Date   
Re: To shield or not to shield, that is the question.

Bill Cromwell
 

Hi,

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.
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"/
//
--
bark less - wag more

Re: Power supply

Jerry Gaffke
 

The Tekpower TP3005T looks like an excellent bench supply.
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:
    https://www.amazon.com/Eventek-KPS305D-Adjustable-Switching-Regulated/dp/B071RNT1CD/ref=sr_1_cc_5?s=aps&ie=UTF8&qid=1543076574&sr=1-5-catcorr&keywords=switching+power+supply+variable+voltage

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: 
    https://www.dxengineering.com/parts/mfj-4230mv
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.
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.

Re: To shield or not to shield, that is the question.

Curt
 

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: To shield or not to shield, that is the question.

Lee
 

I hope that fine case maker in India comes up with a slope front case for the JackAl add-on with options for 5" or 7" display.  I currently have a plastic case uBitx and it works fine.
--
Lee - N9LO  "I Void Warranties"

 

Re: To shield or not to shield, that is the question.

G1KQH
 

If using plastic boxes or the like, you can line the case and shield in important areas with copper foil available quite cheap on ebay:

https://www.ebay.co.uk/itm/99-9-Copper-Foil-Tape-Shielding-Sheet-200-x-500MM-Double-sided-Conductive-Roll/162491360479?hash=item25d53d64df:g:70gAAOSwJ4hZACVK:rk:21:pf:0


73 Steve

Re: Raduino clicking when microphone is connected or keying CW. #ubitx-help #radiuno

Jim Miller
 

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:

Hello, solder-melters,

I'm experiencing constant clicking from the raduino when my microphone is plugged in. The display indicates it is switching from RX to TX continuously. When I disconnect the microphone, it stops. If I key up the PTT, the clicking stops and I am able to transmit. I can hear myself on a receiver, so the microphone is working. As soon as I let go of PTT, the radio continues to switch between RX and TX, clicking the whole time. I have re-soldered all connections to the jack, and also the microphone in an attempt to troubleshoot, but this resulted in no change.

I wired up the key jack for a straight key. When I key CW, I hear a continuous tone behind my dits, and when I cease transmitting, the tone continuous for about a second, then the raduino clicks and the radio returns to RX.

I'm not experienced and have no idea where to start troubleshooting. I've made sure all connections are solid, but I'm starting to wonder if this is a software issue. I am running version 1.08 of KD8CEC's firmware.

Any ideas? Thanks!

Re: Power supply

Jerry Gaffke
 

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.
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:
    https://www.amazon.com/Eventek-KPS305D-Adjustable-Switching-Regulated/dp/B071RNT1CD/ref=sr_1_cc_5?s=aps&ie=UTF8&qid=1543076574&sr=1-5-catcorr&keywords=switching+power+supply+variable+voltage

Re: Raduino clicking when microphone is connected or keying CW. #ubitx-help #radiuno

Curt
 

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: BitX 40 Question

Jerry Gaffke
 

Look at the schematic for the Bitx40.
Long ago, the "Tuning" connector went out to a pot, was used to apply a DC voltage to the varactor diode at D9.
But that analog VFO was not stable enough.

The solution was to add the Raduino in late 2016, all Bitx40's shipped from Dec 2016 on went out with
a Raduino, and with L4 removed.  The Raduino injects a VFO signal into the "DDS" connector,
and with L4 removed the caps at C93,94,95 and D9 are removed from the circuit.
The si5351 on the Raduino is what determines the frequency of the VFO.


On Sat, Nov 24, 2018 at 06:56 AM, Scot McMath wrote:
Looking on the components side of the Bitx 40 board right side about 1/2 way, I see a 2 prong connector labeled TUNING. My instruction sheet from HF Signals shows nothing, no connections. anyone have any idea if this is connected and where to?

Re: 160 metres and the uBITX

Jerry Gaffke
 

Yup, you need an external low pass filter if you want to operate on 160 meters.
That should not be a surprise.
See post    https://groups.io/g/BITX20/message/48125


On Sat, Nov 24, 2018 at 08:24 AM, John wrote:

This was my scope capture with the CW key pressed.

 

John, K5GT

Re: 160 metres and the uBITX

barry underwood
 

I didn't look on a scope, but could well believe that waveform given the harmonics seen on the spectrum analyser. Certainly needs some good filtering. No one should be using the uBITX on 160 as is.
--
Sent from my Android device with K-9 Mail. Please excuse my brevity.

Re: Raduino clicking when microphone is connected or keying CW. #ubitx-help #radiuno

Rick Price
 

Jim,
Does your lapel mike have a TRS (tip/ring/sleeve) plug or just TS(tip/sleeve).  If just a monaural TS plug it is shorting the PTT lead to ground causing it to go into xmit. Just a thought. Also if it has a TRS plug is the ring isolated from the TS.
 
Rick
KN4AIE
 



From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Jim Miller
Sent: Saturday, November 24, 2018 1:36 PM
To: BITX20@groups.io
Subject: Re: [BITX20] 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:

Hello, solder-melters,

I'm experiencing constant clicking from the raduino when my microphone is plugged in. The display indicates it is switching from RX to TX continuously. When I disconnect the microphone, it stops. If I key up the PTT, the clicking stops and I am able to transmit. I can hear myself on a receiver, so the microphone is working. As soon as I let go of PTT, the radio continues to switch between RX and TX, clicking the whole time. I have re-soldered all connections to the jack, and also the microphone in an attempt to troubleshoot, but this resulted in no change.

I wired up the key jack for a straight key. When I key CW, I hear a continuous tone behind my dits, and when I cease transmitting, the tone continuous for about a second, then the raduino clicks and the radio returns to RX.

I'm not experienced and have no idea where to start troubleshooting. I've made sure all connections are solid, but I'm starting to wonder if this is a software issue. I am running version 1.08 of KD8CEC's firmware.

Any ideas? Thanks!

Re: To shield or not to shield, that is the question.

Gwen Patton
 

I put a plastic case on my uBitX...but I sprayed the interior surfaces with several coats of a nickel-based RFI insulating spray. It's highly conductive, and I made sure to bond all the surfaces to one another. I do suggest that a thin clear coat be put over it, as the spray can leave some loose particles. Just put painters' tape over the surfaces that need to be exposed conductor for bonding purposes, and clear-coat just enough to keep particles from shaking loose onto the board.

This is the spray I used: https://www.amazon.com/gp/product/B01N3AWGNX

I plan to do some playing with this stuff to see if one can spray an effective antenna conductor onto some sort of substrate. I'm going to try making a small transmitting loop using this stuff and a cardboard TV moving box. The box is in two parts that slide one inside the other, and am going to try using overlapping sprayed conductor surfaces to create a capacitor to tune the big loop, and put another small box with its own loop of conductor (maybe adhesive copper foil) to couple the rig to the loop. Since you can spray as wide a strip of this stuff as you want, it may be possible to get good efficiency and a wide bandwidth with it. We'll see.

It's been my experience that the spray does work to help keep RFI at bay.

Gwen NG3P

Re: 160 metres and the uBITX

Vince Vielhaber
 

The uBitx isn't designed to be used on 160. The LPFs are for 80 and up.

Vince.

On 11/24/2018 02:01 PM, barry underwood via Groups.Io wrote:
I didn't look on a scope, but could well believe that waveform given the
harmonics seen on the spectrum analyser. Certainly needs some good
filtering. No one should be using the uBITX on 160 as is.
--
Sent from my Android device with K-9 Mail. Please excuse my brevity.

Re: To shield or not to shield, that is the question.

Jerry Gaffke
 

If I were to "shield" the uBitx, I'd first be shielding the various parts of the uBitx from each other.
For example, shield those high gain IF amps from the final amp.

Putting it all in a metal box can help if you have a lot of RF noisy stuff in the area.
Or if you care about some other gear hearing your BFO at 12mhz
or clk1 or clk2 or the 45mhz IF ...
I don't have either issue.

Jerry

Re: CW operation uBitX #ubitxcw

Curt
 

John

Beats me as to what you might be hearing. The lowest frequency made by the ubitx is 12 MHz. Okay possible that it might have some carrier leakage, way down there. Yes its possible you might be hearing result of carrier leakage mixing with bfo. Its likely no issue at all.

Extra connector for cw? Please note that ubitx modulates cw based upon one pin going into raduino. Even stranger,  cw sending is based upon having a resistor in series with key or paddle. On off keying uses a 4.7k resistor you likely already installed. To use paddle, you need 2 added resistors of a particular value for dit and dah. Okay, you could host these resistors inside with an added connector.

Assuming you are adding ND3T agc, yes that should be nice. Enjoy your journey with ubitx.

Curt

Re: To shield or not to shield, that is the question.

Joe Puma
 

Interesting stuff. A person in the comments of that Amazon link wanted to know if it would block wifi and electromagnetic frequencies if you sprayed it on clothes.  Laughing my butt off!!!

 

 

Joe

 

Sent from Mail for Windows 10

 

From: Gwen Patton
Sent: Saturday, November 24, 2018 2:08 PM
To: BITX20@groups.io
Subject: Re: [BITX20] To shield or not to shield, that is the question.

 

I put a plastic case on my uBitX...but I sprayed the interior surfaces with several coats of a nickel-based RFI insulating spray. It's highly conductive, and I made sure to bond all the surfaces to one another. I do suggest that a thin clear coat be put over it, as the spray can leave some loose particles. Just put painters' tape over the surfaces that need to be exposed conductor for bonding purposes, and clear-coat just enough to keep particles from shaking loose onto the board.

This is the spray I used: https://www.amazon.com/gp/product/B01N3AWGNX

I plan to do some playing with this stuff to see if one can spray an effective antenna conductor onto some sort of substrate. I'm going to try making a small transmitting loop using this stuff and a cardboard TV moving box. The box is in two parts that slide one inside the other, and am going to try using overlapping sprayed conductor surfaces to create a capacitor to tune the big loop, and put another small box with its own loop of conductor (maybe adhesive copper foil) to couple the rig to the loop. Since you can spray as wide a strip of this stuff as you want, it may be possible to get good efficiency and a wide bandwidth with it. We'll see.

It's been my experience that the spray does work to help keep RFI at bay.

Gwen NG3P

 

Re: To shield or not to shield, that is the question.

mark audacity romberg
 

For $36 I think I’ll just use a metal enclosure, yikes.

Re: To shield or not to shield, that is the question.

Mike Short
 

That’s what foil is for

On Sat, Nov 24, 2018 at 1:42 PM Joe Puma <kd2nfc@...> wrote:

Interesting stuff. A person in the comments of that Amazon link wanted to know if it would block wifi and electromagnetic frequencies if you sprayed it on clothes.  Laughing my butt off!!!

 

 

Joe

 

Sent from Mail for Windows 10

 

From: Gwen Patton
Sent: Saturday, November 24, 2018 2:08 PM
To: BITX20@groups.io
Subject: Re: [BITX20] To shield or not to shield, that is the question.

 

I put a plastic case on my uBitX...but I sprayed the interior surfaces with several coats of a nickel-based RFI insulating spray. It's highly conductive, and I made sure to bond all the surfaces to one another. I do suggest that a thin clear coat be put over it, as the spray can leave some loose particles. Just put painters' tape over the surfaces that need to be exposed conductor for bonding purposes, and clear-coat just enough to keep particles from shaking loose onto the board.

This is the spray I used: https://www.amazon.com/gp/product/B01N3AWGNX

I plan to do some playing with this stuff to see if one can spray an effective antenna conductor onto some sort of substrate. I'm going to try making a small transmitting loop using this stuff and a cardboard TV moving box. The box is in two parts that slide one inside the other, and am going to try using overlapping sprayed conductor surfaces to create a capacitor to tune the big loop, and put another small box with its own loop of conductor (maybe adhesive copper foil) to couple the rig to the loop. Since you can spray as wide a strip of this stuff as you want, it may be possible to get good efficiency and a wide bandwidth with it. We'll see.

It's been my experience that the spray does work to help keep RFI at bay.

Gwen NG3P

 

Re: To shield or not to shield, that is the question.

Jack, W8TEE
 

Keep us informed!

Jack, W8TEE

On Saturday, November 24, 2018, 2:08:31 PM EST, Gwen Patton <ardrhi@...> wrote:


I put a plastic case on my uBitX...but I sprayed the interior surfaces with several coats of a nickel-based RFI insulating spray. It's highly conductive, and I made sure to bond all the surfaces to one another. I do suggest that a thin clear coat be put over it, as the spray can leave some loose particles. Just put painters' tape over the surfaces that need to be exposed conductor for bonding purposes, and clear-coat just enough to keep particles from shaking loose onto the board.

This is the spray I used: https://www.amazon.com/gp/product/B01N3AWGNX

I plan to do some playing with this stuff to see if one can spray an effective antenna conductor onto some sort of substrate. I'm going to try making a small transmitting loop using this stuff and a cardboard TV moving box. The box is in two parts that slide one inside the other, and am going to try using overlapping sprayed conductor surfaces to create a capacitor to tune the big loop, and put another small box with its own loop of conductor (maybe adhesive copper foil) to couple the rig to the loop. Since you can spray as wide a strip of this stuff as you want, it may be possible to get good efficiency and a wide bandwidth with it. We'll see.

It's been my experience that the spray does work to help keep RFI at bay.

Gwen NG3P