Date   
Re: Isolate any jacks/controls from metal chassis? #ubitx

iz oos
 

My front and back panels are plastic, all the rest is metal. So all connectors are isolated. I used a small piece of coax for the RF connection from the board to the panel instead of the stock twisted line. I think it is doing a good job as well. I chose this enclosure either because I had it for a long time, it was easy to drill and just to exclude the possibility of ground loops if any.

Il 22/ago/2019 04:15, "Tom, wb6b" <wb6b@...> ha scritto:
>
> A metal chassis provides a very good low impedance ground reference to all the circuitry. Best to ground everything, including making sure the screws holding down the circuit board have a good connection to the chassis in all four corners. 
>
> The wires to each of the various jacks and controls should be fairly short and twisted together to reduce RF pickup within the metal box. Such as twisting the volume control wires in a set, the encoder in a set, microphone in a set, the antenna wires in a set. Best to let the antenna connector be at one side of the box, close to where the antenna is connected to the PC board, the power connector close to where it connects to the PC board, and the audio/digital at the other side. That would minimize the very slight possibility of the minimal ground loops (minimized by the low impedance of the chassis ground) having any effect. But the big common ground should be a benefit virtually in all cases. 
>
> Tom, wb6b

Re: raduino crystal question

ashok.das81@...
 

On Wed, Aug 21, 2019 at 10:37 PM, Jerry Gaffke wrote:
Yes, the 25mhz crystal on the Raduino from hfsignals is throughole,
has a parallel capacitance of around 20pf.
That causes the reference oscillator to be off by a few hundred hertz,
but this is easily corrected by calibrating the frequency in software.

Jerry, KE7ER

On Wed, Aug 21, 2019 at 09:02 PM, <ashok.das81@...> wrote:
I am planning to build a clone of raduino. I needed to know what type of crystal is used in original raduino that used through hole parts. Si5351A datasheet says only smd crystals with capacitance less than 10pf are recommended, i am wandering what crystal raduino used ? I wanted to make using through hole crystal and no through hole crystal i could find having less than 10 pf capacitance. So can i make raduino using ordinary microprocessor crystals?

 Thanks KE7ER, thats enough for me to start building.  May I ask for some insight into calibration process ?

Regards
Ashok

Re: raduino crystal question

Jerry Gaffke
 

Yes, the 25mhz crystal on the Raduino from hfsignals is throughole,
has a parallel capacitance of around 20pf.
That causes the reference oscillator to be off by a few hundred hertz,
but this is easily corrected by calibrating the frequency in software.

Jerry, KE7ER

On Wed, Aug 21, 2019 at 09:02 PM, <ashok.das81@...> wrote:
I am planning to build a clone of raduino. I needed to know what type of crystal is used in original raduino that used through hole parts. Si5351A datasheet says only smd crystals with capacitance less than 10pf are recommended, i am wandering what crystal raduino used ? I wanted to make using through hole crystal and no through hole crystal i could find having less than 10 pf capacitance. So can i make raduino using ordinary microprocessor crystals?

raduino crystal question

ashok.das81@...
 

Dears,
I am planning to build a clone of raduino. I needed to know what type of crystal is used in original raduino that used through hole parts. Si5351A datasheet says only smd crystals with capacitance less than 10pf are recommended, i am wandering what crystal raduino used ? I wanted to make using through hole crystal and no through hole crystal i could find having less than 10 pf capacitance. So can i make raduino using ordinary microprocessor crystals?

Regards
Ashok

Re: Where many of the ICs we still use today were born.

jim
 

Someone posted about that (MC12) the other day ...maybe not here, but for all us (L)inux (USERS) ...it seem to load and run just fine on Wine ...Linux Mint 19.1 / wine packages from their repository ..

and thanks for posting about MicroCAP ..Ran ver 4 for years (cause thats all I could afford)

Jim

On Wednesday, August 21, 2019, 9:19:30 PM UTC, Graham <planophore@...> wrote:


speaking of SPICE and circuit simulations, another similar tool Microcap is now a free download. Seems the author has decided to retire or otherwise close shop and has made the tool freely available.

https://www.eevblog.com/forum/projects/microcap-12-is-free-(as-in-beer)-now/

cheers, Graham ve3gtc


On 2019-08-21 04:10, Tom, wb6b wrote:
HI,

This interesting article shows prototypes like I see in projects in this group, are like the test and development prototypes for many analog ICs. A look into the days before SPICE simulations became the standard.

https://www.electronicdesign.com/analog/what-s-all-pease-prototype-stuff-anyhow?NL=ED-001&Issue=ED-001_20190820_ED-001_721&sfvc4enews=42&cl=article_1&utm_rid=CPG05000024615509&utm_campaign=27759&utm_medium=email&elq2=ef539cd304a741688af95f32ee05b17b&oly_enc_id=

Tom, wb6b

Re: Isolate any jacks/controls from metal chassis? #ubitx

Tom, wb6b
 

A metal chassis provides a very good low impedance ground reference to all the circuitry. Best to ground everything, including making sure the screws holding down the circuit board have a good connection to the chassis in all four corners. 

The wires to each of the various jacks and controls should be fairly short and twisted together to reduce RF pickup within the metal box. Such as twisting the volume control wires in a set, the encoder in a set, microphone in a set, the antenna wires in a set. Best to let the antenna connector be at one side of the box, close to where the antenna is connected to the PC board, the power connector close to where it connects to the PC board, and the audio/digital at the other side. That would minimize the very slight possibility of the minimal ground loops (minimized by the low impedance of the chassis ground) having any effect. But the big common ground should be a benefit virtually in all cases. 

Tom, wb6b

Re: Bitx40 very loud, high-pitched, low frequency noise

kh6sky
 

I have a BitX40 that has the same issue.  When I run from a battery, the problem disappears.  . I tried lots of different bypassing caps with no luck.   As I prefer running it from a battery, it has not been a pressing issue

Re: Bitx40 very loud, high-pitched, low frequency noise

Woody
 

The PC supply is also a switcher.  It may also require a "power good" signal to operate and a minimum load to work properly.
I recommend trying a linear regulated supply or battery for trouble shooting.  Your wall-wart switcher may work if the problem is gone with good pure DC if a big filter capacitor (like >1000 uf) and enough ferrite choke beads/sleeves are added to the feed line - and it is not dropping out of regulation.
Woody 

--

Re: Audio pre-amplifier for microphone?

Gordon Gibby <ggibby@...>
 

A simple one transistor preamp makes a huge improvement, but don’t overdrive the amplifier!


On Aug 21, 2019, at 16:52, Neil Tolman via Groups.Io <k1nbt@...> wrote:

Has anyone used a mono pre-amp for the mic on the v5 uBITX?
Any thoughts or references would be helpful.
Thank you and 73,
Neil K1NBT

Re: Where many of the ICs we still use today were born.

Graham <planophore@...>
 

speaking of SPICE and circuit simulations, another similar tool Microcap is now a free download. Seems the author has decided to retire or otherwise close shop and has made the tool freely available.

https://www.eevblog.com/forum/projects/microcap-12-is-free-(as-in-beer)-now/

cheers, Graham ve3gtc


On 2019-08-21 04:10, Tom, wb6b wrote:
HI,

This interesting article shows prototypes like I see in projects in this group, are like the test and development prototypes for many analog ICs. A look into the days before SPICE simulations became the standard.

https://www.electronicdesign.com/analog/what-s-all-pease-prototype-stuff-anyhow?NL=ED-001&Issue=ED-001_20190820_ED-001_721&sfvc4enews=42&cl=article_1&utm_rid=CPG05000024615509&utm_campaign=27759&utm_medium=email&elq2=ef539cd304a741688af95f32ee05b17b&oly_enc_id=

Tom, wb6b

Audio pre-amplifier for microphone?

Neil Tolman <k1nbt@...>
 

Has anyone used a mono pre-amp for the mic on the v5 uBITX?
Any thoughts or references would be helpful.
Thank you and 73,
Neil K1NBT

Re: Bitx40–Apollo Quindar Tones #bitx40

Jim Willis
 

Hi Paul,

A local repeater uses a "roger beep". Personally, I find it annoying.

73,

Jim

Re: Bitx40 very loud, high-pitched, low frequency noise

SP9DEV
 

Found 3 other pairs of headphones (nokia, motorola and some no-name headphones), the problem persists. However, I also found another wall-plug power supply, this one with a ferrite choke and rated 12V 2A. With this supply, the noise is a constant, high-pitched sound (different from the first one). Looks like this depends on the type of power supply. Both are probably switched mode, so I guess that's the issue. I'll try to get my hands on a standard computer ATX supply unit, solder a cable to 12V line and check what happens.

Re: Bitx40 very loud, high-pitched, low frequency noise

Ian Reeve
 

Not being familiar with Apple Jack plug connectivity,what Evan says and I suggested is likely to cause problems.A standard set of stereo headphones would prove the point.


From: BITX20@groups.io <BITX20@groups.io> on behalf of Evan Hand <elhandjr@...>
Sent: Wednesday, August 21, 2019 7:16:39 PM
To: BITX20@groups.io <BITX20@groups.io>
Subject: Re: [BITX20] Bitx40 very loud, high-pitched, low frequency noise
 
You might want to verify the 3.5 mm audio jack will connect correctly to the Apple earbuds.  Apple supplies a Tip, 2 rings and a sleeve to accommodate the microphone.  The supplied jack is audio out only with a Tip, 1 ring and a sleeve. 

FWIW
73
Evan
AC9TU

Re: Bitx40 very loud, high-pitched, low frequency noise

Evan Hand
 

You might want to verify the 3.5 mm audio jack will connect correctly to the Apple earbuds.  Apple supplies a Tip, 2 rings and a sleeve to accommodate the microphone.  The supplied jack is audio out only with a Tip, 1 ring and a sleeve. 

FWIW
73
Evan
AC9TU

Re: Bitx40 very loud, high-pitched, low frequency noise

Ian Reeve
 

The audio chip U1 looks to already have such a network across the output so scrub that idea. I see the instruction refers to the need for a linear power supply,perhaps if your power supply is switch mode,the noise you hear could be from the switch mods supply.To be honest I am running out of ideas but clearly  it points to a audio problem.It might be worth trying a non apple headphones and if you have access to equipment with a line in,disconnect the audio in to the volume control and pass it to a device with line in to see if the problem persists.


From: BITX20@groups.io <BITX20@groups.io> on behalf of SP9DEV <piotrekslawecki2@...>
Sent: Wednesday, August 21, 2019 6:18:43 PM
To: BITX20@groups.io <BITX20@groups.io>
Subject: Re: [BITX20] Bitx40 very loud, high-pitched, low frequency noise
 
I'm running the whole kit at 12V 3A from a wall-plug type of supply. The headphones are 23ohm apple headphones. Where would I exactly solder the 10ohm and 0.1uf?

Re: Bitx40 very loud, high-pitched, low frequency noise

SP9DEV
 

I'm running the whole kit at 12V 3A from a wall-plug type of supply. The headphones are 23ohm apple headphones. Where would I exactly solder the 10ohm and 0.1uf?

Re: Bitx40 very loud, high-pitched, low frequency noise

Ian Reeve
 

Ah my mistake,apologies.As Gary says,it sounds as if the audio chip is oscillating and as Gary says it is high gain and would seem to be some sort of instability.You could try a 10 ohm  resistor and a 0.1 if capacitor in series across the output pin to earth.Is your speaker 8 ohms or less?


From: BITX20@groups.io <BITX20@groups.io> on behalf of Gary Anderson <gary.ag5tx@...>
Sent: Wednesday, August 21, 2019 5:54:24 PM
To: BITX20@groups.io <BITX20@groups.io>
Subject: Re: [BITX20] Bitx40 very loud, high-pitched, low frequency noise
 
Ian, it's a Bitx40.  (good advice, just different radio)
wire-up
http://www.hfsignals.com/index.php/2017/11/23/wiring-up-the-bitx40/

Sounds like the LM386 could be oscillating around 4-5 kHz and making a faint barking dog-like noise.

SP9DEV what voltage are you supplying to the Bitx40?  Are you running or have run the LM386 at too high of a voltage?
The LM386 is set-up for a lot of gain in this configuration.  Amplifiers like to oscillate when the gain is pushed.

Rgds,
Gary

Re: FS: uBITX V4 with case and Nexion display

John Caldwell
 

Doug-

This is amazing timing, I am looking for this exact combination of parts.  Do you accept paypal?

-John

On Wed, Aug 21, 2019 at 9:28 AM Doug Person <doug@...> wrote:

I'm never going to finish this. I just have too many things on my plate right now.

Version 4 uBITX with gray case including 3.5" front panel for Nexion display *including* nexion 3.5" display.

I have partially assembled this. I *think* I have all the parts. But some screws or small parts might have gotten lost.

I just need let someone else have a go at it.

Everything shipped Priority Mail (CONUS) for $100.

Doug -- KJ0F

-- 
73 de Doug -- KJ0F

Re: Stuck at LSB A:7.149.950

Ian Reeve
 

That should read a piece of swarf lodged.


From: BITX20@groups.io <BITX20@groups.io> on behalf of Ian Reeve <ian.radioworkshop@...>
Sent: Wednesday, August 21, 2019 5:29:57 PM
To: BITX20@groups.io <BITX20@groups.io>
Subject: Re: [BITX20] Stuck at LSB A:7.149.950
 
I can only assume that there must be a piece of award lodged somewhere or the display and raduino. needs to be removed and  a very thorough examination made of all connections and pcb.Something is clearly drawing excess current and there is a remote possibility that the raduino has failed.Hope you manage to locate the problem


From: BITX20@groups.io <BITX20@groups.io> on behalf of Luke <iconcal504@...>
Sent: Wednesday, August 21, 2019 4:55:53 PM
To: BITX20@groups.io <BITX20@groups.io>
Subject: Re: [BITX20] Stuck at LSB A:7.149.950
 
Happened after drilled hole on casing with board installed, use compressed air to blow off any metal dust.
Close inspection did not see any. No smoke or smell after turned on.

Stuck at LSB A:7.149.950, cange change frequency.

Encoder changed, same problem, revert back to stock.