A recent thread highlighted the problem of cheap wall warts creating a lot
of RFI - radio interference hash.
I think for the uninitiated some of you may not be aware of just how much
radio noise your wall wart is creating.
A quick check is to run your radio on batteries. Check a couple of free
spots up and down the bands and note the level of noise.
Then switch the wall wart on and take a note of the radio noise at the same
spots you did with it off.
There is an excellent article as to how to rectify a noisy wall wart in the
article:
http://www.dxing.info/equipment/wall_warts_bryant.dx
I'm not at all technical, so this article was beyond my limited
soldering/technical abilities, but I took it down to my local TV repairman
and it seemed quite a simple job for him to fix a noisy wall wart.

Another thread that often arises is that of radio noise from PC's. Firstly,
no name obscure brands of PC's and monitors nearly always give out a lot of
RFI, but the better named brands can be very noise free, although they are
obviously more expensive than the no name brands.
My daughter donated me an IBM ThinkPad laptop to drive my radio's with and
it is ABSOLUTELY noise free, whereas some of my pals laptops create an
enormous RFI hash.

PC monitor's are a great source of noise, so when I last upgraded I chose a
monitor that is rated VLF (very low emission) and it is very noise free. It
cost more but is so much better than my old noisy monitor it has been worth
it.

Then there is the noise from the PC itself. When I last upgraded my PC I
noticed a huge amount of extra noise. It took me awhile to figure out that
this source of noise was coming from the PC even when it was switched OFF.
What to do about this as I am very non technical. One of my more
knowledgeable pals suggested it might be the PSU, so I carted the PC off to
my friendly small town dealer and he had about six other types and makes of
PSU's and offered to try them. Using my portable we spent about half an hour
testing the various other PSU's until we came across one that was markedly
less noisy than the one in my PC.

So now I can DX noise free scanning my radio from the PC using the excellent
ERGO system linked to the ILD database = great fun.

--
John Plimmer, Montagu, Western Cape Province, South Africa
South 33 d 47 m 32 s, East 20 d 07 m 32 s
RX Icom IC-756 PRO III with MW mods
Drake SW8 & ERGO software
Sony 7600D GE SRIII
BW XCR 30, Braun T1000, Sangean 818 & 803A.
Hallicrafters SX-100, Eddystone 940
GE circa 50's radiogram
Antenna's RF Systems DX 1 Pro, Datong AD-270
Kiwa MW Loop
http://www.dxing.info/about/dxers/plimmer.dx

John Plimmer wrote:
A recent thread highlighted the problem of cheap wall warts creating a lot
of RFI - radio interference hash.
I think for the uninitiated some of you may not be aware of just how much
radio noise your wall wart is creating.
A quick check is to run your radio on batteries. Check a couple of free
spots up and down the bands and note the level of noise.
Then switch the wall wart on and take a note of the radio noise at the same
spots you did with it off.
There is an excellent article as to how to rectify a noisy wall wart in the
article:
http://www.dxing.info/equipment/wall_warts_bryant.dx
I'm not at all technical, so this article was beyond my limited
soldering/technical abilities, but I took it down to my local TV repairman
and it seemed quite a simple job for him to fix a noisy wall wart.

Another thread that often arises is that of radio noise from PC's. Firstly,
no name obscure brands of PC's and monitors nearly always give out a lot of
RFI, but the better named brands can be very noise free, although they are
obviously more expensive than the no name brands.
My daughter donated me an IBM ThinkPad laptop to drive my radio's with and
it is ABSOLUTELY noise free, whereas some of my pals laptops create an
enormous RFI hash.

PC monitor's are a great source of noise, so when I last upgraded I chose a
monitor that is rated VLF (very low emission) and it is very noise free. It
cost more but is so much better than my old noisy monitor it has been worth
it.

Then there is the noise from the PC itself. When I last upgraded my PC I
noticed a huge amount of extra noise. It took me awhile to figure out that
this source of noise was coming from the PC even when it was switched OFF.
What to do about this as I am very non technical. One of my more
knowledgeable pals suggested it might be the PSU, so I carted the PC off to
my friendly small town dealer and he had about six other types and makes of
PSU's and offered to try them. Using my portable we spent about half an hour
testing the various other PSU's until we came across one that was markedly
less noisy than the one in my PC.

So now I can DX noise free scanning my radio from the PC using the excellent
ERGO system linked to the ILD database = great fun.

Damn John ! Thanks for the post. It makes "engineering" a wall wart a
lot easier. Worth wading thru all the irrelevant sh*t for this diamond
in the rough. Many on another list (RX 398-ATS909 complain about their
noisy warts will enjoy the url you submitted

Yodar

JP - Your above Link/URL :
http://www.dxing.info/equipment/wall_warts_bryant.dx