Date   
Re: Cooling fan Shroud

Albert Peter
 

I also looked for a fan solution on my uBITX.  I tried several salvaged from computer parts, but all were too noisy  I finally came up with this one:

Noctua NF-A4x20 PWM Premium-Quality Quiet 40mm Fan – $14.99 from Amazon. 

A bit pricey, but it has virtually no acoustic noise and very little, if any electrical noise.  Mounted on the side of my case and now everything is cool as can be.

Al

AC8GY

 

 

Re: Cooling fan Shroud

Jim Sheldon
 

I originally used a 4" fan I got off an old computer power supply on the back of that same style case - electrically and acoustically VERY noisy.  Asked Al yesterday about his little fan and ordered one.  It will be here Friday.  Now I have to find another case like that one so I can do a scratch JackAL/uBITX build with the 5" display.  

Jim - W0EB

------ Original Message ------
From: "Albert Peter" <albertfpeter@...>
To: "BITX20@groups.io" <BITX20@groups.io>
Sent: 1/17/2019 8:43:13 AM
Subject: Re: [BITX20] Cooling fan Shroud

I also looked for a fan solution on my uBITX.  I tried several salvaged from computer parts, but all were too noisy  I finally came up with this one:

Noctua NF-A4x20 PWM Premium-Quality Quiet 40mm Fan – $14.99 from Amazon. 

A bit pricey, but it has virtually no acoustic noise and very little, if any electrical noise.  Mounted on the side of my case and now everything is cool as can be.

Al

AC8GY

 

 

Re: Cooling fan Shroud

Bob Lunsford <nocrud222@...>
 

Try a 2W resister in series with some conventional fans and
the noise is much less. Run it a while and check to see that
the fan is not getting too warm. The resistor value may be in
the 500-1000 ohm range. That's where I would start, anyway.

It's nice to have a few fans of various sizes on hand. They
are sometimes seen at hamfests. Most cost between $1 and
$5 which is not all that much to pay for a small fan. I have
also rescued some from computer-type power supplies and
depending on size of power supply, I have some that range
between 2-in and 4-in. Most are designed to run for years.

Bob — KK5R

--------------------------------------------

On Thu, 1/17/19, Jim Sheldon <@W0EB> wrote:

Subject: Re: [BITX20] Cooling fan Shroud
To: BITX20@groups.io
Date: Thursday, January 17, 2019, 10:02 AM

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originally used a 4" fan I got off an old computer
power supply on the back of that same style case -
electrically and acoustically VERY noisy.  Asked Al
yesterday about his little fan and ordered one.  It will be
here Friday.  Now I have to find another case like that one
so I can do a scratch JackAL/uBITX build with the 5"
display.  
Jim -
W0EB


------ Original Message ------
From: "Albert Peter" <albertfpeter@...>
To: "BITX20@groups.io" <BITX20@groups.io>
Sent: 1/17/2019 8:43:13 AM
Subject: Re: [BITX20] Cooling fan Shroud


I also looked for a fan
solution on my uBITX.  I tried several salvaged from
computer parts, but all were too noisy  I finally came up
with this one:Noctua NF-A4x20 PWM Premium-Quality
Quiet 40mm Fan – $14.99 from Amazon.  A bit pricey, but it has virtually
no acoustic noise and very little, if any electrical
noise.  Mounted on the side of my case and now everything
is cool as can be.AlAC8GY

Re: Electret mic amp with AGC from Adafruit

Ted
 

That's exactly what I've done so far - the mike gain AGC board install previously described ^^, and, a separate gain board just like it after the volume potentiometer (with isolation capacitor). 

The latter gets fed to a mono, 25-watt RMS amp board (cite) with a trim pot between the AGC board and the amp for speaker amp input level reasonableness. The added audio amp doesn't even see the radio's native speaker audio, just the gain-conditioned and amplified vol pot output; there's no reason this can't be done with the native amp circuit, of course though I'd still recommend an input trimmer before the mainboard again.

This setup will blast the operator out of the room when feeding a Motorola 2-way radio external speaker......  Ask SWMBO.


Ted
K3RTA

Re: Cooling fan Shroud

Woody
 

Fan controllers are easy to build and minimize noise when not needed.
Something like these...  YMMV

Variable analog - Had to add the 3.3 ohm to reduce induced noise in the uBITx from high current fan.

OR

Switched - OFF/ON



Inexpensive fans can be had surplus, like at:
https://www.allelectronics.com/category/220/fans/1.html
https://www.mpja.com/DC-Axial-Fans/products/48/


Re: Unexpected measurements

Curt
 

I agree this seems weird.  You did not mention the type of power supply used nor its current, but perhaps its a good low noise supply used with your other rigs? 

Of course to make more power, which is typical at lower frequencies, it must draw more DC current (and dissipate a bit less in heat perhaps).  I have no issues using my uBITX on 160m, into a dummy load or my decently matched vertical with a 3 amp supply made for ham radio use. 

I would definitely checking the wiring for both RF and audio interfaces.  Make sure you don't have the ground connection on the board connected to the center pin of the antenna connector.  Please note there are 2 power supply connections - one is segregated to feed only the PAs - of course both need to be connected to your power supply.  I would look to see that audio ground is going to the expected place on the headphone jack.  Use very light audio gain for your testing, maybe 5 or 10% of the volume control should produce headphone audio of the sidetone. 

The only other thing I can think of for buzzing is to inspect for any broken or missing capacitors. 

As I write doing my own debug - its part of the journey. 

Curt WB8YYY

Re: Cooling fan Shroud

Albert Peter
 

The only problem with fan speed controllers is a reduction in cooling capability.  IMHO it is better to start with a capable quiet fan that does not require more circuitry.  It may cost a bit more, but is a simpler solution.

Al

AC8GY

 

Sent from Mail for Windows 10

 

From: Woody
Sent: Thursday, January 17, 2019 11:57 AM
To: BITX20@groups.io
Subject: Re: [BITX20] Cooling fan Shroud

 

Fan controllers are easy to build and minimize noise when not needed.

Something like these...  YMMV

Variable analog - Had to add the 3.3 ohm to reduce induced noise in the uBITx from high current fan.

OR

Switched - OFF/ON



Inexpensive fans can be had surplus, like at:
https://www.allelectronics.com/category/220/fans/1.html
https://www.mpja.com/DC-Axial-Fans/products/48/

 

Re: Cooling fan Shroud

Woody
 

Not sure why a reduction in cooling capacity with controllers.  Certainly is reduced when not needed. That is the intent.  The temperature proportional analog version could possibly result in less than max CFM, but not much if set up properly.  There is no reduction in CFM with the switched version.  the down side to that is that, when on, it is running at max capacity and more noisy.
Woody - KZ4AK

Re: Cooling fan Shroud

Doug W
 

On Thu, Jan 17, 2019 at 11:18 AM, Albert Peter wrote:
IMHO it is better to start with a capable quiet fan that does not require more circuitry.  It may cost a bit more, but is a simpler solution.
I totally agree with Al.  I have this fan https://www.digikey.com/product-detail/en/sunon-fans/HA60251V4-1000U-A99/259-1793-ND/ running arm's length away from me in a µBITX in an EF-01 enclosure on my desk.  It is so quiet I sometimes have to check that it is still working.
 
--
www.bitxmap.com

Re: Cooling fan Shroud

Evan Hand
 

I believe the point that Albert is making that it is better to have a quite fan that meets all of the requirements without any extra circuitry that can fail.  I would agree that if a noisy fan is the only choice, then putting in a controller to minimize the noise while still removing the heat is the next best solution.  If properly designed, installed, and tuned, then there would not be a change in the amount of heat that can be removed as the heat sinks get hotter.  I would caution that response time can get in the way of keeping cool quick enough to not cause an issue.  An always on at max fan does not have this issue.

My opinion, use as you see fit.

73
Evan
AC9TU

Re: Unexpected measurements

Peter Russell <peter.russell@...>
 

My power supply is home brew 5A with a big capacitor and a LM338.
I've done a bit more work and It seems that the problem was the factory setting of the drive preset.
I've just acquired a rather nice oscilloscope - OWON DS7102 - so I put it to use measuring the voltage at the output bnc connector (into 50 ohms).
Not having used a 'scope for about 20 years, I fell into the obvious trap of measuring the peak - peak voltages and calculating from that! Oh dear, I really should have known better.
Anyway, once I realised my mistake and did it properly, that led me to adjusting the drive level. I've now got it to a point where all bands are happy ( except top band, but who cares about that).
Measured values are now .....

3.5Mhz 6.05W
5 1.88
7 2.4
10 5
14 4
18 1.7
21 5
24 1.03
28 0.85

5Mhz and 21Mhz are a bit of a puzzle, but I'll delve a bit further and see what the drive levels are like.(Could this be a filter thing? I'm not sure what the bandpass filters are tuned to.)

Back to the workbench!

Peter G8FWY


On 17/01/2019 17:14, Curt via Groups.Io wrote:
I agree this seems weird.  You did not mention the type of power supply used nor its current, but perhaps its a good low noise supply used with your other rigs?
Of course to make more power, which is typical at lower frequencies, it must draw more DC current (and dissipate a bit less in heat perhaps).  I have no issues using my uBITX on 160m, into a dummy load or my decently matched vertical with a 3 amp supply made for ham radio use.
I would definitely checking the wiring for both RF and audio interfaces.  Make sure you don't have the ground connection on the board connected to the center pin of the antenna connector.  Please note there are 2 power supply connections - one is segregated to feed only the PAs - of course both need to be connected to your power supply.  I would look to see that audio ground is going to the expected place on the headphone jack.  Use very light audio gain for your testing, maybe 5 or 10% of the volume control should produce headphone audio of the sidetone.
The only other thing I can think of for buzzing is to inspect for any broken or missing capacitors.
As I write doing my own debug - its part of the journey.
Curt WB8YYY
---
This email has been checked for viruses by AVG.
https://www.avg.com

Using 2nd Nano for S meter

Brian Arnott
 

I wired up a second arduino nano to provide an s-meter using the "fun" design from KD8CEC (two 20k resistors and a capacitor). How do I assign an address to the second nano?
Right now it looks as though they are both on the same address, I've tried various combinations of the NX.hex and NX_S.hex without any success. 
Any help would be much appreciated.

de Brian G3YYT

Re: Unexpected measurements

Jerry Gaffke
 

Could be a transmit low pass filter thing, all that stuff around relays KT1,KT2,KT3.
5mhz shares a LPF with 3.5mhz, so if the knee on that filter is a bit low it will attenuate 5mhz.
Likewise 18mhz shares a filter with 14mhz.
Maybe those inductors have too many turns, or wrong caps installed?

However, 10mhz shares a filter with 7mhz, and since it's the low freq that's attenuated 
this suggests something different s going on, but could still be in the LPF somehow.

I'd probably hack the firmware so the 30mhz LPF is always selected, it should then have little effect
on the lower frequencies.  Expect a nasty square wave at your dummy load (lots of harmonics)
but the anomalous readings on 5mhz, 7mhz and 18mhz will disappear if it's LPF trouble.

Jerry


On Thu, Jan 17, 2019 at 11:24 AM, Peter Russell wrote:
5Mhz and 21Mhz are a bit of a puzzle, but I'll delve a bit further and see what the drive levels are like.(Could this be a filter thing? I'm not sure what the bandpass filters are tuned to.)

Re: Using 2nd Nano for S meter

wcars05
 

I used the version from the project repo. Built and flash it in the arduino ide.

Repo used:

https://github.com/phdlee/dspmeterv1

73

KE8KNK

On 1/17/19 3:02 PM, Brian Arnott via Groups.Io wrote:
I wired up a second arduino nano to provide an s-meter using the "fun" design from KD8CEC (two 20k resistors and a capacitor). How do I assign an address to the second nano?
Right now it looks as though they are both on the same address, I've tried various combinations of the NX.hex and NX_S.hex without any success. 
Any help would be much appreciated.

de Brian G3YYT

Re: Unexpected measurements

Evan Hand
 

Of the 3 boards (all v4) that I have had contact with, and the reporting of power to frequency on multiple BITX20 threads, the dip in power on 40 meters is fairly consistent.  No one has jet explained why, and as Jerry stated, it is further away from the LPF than the 30 meter band using the same LPF.

On the one board that I have tested for harmonics, 40 meters is the worst.  I believe that some of that is because the 3rd is below the 30mhz LPF that is in on all bands.  However why then is 80 meters not as bad?

There is something going on with the 40 meter CW transmit side that does not add up with the data that I have seen so far.

Anyone any ideas?

73
Evan
AC9TU

Re: Using 2nd Nano for S meter

Sascha Bohnet | DL5SMB
 

I guess the DSP-S-Meter does not work, if you have installed an AGC, right?

I think it is evaluating the change in volume to calculate the Signal Level. So if the AGC keeps the audio level straight,
this does not work any more. Am I correct?

In the source code you set the adress in  i2cmeter.h (line 58)

Sascha

Re: Using 2nd Nano for S meter

wcars05
 

Hi Brian,

A few follow up questions after thinking about the setup process a bit more.

1) Which version of CEC did you flash to the radiuno?

2) Which display are you using?

3) Does the FFT/DSP1 display anything and is it set to use it in the config menu?

4) My signal level is usually very low, from playing with it I have enough capacitance to touch its input and get noise to show on the meter. I have mine setup inline with a TJC screen as per the instructions. The only hardware mods I have installed are the smeter and Nextion(TJC) display.

5) Have you looked at the settings in the uBitx Manager?

I have my CEC built with:

ubitx.h line 239

    "#define I2CMETER_ADDR     0x58"

And the smeter project as per Sacha's suggestion

i2cmeter1.h line 58

"#define I2CMETER_ADDR     0x58  //changed from 0x6A"

The comment at the end of line might be the key since I left the note about changing the address.

Good luck!

Kyle

KE8KNK


On 1/17/19 3:02 PM, Brian Arnott via Groups.Io wrote:
I wired up a second arduino nano to provide an s-meter using the "fun" design from KD8CEC (two 20k resistors and a capacitor). How do I assign an address to the second nano?
Right now it looks as though they are both on the same address, I've tried various combinations of the NX.hex and NX_S.hex without any success. 
Any help would be much appreciated.

de Brian G3YYT

Re: Unexpected measurements

Jerry Gaffke
 

You might check that the toroids for the 40m LPF have the correct number of turns
as described under "Coil Details" near the bottom of:  http://www.hfsignals.com/index.php/ubitx-circuit-description/

At least one board went out with the wrong number of turns:
    https://groups.io/g/BITX20/message/63947


Jerry, KE7ER



On Thu, Jan 17, 2019 at 01:14 PM, Evan Hand wrote:
Of the 3 boards (all v4) that I have had contact with, and the reporting of power to frequency on multiple BITX20 threads, the dip in power on 40 meters is fairly consistent.  No one has jet explained why, and as Jerry stated, it is further away from the LPF than the 30 meter band using the same LPF.

On the one board that I have tested for harmonics, 40 meters is the worst.  I believe that some of that is because the 3rd is below the 30mhz LPF that is in on all bands.  However why then is 80 meters not as bad?

There is something going on with the 40 meter CW transmit side that does not add up with the data that I have seen so far.

Anyone any ideas?

73
Evan
AC9TU

Re: Cooling fan Shroud

Tom, wb6b
 

Another easy solution is to simply run the fan from the 12V transmit power, assuming that is not what you are already doing. No reason to run the fan while receiving.

Tom, wb6b

Re: Unexpected measurements

Evan Hand
 

I did some testing on my v4 board and found interesting correlation (though not able to verify mathematical accuracy):

The lower the signal at TP1 in CW transmit, the lower the output power.  This would have nothing to do with the LPFs either in the front end prior to the transmit amps, nor on the output.

This went on until above 14mhz, where the power starting dropping with out a decrease in level at TP1.

To me this suggests that there is something in the way that the design unbalances the first mixer to allow for the "bleed through" of the changed frequency of Clock#2.

I then used a constant tone through my mic for the ubitx using a signal generator connected to a powered speaker.  I kept the postion of the mic constant and changed the bands.  With this test, the 7.2mhz signal had more power than the 14.3mhz signal.  This suggests that the transmit power that others and I have been measuring is not indicative of the SSB power.

Again, this points to the CW process of unbalancing the first mixer has having side effects that impact power on some of the bands.

I should also note that the signal I measured with my scope was not at all sine wave clean in CW mode. It was almost square.  Would also explain the large amount of harmonics that I have measured with my inexpensive RF Explorer SA.

At this point I will be going back and coming up with a better way to inject a 1 or 2 tone audio signal into the uBitx to then measure the harmonics.  

Has anyone else seen this type of behavior?

73
Evan
AC9TU