shielded.
I have a slight preference for a metal case, but its effectiveness can be exaggerated.? it is a bit more effective as gathering conductors together. When EM fields outside the box are similar to what's inside, there isn't a strong case for shielding. and even in a metal box, I remember a few rigs that require more distance away from a linear power supply. Your choice may depend upon available packaging materials and your ability to work them. Some folk are using nice 3d printed or other plastic cases can weigh in. Nor am I trying to reduce business for a fine ubitx case maker in India. 73 enjoy your build and radiations. Curt |
Re: Power supply
The Tekpower TP3005T looks like an excellent bench supply.
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A linear power supply using a tapped transformer, so likely cleaner than most switchers, still reasonably efficient. Though at $80, kind of spendy for somebody who spent considerably less on their Bitx40. Here's a cheaper one, this one is a switcher so is probably (but not necessarily if they did it right) noisier: ? ?? Lots and lots of cheap switching power supplies that only have one knob to set the output voltage. Here's a nice 30 Amp switching power supply for use with a 100 Watt transceiver:? ? ?? So for the same price as the Tekpower, you can have 6 times the current out. You can set the output voltage to anything between 4 and 16 Volts. The meter can monitor either voltage out, or output current. Seems to be about as RF quiet as any linear power supply. But does NOT allow you to set the maximum current like the Tekpower,? it's always ready and waiting?to give your project 30 Amps. The Tekpower has that extra knob, allows you to set the maximum current. If you are first checking out a uBitx on receive, you could set the maximum current to perhaps 300ma. So the Tekpower will deliver 12v to the uBitx (or whatever voltage you set) up to 300ma, If the uBitx has a short somewhere, the Tekpower then reduces its output voltage until the current is 300ma, perhaps down to a voltage of nearly zero if that's what it takes.? No burned traces, no smoke. To check out a zener diode, just put it across the output terminals of the Tekpower and set the max current to 10ma. (I'm assuming that you can accurately set the current low enough.? May not be the case.) The way you set the max current is to put a short across the output terminals, then twiddle the knob for the desired current. Weird that there are not more supplies that provide this extra knob to set the maximum current, the additional electronics required is minimal. There is another form of current limiting that you might want to be aware of:? Foldback current limiting. If your project exceeds the maximum set current, the power supply shuts down entirely until reset. Pretty much like a circuit breaker. This is not as common (or useful) in a bench supply as the simple current limiting of the Tekpower supply. ? If you want cheap, I suggest going to a second hand store and buy a 12v desktop "brick" style supply good for 3 to 5 Amps. If it's too noisy during receive (compare it to running from a 12v battery) buy another and use the noisy one for other projects. But these bricks will not have adjustable max output current like the Tekpower. Jerry, KE7ER On Sat, Nov 24, 2018 at 07:44 AM, KD8CGH wrote:
Supplies made for amateur radio are usually quiet. You don't need instruments - if you hear the supply in your transceiver it's too noisy. |
Re: To shield or not to shield, that is the question.
Hi,
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Shielding also protects the receiver circuits from external "crud". So much for the QRP argument. *All of my radios live in steel or aluminum, even the one with pretty plastic panels on the outside. Those are for cosmetics only. Plastic can shield against water:) Stay indoors and it won't get wet. 73, Bill KU8H On 11/24/18 11:25 AM, Jack Purdum via Groups.Io wrote:
If you don't care, a metal case is probably best so you can shield it. I'm doing one for my personal use that has a metal surround, but plastic end panels (easier to cut). However, the "display model" that we will use to show it off will have an acrylic U-shaped cover with an acrylic front panel and metal back panel (e.g., antenna, power, speaker connections). One of our book projects is an antenna tuner with "instant" readout of SWR on a TFT color display, which originally was in a plastic case. That project benefited from shielding, but we were testing it with 100W. We retrofitted copper foil shielding inside the case and that worked well. So, pick what looks good to you and if you think there's an RF issue, line the case with foil. --
bark less - wag more |
STREAM of solar wind is approaching Earth and experts fear it could hit us as early as November 26
?STREAM of solar wind is approaching Earth and experts fear it could hit us as early as November 26On Sat, Nov 24, 2018, 11:26 Jack Purdum via Groups.Io <jjpurdum=[email protected]> wrote:
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Re: To shield or not to shield, that is the question.
Jack Purdum
If you don't care, a metal case is probably best so you can shield it. I'm doing one for my personal use that has a metal surround, but plastic end panels (easier to cut). However, the "display model" that we will use to show it off will have an acrylic U-shaped cover with an acrylic front panel and metal back panel (e.g., antenna, power, speaker connections). One of our book projects is an antenna tuner with "instant" readout of SWR on a TFT color display, which originally was in a plastic case. That project benefited from shielding, but we were testing it with 100W. We retrofitted copper foil shielding inside the case and that worked well. So, pick what looks good to you and if you think there's an RF issue, line the case with foil. Jack, W8TEE
On Saturday, November 24, 2018, 11:09:46 AM EST, Lee <mr.olson@...> wrote:
Some have built in metal boxes, some use plastic boxes, and some put metal shielding inside the plastic boxes.? Is it a ,should do, must do, or doesn't really matter at these low power levels.?? Can you also explain why you made your choice?? Thinking about options for for my JackAl add-on new radio build. -- Lee - N9LO? "I Void Warranties" ? |
Re: Raduino help?
Woody
Barry, Evan,
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Thanks... It is good to know that microphonics an happen to a working board.? Now I can chase other things that may be part of the distorted audio and low sensitivity!? ...Then on to tackle the TX problems. TNX - Woody? KZ4AK On 11/24/2018 3:36, barry halterman wrote:
Woody, I have issues with microphonics too, but with my ubitx on a decent antenna they get drowned out from other background (band) noise. I only notice them if I am on a dummy load or have the antenna disconnected. |
Re: To shield or not to shield, that is the question.
On Sat, Nov 24, 2018, 11:09 Lee <mr.olson@...> wrote: Some have built in metal boxes, some use plastic boxes, and some put metal shielding inside the plastic boxes.? Is it a ,should do, must do, or doesn't really matter at these low power levels.?? Can you also explain why you made your choice?? Thinking about options for for my JackAl add-on new radio build. |
CW operation uBitX
#ubitxcw
Hi all, Have not used CW as of yet, first have to practice? bit more ;) So far my operation have been limited to the higher bands (20+) and FT8. Now that I was playing around and recently also obtained a GP5-SSB I was able to listen to my signal using a dummy load. Listening I discovered that when the key or paddle is not pressed you hear a faint tone (keypress is much louder) Is this because I am so close to my uBitX and is it the zero beat of the 700Hz? that I am hearing? |
To shield or not to shield, that is the question.
Some have built in metal boxes, some use plastic boxes, and some put metal shielding inside the plastic boxes.? Is it a ,should do, must do, or doesn't really matter at these low power levels.?? Can you also explain why you made your choice?? Thinking about options for for my JackAl add-on new radio build.
-- Lee - N9LO? "I Void Warranties" ? |
160 metres and the uBITX
barry underwood
Looking at the output of my uBITX on 160m on a spectrum analyser, you don't want to go there!
However, a simple external low pass filter makes all the difference. Attached is the circuit of a LPF that I built, along with before and after analyser screen shots of the output of my uBITX. 73 de Barry, G4BUD |
Re: Power supply
Supplies made for amateur radio are usually quiet. You don't need instruments - if you hear the supply in your transceiver it's too noisy.I have two 30 amp linear supplies, but my precocious desktop space goes to a Samlex SEC123 switching supply. I use a fused distribution box from a Sotabeam kit.If you are interested in QRP, building kits and different voltages you might consider a bench power supply. I use a Tekpower TP3005T Variable Linear DC Power Supply, 0-30V @ 0-5A which provides current limiting as well as voltage regulation. |