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.

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.

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

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

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

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

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

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

--

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

--

"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