Hehe... Google pulls up all kinds of stuff, even this decade-old thread.

I also live in Garland, and when I turn my computer speakers' volume all the way up, I can hear KRLD on them - but only while my hand is still on the volume dial. As soon as I break physical contact with the speaker, it goes silent. Sometimes it picks up reception all on its' own, which really freaked me out while I'm in bed or another room... until I figured out what it is. I think it's kind of cool, but KRLD will hook you up with a signal blocker if you request it - or you could get something at Radioshack.

On Thursday, October 3, 2002 6:32:01 PM UTC-5, RaZ0r! wrote:
This might be slightly off topic but I know if anyone knows what to do it
would some of you all.

I have an AM radio station VERY close to my house. Less then a quarter mile.

I hear the station in my computer speakers, my telephone headset, etc. Also
on my television, anything connected via RCA or S-Video jacks gets bad
interference like diagonial lines. I have cable TV, and it seems to resist
the signal better.

I was wonder if there was anything I could do to combat this?

I just a casual scanner user, so I'm not real expericenced in radio. If you
do have any suggestions, please go easy on me with the high tech radio stuff
hehe.

--
RaZ0r!
Tweak Monkey & Gaming Extraordinare =)

KRLD - operates with a effective radiated power of 50,000 watts.
Probably when it was built, there were no houses where the transmitter is located. As urban sprawl continues, and property values increases, being in prime real estate becomes an issue.

I would think that there is a problem with their ground radial system, although 50,000 watts is enough power to light a light bulb next to the tower.

You could complain to the FCC, but since they have been licensed since 1925? you are not going to get much satisfaction.. The FCC might even tell you, if you didn't want to be exposed to that much RF, you shouldn't have moved there in the first place.

Or you can use Ferrite Beads on all the lines which will take away the common mode currents that are building up on the lines.
http://en.wikipedia.org/wiki/Ferrite_bead

wrote:
Hehe... Google pulls up all kinds of stuff, even this decade-old thread.

I also live in Garland, and when I turn my computer speakers' volume all
the way up, I can hear KRLD on them - but only while my hand is still on
the volume dial. As soon as I break physical contact with the speaker,
it goes silent. Sometimes it picks up reception all on its' own, which
really freaked me out while I'm in bed or another room... until I figured
out what it is. I think it's kind of cool, but KRLD will hook you up
with a signal blocker if you request it - or you could get something at Radioshack.

Traditional solution: blocking circuit in the feed line. Thatsa lotta blocking.
But if you're not AM dxing you have a bit more hope since it's likely the harmonics
and the odd mixer products (heterodynes) that you'll be trying to remove.

Hard to do a highly directional antenna that covers a lot of shortwave bands
(lotsa bucks) but something like that would be a start. And you can use tuned
lengths of coaxial feedline to try to null out some of the signal without
going to the bother of building or buying a fancy nulling device. Neither
of these is likely to solve the problem outright, though.

You _could_ put a Software Defined Radio in another county and access
it via the 'net. Don't know if they have scanner versions, but the
devices can be quite versatile, so why not?

As far as non-radios picking up radio signals, buy higher quality
equipment or have someone electronics savvy insert bypass caps and
other items as described in the ARRL Handbook. If it comes in via
RCA/S-Video get higher class cables and add ferrite beads (there
are snap-on varieties that do not require surgery on the cable),
at least at the end that's nearest your equipment's inputs. May
also have to do the power cords, maybe in conjunction with a high
quality surge suppressor at the wall.

Get to be friends with the transmitter engineer. Can't hurt, and
if you're on good terms he may know of a few things you might try.

On Thursday, October 3, 2002 6:32:01 PM UTC-5, RaZ0r! wrote:
This might be slightly off topic but I know if anyone knows what to do it
would some of you all.

I have an AM radio station VERY close to my house. Less then a quarter mile.

I hear the station in my computer speakers, my telephone headset, etc. Also
on my television, anything connected via RCA or S-Video jacks gets bad
interference like diagonial lines. I have cable TV, and it seems to resist
the signal better.

I was wonder if there was anything I could do to combat this?

I just a casual scanner user, so I'm not real expericenced in radio. If you
do have any suggestions, please go easy on me with the high tech radio stuff
hehe.

--
RaZ0r!
Tweak Monkey & Gaming Extraordinare =)

Channel Jumper wrote:
KRLD - operates with a effective radiated power of 50,000 watts.
Probably when it was built, there were no houses where the transmitter
is located. As urban sprawl continues, and property values increases,
being in prime real estate becomes an issue.

Simple blocking circuit: a 365 pf variable capacitor and a 240
microhenry ferrite core inductor or coil, connected in series
and connected between the two conductors of the feedline, all
placed in an aluminum box. Readily available RCA or "F" connectors
can be used to connect to the feedline.

Sometimes I see people use two of these, say in the same
box with an aluminum baffle between the two parts, loosely
coupled with, perhaps, a reasonably small capacitor, in
the feed line (or a third, parellel wired, tuned circuit)
between them. Nice little hacker's project, and something
that probably tunes to a good null, but once you're trying
to put three tuned circuits in a homebuilt trap you may
be better off buying a commercial product.

There are some problems that cannot be solved by
high-pass filters or nulling circuits. These are
harmonics, or, less likely but troublesome when
present, heterodynes. Both can be caused by bad
metal-to-metal contacts in the environment -
gutters and downspouts, fencing, even the buried
ground system below the tower. Don't have any
experience tracking these things down, but there's
plenty of information available on reducing RFI -
radio frequency interference. Start with the
Radio Amateur's Handbook and other publications
of the American Radio Relay League.

Calculations:

You might consider an ERP of 50K watts versus, say,
a ham radio at 100 watts. Usually a ham radio at a
distance of one city block pefectly acceptable while
the 50KW AM band signal is well known to cause
problems.

But let's say we want to reduce down to 50 watts.
That's 1000:1 in power. It's is common to just
count the number of decimal places in ratios of
this sort - amplification or attenuation - so that's
10^3 - 3 decimal places. Communications engineers
call one power of 10 a Bel, so it's three Bels,
or, more commonly, 30 deciBels (dB).

So what you want is something that reduces the
unwanted RF signal by at least 30 dB. Thats' doable.
I suspect you could find a high-pass filter with
a low-frequency cutoff of 2 Mhz and an attenuation
of 30 dB, for a 50 or 75 ohm feedline, without much
of a problem.

George Cornelius

George Cornelius wrote:
Channel Jumper wrote:
KRLD - operates with a effective radiated power of 50,000 watts.

[...]

Simple blocking circuit: a 365 pf variable capacitor and a 240
microhenry ferrite core inductor or coil

Rethinking...

I chose the standard tuned circuit components used in
the input stage of an AM radio over the years, but looking
closer I would guess that for a low impedence feed line
you would get better results - a sharper null - using a
smaller inductor and a larger capacitor.

So let's say we divide the inductance L of the
coil by 10.

For 1080 Khz, you need 1/sqrt(L C) = 2 pi f,
or C = 1/( 4 pi^2 f^2 L). This means you'll
need to tune C to about 900 pf for a 24 uh
coil. If you use a 365 pf variable C and add
750 pf or so in parallel to it, then, changing
to using this smaller coil, you should be able
to tune the null plus or minus a few hundred
Khz around the station frequency.

George Cornelius