RF gets into computer
 

When I operate on 75 meter SSB with my transceiver, my computer beeps and
disconnects/reconnects my USB connected keyboard. Note that I do not have
this problem on 40 meter SSB. My computer is located on the second floor of
a brick house, and one end of my dipole is about 15 feet from my shack.

From comments made by others, I may have to put RF filters on the cables
and wires connected to my computer. I am contemplating the use of
Amidon FT-240-77 ferrite toroids, which have an I.D. of 1.4 inches and
cost $9 each. If I buy in quantities of 10, is there a cheaper source
for this toroid?

Any comments or suggestions on this problem would be appreciated.

RF gets into computer
 

Try Snap-on-choke, I think Radio shmack stil carries them.
They are two U shaped ferite pieces with plastic clamp. (Or split core
cylindrical ferite cores as seen on some keyboard or USB cables.)
You open them up, wing the wire or cord around the "legs" and close it. Put
it close to the computer case. It shouyld clear the problem.
You might wanna try which cable is most "antenna" and picking up RF

73 Yuri, K3BU


"John, N9JG" wrote in message
t...
When I operate on 75 meter SSB with my transceiver, my computer beeps and
disconnects/reconnects my USB connected keyboard. Note that I do not have
this problem on 40 meter SSB. My computer is located on the second floor
of
a brick house, and one end of my dipole is about 15 feet from my shack.

From comments made by others, I may have to put RF filters on the cables
and wires connected to my computer. I am contemplating the use of
Amidon FT-240-77 ferrite toroids, which have an I.D. of 1.4 inches and
cost $9 each. If I buy in quantities of 10, is there a cheaper source
for this toroid?

Any comments or suggestions on this problem would be appreciated.

RF gets into computer
 

Good advice Yuri...
But, I think the first thing he needs to do is get some aluminum roof
flashing from Home Depot and cover the top of the operating bench with
it and set the equipment on the flashing... Ground every piece of gear
to the flashing with short connections... THen hang a quarter wave of
wire off the flashing (68 feet for 80/75) - which becomes an RF
counterpoise, and route it down the hall, or out a wind0w, anywhere to
get the far end as far away as possible from the computer and the
110/220 electrical wiring in that room...
Another trick is to use a small antenna tuner as the ground radial
tuner - I prefer simply cutting the RF counterpoise to a quarter
wave, cheaper too...
The next thing is to get the Logic Tech wireless keyboard and mouse...

denny / k8do

RF gets into computer
 

On 26 Oct 2006 09:06:23 -0700, "Denny" wrote:


The next thing is to get the Logic Tech wireless keyboard and mouse...

denny / k8do

Is it better than the Microsoft wireless keyboard & mouse?

bob
k5qwg

RF gets into computer
 

On Thu, 26 Oct 2006 17:17:10 GMT, Bob Miller
wrote:

Is it better than the Microsoft wireless keyboard & mouse?

Hi Bob,

That question is apocryphal. I remember installing Windows 3 and
having one hell of a time getting the mouse to work. I called the M$
help line and they marched me through the complete install.

They pondered my problems and finally asked:
"What mouse I are you using?"
Me:
"A Microsoft mouse."
The voice of the blue screen:
"Microsoft mice are not compatible with Windows."

There was an object lesson there I will never forget.

73's
Richard Clark, KB7QHC

RF gets into computer
 

It's the brand they had at the big box store... Works for me...
Keyboard works across the full length of my shack, ~56 feet...


denny

Bob Miller wrote:
On 26 Oct 2006 09:06:23 -0700, "Denny" wrote:


The next thing is to get the Logic Tech wireless keyboard and mouse...

denny / k8do

Is it better than the Microsoft wireless keyboard & mouse?

bob
k5qwg

RF gets into computer
 

I have the same problem but only with my usb key board when I am on 10
meters...
Joe

The next thing is to get the Logic Tech wireless keyboard and mouse...

denny / k8do

Is it better than the Microsoft wireless keyboard & mouse?

bob
k5qwg

RF gets into computer
 

THAT might have explaination for! MY Mouse
(wireless), has 2 channels available, and
BOTH are C.B. channels! (think ch. 13, and 14
) Might try holding down a key, while tuneing
11 meters? Also, could have harmonic of 75,
on 7th harmonic hitting it ?? Aprox. 3868 kc
for the guy with a problem with his wireless
keyboard? Jim NN7K

Merlin-7 KI4ILB wrote:
I have the same problem but only with my usb key board when I am on 10
meters...
Joe
The next thing is to get the Logic Tech wireless keyboard and mouse...

denny / k8do
Is it better than the Microsoft wireless keyboard & mouse?

bob
k5qwg

RF gets into computer
 

On Thu, 26 Oct 2006 14:06:53 GMT, "John, N9JG"
wrote:

When I operate on 75 meter SSB with my transceiver, my computer beeps and
disconnects/reconnects my USB connected keyboard. Note that I do not have
this problem on 40 meter SSB. My computer is located on the second floor of
a brick house, and one end of my dipole is about 15 feet from my shack.

From comments made by others, I may have to put RF filters on the cables
and wires connected to my computer. I am contemplating the use of
Amidon FT-240-77 ferrite toroids, which have an I.D. of 1.4 inches and
cost $9 each. If I buy in quantities of 10, is there a cheaper source
for this toroid?

Any comments or suggestions on this problem would be appreciated.


John,

You describe a problem that could be caused / exacerbated by one or
both of:
- lack of electromagnetic compatibility (EMC) of your computer; and
- a hostile RF environment.

Before you lay blame at the computer, it is worth whether the RF field
strengths, and conducted and induced currents and voltages in your
shack are unnecessarily high.

You have give very little description of your antenna, feedline, and
station earth... too scant to analyse and offer much advice.

The hint is there that this problem is evident on 80m, while 40m seems
OK. Why is that?

Is the identified PC problem really a manifestation of a "hot" shack?
Have you conducted any experiments to identify excessive common mode
feedline currents in the shack (the same procedures you might follow
if you got an RF burn from something in the shack)?

Owen

--

RF gets into computer
 

"John, N9JG" wrote in
t:

When I operate on 75 meter SSB with my transceiver, my computer beeps
and disconnects/reconnects my USB connected keyboard. Note that I do not
have this problem on 40 meter SSB. My computer is located on the second
floor of a brick house, and one end of my dipole is about 15 feet from
my shack.

From comments made by others, I may have to put RF filters on the cables
and wires connected to my computer. I am contemplating the use of
Amidon FT-240-77 ferrite toroids, which have an I.D. of 1.4 inches and
cost $9 each. If I buy in quantities of 10, is there a cheaper source
for this toroid?

Any comments or suggestions on this problem would be appreciated.



Do CW, you won't know if it's your computer or radio beeping. Problem
solved.


SC

RF gets into computer
 

The following two steps seem to have solved the problem I had on 75 meters,
at least when running the Orion transceiver barefoot.

1) Ran #12 wire through the 2nd-story window sill and down to a 10 feet long
copper clad ground rod. The length of the wire run is about 15 feet. While
this may seem to be an obvious step, at my previous QTH the use of an earth
ground made RF feedback problems worse on some bands.

2) Installed an Amidon FT-240-77 ferrite toroid as a common-mode choke (11
turns) in the Orion's DC power supply cable and located about 18" from the
Orion. I am using an Astron RS-35A linear power supply (the fan on the
Ten-Tec switching PS was too noisy). The cable run between the power supply
and the Orion is somewhat lengthy because the Orion is connected to an
MFJ-1129 multi-outlet strip.

Step 2 above seems to have also corrected an occasional "flakiness" in the
operation of some of the front panel controls, which I had blamed on
progressive failure of the RIT/XIT encoder. Furthermore, for some
inexplicable reason, the computer problem I had with the USB
connected keyboard has disappeared with the installation of the
Orion's power supply cord toriodal filter!

"Owen Duffy" wrote in message
...
On Thu, 26 Oct 2006 14:06:53 GMT, "John, N9JG"
wrote:

When I operate on 75 meter SSB with my transceiver, my computer beeps and
disconnects/reconnects my USB connected keyboard. Note that I do not have
this problem on 40 meter SSB. My computer is located on the second floor
of
a brick house, and one end of my dipole is about 15 feet from my shack.

From comments made by others, I may have to put RF filters on the cables
and wires connected to my computer. I am contemplating the use of
Amidon FT-240-77 ferrite toroids, which have an I.D. of 1.4 inches and
cost $9 each. If I buy in quantities of 10, is there a cheaper source
for this toroid?

Any comments or suggestions on this problem would be appreciated.


John,

You describe a problem that could be caused / exacerbated by one or
both of:
- lack of electromagnetic compatibility (EMC) of your computer; and
- a hostile RF environment.

Before you lay blame at the computer, it is worth whether the RF field
strengths, and conducted and induced currents and voltages in your
shack are unnecessarily high.

You have give very little description of your antenna, feedline, and
station earth... too scant to analyse and offer much advice.

The hint is there that this problem is evident on 80m, while 40m seems
OK. Why is that?

Is the identified PC problem really a manifestation of a "hot" shack?
Have you conducted any experiments to identify excessive common mode
feedline currents in the shack (the same procedures you might follow
if you got an RF burn from something in the shack)?

Owen

--

RF gets into computer
 

"Owen Duffy" wrote in message
...
On Thu, 26 Oct 2006 14:06:53 GMT, "John, N9JG"
wrote:

When I operate on 75 meter SSB with my transceiver, my computer beeps and
disconnects/reconnects my USB connected keyboard. Note that I do not have
this problem on 40 meter SSB. My computer is located on the second floor
of
a brick house, and one end of my dipole is about 15 feet from my shack.

From comments made by others, I may have to put RF filters on the cables
and wires connected to my computer. I am contemplating the use of
Amidon FT-240-77 ferrite toroids, which have an I.D. of 1.4 inches and
cost $9 each. If I buy in quantities of 10, is there a cheaper source
for this toroid?

Any comments or suggestions on this problem would be appreciated.

Just one other thing to be aware of, with the dipole being nearby. Things
other than the computer can be affected. I had an dipole that coupled into
the central air/heat control box, because the control wires ran in the attic
parallel to, and about 15 feet from the dipole. With 100 watts, I managed
to burn out the control box solid state stuff. I didn't look to see what
the control wire resonance might be, but a snap on toroid was used to solve
the problem with the new control box.

--W

RF gets into computer
 

In article .net,
says...
"John, N9JG" wrote in
t:

When I operate on 75 meter SSB with my transceiver, my computer beeps
and disconnects/reconnects my USB connected keyboard. Note that I do not
have this problem on 40 meter SSB. My computer is located on the second
floor of a brick house, and one end of my dipole is about 15 feet from
my shack.

From comments made by others, I may have to put RF filters on the cables
and wires connected to my computer. I am contemplating the use of
Amidon FT-240-77 ferrite toroids, which have an I.D. of 1.4 inches and
cost $9 each. If I buy in quantities of 10, is there a cheaper source
for this toroid?

Any comments or suggestions on this problem would be appreciated.



Do CW, you won't know if it's your computer or radio beeping. Problem
solved.


SC

You know nothing. You have the lowest brain capacity of any living
human in the world!!

RF gets into computer
 

I had similar issues with USB disconnects etc while operating HF QRO. I then
added a ground wire from the case of the PC to my station ground and that
resolved it for me...

--

73,Charlie-AD5TH
www.ad5th.com


"RadioGuy" wrote in message
...
In article .net,
says...
"John, N9JG" wrote in
t:

When I operate on 75 meter SSB with my transceiver, my computer beeps
and disconnects/reconnects my USB connected keyboard. Note that I do
not
have this problem on 40 meter SSB. My computer is located on the second
floor of a brick house, and one end of my dipole is about 15 feet from
my shack.

From comments made by others, I may have to put RF filters on the
cables
and wires connected to my computer. I am contemplating the use of
Amidon FT-240-77 ferrite toroids, which have an I.D. of 1.4 inches and
cost $9 each. If I buy in quantities of 10, is there a cheaper source
for this toroid?

Any comments or suggestions on this problem would be appreciated.



Do CW, you won't know if it's your computer or radio beeping. Problem
solved.


SC

You know nothing. You have the lowest brain capacity of any living
human in the world!!

RF gets into computer
 

Thanks for the reply. The problem was solved when I

1) Ran #12 wire through the 2nd-story window sill and down to a 10 feet long
copper clad ground rod. The length of the wire run is about 15 feet. While
this may seem to be an obvious step, at my previous QTH the use of an earth
ground made RF feedback problems worse on some bands.

2) Installed an Amidon FT-240-77 ferrite toroid as a common-mode choke (11
turns) in the Orion's DC power supply cable and located about 18" from the
Orion. I am using an Astron RS-35A linear power supply (the fan on the
Ten-Tec switching PS was too noisy). The cable run between the power supply
and the Orion is somewhat lengthy because the Orion is connected to an
MFJ-1129 multi-outlet strip.


"Charlie" wrote in message
...
I had similar issues with USB disconnects etc while operating HF QRO. I
then added a ground wire from the case of the PC to my station ground and
that resolved it for me...

--

73,Charlie-AD5TH
www.ad5th.com


"RadioGuy" wrote in message
...
In article .net,
says...
"John, N9JG" wrote in
t:

When I operate on 75 meter SSB with my transceiver, my computer beeps
and disconnects/reconnects my USB connected keyboard. Note that I do
not
have this problem on 40 meter SSB. My computer is located on the
second
floor of a brick house, and one end of my dipole is about 15 feet from
my shack.

From comments made by others, I may have to put RF filters on the
cables
and wires connected to my computer. I am contemplating the use of
Amidon FT-240-77 ferrite toroids, which have an I.D. of 1.4 inches and
cost $9 each. If I buy in quantities of 10, is there a cheaper source
for this toroid?

Any comments or suggestions on this problem would be appreciated.



Do CW, you won't know if it's your computer or radio beeping. Problem
solved.


SC

You know nothing. You have the lowest brain capacity of any living
human in the world!!

RF gets into computer
 

On Thu, 02 Nov 2006 14:52:20 GMT, "John, N9JG"
wrote:

1) Ran #12 wire through the 2nd-story window sill and down to a 10 feet long
copper clad ground rod. The length of the wire run is about 15 feet. While
this may seem to be an obvious step, at my previous QTH the use of an earth
ground made RF feedback problems worse on some bands.

Hi John,

Make sure to connect this in dependant ground to the service ground or
you will have created an yet undiscovered new problem.

I say this because of the clue offered in your statement above about
problems becoming WORSE (you probably didn't have that ground tied to
the service ground then too, did you?).

73's
Richard Clark, KB7QHC

RF gets into computer
 

What you have suggested is on my "to do" list. The run to the service ground
will be quite long, however.

"Richard Clark" wrote in message
...
On Thu, 02 Nov 2006 14:52:20 GMT, "John, N9JG"
wrote:

1) Ran #12 wire through the 2nd-story window sill and down to a 10 feet
long
copper clad ground rod. The length of the wire run is about 15 feet. While
this may seem to be an obvious step, at my previous QTH the use of an
earth
ground made RF feedback problems worse on some bands.

Hi John,

Make sure to connect this in dependant ground to the service ground or
you will have created an yet undiscovered new problem.

I say this because of the clue offered in your statement above about
problems becoming WORSE (you probably didn't have that ground tied to
the service ground then too, did you?).

73's
Richard Clark, KB7QHC

RF gets into computer
 

I guess I didn't answer your question. You are quite right that at the
previous QTH, the shack ground rod was not strapped to the AC service rod.

"Richard Clark" wrote in message
...
On Thu, 02 Nov 2006 14:52:20 GMT, "John, N9JG"
wrote:

1) Ran #12 wire through the 2nd-story window sill and down to a 10 feet
long
copper clad ground rod. The length of the wire run is about 15 feet. While
this may seem to be an obvious step, at my previous QTH the use of an
earth
ground made RF feedback problems worse on some bands.

Hi John,

Make sure to connect this in dependant ground to the service ground or
you will have created an yet undiscovered new problem.

I say this because of the clue offered in your statement above about
problems becoming WORSE (you probably didn't have that ground tied to
the service ground then too, did you?).

73's
Richard Clark, KB7QHC

RF gets into computer
 

On Thu, 02 Nov 2006 21:35:22 GMT, "John, N9JG"
wrote:

I guess I didn't answer your question. You are quite right that at the
previous QTH, the shack ground rod was not strapped to the AC service rod.

Notice the correlation to:

at my previous QTH the use of an
earth
ground made RF feedback problems worse on some bands.

Hi John,

This is classic ground-loop conditions. One ground may have an
elevated potential over another ground (hard to believe, but it is the
practical reality). Current flows as a consequence. This is Common
Mode current (from a Common Mode potential).

You should in the short space of those three sentences be able to
observe several terms that are bandied about, but rarely understood.
This is because they follow on mysterious problems that defy
shielding, "grounding," and almost any other ad-hoc attempt that
inevitably fails as a solution.

One classic solution for providing ground to a tower is "I let the
coax shield do that!" Rarely does the operator consider that there
could be a huge potential difference between that remote point's
ground, and that at the house. The hidden killer here is when the
operator disconnects that coax (for whatever reason) and in that act
is holding the shield of the cable and some ground. He completes the
circuit, and like a fuse, may blow out.

More often I've heard:
"Look at the sparks I'm drawing!"
as the coax plug's shell is brushed up against the socket mounting
screws. My buddy pointed this out as the current burnt out most of
his ground traces inside his rig. It only cost a couple hundred and 3
weeks down time to provide remote grounding through the coax.

73's
Richard Clark, KB7QHC

RF gets into computer
 

To reiterate what has been said by others...
There are two issues here for your elevated ham shack... RF ground and
AC/DC ground... Not the same critters and in your case one will not do
both jobs...

First, for life and limb you need an AC/DC connection to the service
panel, i.e. local electrical ground... Length of this does not
matter... Second you need an earth ground as close to the rig as you
can get... As I read this you have dropped wire out the window to a
ground stake... Excellent, now get busy and continue on with that
ground wire also along the edge of the house to the electrical service
panel ground...

Now for the really important stuff, i.e. working DX, you need an RF
ground... In your case I suggest that you use a quarter wave length
insulated wire for each band you operate, attached to the common ground
behind the rig... Hang or fan them out the window, run them through the
ceiling to the attic, run them around the walls of the room, run them
down the hall behind the baseboard, just whatever you can do to spread
them out as long as possible .... Grounding a quarter wave radial at
the far end is not a good idea... Tape the end so no one can touch the
bare wire and leave it... That should cool off your RF problems...

GL denny / k8do

RF gets into computer
 

To iterate what I have reported earlier. The problem was SOLVED,
for the bands I operate on, when I :
1) Ran #12 wire through the 2nd-story window sill and down to a 10 feet long
copper clad ground rod. The length of the wire run is about 15 feet. (Let me
worry about satisfying the "code" requirement of bonding this ground rod to
the rod at the power service entrance.)

2) Installed an Amidon FT-240-77 ferrite toroid as a common-mode choke (11
turns) in the Orion's DC power supply cable and located about 18" from the
Orion. http://tinyurl.com/qnzs3 The cable run between the power supply
and the Orion is somewhat lengthy because the Orion is connected to an
MFJ-1129 multi-outlet strip.

I thank you for your support.
John, N9JG

"Denny" wrote in message
ups.com...
To reiterate what has been said by others...
There are two issues here for your elevated ham shack... RF ground and
AC/DC ground... Not the same critters and in your case one will not do
both jobs...

First, for life and limb you need an AC/DC connection to the service
panel, i.e. local electrical ground... Length of this does not
matter... Second you need an earth ground as close to the rig as you
can get... As I read this you have dropped wire out the window to a
ground stake... Excellent, now get busy and continue on with that
ground wire also along the edge of the house to the electrical service
panel ground...

Now for the really important stuff, i.e. working DX, you need an RF
ground... In your case I suggest that you use a quarter wave length
insulated wire for each band you operate, attached to the common ground
behind the rig... Hang or fan them out the window, run them through the
ceiling to the attic, run them around the walls of the room, run them
down the hall behind the baseboard, just whatever you can do to spread
them out as long as possible .... Grounding a quarter wave radial at
the far end is not a good idea... Tape the end so no one can touch the
bare wire and leave it... That should cool off your RF problems...

GL denny / k8do

RF gets into computer
 

"Denny" wrote in message
ups.com...
To reiterate what has been said by others...
There are two issues here for your elevated ham shack... RF ground and
AC/DC ground... Not the same critters and in your case one will not do
both jobs...

First, for life and limb you need an AC/DC connection to the service
panel, i.e. local electrical ground... Length of this does not
matter... Second you need an earth ground as close to the rig as you
can get... As I read this you have dropped wire out the window to a
ground stake... Excellent, now get busy and continue on with that
ground wire also along the edge of the house to the electrical service
panel ground...

Now for the really important stuff, i.e. working DX, you need an RF
ground... In your case I suggest that you use a quarter wave length
insulated wire for each band you operate, attached to the common ground
behind the rig... Hang or fan them out the window, run them through the
ceiling to the attic, run them around the walls of the room, run them
down the hall behind the baseboard, just whatever you can do to spread
them out as long as possible .... Grounding a quarter wave radial at
the far end is not a good idea... Tape the end so no one can touch the
bare wire and leave it... That should cool off your RF problems...

GL denny / k8do


Ah yes, violate all NEC grounding rules in the name of propagation. Nothing
like having ground loops, eh?

RF gets into computer
 

"RadioGuy" wrote in message
...

You know nothing. You have the lowest brain capacity of any living
human in the world!!

pse don't feed the troll

RF gets into computer
 

"Sal M. Onella" wrote in
:


"RadioGuy" wrote in message
...

You know nothing. You have the lowest brain capacity of any living
human in the world!!

pse don't feed the troll


How's your code practice coming, or did you give up on it because you're
lazy?

SC