Re: [Elecraft] Noise from KAT500?

[Jim Brown]

On 12/2/2023 7:33 PM, David Gilbert wrote:
Most of them have almost no reliable voltage regulation either. They are 
typically designed for a certain load, and if they don't see that load 
the voltage is much higher than rated.  I've tested dozens of these 
things (I tend not to throw anything away) and it's fairly typical that 
a 12 volt rated wall wart power supply presents 16 to 18 volts (or 
higher) no load.  That can be death to a piece of 12 volt gear that 
doesn't draw much current.


Exactly right, Dave! I discussed in detail in the tutorial. Nearly all 
of the warts, lumps, and the equipment they power are labeled with 
voltage and current. My advice in the tutorial, with pictures, is break 
the DC cable, add Power Poles, and use one of the inline volt-ammeters 
to confirm that the PSU is within the safe operating range of the unit 
being powered. In the 20 years I've been making these replacements, I've 
yet to blow anything up!


73, Jim K9YC


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Re: [Elecraft] Noise from KAT500?

[Bill Johnson]

It gets worse with all the new gadgets and LED lighting.  I just installed new 
plant lights, LEDs, and the racket from the wall warts is terrible.  I shut 
them off when operating, or not interested in lighting up the plants.  Terrible 
view of the noise on K4 graphic display.  

Bill
K9YEQ

-Original Message-
From: elecraft-boun...@mailman.qth.net  On 
Behalf Of Jim Brown
Sent: Saturday, December 2, 2023 8:25 PM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] Noise from KAT500?

On 12/2/2023 5:48 PM, W2HX wrote:
> I then replaced the wall-wart power supply with a 12V battery. And 
> this is what I saw for BOTH bypass and inline. Clearly the problem.
> 
> https://w2hx.com/x/Elecraft/KAT500/Noise-Issue/KAT500-battery.png
> 
> using a battery, the noise is about -80 dBm. Using the wall-wart, in 
> some cases the noise is as high as -60 dBm
> 
> 
> 
> My task now is to either leave it on battery or preferably, find a low noise 
> PS.

99.9% of stuff that plugs into the wall has a Switch-mode power supply, most of 
which are varying degrees of noisy. They were mandated to save energy about 20 
years ago, but thanks to small government, the FCC has no money to enforce 
their Rules that they be quiet. So they aren't.

A typical home has several dozen of them, either in the form of wall warts and 
line lumps or built into equipment and appliances. Rather than buying bigger 
and better anything for our station, our time and money is far better spent 
identifying and replacing as many as possible of these nasty noise sources.

There's a tutorial on my website, k9yc.com/publish.htm  about how to find and 
replace them. All of the 12V gear in my shack runs on two big batteries that 
are float charged by re-purposed Thinkpad power supplies using Genasun charge 
regulators. A 100Ah LiFePO4 runs the rigs, a 100Ah Sealed Lead Acid runs the 
rest of the stuff.

73, Jim K9YC

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Re: [Elecraft] Noise from KAT500?

[David Gilbert]

The ones I measured just a couple of months ago were way too small and 
light to have a transformer in them, and they were horrible.  In any 
case, I recommend that anyone using a wall wart for other than its 
intended equipment (or any standalone new one) be sure to check it for 
both noise and no load voltage regulation.  It's quick and easy to do 
and could save a lot of headaches.


73,
Dave  AB7E



On 12/2/2023 9:09 PM, Victor Rosenthal 4X6GP wrote:
This is usually true of the linear type of wall-wart, which is the 
quiet kind! They generally are composed of just a transformer, 
rectifier, and capacitor.They are almost extinct these days, but I 
look for discarded ones for use with equipment for which it is safe to 
use an unregulated power source.
The switching types mostly are well-regulated, but of course they are 
often noisy.


73,
Victor, 4X6GP
Rehovot, Israel
formerly K2VCO
CWops no. 5
http://www.qsl.net/k2vco/

On 03/12/2023 5:33, David Gilbert wrote:


Most of them have almost no reliable voltage regulation either. They 
are typically designed for a certain load, and if they don't see that 
load the voltage is much higher than rated.  I've tested dozens of 
these things (I tend not to throw anything away) and it's fairly 
typical that a 12 volt rated wall wart power supply presents 16 to 18 
volts (or higher) no load.  That can be death to a piece of 12 volt 
gear that doesn't draw much current.


Dave   AB7E



On 12/2/2023 8:25 PM, Jim Brown wrote:


99.9% of stuff that plugs into the wall has a Switch-mode power 
supply, most of which are varying degrees of noisy. They were 
mandated to save energy about 20 years ago, but thanks to small 
government, the FCC has no money to enforce their Rules that they be 
quiet. So they aren't.


A typical home has several dozen of them, either in the form of wall 
warts and line lumps or built into equipment and appliances. Rather 
than buying bigger and better anything for our station, our time and 
money is far better spent identifying and replacing as many as 
possible of these nasty noise sources.


There's a tutorial on my website, k9yc.com/publish.htm  about how to 
find and replace them. All of the 12V gear in my shack runs on two 
big batteries that are float charged by re-purposed Thinkpad power 
supplies using Genasun charge regulators. A 100Ah LiFePO4 runs the 
rigs, a 100Ah Sealed Lead Acid runs the rest of the stuff.


73, Jim K9YC

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Re: [Elecraft] Noise from KAT500?

[Victor Rosenthal 4X6GP]

This is usually true of the linear type of wall-wart, which is the quiet 
kind! They generally are composed of just a transformer, rectifier, and 
capacitor.They are almost extinct these days, but I look for discarded 
ones for use with equipment for which it is safe to use an unregulated 
power source.
The switching types mostly are well-regulated, but of course they are 
often noisy.


73,
Victor, 4X6GP
Rehovot, Israel
formerly K2VCO
CWops no. 5
http://www.qsl.net/k2vco/

On 03/12/2023 5:33, David Gilbert wrote:


Most of them have almost no reliable voltage regulation either. They are 
typically designed for a certain load, and if they don't see that load 
the voltage is much higher than rated.  I've tested dozens of these 
things (I tend not to throw anything away) and it's fairly typical that 
a 12 volt rated wall wart power supply presents 16 to 18 volts (or 
higher) no load.  That can be death to a piece of 12 volt gear that 
doesn't draw much current.


Dave   AB7E



On 12/2/2023 8:25 PM, Jim Brown wrote:


99.9% of stuff that plugs into the wall has a Switch-mode power 
supply, most of which are varying degrees of noisy. They were mandated 
to save energy about 20 years ago, but thanks to small government, the 
FCC has no money to enforce their Rules that they be quiet. So they 
aren't.


A typical home has several dozen of them, either in the form of wall 
warts and line lumps or built into equipment and appliances. Rather 
than buying bigger and better anything for our station, our time and 
money is far better spent identifying and replacing as many as 
possible of these nasty noise sources.


There's a tutorial on my website, k9yc.com/publish.htm  about how to 
find and replace them. All of the 12V gear in my shack runs on two big 
batteries that are float charged by re-purposed Thinkpad power 
supplies using Genasun charge regulators. A 100Ah LiFePO4 runs the 
rigs, a 100Ah Sealed Lead Acid runs the rest of the stuff.


73, Jim K9YC

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[Elecraft] Elecraft CW Net Announcement

[kevin]

Good Evening,

   It has been mostly sunny but cool.  The first snow of the season 
fell yesterday.  Early in the week I heard branches breaking so I went 
outside for a look.  A herd of elk was spread through the forest.  The 
younger elk were chasing each other around the clearest areas breaking 
rotting slash.  Two dozen cows were busy ignoring them and eating.  A 
medium sized bull was trailing the group.


   A cannibalistic CME  struck our ionosphere this week, many prominent 
aurora glowed in both hemispheres.  More CMEs are coming due to a number 
of active sunspot groups.  There is also a hole in the sun's atmosphere 
aimed right at us.  The sun is no longer quiescent; the next few days 
should prove noisy.



Please join us on (or near):

14050 kHz at 2300z Sunday  (3 PM PST Sunday)
 7047 kHz at 0100z Monday  (5 PM PST Sunday)



73,
  Kevin.  KD5ONS





-




"For, in the final analysis, our most basic common link is that we all 
inhabit this small planet.  We all breathe the same air. We all cherish 
our children's future.  And we are all mortal."


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Re: [Elecraft] Noise from KAT500?

[David Gilbert]

Most of them have almost no reliable voltage regulation either. They are 
typically designed for a certain load, and if they don't see that load 
the voltage is much higher than rated.  I've tested dozens of these 
things (I tend not to throw anything away) and it's fairly typical that 
a 12 volt rated wall wart power supply presents 16 to 18 volts (or 
higher) no load.  That can be death to a piece of 12 volt gear that 
doesn't draw much current.


Dave   AB7E



On 12/2/2023 8:25 PM, Jim Brown wrote:


99.9% of stuff that plugs into the wall has a Switch-mode power 
supply, most of which are varying degrees of noisy. They were mandated 
to save energy about 20 years ago, but thanks to small government, the 
FCC has no money to enforce their Rules that they be quiet. So they 
aren't.


A typical home has several dozen of them, either in the form of wall 
warts and line lumps or built into equipment and appliances. Rather 
than buying bigger and better anything for our station, our time and 
money is far better spent identifying and replacing as many as 
possible of these nasty noise sources.


There's a tutorial on my website, k9yc.com/publish.htm  about how to 
find and replace them. All of the 12V gear in my shack runs on two big 
batteries that are float charged by re-purposed Thinkpad power 
supplies using Genasun charge regulators. A 100Ah LiFePO4 runs the 
rigs, a 100Ah Sealed Lead Acid runs the rest of the stuff.


73, Jim K9YC

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Re: [Elecraft] Noise from KAT500?

[Jim Brown]

On 12/2/2023 5:48 PM, W2HX wrote:

I then replaced the wall-wart power supply with a 12V battery. And this
is what I saw for BOTH bypass and inline. Clearly the problem.

https://w2hx.com/x/Elecraft/KAT500/Noise-Issue/KAT500-battery.png

using a battery, the noise is about -80 dBm. Using the wall-wart, in some cases 
the noise is as high as -60 dBm



My task now is to either leave it on battery or preferably, find a low noise PS.


99.9% of stuff that plugs into the wall has a Switch-mode power supply, 
most of which are varying degrees of noisy. They were mandated to save 
energy about 20 years ago, but thanks to small government, the FCC has 
no money to enforce their Rules that they be quiet. So they aren't.


A typical home has several dozen of them, either in the form of wall 
warts and line lumps or built into equipment and appliances. Rather than 
buying bigger and better anything for our station, our time and money is 
far better spent identifying and replacing as many as possible of these 
nasty noise sources.


There's a tutorial on my website, k9yc.com/publish.htm  about how to 
find and replace them. All of the 12V gear in my shack runs on two big 
batteries that are float charged by re-purposed Thinkpad power supplies 
using Genasun charge regulators. A 100Ah LiFePO4 runs the rigs, a 100Ah 
Sealed Lead Acid runs the rest of the stuff.


73, Jim K9YC

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Re: [Elecraft] Noise from KAT500?

[W2HX]

Mike, K8CN wins the cigar!



The issue is the power supply ☹ I took some spectrum analyzer plots to 7 MHz 
and you can see what I saw. The set up is spectrum analyzer -> KAT500 -> Dummy 
Load. First picture are two "max hold" traces superimposed where the problem 
can be seen.

https://w2hx.com/x/Elecraft/KAT500/Noise-Issue/KAT500-AC-Power.png

The "lower" trace is what I saw with the kat500 in bypass. The "top" trace is 
with the kat500 inline (auto or manual).



I then replaced the wall-wart power supply with a 12V battery. And this is what 
I saw for BOTH bypass and inline. Clearly the problem.

https://w2hx.com/x/Elecraft/KAT500/Noise-Issue/KAT500-battery.png

using a battery, the noise is about -80 dBm. Using the wall-wart, in some cases 
the noise is as high as -60 dBm



My task now is to either leave it on battery or preferably, find a low noise PS.



Thanks everyone for the ideas.



73 Eugene W2HX

Subscribe to my Youtube Channel: https://www.youtube.com/@w2hx/videos



-Original Message-
From: elecraft-boun...@mailman.qth.net  On 
Behalf Of Michael Carter via Elecraft
Sent: Saturday, December 2, 2023 5:52 PM
To: Elecraft Reflector Reflector 
Subject: Re: [Elecraft] Noise from KAT500?



Hi Eugene,



Are you using a switch-mode power supply to feed the KAT500?  If so, try a 
linear regulator supply or a battery instead.



Is your KAT500 bonded to your other station equipment and AC ground with a 
short, wide conductor? (not just the coax shields)



Since you're not the original constructor of the KAT500, I would check inside 
the case to be sure that the case sections have the powder coat removed where 
circuit board standoffs and case section screws are placed.



What kind of cable do you use to connect the KAT500 to your shack computer?  
One should NOT use a standard VGA cable as the manual makes clear.



73,

Mike, K8CN

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Re: [Elecraft] Noise from KAT500?

[Michael Carter via Elecraft]

One more thing to check, Eugene:

Are the other two antenna ports
on the KAT500 connected to
anything?  If so, disconnect
those ports other than the one
you used in your video demonstration.

73,
Mike,
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Re: [Elecraft] Noise from KAT500?

[Michael Carter via Elecraft]

Hi Eugene,

Are you using a switch-mode power supply
to feed the KAT500?  If so, try a linear regulator
supply or a battery instead.

Is your KAT500 bonded to your other station
equipment and AC ground with a short, wide
conductor? (not just the coax shields)

Since you're not the original constructor of
the KAT500, I would check inside the case
to be sure that the case sections have the
powder coat removed where circuit board
standoffs and case section screws are placed.

What kind of cable do you use to connect
the KAT500 to your shack computer?  One
should NOT use a standard VGA cable as
the manual makes clear.

73,
Mike, K8CN
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Re: [Elecraft] Noise from KAT500?

[Ken Winterling]

Eugene,

This may or may not address your issue but the KAT500 user manual reports
that a signal may be heard from an oscillator in the unit. The manual
advises that this can be shut down when not in use by running the KAT500
Utility.

Below is the reference to Idle Sleep in the manual.


*Idle SleepIn some installations a 28004.5 MHz signal may be heard from an
oscillator in the KAT500. If this is an issue, you can cause the KAT500
oscillator to shut down when it is not needed. Click on Idle Sleep to put a
check in the radio button. The oscillator will stop running shortly after
the last key press or the last data communication with other equipment and
restart automatically when needed.*

*Ken*
*WA2LBI*




On Sat, Dec 2, 2023 at 5:14 PM W2HX  wrote:

> Hello all,
>
> I have my new (to me) KAT500 up and running but I am noticing it is
> introducing quite a lot of noise when "inline" but the noise is gone in
> "bypass."
> Here is a video I made of the situation. The video shows the issue on 60m,
> but I will note, that I also checked the situation on 20m and it is the
> same. The problem is significant and might prohibit me from using the
> KAT500.
>
> Anyone know what might be going on?
> https://youtu.be/5EvByZDYI3g
>
>
> 73 Eugene W2HX
> Subscribe to my Youtube Channel: https://www.youtube.com/@w2hx/videos
>
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[Elecraft] Noise from KAT500?

[W2HX]

Hello all,

I have my new (to me) KAT500 up and running but I am noticing it is introducing 
quite a lot of noise when "inline" but the noise is gone in "bypass."
Here is a video I made of the situation. The video shows the issue on 60m, but 
I will note, that I also checked the situation on 20m and it is the same. The 
problem is significant and might prohibit me from using the KAT500.

Anyone know what might be going on?
https://youtu.be/5EvByZDYI3g


73 Eugene W2HX
Subscribe to my Youtube Channel: https://www.youtube.com/@w2hx/videos

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